In JoVE (3)

Other Publications (240)

Articles by Felipe Fregni in JoVE

 JoVE Neuroscience

Electrode Positioning and Montage in Transcranial Direct Current Stimulation

1Headache & Orofacial Pain Effort (H.O.P.E.), Biologic & Material Sciences, School of Dentistry, University of Michigan, 2Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 3Charité, University Medicine Berlin, 4Department of Biomedical Engineering, The City College of New York

JoVE 2744

 JoVE Behavior

Simultaneous EEG Monitoring During Transcranial Direct Current Stimulation

1Programa de Pós-Graduação em Ciências Médica, Universidade Federal do Rio Grande do Sul, 2Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), 3Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 4De Montfort University

JoVE 50426

 JoVE Medicine

Technique and Considerations in the Use of 4x1 Ring High-definition Transcranial Direct Current Stimulation (HD-tDCS)

1Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 2School of Medicine, Pontifical Catholic University of Ecuador, 3Charité University Medicine Berlin, 4The City College of The City University of New York, 5Headache & Orofacial Pain Effort (H.O.P.E.), Biologic & Materials Sciences, School of Dentistry, University of Michigan

JoVE 50309

Other articles by Felipe Fregni on PubMed

Pure Alexia and Hemianopia Related to Dissection of the Internal Carotid Artery

Cerebrovascular Diseases (Basel, Switzerland). 2003  |  Pubmed ID: 12499728

Treatment of Subclavian Steal Syndrome with Percutaneous Transluminal Angioplasty and Stenting: Case Report

Arquivos De Neuro-psiquiatria. Mar, 2003  |  Pubmed ID: 12715028

Subclavian steal syndrome refers to the association of neurological symptoms related to vertebrobasilar insufficiency and the phenomenon of subclavian steal. We report the case of a 63 year-old male patient that presented subclavian steal syndrome and severe proximal (80%) stenosis of the left subclavian artery. The patient was submitted to percutaneous transluminal angioplasty and stenting on the left SA. The procedure was well tolerated and immediately afterwards, there was complete remission of the symptoms and of the phenomenon of subclavian steal evaluated by angiography and transcranial doppler. We propose that percutaneous transluminal angioplasty with stenting placement is a good therapeutic option for subclavian steal syndrome.

[Bilateral Hemifacial Spasm: Case Report]

Arquivos De Neuro-psiquiatria. Mar, 2003  |  Pubmed ID: 12715033

Bilateral hemifacial spasm (BHS) is a rare focal movement disorder often associated with vascular compression of both facial nerves. The contractions are usually asymmetric and asynchronous. Typically, one side is affected first and there is a long but variable interval for the symptoms on the other side to occur. BHS must be differentiated from other conditions including blefarospasm, facial myokymia, facial tics, oromandibular dystonia, and hemimasticatory spasm. The most successful and non-invasive symtomatic treatment is botulinum toxin injections but microvascular decompression surgery is another therapeutic option. We report the case of a 70 years old man with bilateral hemifacial spasms and present a brief review of the literature.

Magnetic Resonance Imaging of Wallerian Degeneration in Stroke

Archives of Neurology. Oct, 2003  |  Pubmed ID: 14568820

Modulation in Motor Threshold After a Severe Episode of Gastrointestinal Distress

The Journal of ECT. Mar, 2004  |  Pubmed ID: 15087999

Transcranial Magnetic Stimulation As a Complementary Treatment for Aphasia

Seminars in Speech and Language. May, 2004  |  Pubmed ID: 15118944

Functional brain imaging with nonfluent aphasia patients has shown increased cortical activation (perhaps "overactivation") in right (R) hemisphere language homologues. These areas of overactivation may represent a maladaptive strategy that interferes with, rather than promotes, aphasia recovery. Repetitive transcranial magnetic stimulation (rTMS) is a painless, noninvasive procedure that utilizes magnetic fields to create electric currents in discrete brain areas affecting about a 1-cm square area of cortex. Slow frequency, 1 Hz rTMS reduces cortical excitability. When rTMS is applied to an appropriate cortical region, it may suppress the possible overactivation and thus modulate a distributed neural network for language. We provide information on rTMS and report preliminary results following rTMS application to R Broca's area (posterior, R pars triangularis) in four stroke patients with nonfluent aphasia (5-11 years after left hemisphere stroke). Following 10 rTMS treatments, significant improvement in naming pictures was observed. This form of rTMS may provide a novel, complementary treatment for aphasia.

Transcranial Magnetic Stimulation Accelerates the Antidepressant Effect of Amitriptyline in Severe Depression: a Double-blind Placebo-controlled Study

Biological Psychiatry. Jan, 2005  |  Pubmed ID: 15652875

Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex, and the treatment of depression is one of its potential therapeutic applications. Three recent meta analyses strongly suggest its benefits in the treatment of depression. The present study investigates whether repetitive TMS (rTMS) accelerates the onset of action and increases the therapeutic effects of amitriptyline.

Transient Disruption of Ventrolateral Prefrontal Cortex During Verbal Encoding Affects Subsequent Memory Performance

Journal of Neurophysiology. Jul, 2005  |  Pubmed ID: 15758048

Episodic memory supports conscious remembrance of everyday experience. Prior functional neuroimaging data indicate that episodic encoding during phonological task performance is correlated with activation in bilateral posterior ventrolateral prefrontal cortex (pVLPFC), although uncertainty remains regarding whether these prefrontal regions make necessary contributions to episodic memory formation. Using functional MRI data to guide application of single-pulse transcranial magnetic stimulation (spTMS), this study examined the necessity of left and right pVLPFC for episodic encoding (as expressed through subsequent memory performance). To assess the timing of critical computations, pVLPFC function was transiently disrupted at different poststimulus onset times while subjects made syllable decisions about visually presented familiar and unfamiliar words; subsequent memory for these stimuli was measured. Results revealed that left pVLPFC disruption during encoding of familiar words impaired subsequent memory, expressed as a decline in recognition confidence, with disruption being maximal at 380 ms after stimulus onset. In contrast, right pVLPFC disruption facilitated subsequent memory for familiar words, expressed as an increase in medium confidence recognition, with this facilitation being maximal at 380 ms. Finally, phonological (syllable) decision accuracy was facilitated by right pVLPFC disruption, with this effect being maximal at 340 ms, but was unaffected by left pVLPFC disruption. These findings suggest that left pVLPFC mechanisms onset between 300 and 400 ms during phonological processing of words, with these mechanisms appearing necessary for effective episodic encoding. In contrast, disruption of correlated mechanisms in right pVLPFC facilitates encoding, perhaps by inducing a functional shift in the mechanisms engaged during learning.

Improved Picture Naming in Chronic Aphasia After TMS to Part of Right Broca's Area: an Open-protocol Study

Brain and Language. Apr, 2005  |  Pubmed ID: 15766771

Functional imaging studies with nonfluent aphasia patients have observed "over-activation" in right (R) language homologues. This may represent a maladaptive strategy; suppression may result in language improvement. We applied slow, 1 Hz repetitive transcranial magnetic stimulation (rTMS) to an anterior portion of R Broca's homologue daily, for 10 days in four aphasia patients who were 5-11 years poststroke. Significant improvement was observed in picture naming at 2 months post-rTMS, with lasting benefit at 8 months in three patients. This preliminary, open trial suggests that rTMS may provide a novel treatment approach for aphasia by possibly modulating the distributed, bi-hemispheric language network.

Left Prefrontal Repetitive Transcranial Magnetic Stimulation Impairs Performance in Affective Go/no-go Task

Neuroreport. Apr, 2005  |  Pubmed ID: 15812319

Functional neuroimaging studies have associated affective go/no-go function with lateral prefrontal activation, but they have not established a causal role and have not determined whether one hemisphere is predominantly engaged. In the present study, 11 normal volunteers underwent slow repetitive transcranial magnetic stimulation of the left and right dorsolateral prefrontal cortex, and the occipital cortex prior to performance of a picture-based affective go/no-go task. We found an interfering effect of left prefrontal repetitive transcranial magnetic stimulation compared with both right prefrontal and occipital repetitive transcranial magnetic stimulation. This impairment concerned positive and negative task stimuli to a similar extent, and tended to be greater in shift compared with nonshift blocks. Our findings demonstrate a functionally relevant lateralization of the prefrontal contribution to affective go/no-go tasks.

Lasting Accelerative Effects of 1 Hz and 20 Hz Electrical Stimulation on Cortical Spreading Depression: Relevance for Clinical Applications of Brain Stimulation

The European Journal of Neuroscience. Apr, 2005  |  Pubmed ID: 15869525

Clinical applications of brain stimulation have been increasing during the last decade; however, the mechanisms of action remain unknown. One proposed mechanism of action is that repetitive stimulation modulates cortical excitability. Herein, we explore the question of whether repetitive electric stimulation increases cortical excitability as indexed by the cortical spreading depression. Twenty-four Wistar rats were divided into three groups according to the treatment: sham, 1-Hz and 20-Hz stimulation. Stimulation was applied to the left frontal cortex through a pair of epidurally implanted silver-wire electrodes. The cortical spreading depression-features were analysed at three time points (one day before, one day after and 2 weeks after treatment) in both the stimulated and unstimulated hemisphere. A 3 x 2 x 3 factorial anova with repeated measures showed significant differences in the main effect of time (P < 0.0001), hemisphere (P = 0.0002) and stimulation group (P = 0.008). The interaction between time vs. hemisphere vs. stimulation group was also significant (P < 0.0001). Posthoc analysis demonstrated that 1-Hz and 20-Hz repetitive electrical stimulation significantly increased the velocity of cortical spreading depression in the stimulated hemisphere. Furthermore, 20-Hz stimulation showed a greater effect on cortical spreading depression compared to 1-Hz stimulation. The results show that 1-Hz and 20-Hz repetitive electrical stimulation results in an increase in cortical spreading depression velocity that is associated with the frequency and the hemisphere of stimulation. Furthermore, the effects are found to be long lasting. We believe that these findings have strong relevance to support the clinical application of therapies involving electrical stimulation for diseases of reduced cortical excitability.

Effect of Repetitive TMS and Fluoxetine on Cognitive Function in Patients with Parkinson's Disease and Concurrent Depression

Movement Disorders : Official Journal of the Movement Disorder Society. Sep, 2005  |  Pubmed ID: 15895421

Previous studies show that cognitive functions are more impaired in patients with Parkinson's disease (PD) and depression than in nondepressed PD patients. We compared the cognitive effects of two types of antidepressant treatments in PD patients: fluoxetine (20 mg/day) versus repetitive transcranial magnetic stimulation (rTMS, 15 Hz, 110% above motor threshold, 10 daily sessions) of the left dorsolateral prefrontal cortex. Twenty-five patients with PD and depression were randomly assigned either to Group 1 (active rTMS and placebo medication) or to Group 2 (sham rTMS and fluoxetine). A neuropsychological battery was assessed by a rater blind to treatment arm at baseline and 2 and 8 weeks after treatment. Patients in both groups had a significant improvement of Stroop (colored words and interference card) and Hooper and Wisconsin (perseverative errors) test performances after both treatments. Furthermore, there were no adverse effects after either rTMS or fluoxetine in any neuropsychological test of the cognitive test battery. The results show that rTMS could improve some aspects of cognition in PD patients similar to that of fluoxetine. The mechanisms for this cognitive improvement are unclear, but it is in the context of mood improvement.

Antiepileptic Effects of Repetitive Transcranial Magnetic Stimulation in Patients with Cortical Malformations: an EEG and Clinical Study

Stereotactic and Functional Neurosurgery. 2005  |  Pubmed ID: 15990468

To study the effects of repetitive transcranial magnetic stimulation (rTMS) on epileptic EEG discharges in patients with refractory epilepsy and malformations of cortical development (MCDs).

Anodal Transcranial Direct Current Stimulation of Prefrontal Cortex Enhances Working Memory

Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale. Sep, 2005  |  Pubmed ID: 15999258

Previous studies have claimed that weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex that can be more pronounced than cortical modulation induced by transcranial magnetic stimulation, but there are no studies that have evaluated the effects of tDCS on working memory. Our aim was to determine whether anodal transcranial direct current stimulation, which enhances brain cortical excitability and activity, would modify performance in a sequential-letter working memory task when administered to the dorsolateral prefrontal cortex (DLPFC). Fifteen subjects underwent a three-back working memory task based on letters. This task was performed during sham and anodal stimulation applied over the left DLPFC. Moreover seven of these subjects performed the same task, but with inverse polarity (cathodal stimulation of the left DLPFC) and anodal stimulation of the primary motor cortex (M1). Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.

Improved Naming After TMS Treatments in a Chronic, Global Aphasia Patient--case Report

Neurocase. Jun, 2005  |  Pubmed ID: 16006338

We report improved ability to name pictures at 2 and 8 months after repetitive transcranial magnetic stimulation (rTMS) treatments to the pars triangularis portion of right Broca's homologue in a 57 year-old woman with severe nonfluent/global aphasia (6.5 years post left basal ganglia bleed, subcortical lesion). TMS was applied at 1 Hz, 20 minutes a day, 10 days, over a two-week period. She received no speech therapy during the study. One year after her TMS treatments, she entered speech therapy with continued improvement. TMS may have modulated activity in the remaining left and right hemisphere neural network for naming.

The Plastic Human Brain Cortex

Annual Review of Neuroscience. 2005  |  Pubmed ID: 16022601

Plasticity is an intrinsic property of the human brain and represents evolution's invention to enable the nervous system to escape the restrictions of its own genome and thus adapt to environmental pressures, physiologic changes, and experiences. Dynamic shifts in the strength of preexisting connections across distributed neural networks, changes in task-related cortico-cortical and cortico-subcortical coherence and modifications of the mapping between behavior and neural activity take place in response to changes in afferent input or efferent demand. Such rapid, ongoing changes may be followed by the establishment of new connections through dendritic growth and arborization. However, they harbor the danger that the evolving pattern of neural activation may in itself lead to abnormal behavior. Plasticity is the mechanism for development and learning, as much as a cause of pathology. The challenge we face is to learn enough about the mechanisms of plasticity to modulate them to achieve the best behavioral outcome for a given subject.

Transcranial Magnetic Stimulation Treatment for Epilepsy: Can It Also Improve Depression and Vice Versa?

Epilepsy & Behavior : E&B. Sep, 2005  |  Pubmed ID: 16054872

Comorbidity with depression is an important determinant of the quality of life for patients with epilepsy. Antidepressant medications can effectively treat depression in epileptic patients, but drug-drug interactions and epileptogenic effects of these drugs pose therapeutic challenges. The mood-stabilizing effects of antiepileptic medications may not be sufficient to treat depression. Therefore, treatments that alleviate the burden of depression without increasing seizure risk or, better yet, with the possibility of improving seizure control are worth exploring. Neuroimaging techniques, such as functional magnetic resonance imaging, are providing novel insights into the pathophysiology of depression in epilepsy. For example, there appears to be prominent brain prefrontal hypoactivity, which may be sustained by the hyperactivity of the seizure focus. If so, neuromodulatory approaches that suppress epileptic focus hyperactivity and concurrently enhance prefrontal activity may be ideally suited. Indeed, vagus nerve stimulation has been shown to yield simultaneous antiseizure and mood effects. Another neuromodulatory technique, transcranial magnetic stimulation (TMS), can also modulate brain activity, but in a noninvasive, painless, and focal manner. Depending on the stimulation parameters, it is possible to enhance or reduce activity in the targeted brain region. Furthermore, TMS has been shown to be effective in treating depression, and preliminary data suggest that this treatment may also be effective for epilepsy treatment. This article reviews these data and explores further the question of whether depression and epilepsy can be simultaneously treated with TMS for optimal therapeutic impact.

Transcranial Direct Current Stimulation of the Unaffected Hemisphere in Stroke Patients

Neuroreport. Sep, 2005  |  Pubmed ID: 16148743

Recovery of function after a stroke is determined by a balance of activity in the neural network involving both the affected and the unaffected brain hemispheres. Increased activity in the affected hemisphere can promote recovery, while excessive activity in the unaffected hemisphere may represent a maladaptive strategy. We therefore investigated whether reduction of the excitability in the unaffected hemisphere by cathodal transcranial direct current stimulation could result in motor performance improvement in stroke patients. We compared these results with excitability-enhancing anodal transcranial direct current stimulation of the affected hemisphere and sham transcranial direct current stimulation. Both cathodal stimulation of the unaffected hemisphere and anodal stimulation of the affected hemisphere (but not sham transcranial direct current stimulation) improved motor performance significantly. These results suggest that the appropriate modulation of bihemispheric brain structures can promote motor function recovery.

Transcranial Magnetic Stimulation for the Treatment of Depression in Neurologic Disorders

Current Psychiatry Reports. Oct, 2005  |  Pubmed ID: 16216159

Depression is commonly associated with neurologic disorders. Although depression in neurologic conditions often is associated with a negative impact on quality of life, it frequently is poorly managed. Some factors, such as a multidrug regimen, lack of efficacy, and side effects of antidepressants may explain why depression is not adequately treated in patients with neurologic disorders. Therefore, this population needs new approaches for depression treatment, and repetitive transcranial magnetic stimulation (rTMS) may be one of them because it has been shown to be effective for the treatment of depression alone and depression in certain neurologic diseases such as Parkinson's disease and stroke. rTMS is a noninvasive, focal, and painless treatment associated with few, mild side effects. It may be effective in the treatment of neurologic diseases such as Parkinson's disease, stroke, and epilepsy. In this paper, we discuss the potential risks and benefits of rTMS treatment for depression in Parkinson's disease, epilepsy, stroke, multiple sclerosis, and Alzheimer's disease. Lastly, a framework that includes the parameters of stimulation (intensity, frequency, number of pulses, and site of stimulation) for the treatment of depression in neurologic diseases is proposed.

Treatment of Chronic Visceral Pain with Brain Stimulation

Annals of Neurology. Dec, 2005  |  Pubmed ID: 16315281

Repetitive Transcranial Magnetic Stimulation for the Treatment of Depression

Journal of Psychiatry & Neuroscience : JPN. Nov, 2005  |  Pubmed ID: 16327880

Dissociable Networks for the Expectancy and Perception of Emotional Stimuli in the Human Brain

NeuroImage. Apr, 2006  |  Pubmed ID: 16275018

William James posited that comparable brain regions were implicated in the anticipation and perception of a stimulus; however, dissociable networks (at least in part) may also underlie these processes. Recent functional neuroimaging studies have addressed this issue by comparing brain systems associated with the expectancy and perception of visual, tactile, nociceptive, and reward stimuli. In the present fMRI study, we addressed this issue in the domain of pictorial emotional stimuli (IAPS). Our paradigm involved the experimental conditions emotional expectancy, neutral expectancy, emotional picture perception, and neutral picture perception. Specifically, the emotional expectancy cue was uncertain in that it did not provide additional information regarding the positive or negative valence of the subsequent picture. Neutral expectancy and neutral picture perception served as control conditions, allowing the identification of expectancy and perception effects specific for emotion processing. To avoid contamination of the perception conditions by the preceding expectancy periods, 50% of the pictorial stimuli were presented without preceding expectancy cues. We found that the emotional expectancy cue specifically produced activation in the supracallosal anterior cingulate, cingulate motor area, and parieto-occipital sulcus. These regions were not significantly activated by emotional picture perception which recruited a different neuronal network, including the amygdala, insula, medial and lateral prefrontal cortex, cerebellum, and occipitotemporal areas. This dissociation may reflect a distinction between anticipatory and perceptive components of emotional stimulus processing.

Attentional Modulation of Emotional Stimulus Processing: an FMRI Study Using Emotional Expectancy

Human Brain Mapping. Aug, 2006  |  Pubmed ID: 16317710

We used emotional expectancy to study attentional modulation in the processing of emotional stimuli. During functional magnetic resonance imaging (fMRI), volunteers saw emotional and neutral expectancy cues signaling the subsequent presentation of corresponding emotional or neutral pictorial stimuli. As a control, emotional and neutral pictures were presented without preceding expectancy cue, resulting in a 2 x 2 factorial design with the factors "expectancy" and "emotion." Statistical analysis revealed a significant positive interaction effect between these factors in the medial prefrontal cortex (MPFC, Brodmann area [BA] 9/10), amygdala, and dorsal midbrain. In all these regions, expectancy augmented the neural response to emotional but not to neutral pictures. Time course analysis of raw data suggests that this augmented activation was not preceded by baseline increases in MPFC and amygdala during the period of emotional expectancy. In a post-scanning session, the paradigm was presented for a second time to allow emotional intensity rating. Again, a significant interaction between expectancy and emotion was observed, with intensity ratings specifically enhanced in emotional photographs preceded by expectancy. There was a positive correlation between intensity ratings and blood oxygenation level-dependent (BOLD) signals in the left amygdala. We conclude that specific components of the emotion network show enhanced activation in response to emotional stimuli when these are preceded by expectancy. This enhancement effect is not present in neutral pictures and might parallel accentuated subjective feeling states.

Effect of Low-frequency Transcranial Magnetic Stimulation on an Affective Go/no-go Task in Patients with Major Depression: Role of Stimulation Site and Depression Severity

Psychiatry Research. Jan, 2006  |  Pubmed ID: 16352348

Repetitive transcranial magnetic stimulation (rTMS) holds promise as a therapeutic tool in major depression. However, a means to assess the effects of a single rTMS session on mood to guide subsequent sessions would be desirable. The present study examined the effects of a single rTMS session on an affective go/no-go task known to measure emotional-cognitive deficits associated with major depression. Ten patients with an acute episode of unipolar major depression and eight partially or completely remitted (improved) patients underwent 1 Hz rTMS over the left and right dorsolateral prefrontal cortex prior to task performance. TMS over the mesial occipital cortex was used as a control. We observed significantly improved performance in depressed patients following right prefrontal rTMS. This beneficial effect declined with decreasing depression severity and tended to reverse in the improved group. Left prefrontal rTMS had no significant effect in the depressed group, but it resulted in impaired task performance in the improved group. Our findings indicate that the acute response of depressed patients to rTMS varies with the stimulation site and depression severity. Further studies are needed to determine whether the present paradigm could be used to predict antidepressant treatment success or to individualize stimulation parameters according to specific pathology.

After-effects of Transcranial Direct Current Stimulation (tDCS) on Cortical Spreading Depression

Neuroscience Letters. May, 2006  |  Pubmed ID: 16448754

Abnormal cortical excitability influences susceptibility to cortical spreading depression (CSD) in migraine. Because transcranial direct current stimulation (tDCS) is capable of inducing lasting changes of cortical excitability, we investigated the after-effects of tDCS on the propagation velocity of CSD in the rat. Twenty-five anesthetised rats received either anodal, cathodal or sham tDCS. The stimulation was applied for 20 min at a current strength of 200 microA after the recording of three baseline CSD measurements. Starting 5 min after tDCS, a further three CSDs were elicited and CSD velocity recorded at intervals of 20 min. tDCS and CSD recording was performed under anaesthesia with chloralose and urethane. As compared to the baseline velocity of 3.14 mm/min, anodal tDCS induced a significant increase of propagation velocity during the first post-tDCS recording (3.49 mm/min). In contrast to anodal tDCS, neither cathodal tDCS nor sham tDCS, which consisted of an initial ramped DC stimulation lasting only 20 s, showed a significant effect on CSD propagation velocity. As anodal tDCS is known to induce a lasting increase of cortical excitability in the clinical setting, our results support the notion that CSD propagation velocity reflects cortical excitability. Since cortical excitability and susceptibility to CSD is elevated in migraine patients, anodal tDCS - by increasing cortical excitability - might increase the probability of migraine attack in these patients, even beyond the end of its application.

Transcranial Magnetic Stimulation and Stroke: a Computer-based Human Model Study

NeuroImage. Apr, 2006  |  Pubmed ID: 16473528

This paper explores how transcranial magnetic stimulation (TMS) induced currents in the brain are perturbed by electrical and anatomical changes following a stroke in its chronic stage. Multiple MRI derived finite element head models were constructed and evaluated to address the effects that strokes can have on the induced stimulating TMS currents by comparing stroke models of various sizes and geometries to a healthy head model under a number of stimulation conditions. The TMS induced currents were significantly altered for stimulation proximal to the lesion site in all of the models analyzed. The current density distributions were modified in magnitude, location, and orientation such that the population of neural elements that are stimulated will be correspondingly altered. The current perturbations were minimized for conditions tested where the coil was far removed from the lesion site, including models of stimulation contralateral to the lesioned hemisphere. The present limitations of TMS to the peri-lesional cortex are explored, ultimately concluding that conventional clinical standards for stimulation are unreliable and potentially dangerous predictors of the site and degree of stimulation when TMS is applied proximal to infarction site.

A Controlled Clinical Trial of Cathodal DC Polarization in Patients with Refractory Epilepsy

Epilepsia. Feb, 2006  |  Pubmed ID: 16499758

To study the effects of cathodal DC polarization in patients with refractory epilepsy and malformations of cortical development (MCDs) as indexed by seizure frequency and epileptiform EEG discharges.

Treatment of Major Depression with Transcranial Direct Current Stimulation

Bipolar Disorders. Apr, 2006  |  Pubmed ID: 16542193

A Sham-controlled, Phase II Trial of Transcranial Direct Current Stimulation for the Treatment of Central Pain in Traumatic Spinal Cord Injury

Pain. May, 2006  |  Pubmed ID: 16564618

Past evidence has shown that motor cortical stimulation with invasive and non-invasive brain stimulation is effective to relieve central pain. Here we aimed to study the effects of another, very safe technique of non-invasive brain stimulation--transcranial direct current stimulation (tDCS)--on pain control in patients with central pain due to traumatic spinal cord injury. Patients were randomized to receive sham or active motor tDCS (2mA, 20 min for 5 consecutive days). A blinded evaluator rated the pain using the visual analogue scale for pain, Clinician Global Impression and Patient Global Assessment. Safety was assessed with a neuropsychological battery and confounders with the evaluation of depression and anxiety changes. There was a significant pain improvement after active anodal stimulation of the motor cortex, but not after sham stimulation. These results were not confounded by depression or anxiety changes. Furthermore, cognitive performance was not significantly changed throughout the trial in both treatment groups. The results of our study suggest that this new approach of cortical stimulation can be effective to control pain in patients with spinal cord lesion. We discuss potential mechanisms for pain amelioration after tDCS, such as a secondary modulation of thalamic nuclei activity.

[Transcranial Magnetic Stimulation in Neuropsychology: New Horizons for Brain Research]

Revista Brasileira De Psiquiatria (São Paulo, Brazil : 1999). Mar, 2006  |  Pubmed ID: 16612490

This review addresses the use of transcranial magnetic stimulation as a research tool of neuropsychological functions. Transcranial magnetic stimulation is a non-invasive and painless technique to modulate brain function that can be applied to conscious human beings and is based on a variable magnetic field. Using this technique, it is possible to generate virtual transient lesions in healthy people or modulate the brain activity, increasing or decreasing the activity of the stimulated areas. In this review we discuss studies with transcranial magnetic stimulation in which broad aspects of language, memory and neuropsychological tests have been evaluated following or during the application of transcranial magnetic stimulation. We concluded that transcranial magnetic stimulation open new horizons for brain research in the neuropsychological field as transcranial magnetic stimulation allows the investigation of the relationship between focal cortical activity and behavior therefore contributing to the study of the functional brain activity.

Hand Motor Recovery After Stroke: Tuning the Orchestra to Improve Hand Motor Function

Cognitive and Behavioral Neurology : Official Journal of the Society for Behavioral and Cognitive Neurology. Mar, 2006  |  Pubmed ID: 16633016

The motor deficits after stroke are not only the manifestation of the injured brain region, but rather the expression of the ability of the rest of the brain to maintain function. After a lesion in the primary motor cortex, parallel motor circuits might be activated to generate some alternative input to the spinal motoneurons. These parallel circuits may originate from areas such as the contralateral, undamaged primary motor area, bilateral premotor areas, bilateral supplementary motor areas, bilateral somatosensory areas, cerebellum, and basal ganglia. Most importantly, the efferent, cortico-spinal output pathways must be preserved for a desired behavioral result. Most of the recovery of function after a stroke may represent actual relearning of the skills with the injured brain. The main neural mechanisms underlying this relearning process after stroke involve shifts of distributed contributions across a specific neural network (fundamentally the network engaged in skill learning in the healthy). If these notions are indeed correct, then neuromodulatory approaches, such as transcranial magnetic stimulation, targeting these parallel circuits might be useful to limit injury and promote recovery after a stroke. This paper reviews the stroke characteristics that can predict a good recovery and compensations across brain areas that can be implemented after a stroke to accelerate motor function recovery.

Novel Therapeutic Approaches to the Treatment of Chronic Abdominal Visceral Pain

TheScientificWorldJournal. 2006  |  Pubmed ID: 16633700

Chronic abdominal visceral pain (CAVP) has a significant clinical impact and represents one of the most frequent and debilitating disorders in the general population. It also leads to a significant economic burden due to workdays lost, reduced productivity, and long-term use of medications with their associated side effects. Despite the availability of several therapeutic options, the management of patients with CAVP is often inadequate, resulting in frustration for both patients and physicians. This may in part be explained by the lack of understanding of the mechanisms underlying chronic pain; in contrast with acute pain in which the pathophysiology is relatively well known and has several satisfactory therapeutic options. Recently, the development of tools for brain investigation, such as functional magnetic resonance imaging, has provided new insights on the pathophysiology of chronic pain. These new data have shown that plastic changes in the central and peripheral nervous system might play an important role in the maintenance of chronic pain. Therefore, approaches aimed at the modulation of the nervous system, rather than the ones interfering with the inflammatory pathways, may be more effective for chronic pain treatment. We propose that noninvasive central nervous system stimulation, with transcranial magnetic stimulation (TMS), might be a novel therapeutic option for CAVP. This paper will present an overview of the pathophysiology and the available therapies for CAVP, focusing on the recent advances in the treatment of this pathology.

Homeostatic Effects of Plasma Valproate Levels on Corticospinal Excitability Changes Induced by 1Hz RTMS in Patients with Juvenile Myoclonic Epilepsy

Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology. Jun, 2006  |  Pubmed ID: 16644277

The preliminary results of noninvasive brain stimulation for epilepsy treatment have been encouraging, but mixed. Two important factors may contribute to this heterogeneity: the altered brain physiology of patients with epilepsy and the variable presence of antiepileptic drugs. Therefore, we aimed to study the effects of 1 Hz rTMS on corticospinal excitability in patients with juvenile myoclonic epilepsy (JME) in two different conditions: low- or high-plasma valproate levels.

Tinnitus and Brain Activation: Insights from Transcranial Magnetic Stimulation

Ear, Nose, & Throat Journal. Apr, 2006  |  Pubmed ID: 16696357

The mechanisms underlying tinnitus are still not completely elucidated, but advances in neuroimaging and brain stimulation have provided us with new insights. Evidence suggests that tinnitus might actually be generated by central rather than peripheral structures. To illustrate the importance of brain activity changes in the pathology of tinnitus, we report the cases of 2 patients who experienced a recurrence/worsening of their tinnitus after they had undergone treatment for major depression with repetitive transcranial magnetic stimulation. We suggest that the tinnitus in these 2 patients was induced by changes in brain activity resulting from transcranial magnetic stimulation of the prefrontal cortex. We also review the pathophysiology and other aspects of tinnitus, focusing on associated brain reorganization.

Enhancement of Non-dominant Hand Motor Function by Anodal Transcranial Direct Current Stimulation

Neuroscience Letters. Aug, 2006  |  Pubmed ID: 16808997

Transcranial direct current stimulation (tDCS) is a non-invasive powerful method to modulate brain activity. It can enhance motor learning and working memory in healthy subjects. To investigate the effects of anodal tDCS (1 mA, 20 min) of the dominant and non-dominant primary motor cortex (M1) on hand motor performance in healthy right-handed volunteers, healthy subjects underwent one session of both sham and active anodal stimulation of the non-dominant or dominant primary motor cortex. A blinded rater assessed motor function using the Jebsen Taylor Hand Function Test. For the non-dominant hand, active tDCS was able to improve motor function significantly-there was a significant interaction between time and condition of stimulation (p = 0.003). Post hoc tests showed a significant enhancement of JTT performance after 1 mA anodal tDCS of M1 (mean improvement of 9.41%, p = 0.0004), but not after sham tDCS (mean improvement of 1.3%, p = 0.84). For the dominant hand, however, neither active nor sham tDCS resulted in a significant change in motor performance. Our findings show that anodal tDCS of the non-dominant primary motor cortex results in motor function enhancement and thus confirm and extend the notion that tDCS can change behavior. We speculate that the under-use of the non-dominant hand with its associated consequences in cortical plasticity might be one of the reasons to explain motor performance enhancement in the non-dominant hand only.

A Sham-controlled Trial of a 5-day Course of Repetitive Transcranial Magnetic Stimulation of the Unaffected Hemisphere in Stroke Patients

Stroke; a Journal of Cerebral Circulation. Aug, 2006  |  Pubmed ID: 16809569

It has been recently shown that a single session of repetitive transcranial magnetic stimulation (rTMS) of the unaffected hemisphere can improve motor function in stroke patients; however, this improvement is short-lasting. We therefore conducted a randomized, sham-controlled, phase II trial to evaluate whether five sessions of low-frequency rTMS can increase the magnitude and duration of these effects and whether this approach is safe.

Noninvasive Cortical Stimulation with Transcranial Direct Current Stimulation in Parkinson's Disease

Movement Disorders : Official Journal of the Movement Disorder Society. Oct, 2006  |  Pubmed ID: 16817194

Electrical stimulation of deep brain structures, such as globus pallidus and subthalamic nucleus, is widely accepted as a therapeutic tool for patients with Parkinson's disease (PD). Cortical stimulation either with epidural implanted electrodes or repetitive transcranial magnetic stimulation can be associated with motor function enhancement in PD. We aimed to study the effects of another noninvasive technique of cortical brain stimulation, transcranial direct current stimulation (tDCS), on motor function and motor-evoked potential (MEP) characteristics of PD patients. We tested tDCS using different electrode montages [anodal stimulation of primary motor cortex (M1), cathodal stimulation of M1, anodal stimulation of dorsolateral prefrontal cortex (DLPFC), and sham-stimulation] and evaluated the effects on motor function--as indexed by Unified Parkinson's Disease Rating Scale (UPDRS), simple reaction time (sRT) and Purdue Pegboard test--and on corticospinal motor excitability (MEP characteristics). All experiments were performed in a double-blinded manner. Anodal stimulation of M1 was associated with a significant improvement of motor function compared to sham-stimulation in the UPDRS (P < 0.001) and sRT (P = 0.019). This effect was not observed for cathodal stimulation of M1 or anodal stimulation of DLPFC. Furthermore, whereas anodal stimulation of M1 significantly increased MEP amplitude and area, cathodal stimulation of M1 significantly decreased them. There was a trend toward a significant correlation between motor function improvement after M1 anodal-tDCS and MEP area increase. These results confirm and extend the notion that cortical brain stimulation might improve motor function in patients with PD.

Effects of Transcranial Direct Current Stimulation on Working Memory in Patients with Parkinson's Disease

Journal of the Neurological Sciences. Nov, 2006  |  Pubmed ID: 16843494

Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important predictor of quality of life. Past studies showed that some aspects of cognition, such as working memory, can be enhanced following dopaminergic therapy and transcranial magnetic stimulation. The aim of our study was to investigate whether another form of noninvasive brain stimulation, anodal transcranial direct current stimulation (tDCS), which increases cortical excitability, is associated with a change in a working memory task performance in PD patients.

Cognitive Effects of Repeated Sessions of Transcranial Direct Current Stimulation in Patients with Depression

Depression and Anxiety. 2006  |  Pubmed ID: 16845648

RTMS Combined with Motor Learning Training in Healthy Subjects

Restorative Neurology and Neuroscience. 2006  |  Pubmed ID: 16873974

This study explored the effects of motor learning training combined with repetitive transcranial magnetic stimulation (rTMS) on motor performance in healthy subjects.

Comparison Between Digital Subtraction Angiography and Magnetic Resonance Angiography in Investigation of Nonlacunar Ischemic Stroke in Young Patients: Preliminary Results

Arquivos De Neuro-psiquiatria. Jun, 2006  |  Pubmed ID: 16917600

We preliminarily investigated the relevance of performing digital subtraction angiography (DSA) in addition to magnetic resonance angiography (MRA) in definition of ischemic stroke etiology in young patients.

Comparison of Repetitive Transcranial Magnetic Stimulation and Electroconvulsive Therapy in Unipolar Non-psychotic Refractory Depression: a Randomized, Single-blind Study

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Dec, 2006  |  Pubmed ID: 16923322

Repetitive transcranial magnetic stimulation (rTMS) can induce significant antidepressant effects and, for some patients, might be an alternative to electroconvulsive therapy (ECT). The results of studies comparing the efficacy of rTMS and ECT are mixed and, therefore, comparison of these two therapies needs to be further explored. Forty-two patients aged between 18 and 65 yr, referred to ECT due to unipolar non-psychotic depression refractoriness entered the trial. They were randomly assigned to receive either rTMS or ECT. Depressive symptom changes were blindly measured by Hamilton Depression Rating Scale, Visual Analogue Scale and Clinical Global Impression at baseline, after 2 wk and after 4 wk of treatment. There was no difference in the antidepressant efficacy of ECT and rTMS. Response rates were relatively low in both groups (40% and 50% respectively), with no significant difference between them (p=0.55). Remission rates were also low for both groups (20% and 10% respectively), also with no significant difference (p=0.631). There was no significant difference in the neuropsychological test performance after either one of these therapies. Both treatments were associated with a degree of improvement in refractory depression and therefore add to the literature that rTMS can be an effective option to ECT as it is a less costly treatment and is not associated with anaesthetic and other ECT risks.

Predictors of Antidepressant Response in Clinical Trials of Transcranial Magnetic Stimulation

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Dec, 2006  |  Pubmed ID: 16939662

Although previous clinical trials have suggested that repetitive transcranial magnetic stimulation (rTMS) has a significant antidepressant effect, the results of these trials are heterogeneous. We hypothesized that individual patients' characteristics might contribute to such heterogeneity. Our aim was to identify predictors of antidepressant response to rTMS. We pooled data from six separate clinical trials conducted independently, which evaluated the effects of rapid rTMS of the left dorsolateral prefrontal cortex in patients with major depression. We investigated 195 patients with regard to demographic, depression and treatment characteristics, psychiatric and drug history. Results showed that age and treatment refractoriness were significant negative predictors of depression improvement when adjusting these variables to other significant predictors and confounders. These findings were not confounded by methodological differences from the six studies, as the results were adjusted for the study site. In conclusion TMS antidepressant therapy in younger and less treatment-resistant patients is associated with better outcome.

Immediate Placebo Effect in Parkinson's Disease--is the Subjective Relief Accompanied by Objective Improvement?

European Neurology. 2006  |  Pubmed ID: 17057382

A recent well-conducted meta-analysis showed that placebo effect is associated with a possible small benefit for subjective outcomes, but has no significant effects on objective outcomes. Objective: Herein, we aimed to investigate the immediate effects of two different types of placebo [placebo pill and sham transcranial magnetic stimulation (TMS)] in Parkinson's disease (PD) patients and compared them to the standard treatment (levodopa) in a proper randomized, double-blind, crossover clinical trial.

Transient Visual Changes Associated with Repetitive Transcranial Magnetic Stimulation of the Dorsolateral Prefrontal Cortex in Cases of Major Depression

Revista Brasileira De Psiquiatria (São Paulo, Brazil : 1999). Sep, 2006  |  Pubmed ID: 17063224

A Randomized Clinical Trial of Repetitive Transcranial Magnetic Stimulation in Patients with Refractory Epilepsy

Annals of Neurology. Oct, 2006  |  Pubmed ID: 17068786

To study the antiepileptic effects of rTMS in patients with refractory epilepsy and malformations of cortical development in a randomized, double-blind, sham-controlled trial.

Hand Function Improvement with Low-frequency Repetitive Transcranial Magnetic Stimulation of the Unaffected Hemisphere in a Severe Case of Stroke

American Journal of Physical Medicine & Rehabilitation / Association of Academic Physiatrists. Nov, 2006  |  Pubmed ID: 17079967

Previous research has shown that low-frequency rTMS of the unaffected hemisphere can improve motor function in acute and chronic stroke patients. However, these studies only investigated patients with mild or moderate motor deficits. We report a case of a stroke patient with a severe motor impairment who underwent sham and active repetitive transcranial magnetic stimulation (rTMS) of the unaffected hemisphere and had significantly improved motor function after active, but not after sham, stimulation of the unaffected primary motor cortex. In an additional session of active rTMS, this patient maintained and further enhanced the initial motor improvement. This case report shows that inhibitory rTMS of the unaffected hemisphere can also be beneficial for stroke patients with severe motor deficits and suggests that this approach of noninvasive brain stimulation should be further investigated in this population of patients.

A Randomized, Sham-controlled, Proof of Principle Study of Transcranial Direct Current Stimulation for the Treatment of Pain in Fibromyalgia

Arthritis and Rheumatism. Dec, 2006  |  Pubmed ID: 17133529

Recent evidence suggests that fibromyalgia is a disorder characterized by dysfunctional brain activity. Because transcranial direct current stimulation (tDCS) can modulate brain activity noninvasively and can decrease pain in patients with refractory central pain, we hypothesized that tDCS treatment would result in pain relief in patients with fibromyalgia.

Imaging Correlates of Motor Recovery from Cerebral Infarction and Their Physiological Significance in Well-recovered Patients

NeuroImage. Jan, 2007  |  Pubmed ID: 17070707

We studied motor representation in well-recovered stroke patients. Eighteen right-handed stroke patients and eleven age-matched control subjects underwent functional Magnetic Resonance Imaging (fMRI) while performing unimanual index finger (abduction-adduction) and wrist movements (flexion-extension) using their recovered and non-affected hand. A subset of these patients underwent Transcranial Magnetic Stimulation (TMS) to elicit motor evoked potentials (MEP) in the first dorsal interosseous muscle of both hands. Imaging results suggest that good recovery utilizes both ipsi- and contralesional resources, although results differ for wrist and index finger movements. Wrist movements of the recovered arm resulted in significantly greater activation of the contralateral (lesional) and ipsilateral (contralesional) primary sensorimotor cortex (SM1), while comparing patients to control subjects performing the same task. In contrast, recovered index finger movements recruited a larger motor network, including the contralateral SM1, Supplementary Motor Area (SMA) and cerebellum when patients were compared to control subjects. TMS of the lesional hemisphere but not of the contralesional hemisphere induced MEPs in the recovered hand. TMS parameters also revealed greater transcallosal inhibition, from the contralesional to the lesional hemisphere than in the reverse direction. Disinhibition of the contralesional hemisphere observed in a subgroup of our patients suggests persistent alterations in intracortical and transcallosal (interhemispheric) interactions, despite complete functional recovery.

Effects of Transcranial Direct Current Stimulation Coupled with Repetitive Electrical Stimulation on Cortical Spreading Depression

Experimental Neurology. Mar, 2007  |  Pubmed ID: 17113079

We have recently shown that two techniques of brain stimulation - repetitive electrical stimulation (ES) (that mimics transcranial magnetic stimulation) and transcranial direct current stimulation (tDCS) - modify the velocity of cortical spreading depression (CSD) significantly. Herein we aimed to study the effects of these two techniques combined on CSD. Thirty-two Wistar rats were divided into four groups according to the treatment: sham tDCS/sham ES, sham tDCS/1 Hz ES, anodal tDCS/1 Hz ES, cathodal tDCS/1 Hz ES. Our findings show that 1 Hz ES reduced CSD velocity, and this effect was modified by either anodal or cathodal tDCS. Anodal tDCS induced larger effects than cathodal tDCS. Hereby CSD velocity was actually increased significantly after anodal tDCS/1 Hz ES. Our results show that combining two techniques of brain stimulation can modify significantly the effects of ES alone on cortical excitability as measured by the neurophysiological parameter of cortical spreading depression and therefore provide important insights into the effects of this new approach of brain stimulation on cortical activity.

Go-no-go Task Performance Improvement After Anodal Transcranial DC Stimulation of the Left Dorsolateral Prefrontal Cortex in Major Depression

Journal of Affective Disorders. Aug, 2007  |  Pubmed ID: 17166593

We recently showed that repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) can affect the performance in an affective go-no-go (AGN) task. We aimed to extend this previous investigation testing whether one session of anodal transcranial direct current stimulation (tDCS) of the left DLPFC, as compared with anodal occipital and sham tDCS, affects this AGN task performance.

RTMS over the Intraparietal Sulcus Disrupts Numerosity Processing

Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale. Jun, 2007  |  Pubmed ID: 17216413

It has been widely argued that the intraparietal sulcus (IPS) is involved in tasks that evoke representations of numerical magnitude, among other cognitive functions. However, the causal role of this parietal region in processing symbolic and non-symbolic numerosity has not been established. The current study used repetitive Transcranial Magnetic Stimulation (rTMS) to the left and right IPS to investigate the effects of temporary deactivations of these regions on the capacity to represent symbolic (Arabic numbers) and non-symbolic (arrays of dots) numerosities. We found that comparisons of both symbolic and non-symbolic numerosities were impaired after rTMS to the left IPS but enhanced by rTMS to the right IPS. A signature effect of numerical distance was also found: greater impairment (or lesser facilitation) when comparing numerosities of similar magnitude. The reverse pattern of impairment and enhancement was found in a control task that required judging an analogue stimulus property (ellipse orientation) but no numerosity judgements. No rTMS effects for the numerosity tasks were found when stimulating an area adjacent but distinct from the IPS, the left and right angular gyrus. These data suggest that left IPS is critical for processing symbolic and non-symbolic numerosity; this processing may thus depend on common neural mechanisms, which are distinct from mechanisms supporting the processing of analogue stimulus properties.

Recent Advances in the Treatment of Chronic Pain with Non-invasive Brain Stimulation Techniques

Lancet Neurology. Feb, 2007  |  Pubmed ID: 17239806

BACKGROUND: Brain stimulation is a technique that can guide brain plasticity and thus be suitable to treat chronic pain-a disorder that is associated with substantial reorganisation of CNS activity. In fact, the idea of using invasive and non-invasive brain stimulation for pain relief is not new. Studies from the 1950s investigated the use of this therapeutic method for the treatment of chronic pain. However, recent advancements in the techniques of non-invasive brain stimulation have enhanced their modulatory effects and thus become a new, attractive alternative for chronic pain treatment. RECENT DEVELOPMENTS: Recent studies with non-invasive brain stimulation--eg, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS)--using new parameters of stimulation have shown encouraging results. These studies explored alternative sites of stimulation, such as the secondary somatosensory cortex (rather than primary motor cortex) for the treatment of chronic visceral pain and new parameters of stimulation, such as repeated sessions of tDCS with 2 mA for the treatment of chronic central pain. WHERE NEXT?: The investigation of non-invasive brain stimulation for therapeutic effects is in its at initial stages; but the preliminary data make us optimistic. Several questions still need to be addressed before any firm conclusion about this therapy is made. Other parameters of stimulation need to be further explored such as theta-burst stimulation and the combination of tDCS and rTMS. The duration of the therapeutic effects is another important issue to be considered, especially because the current devices for brain stimulation do not allow patients to receive this therapy in their homes; therefore, maintenance therapy regimens, as well as the development of portable stimulators, need to be investigated. Further trials must determine the optimum parameters of stimulation. After that, confirmatory, larger studies are mandatory.

Transcranial Direct Current Stimulation: a Computer-based Human Model Study

NeuroImage. Apr, 2007  |  Pubmed ID: 17337213

Interest in transcranial direct current stimulation (tDCS) in clinical practice has been growing, however, the knowledge about its efficacy and mechanisms of action remains limited. This paper presents a realistic magnetic resonance imaging (MRI)-derived finite element model of currents applied to the human brain during tDCS.

Visual Phosphene Perception Modulated by Subthreshold Crossmodal Sensory Stimulation

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Apr, 2007  |  Pubmed ID: 17428995

Crossmodal sensory interactions serve to integrate behaviorally relevant sensory stimuli. In this study, we investigated the effect of modulating crossmodal interactions between visual and somatosensory stimuli that in isolation do not reach perceptual awareness. When a subthreshold somatosensory stimulus was delivered within close spatiotemporal congruency to the expected site of perception of a phosphene, a subthreshold transcranial magnetic stimulation pulse delivered to the occipital cortex evoked a visual percept. The results suggest that under subthreshold conditions of visual and somatosensory stimulation, crossmodal interactions presented in a spatially and temporally specific manner can sum up to become behaviorally significant. These interactions may reflect an underlying anatomical connectivity and become further enhanced by attention modulation mechanisms.

Cardiovascular Effects of Anesthesia in ECT: a Randomized, Double-blind Comparison of Etomidate, Propofol, and Thiopental

The Journal of ECT. Mar, 2007  |  Pubmed ID: 17435563

Cardiovascular alterations during electroconvulsive therapy (ECT) are a major concern for this treatment. Although several studies have been performed to compare the effects of anesthetics on these alterations, the results are mixed and doubt still exists regarding the choice of the best drug. We conducted a randomized, double-blind clinical trial to compare the effects of 3 anesthetics used in ECT: etomidate, propofol, and thiopental. Patients (N=30) were randomized to receive one of these drugs as the anesthetic for the ECT procedure. Cardiovascular evaluation consisted of the measurement of blood systolic and diastolic pressure and heart rate before and immediately after the end of the seizure for each patient during a course of ECT. The results showed that etomidate, propofol, and thiopental were associated with similar cardiovascular effects.

Activation of Prefrontal Cortex by Transcranial Direct Current Stimulation Reduces Appetite for Risk During Ambiguous Decision Making

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Jun, 2007  |  Pubmed ID: 17553993

As adult humans, we are continuously faced with decisions in which proper weighing of the risk involved is critical. Excessively risky or overly cautious decision making can both have disastrous real-world consequences. Weighing of risks and benefits toward decision making involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC), but its role remains unclear. Repetitive transcranial magnetic stimulation studies have shown that disruption of the DLPFC increases risk-taking behavior. Transcranial direct current stimulation (tDCS) allows upregulation of activity in the DLPFC, and we predicted that it might promote more cautious decision making. Healthy participants received one of the following treatments while they performed the Balloon Analog Risk Task: (1) right anodal/left cathodal DLPFC tDCS, (2) left anodal/right cathodal DLPFC tDCS, or (3) sham tDCS. This experiment revealed that participants receiving either one of the bilateral DLPFC tDCS strategies adopted a risk-averse response style. In a control experiment, we tested whether unilateral DLPFC stimulation (anodal tDCS over the right or left DLPFC with the cathodal electrode over the contralateral supraorbital area) was sufficient to decrease risk-taking behaviors. This experiment showed no difference in decision-making behaviors between the groups of unilateral DLPFC stimulation and sham stimulation. These findings extend the notion that DLPFC activity is critical for adaptive decision making, possibly by suppressing riskier responses. Anodal tDCS over DLPFC by itself did not significantly change risk-taking behaviors; however, when the contralateral DLPFC was modulated with cathodal tCDS, an important decrease in risk taking was observed. Also, the induced cautious decision-making behavior was observed only when activity of both DLPFCs was modulated. The ability to modify risk-taking behavior may be translated into therapeutic interventions for disorders such as drug abuse, overeating, or pathological gambling.

Low and High Frequency Repetitive Transcranial Magnetic Stimulation for the Treatment of Spasticity

Developmental Medicine and Child Neurology. Jul, 2007  |  Pubmed ID: 17593127

The development of non-invasive techniques of cortical stimulation, such as transcranial magnetic stimulation (TMS), has opened new potential avenues for the treatment of neuropsychiatric diseases. We hypothesized that an increase in the activity in the motor cortex by cortical stimulation would increase its inhibitory influence on spinal excitability through the corticospinal tract and, thus, reduce the hyperactivity of the gamma and alpha neurons, improving spasticity. Seventeen participants (eight males, nine females; mean age 9y 1mo [SD 3y 2mo]) with cerebral palsy and spastic quadriplegia were randomized to receive sham, active 1Hz, or active 5Hz repetitive TMS of the primary motor cortex. Stimulation was applied for 5 consecutive days (90% of motor threshold). The results showed that there was a significant reduction of spasticity after 5Hz, but not sham or 1Hz, stimulation as indexed by the degree of passive movement; however this was not evident when using the Ashworth scale, although a trend for improvement was seen for elbow movement. The safety evaluation showed that stimulation with either 1Hz or 5Hz did not result in any adverse events as compared with sham stimulation. Results of this trial provide initial evidence to support further trials exploring the use of cortical stimulation in the treatment of spasticity.

Technology Insight: Noninvasive Brain Stimulation in Neurology-perspectives on the Therapeutic Potential of RTMS and TDCS

Nature Clinical Practice. Neurology. Jul, 2007  |  Pubmed ID: 17611487

In neurology, as in all branches of medicine, symptoms of disease and the resulting burden of illness and disability are not simply the consequence of the injury, inflammation or dysfunction of a given organ; they also reflect the consequences of the nervous system's attempt to adapt to the insult. This plastic response includes compensatory changes that prove adaptive for the individual, as well as changes that contribute to functional disability and are, therefore, maladaptive. In this context, brain stimulation techniques tailored to modulate individual plastic changes associated with neurological diseases might enhance clinical benefits and minimize adverse effects. In this Review, we discuss the use of two noninvasive brain stimulation techniques--repetitive transcranial magnetic stimulation and transcranial direct current stimulation--to modulate activity in the targeted cortex or in a dysfunctional network, to restore an adaptive equilibrium in a disrupted network for best behavioral outcome, and to suppress plastic changes for functional advantage. We review randomized controlled studies, in focal epilepsy, Parkinson's disease, recovery from stroke, and chronic pain, to illustrate these principles, and we present evidence for the clinical effects of these two techniques.

Repeated Sessions of Noninvasive Brain DC Stimulation is Associated with Motor Function Improvement in Stroke Patients

Restorative Neurology and Neuroscience. 2007  |  Pubmed ID: 17726271

Recent evidence has suggested that a simple technique of noninvasive brain stimulation - transcranial direct current stimulation (tDCS) - is associated with a significant motor function improvement in stroke patients.

Pain in Chronic Pancreatitis: a Salutogenic Mechanism or a Maladaptive Brain Response?

Pancreatology : Official Journal of the International Association of Pancreatology (IAP) ... [et Al.]. 2007  |  Pubmed ID: 17898531

Pain in chronic pancreatitis is frequently refractory to medical and even surgical treatment. This refractoriness leads us to believe that a pancreas-independent, brain-mediated mechanism must be responsible. If so, several scenarios are worth considering. First, chronic pain could be the consequence of undesirable neuroplastic changes, by which pathology becomes established and causes disability. Alternatively, pain may be linked to the salutogenic (from salutogenesis, the Latin word for health and well-being) central nervous system response (we defined 'salutogenic response' as the specific modulation of the immune system induced by brain activity changes) to promote healing of the injured viscera. If so, chronic pain could index the ongoing nervous system attempt to promote healing. In this review, we discuss (1) the mechanisms of pain in chronic pancreatitis; (2) potential brain-related salutogenic mechanisms, and (3) the potential relationship of these two factors to the disease status. Furthermore, we consider these aspects in light of a new approach to treat visceral pain: transcranial magnetic stimulation, a noninvasive method of brain stimulation.

Treatment of Cancer Pain with Noninvasive Brain Stimulation

Journal of Pain and Symptom Management. Oct, 2007  |  Pubmed ID: 17903664

Brain Stimulation in Poststroke Rehabilitation

Cerebrovascular Diseases (Basel, Switzerland). 2007  |  Pubmed ID: 17971652

Brain stimulation techniques provide a powerful means to modulate the function of specific neural structures, and show potential for future applications in the rehabilitation of stroke patients. Recent studies have started to translate to the bedside the body of data gathered over the last few years on mechanisms underlying brain plasticity and stroke recovery. Both noninvasive and invasive brain stimulation techniques, such as repetitive transcranial magnetic stimulation, transcranial direct current stimulation and direct cortical stimulation with epidural electrodes, have recently been tested in small studies with stroke patients. The results to date are very promising. Nonetheless, we are still at an early stage in the field and further evidence is needed to assess the clinical impact of this new approach. In this review, we provide readers with a basic introduction to the field, summarize preliminary studies and discuss future directions.

Site-specific Effects of Transcranial Direct Current Stimulation on Sleep and Pain in Fibromyalgia: a Randomized, Sham-controlled Study

Pain Practice : the Official Journal of World Institute of Pain. Dec, 2007  |  Pubmed ID: 17986164

To investigate whether active anodal transcranial direct current stimulation (tDCS) (of dorsolateral prefrontal cortex [DLPFC] and primary motor cortex [M1]) as compared to sham treatment is associated with changes in sleep structure in fibromyalgia.

Diminishing Risk-taking Behavior by Modulating Activity in the Prefrontal Cortex: a Direct Current Stimulation Study

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Nov, 2007  |  Pubmed ID: 18003828

Studies have shown increased risk taking in healthy individuals after low-frequency repetitive transcranial magnetic stimulation, known to transiently suppress cortical excitability, over the right dorsolateral prefrontal cortex (DLPFC). It appears, therefore, plausible that differential modulation of DLPFC activity, increasing the right while decreasing the left, might lead to decreased risk taking, which could hold clinical relevance as excessively risky decision making is observed in clinical populations leading to deleterious consequences. The goal of the present study was to investigate whether risk-taking behaviors could be decreased using concurrent anodal transcranial direct current stimulation (tDCS) of the right DLPFC, which allows upregulation of brain activity, with cathodal tDCS of the left DLPCF, which downregulates activity. Thirty-six healthy volunteers performed the risk task while they received either anodal over the right with cathodal over the left DLPFC, anodal over the left with cathodal over the right DLPFC, or sham stimulation. We hypothesized that right anodal/left cathodal would decrease risk-taking behavior compared with left anodal/right cathodal or sham stimulation. As predicted, during right anodal/left cathodal stimulation over the DLPFC, participants chose more often the safe prospect compared with the other groups. Moreover, these participants appeared to be insensitive to the reward associated with the prospects. These findings support the notion that the interhemispheric balance of activity across the DLPFCs is critical in decision-making behaviors. Most importantly, the observed suppression of risky behaviors suggests that populations with boundless risk-taking behaviors leading to negative real-life consequences, such as individuals with addiction, might benefit from such neuromodulation-based approaches.

Focusing Effect of Acetylcholine on Neuroplasticity in the Human Motor Cortex

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Dec, 2007  |  Pubmed ID: 18160652

Cholinergic neuromodulation is pivotal for arousal, attention, and cognitive processes. Loss or dysregulation of cholinergic inputs leads to cognitive impairments like those manifested in Alzheimer's disease. Such dysfunction can be at least partially restored by an increase of acetylcholine (ACh). In animal studies, ACh selectively facilitates long-term excitability changes induced by feed-forward afferent input. Consequently, it has been hypothesized that ACh enhances the signal-to-noise ratio of input processing. However, the neurophysiological foundation for its ability to enhance cognition in humans is not well documented. In this study we explore the effects of rivastigmine, a cholinesterase inhibitor, on global and synapse-specific forms of cortical plasticity induced by transcranial direct current stimulation (tDCS) and paired associative stimulation (PAS) on 10-12 healthy subjects, respectively. Rivastigmine essentially blocked the induction of the global excitability enhancement elicited by anodal tDCS and revealed a tendency to first reduce and then stabilize cathodal tDCS-induced inhibitory aftereffects. However, ACh enhanced the synapse-specific excitability enhancement produced by facilitatory PAS and consolidated the inhibitory PAS-induced excitability diminution. These findings are in line with a cholinergic focusing effect that optimizes the detection of relevant signals during information processing in humans.

Transcranial Magnetic Stimulation in Neurology: What We Have Learned from Randomized Controlled Studies

Neuromodulation : Journal of the International Neuromodulation Society. Oct, 2007  |  Pubmed ID: 22150892

Background.  Initially developed to excite peripheral nerves, magnetic stimulation was quickly recognized as a valuable tool to noninvasively activate the cerebral cortex. The subsequent discovery that repetitive transcranial magnetic stimulation (rTMS) could have long-lasting effects on cortical excitability spawned a broad interest in the use of this technique as a new therapeutic method in a variety of neuropsychiatric disorders. Although the current outcomes from initial trials include some conflicting results, initial evidence supports that rTMS might have a therapeutic value in different neurologic conditions. Methods.  We reviewed the results of clinical trials of rTMS on four different disorders: stroke, Parkinson's disease, chronic refractory pain, and epilepsy. We reviewed randomized, controlled studies only in order to obtain the strongest evidence for the clinical effects of rTMS. Results.  An extensive literature review revealed 32 articles that met our criteria. From these studies, we found evidence for the therapeutic efficacy of rTMS, particularly in the relief of chronic pain and motor neurorehabilitation in single hemisphere stroke patients. Repetitive TMS also seems to have a therapeutic effect on motor function in Parkinson's disease, but the evidence is somewhat confounded by the uncontrolled variability of multiple factors. Lastly, only two randomized, sham-controlled studies have been performed for epilepsy; although evidence indicates rTMS may reduce seizure frequency in patients with neocortical foci, more research is needed to confirm these initial findings. Conclusions.  There is mounting evidence for the efficacy of rTMS in the short-term treatment of certain neurologic conditions. More long-term research is needed in order to properly evaluate the effects of this method in a clinical setting.

A Randomized, Double-blind Clinical Trial on the Efficacy of Cortical Direct Current Stimulation for the Treatment of Major Depression

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Mar, 2008  |  Pubmed ID: 17559710

Preliminary findings suggest that transcranial direct current stimulation (tDCS) can have antidepressant effects. We sought to test this further in a parallel-group, double-blind clinical trial with 40 patients with major depression, medication-free randomized into three groups of treatment: anodal tDCS of the left dorsolateral prefrontal cortex (active group - 'DLPFC'); anodal tDCS of the occipital cortex (active control group - 'occipital') and sham tDCS (placebo control group - 'sham'). tDCS was applied for 10 sessions during a 2-wk period. Mood was evaluated by a blinded rater using the Hamilton Depression Rating Scale (HDRS) and Beck Depression Inventory (BDI). The treatment was well tolerated with minimal side-effects that were distributed equally across all treatment groups. We found significantly larger reductions in depression scores after DLPFC tDCS [HDRS reduction of 40.4% (+/-25.8%)] compared to occipital [HDRS reduction of 21.3% (+/-12.9%)] and sham tDCS [HDRS reduction of 10.4% (+/-36.6%)]. The beneficial effects of tDCS in the DLPFC group persisted for 1 month after the end of treatment. Our findings support further investigation on the effects of this novel potential therapeutic approach - tDCS - for the treatment of major depression.

Prefrontal Cortex Modulation Using Transcranial DC Stimulation Reduces Alcohol Craving: a Double-blind, Sham-controlled Study

Drug and Alcohol Dependence. Jan, 2008  |  Pubmed ID: 17640830

Functional neuroimaging studies have shown that specific brain areas are associated with alcohol craving including the dorsolateral prefrontal cortex (DLPFC). We tested whether modulation of DLPFC using transcranial direct current stimulation (tDCS) could alter alcohol craving in patients with alcohol dependence while being exposed to alcohol cues.

RTMS Treatment for Depression in Parkinson's Disease Increases BOLD Responses in the Left Prefrontal Cortex

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Mar, 2008  |  Pubmed ID: 17708780

The mechanisms underlying the effects of antidepressant treatment in patients with Parkinson's disease (PD) are unclear. The neural changes after successful therapy investigated by neuroimaging methods can give insights into the mechanisms of action related to a specific treatment choice. To study the mechanisms of neural modulation of repetitive transcranial magnetic stimulation (rTMS) and fluoxetine, 21 PD depressed patients were randomized into only two active treatment groups for 4 wk: active rTMS over left dorsolateral prefrontal cortex (DLPFC) (5 Hz rTMS; 120% motor threshold) with placebo pill and sham rTMS with fluoxetine 20 mg/d. Event-related functional magnetic resonance imaging (fMRI) with emotional stimuli was performed before and after treatment - in two sessions (test and re-test) at each time-point. The two groups of treatment had a significant, similar mood improvement. After rTMS treatment, there were brain activity decreases in left fusiform gyrus, cerebellum and right DLPFC and brain activity increases in left DLPFC and anterior cingulate gyrus compared to baseline. In contrast, after fluoxetine treatment, there were brain activity increases in right premotor and right medial prefrontal cortex. There was a significant interaction effect between groups vs. time in the left medial prefrontal cortex, suggesting that the activity in this area changed differently in the two treatment groups. Our findings show that antidepressant effects of rTMS and fluoxetine in PD are associated with changes in different areas of the depression-related neural network.

Transcranial Direct Stimulation and Fluoxetine for the Treatment of Depression

European Psychiatry : the Journal of the Association of European Psychiatrists. Jan, 2008  |  Pubmed ID: 18023968

Processing Nouns and Verbs in the Left Frontal Cortex: a Transcranial Magnetic Stimulation Study

Journal of Cognitive Neuroscience. Apr, 2008  |  Pubmed ID: 18052789

Neuropsychological and neurophysiological studies suggest that the production of verbs in speech depends on cortical regions in the left frontal lobe. However, the precise topography of these regions, and their functional roles in verb production, remains matters of debate. In an earlier study with repetitive transcranial magnetic stimulation (rTMS), we showed that stimulation to the left anterior midfrontal gyrus disrupted verb production, but not noun production, in a task that required subjects to perform simple morphological alternations. This result raises a number of questions: for example, is the effect of stimulation focal and specific to that brain region? Is the behavioral effect limited to rule-based, regular transformations, or can it be generalized over the grammatical category? In the present study, we used rTMS to suppress the excitability of distinct parts of the left prefrontal cortex to assess their role in producing regular and irregular verbs compared to nouns. We compared rTMS to sham stimulation and to stimulation of homologous areas in the right hemisphere. Response latencies increased for verbs, but were unaffected for nouns, following stimulation to the left anterior midfrontal gyrus. No significant interference specific for verbs resulted after stimulation to two other areas in the left frontal lobe, the posterior midfrontal gyrus and Broca's area. These results therefore reinforce the idea that the left anterior midfrontal cortex is critical for processing verbs. Moreover, none of the regions stimulated was preferentially engaged in the production of regular or irregular inflection, raising questions about the role of the frontal lobes in processing inflectional morphology.

New Insights into Neuromodulatory Approaches for the Treatment of Pain

The Journal of Pain : Official Journal of the American Pain Society. Mar, 2008  |  Pubmed ID: 18096437

Two lines of evidence about the association between the experience of pain and brain state (measured via electroencephalogram or EEG) have recently come to light. First, research from a number of sources suggests a link between brain EEG activity and the experience of pain. Specifically, this research suggests that the subjective experience of pain is associated with relatively lower amplitudes of slower wave (delta, theta, and alpha) activity and relatively higher amplitudes of faster wave (beta) activity. Second, there has been a recent increase in interest in interventions that impact the cortical neuromodulation of pain, including behavioral treatments (such as self-hypnosis training and neurofeedback) and both invasive and noninvasive brain stimulation. Although a direct causal link between experience of pain and brain activity as measured by EEG has not been established, the targeting of pain treatment at a cortical level by trying to affect EEG rhythms directly is an intriguing possibility. PERSPECTIVE: Preliminary evidence suggests the possibility, which has not yet adequately tested or proven, that the experience of chronic pain is linked to cortical activity as assessed via an electroencephalogram. Support for this hypothesis would have important implications for understanding the mechanisms that underlie a number of pain treatments, and for developing new innovative treatments for chronic pain management.

Transcranial Magnetic Stimulation and Brain Atrophy: a Computer-based Human Brain Model Study

Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale. Apr, 2008  |  Pubmed ID: 18193208

This paper is aimed at exploring the effect of cortical brain atrophy on the currents induced by transcranial magnetic stimulation (TMS). We compared the currents induced by various TMS conditions on several different MRI derived finite element head models of brain atrophy, incorporating both decreasing cortical volume and widened sulci. The current densities induced in the cortex were dependent upon the degree and type of cortical atrophy and were altered in magnitude, location, and orientation when compared to healthy head models. Predictive models of the degree of current density attenuation as a function of the scalp-to-cortex distance were analyzed, concluding that those which ignore the electromagnetic field-tissue interactions lead to inaccurate conclusions. Ultimately, the precise site and population of neural elements stimulated by TMS in an atrophic brain cannot be predicted based on healthy head models which ignore the effects of the altered cortex on the stimulating currents. Clinical applications of TMS should be carefully considered in light of these findings.

Bartholow, Sciamanna, Alberti: Pioneers in the Electrical Stimulation of the Exposed Human Cerebral Cortex

The Neuroscientist : a Review Journal Bringing Neurobiology, Neurology and Psychiatry. Oct, 2008  |  Pubmed ID: 18219054

Although the past 25 years have witnessed increasing interest in human brain stimulation, its historical development is marked by phases of fascination and obscurity. Its history dates back to the 19th century when the first reports describing application of an electric current to an isolated point on the exposed brain made brain stimulation a major neuroscientific novelty of the time. In this article, the authors present and discuss a number of early experiments involving electrical stimulation of the exposed human brain. In this important, albeit unexplored, historical chapter of brain stimulation, the 3 investigators, Bartholow, Sciamanna, and Alberti, were the first to reproduce findings in animals with electrical brain stimulation in humans.

Transcranial Direct Current Stimulation of the Prefrontal Cortex Modulates the Desire for Specific Foods

Appetite. Jul, 2008  |  Pubmed ID: 18243412

We aimed to assess whether modulation of the dorsolateral prefrontal cortex (DLFPC) with noninvasive brain stimulation, namely transcranial direct current stimulation (tDCS), modifies food craving in healthy subjects. We performed a randomized sham-controlled cross-over study in which 23 subjects received sham and active tDCS (anode left/cathode right and anode right/cathode left) of the DLPFC. Subjects were exposed to food and also watched a movie of food associated with strong craving. Desire for food consumption was evaluated by visual analogue scales (VAS) and food consumption before and after treatment. In addition we measured visual attention to food using an eye tracking system. Craving for viewed foods as indexed by VAS was reduced by anode right/cathode left tDCS. After sham stimulation, exposure to real food or food-related movie increased craving; whereas after anode left/cathode right tDCS, the food-related stimuli did not increase craving levels, as revealed by the VAS scale. Moreover, compared with sham stimulation, subjects fixated food-related pictures less frequently after anode right/cathode left tDCS and consumed less food after both active stimulation conditions. These changes were not related to mood changes after any type of tDCS treatment. The effects of tDCS on food craving might be related to a modulation of neural circuits associated with reward and decision-making.

Cortical Stimulation of the Prefrontal Cortex with Transcranial Direct Current Stimulation Reduces Cue-provoked Smoking Craving: a Randomized, Sham-controlled Study

The Journal of Clinical Psychiatry. Jan, 2008  |  Pubmed ID: 18312035

Because neuroimaging studies have shown that cue-provoked smoking craving is associated with changes in the activity of the bilateral dorsolateral prefrontal cortex (DLPFC), we aimed to investigate whether a powerful technique of noninvasive brain stimulation, transcranial direct current stimulation (tDCS), reduces cue-provoked smoking craving as indexed by a visual analog scale.

Modulating the Healthy and Affected Motor Cortex with Repetitive Transcranial Magnetic Stimulation in Stroke: Development of New Strategies for Neurorehabilitation

NeuroRehabilitation. 2008  |  Pubmed ID: 18356585

Noninvasive Brain Stimulation for Parkinson's Disease and Dystonia

Neurotherapeutics : the Journal of the American Society for Experimental NeuroTherapeutics. Apr, 2008  |  Pubmed ID: 18394576

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are promising noninvasive cortical stimulation methods for adjunctive treatment of movement disorders. They avoid surgical risks and provide theoretical advantages of specific neural circuit neuromodulation. Neuromodulatory effects depend on extrinsic stimulation factors (cortical target, frequency, intensity, duration, number of sessions), intrinsic patient factors (disease process, individual variability and symptoms, state of medication treatment), and outcome measures. Most studies to date have shown beneficial effects of rTMS or tDCS on clinical symptoms in Parkinson's disease (PD) and support the notion of spatial specificity to the effects on motor and nonmotor symptoms. Stimulation parameters have varied widely, however, and some studies are poorly controlled. Studies of rTMS or tDCS in dystonia have provided abundant data on physiology, but few on clinical effects. Multiple mechanisms likely contribute to the clinical effects of rTMS and tDCS in movement disorders, including normalization of cortical excitability, rebalancing of distributed neural network activity, and induction of dopamine release. It remains unclear how to individually adjust rTMS or tDCS factors for the most beneficial effects on symptoms of PD or dystonia. Nonetheless, the noninvasive nature, minimal side effects, positive effects in preliminary clinical studies, and increasing evidence for rational mechanisms make rTMS and tDCS attractive for ongoing investigation.

Can the 'yin and Yang' BDNF Hypothesis Be Used to Predict the Effects of RTMS Treatment in Neuropsychiatry?

Medical Hypotheses. Aug, 2008  |  Pubmed ID: 18434040

Repetitive transcranial magnetic stimulation (rTMS) is a novel technique of non-invasive brain stimulation which has been used to treat several neuropsychiatric disorders such as major depressive disorder, chronic pain and epilepsy. Recent studies have shown that the therapeutic effects of rTMS are associated with plastic changes in local and distant neural networks. In fact, it has been suggested that rTMS induces long-term potentiation (LTP) and long-term depression (LTD) - like effects. Besides the initial positive clinical results; the effects of rTMS are still mixed. Therefore new tools to assess the effects of plasticity non-invasively might be useful to predict its therapeutic effects and design novel therapeutic approaches using rTMS. In this paper we propose that brain-derived neurotrophic factor (BDNF) might be such a tool. Brain-derived neurotrophic factor is a neurotrophin that plays a key role in neuronal survival and synaptic strength, which has also been studied in several neuropsychiatric disorders. There is robust evidence associating BDNF with the LTP/LTD processes, and indeed it has been proposed that BNDF might index an increase or decrease of brain activity - the 'yin and yang' BDNF hypothesis. In this article, we review the initial studies combining measurements of BDNF in rTMS clinical trials and discuss the results and potential usefulness of this instrument in the field of rTMS.

Towards Novel Treatments for Paediatric Stroke: is Transcranial Magnetic Stimulation Beneficial?

Lancet Neurology. Jun, 2008  |  Pubmed ID: 18455962

Recovery After ECT: Comparison of Propofol, Etomidate and Thiopental

Revista Brasileira De Psiquiatria (São Paulo, Brazil : 1999). Jun, 2008  |  Pubmed ID: 18470404

To compare post anesthetic time for patient recovery after electroconvulsive therapy, as measured by the post anesthetic Recovery Score of Aldrete and Kroulik, using three different types of hypnotic drugs (propofol, etomidate and thiopental).

Motor Cortex Stimulation for Chronic Pain: Systematic Review and Meta-analysis of the Literature

Neurology. Jun, 2008  |  Pubmed ID: 18541887

To conduct a systematic review and meta-analysis to quantify the efficacy of invasive and noninvasive brain stimulation for the treatment of chronic pain.

Novelty Seeking Modulates Medial Prefrontal Activity During the Anticipation of Emotional Stimuli

Psychiatry Research. Oct, 2008  |  Pubmed ID: 18703319

In a functional magnetic resonance imaging experiment, expectancy cues signaling emotional stimuli were used to study the personality trait of novelty seeking. BOLD responses to emotional expectancy were positively correlated with novelty-seeking scores in the medial prefrontal cortex. This correlation was strongest for the sub-dimension of exploratory excitability.

A Systematic Review and Meta-analysis of Clinical Studies on Major Depression and BDNF Levels: Implications for the Role of Neuroplasticity in Depression

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Dec, 2008  |  Pubmed ID: 18752720

Several clinical studies on major depressive disorder (MDD) have shown that blood brain-derived neurotrophic factor (BDNF) - a factor used to index neuroplasticity - is associated with depression response; however, the results are mixed. The purpose of our study was to evaluate whether BDNF levels are correlated with improvement of depression. We performed a systematic review and meta-analysis of the literature, searching Medline, Cochrane Central, SciELO databases and reference lists from retrieved articles for clinical studies comparing mean BDNF blood levels in depressed patients pre- and post-antidepressant treatments or comparing depressed patients with healthy controls. Two reviewers independently searched for eligible studies and extracted outcome data using a structured form previously elaborated. Twenty articles, including 1504 subjects, met our inclusion criteria. The results showed that BDNF levels increased significantly after antidepressant treatment (effect size 0.62, 95% CI 0.36-0.88, random effects model). In addition, there was a significant correlation between changes in BDNF level and depression scores changes (p=0.02). Moreover, the results were robust according to the sensitivity analysis and Begg's funnel plot results did not suggest publication bias. Finally, there was a difference between pre-treatment patients and healthy controls (effect size 0.91, 95% CI 0.70-1.11) and a small but significant difference between treated patients and healthy controls (effect size 0.34, 95% CI 0.02-0.66). Our results show that BDNF levels are associated with clinical changes in depression; supporting the notion that depression improvement is associated with neuroplastic changes.

Impaired Interhemispheric Interactions in Patients with Major Depression

The Journal of Nervous and Mental Disease. Sep, 2008  |  Pubmed ID: 18791428

Previous studies have shown that patients with major depression have an interhemispheric imbalance between right and left prefrontal and motor cortex. We aimed to investigate the interhemispheric interactions in patients with major depression using repetitive transcranial magnetic stimulation (rTMS). Thirteen patients with major depression and 14 age-matched healthy subjects participated in this study. Corticospinal excitability before and after 1 Hz rTMS (applied to the left primary motor cortex) was assessed in the left and right motor cortex and these results were compared with those in healthy subjects. There was a significant difference in the interhemispheric effects between patients with depression and healthy subjects. In healthy subjects, 1 Hz rTMS significantly decreased corticospinal excitability in the stimulated, left hemisphere and increased it in the contralateral, right hemisphere. In depressed subjects, 1 Hz rTMS also decreased corticospinal excitability in the left hemisphere; however, it induced no significant changes in corticospinal excitability in the contralateral, right hemisphere. In addition, there was a significant correlation between the degree of interhemispheric modulation and the severity of the depression as indexed by the Beck Depression Inventory scores. Our findings showing a decreased interhemispheric modulation in patients with major depression are consistent with the notion that mood disorders are associated with slow interhemispheric switching mechanisms.

Impact of Nervous System Hyperalgesia on Pain, Disability, and Quality of Life in Patients with Knee Osteoarthritis: a Controlled Analysis

Arthritis and Rheumatism. Oct, 2008  |  Pubmed ID: 18821657

Refractory, disabling pain associated with knee osteoarthritis (OA) is usually treated with total knee replacement. However, pain in these patients might be associated with central nervous sensitization rather than peripheral inflammation and injury. We evaluated the presence of hyperalgesia in patients scheduled for a total knee replacement due to knee osteoarthritis with refractory pain, and we assessed the impact of pressure pain threshold measurements (PPT) on pain, disability, and quality of life of these patients.

CNS or Classic Drugs for the Treatment of Pain in Functional Dyspepsia? A Systematic Review and Meta-analysis of the Literature

Pain Physician. Sep-Oct, 2008  |  Pubmed ID: 18850025

Recent evidence has suggested that pain in functional dyspepsia (FD) is associated with nervous system dysfunction; indicating that therapies aimed at nervous system modulation might be associated with pain relief in FD.

Differential Modulatory Effects of Transcranial Direct Current Stimulation on a Facial Expression Go-no-go Task in Males and Females

Neuroscience Letters. Dec, 2008  |  Pubmed ID: 18926878

The ability to recognize facial expressions has been shown to be different between males and females. Here we aimed to explore further this matter and investigate whether the effects of tDCS applied over the superior temporal cortex differs between males and females during a facial expression go-no-go task. Fourteen healthy subjects were exposed to a facial expression go-no-go task while they received two different conditions of stimulation: anodal tDCS of the left temporal cortex (with cathodal stimulation of the right temporal cortex) and sham tDCS. The order of conditions was randomized and counterbalanced across subjects. During each stimulation session (after 5 min of stimulation), subjects underwent a go-no-go task. The results showed that women had significantly more correct answers when compared to men (p=0.03) that was independent of condition of stimulation and valence of figures. In addition, women made significantly less errors during temporal stimulation when compared to sham stimulation (p=0.009) when responding to sad faces. Similarly, men made significantly more errors during temporal active stimulation as compared with sham stimulation (p=0.004) when responding to sad faces. Our results confirmed the notion that performance to facial expression recognition is increased in females compared with males and that modulation of temporal cortex with tDCS leads to differential effects according to gender.

New Perspectives on Techniques for the Clinical Psychiatrist: Brain Stimulation, Chronobiology and Psychiatric Brain Imaging

Psychiatry and Clinical Neurosciences. Dec, 2008  |  Pubmed ID: 19067998

This review summarizes a scientific dialogue between representatives in non-pharmacological treatment options of affective disorders. Among the recently introduced somatic treatments for depression those with most evidenced efficacy will be discussed. The first part of this article presents current opinions about the clinical applications of transcranial magnetic stimulation in the treatment of depression. The second part explains the most relevant uses of chronobiology in mood disorders, while the last part deals with the main perspectives on brain imaging techniques in psychiatry. The aim was to bridge gaps between the research evidence and clinical decisions, and reach an agreement on several key points of chronobiological and brain stimulation techniques, as well as on relevant objectives for future research.

Exploring a Novel Therapeutic Approach with Noninvasive Cortical Stimulation for Vulvodynia

American Journal of Obstetrics and Gynecology. Dec, 2008  |  Pubmed ID: 19084092

Existing therapies for vulvodynia are inadequate. Because vulvodynia has a pathophysiology similar to chronic pain, central nervous system dysfunction may underlie this painful disorder, and noninvasive methods of neuromodulation may prove highly effective. We report a case of severe, medically refractory vulvodynia that responded remarkably to treatment with transcranial direct current stimulation.

Controversy: Does Repetitive Transcranial Magnetic Stimulation/ Transcranial Direct Current Stimulation Show Efficacy in Treating Tinnitus Patients?

Brain Stimulation. Jul, 2008  |  Pubmed ID: 20633385

Tinnitus affects 10% of the population, its pathophysiology remains incompletely understood, and treatment is elusive. Functional imaging has demonstrated a relationship between the intensity of tinnitus and the degree of reorganization in the auditory cortex. Experimental studies have further shown that tinnitus is associated with synchronized hyperactivity in the auditory cortex. Therefore, targeted modulation of auditory cortex has been proposed as a new therapeutic approach for chronic tinnitus.

Transcranial Direct Current Stimulation: State of the Art 2008

Brain Stimulation. Jul, 2008  |  Pubmed ID: 20633386

Effects of weak electrical currents on brain and neuronal function were first described decades ago. Recently, DC polarization of the brain was reintroduced as a noninvasive technique to alter cortical activity in humans. Beyond this, transcranial direct current stimulation (tDCS) of different cortical areas has been shown, in various studies, to result in modifications of perceptual, cognitive, and behavioral functions. Moreover, preliminary data suggest that it can induce beneficial effects in brain disorders. Brain stimulation with weak direct currents is a promising tool in human neuroscience and neurobehavioral research. To facilitate and standardize future tDCS studies, we offer this overview of the state of the art for tDCS.

Use of Repetitive Transcranial Magnetic Stimulation for the Management of Bipolar Disorder During the Postpartum Period

Brain Stimulation. Jul, 2008  |  Pubmed ID: 20633387

Efficacy of Repetitive Transcranial Magnetic Stimulation/transcranial Direct Current Stimulation in Cognitive Neurorehabilitation

Brain Stimulation. Oct, 2008  |  Pubmed ID: 20633391

Cognitive deficits are a common consequence of neurologic disease, in particular, of traumatic brain injury, stroke, and neurodegenerative disorders, and there is evidence that specific cognitive training may be effective in cognitive rehabilitation. Several investigations emphasize the fact that interacting with cortical activity, by means of cortical stimulation, can positively affect the short-term cognitive performance and improve the rehabilitation potential of neurologic patients. In this respect, preliminary evidence suggests that cortical stimulation may play a role in treating aphasia, unilateral neglect, and other cognitive disorders. Several possible mechanisms can account for the effects of transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) on cognitive performance. They all reflect the potential of these methods to improve the subject's ability to relearn or to acquire new strategies for carrying out behavioral tasks. The responsible mechanisms remain unclear but they are most likely related to the activation of impeded pathways or inhibition of maladaptive responses. Modifications of the brain activity may assist relearning by facilitating local activity or by suppressing interfering activity from other brain areas. Notwithstanding the promise of these preliminary findings, to date no systematic application of these methods to neurorehabilitation research has been reported. Considering the potential benefit of these interventions, further studies taking into consideration large patient populations, long treatment periods, or the combination of different rehabilitation strategies are needed. Brain stimulation is indeed an exciting opportunity in the field of cognitive neurorehabilitation, which is clearly in need of further research.

The Use of Repetitive Transcranial Magnetic Stimulation (rTMS) and Transcranial Direct Current Stimulation (tDCS) to Relieve Pain

Brain Stimulation. Oct, 2008  |  Pubmed ID: 20633392

Chronic pain resulting from injury of the peripheral or central nervous system may be associated with a significant dysfunction of extensive neural networks. Noninvasive stimulation techniques, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) may be suitable to treat chronic pain as they can act on these networks by modulating neural activities not only in the stimulated area, but also in remote regions that are interconnected to the site of stimulation. Motor cortex was the first cortical target that was proved to be efficacious in chronic pain treatment. At present, significant analgesic effects were also shown to occur after the stimulation of other cortical targets (including prefrontal and parietal areas) in acute provoked pain, chronic neuropathic pain, fibromyalgia, or visceral pain. Therapeutic applications of rTMS in pain syndromes are limited by the short duration of the induced effects, but prolonged pain relief can be obtained by repeating rTMS sessions every day for several weeks. Recent tDCS studies also showed some effects on various types of chronic pain. We review the evidence to date of these two techniques of noninvasive brain stimulation for the treatment of pain.

Controversy: Noninvasive and Invasive Cortical Stimulation Show Efficacy in Treating Stroke Patients

Brain Stimulation. Oct, 2008  |  Pubmed ID: 20633395

Stroke is the leading cause of disability in the adult population of western industrialized countries. Despite significant improvements of acute stroke care, two thirds of stroke survivors have to cope with persisting neurologic deficits. Adjuvant brain stimulation is a novel approach to improving the treatment of residual deficits after stroke. Transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and epidural electrical stimulation have been used in first trials on small cohorts of stroke patients. Effect sizes in the order of 8% to 30% of functional improvement have been reported, but a publication bias toward presenting "promising" but not negative results is likely. Many questions regarding underlying mechanisms, optimal stimulation parameters, combination with other types of interventions, among others, are open. This review addresses six controversies related to the experimental application of brain stimulation techniques to stroke patients. Cortical stimulation after stroke will need to be individually tailored and a thorough patient stratification according to type and extent of clinical deficit, lesion location, lesion size, comorbidities, time in the recovery process, and perhaps also age and gender will be necessary. There is consensus that cortical stimulation in stroke patients is still experimental and should only be applied in the frame of scientific studies.

Modulation of Emotions Associated with Images of Human Pain Using Anodal Transcranial Direct Current Stimulation (tDCS)

Neuropsychologia. Jan, 2009  |  Pubmed ID: 18725237

Viewing images of other humans in pain elicits a variety of responses including distress, anxiety, and a sensation that is similar to pain. We aimed to evaluate whether transcranial direct current stimulation (tDCS) could be effective in modulating the emotional aspects of pain as to further explore mechanisms of tDCS in pain relief. Twenty-three healthy subjects rated images with respect to unpleasantness and discomfort/pain (baseline), and then received stimulation with tDCS under four different conditions of stimulation: anodal tDCS of the left primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), occipital cortex (V1); and sham tDCS. The order of conditions was randomized and counterbalanced across subjects. During each stimulation session (after 3 min of stimulation), subjects were shown a new set of aversive images and were again asked to rate the images with respect to unpleasantness and discomfort/pain. The results showed that ratings of unpleasantness and discomfort/pain were significantly decreased during DLPFC tDCS only, as compared to baseline and sham tDCS. The other conditions of stimulation (M1 and V1 tDCS) did not result in any significant changes. These results support the notion that DLPFC is a critical area for the emotional processing of pain and also suggests that DLPFC may be a potential target of stimulation for alleviation of pain with a significant emotional-affective component. Our results also suggest that the mechanism of tDCS in modulating emotional pain involve pathways that are independent of those modulating the somatosensory perception of pain.

Meta-analysis of the Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) on Negative and Positive Symptoms in Schizophrenia

Schizophrenia Research. Mar, 2009  |  Pubmed ID: 19138833

A growing body of evidence suggests that repetitive transcranial magnetic stimulation (rTMS) can alleviate negative and positive symptoms of refractory schizophrenia. However, trials to date have been small and results are mixed.

Risk Factors for Relapse After Remission with Repetitive Transcranial Magnetic Stimulation for the Treatment of Depression

Depression and Anxiety. 2009  |  Pubmed ID: 19170101

Several studies have shown that repetitive transcranial magnetic stimulation (rTMS) treatment is associated with a significant antidepressant effect that can last for several months.

Cortical Stimulation with Weak Electrical Currents for Cognitive Modulation in Attention Deficit Hyperactivity Disorder

Medical Hypotheses. May, 2009  |  Pubmed ID: 19171437

Feasibility of a Home Constraint-induced Movement Therapy for Hand Weakness After Stroke

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. Jan, 2009  |  Pubmed ID: 19197578

How to Develop Research Capacity Using a Collaborative Training Approach: the International Society of Physical and Rehabilitation Medicine (ISPRM) International Training Program Experience

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. Mar, 2009  |  Pubmed ID: 19247555

Using Non-invasive Brain Stimulation to Augment Motor Training-induced Plasticity

Journal of Neuroengineering and Rehabilitation. 2009  |  Pubmed ID: 19292910

Therapies for motor recovery after stroke or traumatic brain injury are still not satisfactory. To date the best approach seems to be the intensive physical therapy. However the results are limited and functional gains are often minimal. The goal of motor training is to minimize functional disability and optimize functional motor recovery. This is thought to be achieved by modulation of plastic changes in the brain. Therefore, adjunct interventions that can augment the response of the motor system to the behavioural training might be useful to enhance the therapy-induced recovery in neurological populations. In this context, noninvasive brain stimulation appears to be an interesting option as an add-on intervention to standard physical therapies. Two non-invasive methods of inducing electrical currents into the brain have proved to be promising for inducing long-lasting plastic changes in motor systems: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). These techniques represent powerful methods for priming cortical excitability for a subsequent motor task, demand, or stimulation. Thus, their mutual use can optimize the plastic changes induced by motor practice, leading to more remarkable and outlasting clinical gains in rehabilitation. In this review we discuss how these techniques can enhance the effects of a behavioural intervention and the clinical evidence to date.

Placebo Response of Non-pharmacological and Pharmacological Trials in Major Depression: a Systematic Review and Meta-analysis

PloS One. 2009  |  Pubmed ID: 19293925

Although meta-analyses have shown that placebo responses are large in Major Depressive Disorder (MDD) trials; the placebo response of devices such as repetitive transcranial magnetic stimulation (rTMS) has not been systematically assessed. We proposed to assess placebo responses in two categories of MDD trials: pharmacological (antidepressant drugs) and non-pharmacological (device- rTMS) trials.

Temporal Lobe Cortical Electrical Stimulation During the Encoding and Retrieval Phase Reduces False Memories

PloS One. 2009  |  Pubmed ID: 19319182

A recent study found that false memories were reduced by 36% when low frequency repetitive transcranial magnetic stimulation (rTMS) was applied to the left anterior temporal lobe after the encoding (study) phase. Here we were interested in the consequences on a false memory task of brain stimulation throughout the encoding and retrieval task phases. We used transcranial direct current stimulation (tDCS) because it has been shown to be a useful tool to enhance cognition. Specifically, we examined whether tDCS can induce changes in a task assessing false memories. Based on our preliminary results, three conditions of stimulation were chosen: anodal left/cathodal right anterior temporal lobe (ATL) stimulation ("bilateral stimulation"); anodal left ATL stimulation (with a large contralateral cathodal electrode--referred as "unilateral stimulation") and sham stimulation. Our results showed that false memories were reduced significantly after the two active conditions (unilateral and bilateral stimulation) as compared with sham stimulation. There were no significant changes in veridical memories. Our findings show that false memories are reduced by 73% when anodal tDCS is applied to the anterior temporal lobes throughout the encoding and retrieval stages, suggesting a possible strategy for improving certain aspects of learning.

Transcranial Direct Current Stimulation As a Therapeutic Tool for the Treatment of Major Depression: Insights from Past and Recent Clinical Studies

Current Opinion in Psychiatry. May, 2009  |  Pubmed ID: 19339889

Transcranial direct current stimulation (tDCS) is a noninvasive method of brain stimulation that has been increasingly tested for the treatment of neuropsychiatric disorders. It has useful characteristics, such as low cost, ease of use, reliable sham methodology, and relatively powerful effects on cortical excitability. Because of its potential to modulate cortical excitability noninvasively, tDCS has been tested for the treatment of depression for several decades. Therefore, we reviewed evidence on the use of tDCS for major depression examining evidence from past and recent tDCS studies. We also briefly compared tDCS with other techniques of neuromodulation, namely deep brain stimulation, vagal nerve stimulation, and transcranial magnetic stimulation; and suggest future directions for the use of tDCS in major depression.

Treatment of Depression with Transcranial Direct Current Stimulation (tDCS): a Review

Experimental Neurology. Sep, 2009  |  Pubmed ID: 19348793

Major Depression Disorder (MDD) is usually accompanied by alterations of cortical activity and excitability, especially in prefrontal areas. These are reflections of a dysfunction in a distributed cortico-subcortical, bihemispheric network. Therefore it is reasonable to hypothesize that altering this pathological state with techniques of brain stimulation may offer a therapeutic target. Besides repetitive transcranial magnetic stimulation, tonic stimulation with weak direct currents (tDCS) modulates cortical excitability for hours after the end of stimulation, thus, it is a promising non-invasive therapeutic option. Early studies from the 1960s suggested some efficacy of DC stimulation to reduce symptoms in depression, but mixed results and development of psychotropic drugs resulted in an early abandonment of this technique. In the last years tDCS protocols have been optimized. Application of the newly developed stimulation protocols in patients with major depression has shown promise in few pilot studies. Further studies are needed to identify the optimal parameters of stimulation and the clinical and patient characteristics that may condition response to tDCS.

Updates on the Use of Non-invasive Brain Stimulation in Physical and Rehabilitation Medicine

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. Apr, 2009  |  Pubmed ID: 19363560

Brain stimulation for the treatment of neuropsychiatric diseases has been used for more than 50 years. Although its development has been slow, current advances in the techniques of brain stimulation have improved its clinical efficacy. The use of non-invasive brain stimulation has significant advantages, such as not involving surgical procedures and having relatively mild adverse effects. In this paper we briefly review the use of 2 non-invasive brain stimulation techniques, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), as therapeutic approaches in physical and rehabilitation medicine. We also compare the effects of non-invasive central nervous system stimulation with techniques of non-invasive peripheral electrical stimulation, in order to provide new insights for future developments. Although the outcomes of these initial trials include some conflicting results, the evidence supports that rTMS and tDCS might have a therapeutic value in different neurological conditions. Studies published within the last year have examined new approaches of stimulation, such as longer intensities of stimulation, new electrode sizes for tDCS, novel coils for stimulation of deeper areas, and new frequencies of stimulation for rTMS. These new approaches need to be tested in larger clinical trials in order to determine whether they offer significant clinical effects.

Depression in Parkinson's Disease: Convergence from Voxel-based Morphometry and Functional Magnetic Resonance Imaging in the Limbic Thalamus

NeuroImage. Aug, 2009  |  Pubmed ID: 19398020

Depression is the most frequent psychiatric disorder in Parkinson's disease (PD). Although evidence suggests that depression in PD is related to the degenerative process that underlies the disease, further studies are necessary to better understand the neural basis of depression in this population of patients. In order to investigate neuronal alterations underlying the depression in PD, we studied thirty-six patients with idiopathic PD. Twenty of these patients had the diagnosis of major depression disorder and sixteen did not. The two groups were matched for PD motor severity according to Unified Parkinson Disease Rating Scale (UPDRS). First we conducted a functional magnetic resonance imaging (fMRI) using an event-related parametric emotional perception paradigm with test retest design. Our results showed decreased activation in the left mediodorsal (MD) thalamus and in medial prefrontal cortex in PD patients with depression compared to those without depression. Based upon these results and the increased neuron count in MD thalamus found in previous studies, we conducted a region of interest (ROI) guided voxel-based morphometry (VBM) study comparing the thalamic volume. Our results showed an increased volume in mediodorsal thalamic nuclei bilaterally. Converging morphological changes and functional emotional processing in mediodorsal thalamus highlight the importance of limbic thalamus in PD depression. In addition this data supports the link between neurodegenerative alterations and mood regulation.

Transcranial Direct Current Stimulation: a Novel Approach to Control Hyperphagia in Prader-Willi Syndrome

Journal of Child Neurology. May, 2009  |  Pubmed ID: 19406762

Cumulative Priming Effects of Cortical Stimulation on Smoking Cue-induced Craving

Neuroscience Letters. Sep, 2009  |  Pubmed ID: 19619607

Smoking cue-provoked craving is an intricate behavior associated with strong changes in neural networks. Craving is one of the main reasons subjects continue to smoke; therefore interventions that can modify activity in neural networks associated with craving can be useful tools in future research investigating novel treatments for smoking cessation. The goal of this study was to use a neuromodulatory technique associated with a powerful effect on spontaneous neuronal firing - transcranial direct current stimulation (tDCS) - to modify cue-provoked smoking craving. Based on preliminary data showing that craving can be modified after a single tDCS session, here we investigated the effects of repeated tDCS sessions on craving behavior. Twenty-seven subjects were randomized to receive sham or active tDCS (anodal tDCS of the left DLPFC). Our results show a significant cumulative effect of tDCS on modifying smoking cue-provoked craving. In fact, in the group of active stimulation, smoking cues had an opposite effect on craving after stimulation - it decreased craving - as compared to sham stimulation in which there was a small decrease or increase on craving. In addition, during these 5 days of stimulation there was a small but significant decrease in the number of cigarettes smoked in the active as compared to sham tDCS group. Our findings extend the results of our previous study as they confirm the notion that tDCS has a specific effect on craving behavior and that the effects of several sessions can increase the magnitude of its effect. These results open avenues for the exploration of this method as a therapeutic alternative for smoking cessation and also as a mean to change stimulus-induced behavior.

Overt Naming FMRI Pre- and Post-TMS: Two Nonfluent Aphasia Patients, with and Without Improved Naming Post-TMS

Brain and Language. Oct, 2009  |  Pubmed ID: 19695692

Two chronic, nonfluent aphasia patients participated in overt naming fMRI scans, pre- and post-a series of repetitive transcranial magnetic stimulation (rTMS) treatments as part of a TMS study to improve naming. Each patient received 10, 1-Hz rTMS treatments to suppress a part of R pars triangularis. P1 was a 'good responder' with improved naming and phrase length; P2 was a 'poor responder' without improved naming. Pre-TMS (10 years poststroke), P1 had significant activation in R and L sensorimotor cortex, R IFG, and in both L and R SMA during overt naming fMRI (28% pictures named). At 3 mo. post-TMS (42% named), P1 showed continued activation in R and L sensorimotor cortex, R IFG, and in R and L SMA. At 16 mo. post-TMS (58% named), he also showed significant activation in R and L sensorimotor cortex mouth and R IFG. He now showed a significant increase in activation in the L SMA compared to pre-TMS and at 3 mo. post-TMS (p < .02; p < .05, respectively). At 16 mo. there was also greater activation in L than R SMA (p < .08). At 46 mo. post-TMS (42% named), this new LH pattern of activation continued. He improved on the Boston Naming Test from 11 pictures named pre-TMS, to scores ranging from 14 to 18 pictures, post-TMS (2-43 mo. post-TMS). His longest phrase length (Cookie Theft picture) improved from three words pre-TMS, to 5-6 words post-TMS. Pre-TMS (1.5 years poststroke), P2 had significant activation in R IFG (3% pictures named). At 3 and 6 mo. post-TMS, there was no longer significant activation in R IFG, but significant activation was present in R sensorimotor cortex. On all three fMRI scans, P2 had significant activation in both the L and R SMA. There was no new, lasting perilesional LH activation across sessions for this patient. Over time, there was little or no change in his activation. His naming remained only at 1-2 pictures during all three fMRI scans. His BNT score and longest phrase length remained at one word, post-TMS. Lesion site may play a role in each patient's fMRI activation pattern and response to TMS treatment. P2, the poor responder, had an atypical frontal lesion in the L motor and premotor cortex that extended high, near brain vertex, with deep white matter lesion near L SMA. P2 also had frontal lesion in the posterior middle frontal gyrus, an area important for naming (Duffau et al., 2003); P1 did not. Additionally, P2 had lesion inferior and posterior to Wernicke's area, in parts of BA 21 and 37, whereas P1 did not. The fMRI data of our patient who had good response following TMS support the notion that restoration of the LH language network is linked in part, to better recovery of naming and phrase length in nonfluent aphasia.

One-year RTMS Treatment for Refractory Trigeminal Neuralgia

Journal of Pain and Symptom Management. Oct, 2009  |  Pubmed ID: 19713068

Transcranial DC Stimulation Coupled with TENS for the Treatment of Chronic Pain: a Preliminary Study

The Clinical Journal of Pain. Oct, 2009  |  Pubmed ID: 19920718

Based on evidence showing that electrical stimulation of the nervous system is an effective method to decrease chronic neurogenic pain, we aimed to investigate whether the combination of 2 methods of electrical stimulation-a method of peripheral stimulation [transcutaneous electrical nerve stimulation (TENS)] and a method of noninvasive brain stimulation [transcranial direct current stimulation (tDCS)]-induces greater pain reduction as compared with tDCS alone and sham stimulation.

Pharmacological and Combined Interventions for the Acute Depressive Episode: Focus on Efficacy and Tolerability

Therapeutics and Clinical Risk Management. 2009  |  Pubmed ID: 19956554

Use of antidepressants is the gold standard therapy for major depression. However, despite the large number of commercially available antidepressant drugs there are several differences among them in efficacy, tolerability, and cost-effectiveness. In addition the optimal augmentation strategy is still not clear when dealing with treatment-resistant depression, a condition that affects 15% to 40% of depressed patients.

Brain Stimulation for the Treatment of Pain: A Review of Costs, Clinical Effects, and Mechanisms of Treatment for Three Different Central Neuromodulatory Approaches

Journal of Pain Management. Aug, 2009  |  Pubmed ID: 20585474

Methods of cortical stimulation including epidural motor cortex stimulation (MCS), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) are emerging as alternatives in the management of pain in patients with chronic medically-refractory pain disorders. Here we consider the three methods of brain stimulation that have been investigated for the treatment of central pain: MCS, rTMS, and tDCS. While all three treatment modalities appear to induce significant clinical gains in patients with chronic pain, tDCS is revealed as the most cost-effective approach (compared to rTMS and MCS) when considering a single year of treatment. However, if a 5-year treatment is considered, MCS is revealed as the most cost-effective modality (as compared to rTMS and tDCS) for the neuromodulatory treatment of chronic pain. We discuss the theory behind the application of each modality as well as efficacy, cost, safety, and practical considerations.

A Preliminary Study of Transcranial Direct Current Stimulation for the Treatment of Refractory Chronic Pelvic Pain

Brain Stimulation. Apr, 2009  |  Pubmed ID: 20633407

The modulatory effects of transcranial direct current stimulation (tDCS) appear beneficial for different chronic pain syndromes; however, it is unclear whether this method can be used to treat refractory chronic pelvic pain.

Challenges in Consenting Subjects for Studies with Brain Stimulation: Feasibility of Multimedia Video Use During the Informed Consent Process

Brain Stimulation. Jul, 2009  |  Pubmed ID: 20633416

Neuromodulation in Hypoxic-ischemic Injury

Brain Stimulation. Jul, 2009  |  Pubmed ID: 20633417

Fibromyalgia: From Treatment to Rehabilitation

European Journal of Pain (London, England). Nov, 2009  |  Pubmed ID: 20657807

Fibromyalgia is a clinical syndrome of chronic widespread pain and reduced pain thresholds to palpation. The pathophysiology remains unknown, but there is increasing evidence that peripheral and central sensitization cause an amplification of sensory impulses that may alter pain perception in fibromyalgia patients. Interventions to treat fibromyalgia should aim at different targets simultaneously in order to reduce peripheral and central sensitization. There are both pharmacologic and non-pharmacologic approaches with evidence for effectiveness in the treatment of fibromyalgia and its associated symptoms. Evidence from randomized trials and meta-analyses shows that partial and short-term improvements in fibromyalgia symptoms can be achieved with low doses of antidepressants and with physical activity such as aerobic and strengthening exercises. A multidimensional approach which emphasizes education and integration of exercise and cognitive behavior therapy improves quality of life and reduces pain, fatigue and depressive symptoms when measured on a short term basis. More recently, trials have shown the neuromodulators gabapentin and pregabalin to be effective in reducing pain and improving quality of sleep in fibromyalgia. In addition, small trials of noninvasive brain stimulation have also shown benefits in reducing pain in fibromyalgia. It is essential to keep in mind that some important clinical conditions can mimic and overlap with fibromyalgia and should always be ruled out by a complete history, physical examination and appropriate laboratory testing.

Efficacy of Anodal Transcranial Direct Current Stimulation (tDCS) for the Treatment of Fibromyalgia: Results of a Randomized, Sham-controlled Longitudinal Clinical Trial

Journal of Pain Management. 2009  |  Pubmed ID: 21170277

Fibromyalgia has been recognized as a central pain disorder with evidence of neuroanatomic and neurophysiologic alterations. Previous studies with techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS)--have shown that these methods are associated with a significant alleviation of fibromyalgia-associated pain and sleep dysfunction. Here we sought to determine whether a longer treatment protocol involving 10 sessions of 2 mA, 20 min tDCS of the left primary motor (M1) or dorsolateral prefrontal cortex (DLPFC) could offer additional, more long-lasting clinical benefits in the management of pain from fibromyalgia. METHODS: Forty-one women with chronic, medically refractory fibromyalgia were randomized to receive 10 daily sessions of M1, DLPFC, or sham tDCS. RESULTS: Our results show that M1 and DLPFC stimulation both display improvements in pain scores (VAS) and quality of life (FIQ) at the end of the treatment protocol, but only M1 stimulation resulted in long-lasting clinical benefits as assessed at 30 and 60 days after the end of treatment. CONCLUSIONS: This study demonstrates the importance of the duration of the treatment period, suggesting that 10 daily sessions of tDCS result in more long lasting outcomes than only five sessions. Furthermore, this study supports the findings of a similarly designed rTMS trial as both induce pain reductions that are equally long-lasting.

Why Do Some Promising Brain-stimulation Devices Fail the Next Steps of Clinical Development?

Expert Review of Medical Devices. Jan, 2010  |  Pubmed ID: 20021241

Interest in techniques of noninvasive brain stimulation (NIBS) has been growing exponentially in the last decade. Recent studies have shown that some of these techniques induce significant neurophysiological and clinical effects. Although recent results are promising, there are several techniques that have been abandoned despite positive initial results. In this study, we performed a systematic review to identify NIBS methods with promising preliminary clinical results that were not fully developed and adopted into clinical practice, and discuss its clinical, research and device characteristics. We identified five devices (transmeatal cochlear laser stimulation, transcranial micropolarization, transcranial electrostimulation, cranial electric stimulation and stimulation with weak electromagnetic fields) and compared them with two established NIBS devices (transcranial magnetic stimulation and transcranial direct current stimulation) and with well-known drugs used in neuropsychiatry (pramipexole and escitalopram) in order to understand the reasons why they failed to reach clinical practice and further steps of research development. Finally, we also discuss novel NIBS devices that have recently showed promising results: brain ultrasound and transcranial high-frequency random noise stimulation. Our results show that some of the reasons for the failure of NIBS devices with promising clinical findings are the difficulty to disseminate results, lack of controlled studies, duration of research development, mixed results and lack of standardization.

Noninvasive Brain Stimulation with Low-intensity Electrical Currents: Putative Mechanisms of Action for Direct and Alternating Current Stimulation

The Neuroscientist : a Review Journal Bringing Neurobiology, Neurology and Psychiatry. Jun, 2010  |  Pubmed ID: 20040569

Transcranial stimulation with weak direct current (DC) has been valuable in exploring the effect of cortical modulation on various neural networks. Less attention has been given, however, to cranial stimulation with low-intensity alternating current (AC). Reviewing and discussing these methods simultaneously with special attention to what is known about their mechanisms of action may provide new insights for the field of noninvasive brain stimulation. Direct current appears to modulate spontaneous neuronal activity in a polarity-dependent fashion with site-specific effects that are perpetuated throughout the brain via networks of interneuronal circuits, inducing significant effects on high-order cortical processes implicated in decision making, language, memory, sensory perception, and pain. AC stimulation has also been associated with a significant behavioral and clinical impact, but the mechanism of AC stimulation has been underinvestigated in comparison with DC stimulation. Even so, preliminary studies show that although AC stimulation has only modest effects on cortical excitability, it has been shown to induce synchronous changes in brain activity as measured by EEG activity. Thus, cranial AC stimulation may render its effects not by polarizing brain tissue, but rather via rhythmic stimulation that synchronizes and enhances the efficacy of endogenous neurophysiologic activity. Alternatively, secondary nonspecific central and peripheral effects may explain the clinical outcomes of DC or AC stimulation. Here the authors review what is known about DC and AC stimulation, and they discuss features that remain to be investigated.

Noninvasive Brain Stimulation with High-frequency and Low-intensity Repetitive Transcranial Magnetic Stimulation Treatment for Posttraumatic Stress Disorder

The Journal of Clinical Psychiatry. Aug, 2010  |  Pubmed ID: 20051219

We aimed to investigate the efficacy of 20 Hz repetitive transcranial magnetic stimulation (rTMS) of either right or left dorsolateral prefrontal cortex (DLPFC) as compared to sham rTMS for the relief of posttraumatic stress disorder (PTSD)-associated symptoms.

Challenges and Recommendations for Placebo Controls in Randomized Trials in Physical and Rehabilitation Medicine: a Report of the International Placebo Symposium Working Group

American Journal of Physical Medicine & Rehabilitation / Association of Academic Physiatrists. Feb, 2010  |  Pubmed ID: 20090428

Compared with other specialties, the field of physical and rehabilitation medicine has not received the deserved recognition from clinicians and researchers in the scientific community. One of the reasons is the lack of sound evidence to support the traditional physical and rehabilitation medicine treatments. The best way to change this disadvantage is through a well conducted clinical research, such as standard placebo- or sham-controlled randomized clinical trials. Therefore, having placebo groups in clinical trials is essential to improve the level of evidence-based practice in physical and rehabilitation medicine that ultimately translates to better clinical care. To address the challenges for the use of placebo in physical and rehabilitation medicine and randomized clinical trials and to create useful recommendations, we convened a working group during the inaugural International Symposium in Placebo (February 2009, in Sao Paulo, Brazil) in which the following topics were discussed: (1) current status of randomized clinical trials in physical and rehabilitation medicine, (2) challenges for the use of placebo in physical and rehabilitation medicine, (3) bioethics, (4) use of placebo in acupuncture trials and for the treatment of low-back pain, (5) mechanisms of placebo, and (6) insights from other specialties. The current article represents the consensus report from the working group.

Accelerating Response to Antidepressant Treatment in Depression: a Review and Clinical Suggestions

Progress in Neuro-psychopharmacology & Biological Psychiatry. Mar, 2010  |  Pubmed ID: 20093162

Modulation of Decision-making in a Gambling Task in Older Adults with Transcranial Direct Current Stimulation

The European Journal of Neuroscience. Feb, 2010  |  Pubmed ID: 20105234

Cognitive performance usually declines in older adults as a result of neurodegenerative processes. One of the cognitive domains usually affected is decision-making. Based on our recent findings suggesting that non-invasive brain stimulation can improve decision-making in young participants, we studied whether bifrontal transcranial direct current stimulation (tDCS) applied over the right and left prefrontal cortex of older adult subjects can change balance of risky and safe responses as it can in younger individuals. Twenty-eight subjects (age range from 50 to 85 years) performed a gambling risk task while receiving either anodal tDCS over the right and cathodal tDCS over the left dorsolateral prefrontal cortex (DLPFC), anodal tDCS over the left with cathodal tDCS over the right DLPFC, or sham stimulation. Our main finding was a significant group effect showing that participants receiving left anodal/right cathodal stimulation chose more often high-risk prospects as compared with participants receiving sham or those receiving right anodal/left cathodal stimulation. This result is contrary to previous findings in young subjects, suggesting that modulation of cortical activity in young and elderly results in opposite behavioral effects; thus supporting fundamental changes in cognitive processing in the elderly.

Interhemispheric Modulation Induced by Cortical Stimulation and Motor Training

Physical Therapy. Mar, 2010  |  Pubmed ID: 20110339

Interhemispheric inhibition might be a beneficial cortico-cortical interaction, but also might be maladaptive in people with neurological disorders. One recently revisited technique that has been shown to be effective in improving motor function in people with stroke using interhemispheric modulation is transcranial direct current stimulation (tDCS).

Changes in Clinical Trials Methodology over Time: a Systematic Review of Six Decades of Research in Psychopharmacology

PloS One. 2010  |  Pubmed ID: 20209133

There have been many changes in clinical trials methodology since the introduction of lithium and the beginning of the modern era of psychopharmacology in 1949. The nature and importance of these changes have not been fully addressed to date. As methodological flaws in trials can lead to false-negative or false-positive results, the objective of our study was to evaluate the impact of methodological changes in psychopharmacology clinical research over the past 60 years.

An Innovative Method of Global Clinical Research Training Using Collaborative Learning with Web 2.0 Tools

Medical Teacher. 2010  |  Pubmed ID: 20218845

Transcranial Direct Current Stimulation in Patients with Skull Defects and Skull Plates: High-resolution Computational FEM Study of Factors Altering Cortical Current Flow

NeuroImage. Oct, 2010  |  Pubmed ID: 20435146

Preliminary positive results of transcranial direct current stimulation (tDCS) in enhancing the effects of cognitive and motor training indicate that this technique might also be beneficial in traumatic brain injury or patients who had decompressive craniectomy for trauma and cerebrovascular disease. One perceived hurdle is the presence of skull defects or skull plates in these patients that would hypothetically alter the intensity and location of current flow through the brain. We aimed to model tDCS using a magnetic resonance imaging (MRI)-derived finite element head model with several conceptualized skull injuries. Cortical electric field (current density) peak intensities and distributions were compared with the healthy (skull intact) case. The factors of electrode position (C3-supraorbital or O1-supraorbital), electrode size skull defect size, skull defect state (acute and chronic) or skull plate (titanium and acrylic) were analyzed. If and how electric current through the brain was modulated by defects was found to depend on a specific combination of factors. For example, the condition that led to largest increase in peak cortical electric field was when one electrode was placed directly over a moderate sized skull defect. In contrast, small defects midway between electrodes did not significantly change cortical currents. As the conductivity of large skull defects/plates was increased (chronic to acute to titanium), current was shunted away from directly underlying cortex and concentrated in cortex underlying the defect perimeter. The predictions of this study are the first step to assess safety of transcranial electrical therapy in subjects with skull injuries and skull plates.

Inhibition of Motor Cortex Excitability with 15Hz Transcranial Alternating Current Stimulation (tACS)

Neuroscience Letters. Aug, 2010  |  Pubmed ID: 20553804

There remains a lack of solid evidence showing whether transcranial stimulation with weak alternating current (transcranial alternating current stimulation, tACS) can in fact induce significant neurophysiological effects. Previously, a study in which tACS was applied for 2 and 5min with current density=0.16-0.25A/m(2) was unable to show robust effects on cortical excitability. Here we applied tACS at a significantly higher current density (0.80A/m(2)) for a considerably longer duration (20min) and were indeed able to demonstrate measurable changes to cortical excitability. Our results show that active 15Hz tACS of the motor cortex (electrodes placed at C3 and C4) significantly diminished the amplitude of motor evoked potentials and decreased intracortical facilitation (ICF) as compared to baseline and sham stimulation. In addition, we show that our method of sham tACS is a reliable control condition. These results support the notion that AC stimulation with weak currents can induce significant changes in brain excitability; in this case, 15Hz tACS led to a pattern of inhibition of cortical excitability. We propose that tACS may have a dampening effect on cortical networks and perhaps interfere with the temporal and spatial summation of weak subthreshold electric potentials.

Neuromodulation of Decision-making in the Addictive Brain

Substance Use & Misuse. Sep, 2010  |  Pubmed ID: 20590399

Noninvasive brain stimulation of the dorsolateral prefrontal cortex with repetitive transcranial magnetic stimulation and transcranial direct current stimulation can modify decision-making behaviors in healthy subjects. The same type of noninvasive brain stimulation can suppress drug craving in substance user patients, who often display impaired decision-making behaviors. We discuss the implications of these studies for the cognitive neurosciences and their translational applications to the treatment of addictions. We propose a neurocognitive model that can account for our findings and suggests a promising therapeutic role of brain stimulation in the treatment of substance abuse and addictive behavior disorders.

Brain Polarization of Parietal Cortex Augments Training-induced Improvement of Visual Exploratory and Attentional Skills

Brain Research. Aug, 2010  |  Pubmed ID: 20599813

Recent evidence suggests that behavioural gains induced by behavioural training are maximized when combined with techniques of cortical neuromodulation, such as transcranial Direct Current Stimulation (tDCS). Here we address the validity of this appealing approach by investigating the effect of coupling a multisensory visual field exploration training with tDCS of the posterior parietal cortex (PPC). The multisensory visual field exploration training consisted in the practice of visual search through the systematic audio-visual stimulation of the visual field. Neurologically unimpaired participants performed a bimodal exploration training for 30 min, while simultaneously receiving anodal-excitatory PPC tDCS or sham tDCS. In two different experiments, the left and the right hemisphere were stimulated. Outcome measures included visual exploration speed at different time intervals during the training, and the post-training effects on tests assessing visual scanning and visuo-spatial orienting. Results show that PPC tDCS applied to the right, but not to the left, hemisphere increases the training-induced behavioural improvement of visual exploration, as compared to sham tDCS. In addition, right PPC tDCS brings about an improvement of covert visual orienting, in a task different from the visual search practice. In an additional experiment, we confirm that right parietal tDCS by itself, even without the associated training, can lead to enhancement of visual search. Overall, anodal PPC tDCS is a promising technique to enhance visuo-spatial abilities, when combined to a visual field exploration training task.

Neuromodulation Approaches for the Treatment of Major Depression: Challenges and Recommendations from a Working Group Meeting

Arquivos De Neuro-psiquiatria. Jun, 2010  |  Pubmed ID: 20602051

The use of neuromodulation as a treatment for major depressive disorder (MDD) has recently attracted renewed interest due to development of other non-pharmacological therapies besides electroconvulsive therapy (ECT) such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), and vagus nerve stimulation (VNS).

Abnormal Visual Activation in Parkinson's Disease Patients

Movement Disorders : Official Journal of the Movement Disorder Society. Aug, 2010  |  Pubmed ID: 20623771

Among nonmotor symptoms observed in Parkinson's disease (PD) dysfunction in the visual system, including hallucinations, has a significant impact in their quality of life. To further explore the visual system in PD patients we designed two fMRI experiments comparing 18 healthy volunteers with 16 PD patients without visual complaints in two visual fMRI paradigms: the flickering checkerboard task and a facial perception paradigm. PD patients displayed a decreased activity in the primary visual cortex (Broadmann area 17) bilaterally as compared to healthy volunteers during flickering checkerboard task and increased activity in fusiform gyrus (Broadmann area 37) during facial perception paradigm. Our findings confirm the notion that PD patients show significant changes in the visual cortex system even before the visual symptoms are clinically evident. Further studies are necessary to evaluate the contribution of these abnormalities to the development visual symptoms in PD.

The Efficacy of Web-based Cognitive Behavioral Interventions for Chronic Pain: a Systematic Review and Meta-analysis

The Journal of Pain : Official Journal of the American Pain Society. Oct, 2010  |  Pubmed ID: 20650691

Our objective was to conduct a systematic review and meta-analysis to quantify the efficacy of web-based cognitive behavioral interventions for the treatment of patients with chronic pain. MEDLINE and other databases were searched as data sources. Reference lists were examined for other relevant articles. We included 11 studies that evaluated the effects of web-based interventions on chronic pain using specific scales of pain. The pooled effect size (standardized mean difference between intervention versus waiting-list group means) from a random effects model was .285 (95% confidence interval: .145-.424), favoring the web-based intervention compared with the waiting-list group, although the effect was small. In addition, these results were not driven by any particular study, as shown by sensitivity analysis. Results from funnel plot argue against publication bias. Finally, the average dropout rate was 26.6%. In our meta-analysis, we demonstrate a small effect of web-based interventions, when using pain scale as the main outcome. Despite the minor effects and high dropout rates, the decreased costs and minor risk of adverse effects compared with pharmacological treatments support additional studies in chronic pain patients using web-based interventions. Further studies will be important to confirm the effects and determine the best responders to this intervention. PERSPECTIVE: Our findings suggest that web-based interventions for chronic pain result in small pain reductions in the intervention group compared with waiting-list control groups. These results advance the field of web-based cognitive behavioral interventions as a potential therapeutic tool for chronic pain and can potentially help clinicians and patients with chronic pain by decreasing treatment costs and side effects.

Visual Memory Improved by Non-invasive Brain Stimulation

Brain Research. Sep, 2010  |  Pubmed ID: 20682299

Our visual memories are susceptible to errors, but less so in people who have a more literal cognitive style. This inspired us to attempt to improve visual memory with non-invasive brain stimulation. We applied 13 min of bilateral transcranial direct current stimulation (tDCS) to the anterior temporal lobes. Our stimulation protocol included 3 conditions, each with 12 neurotypical participants: (i) left cathodal stimulation together with right anodal stimulation, (ii) left anodal stimulation together with right cathodal stimulation, and (iii) sham (control) stimulation. Only participants who received left cathodal stimulation (decrease in excitability) together with right anodal stimulation (increase in excitability) showed an improvement in visual memory. This 110% improvement in visual memory was similar to the advantage people with autism, who are known to be more literal, show over normal people in the identical visual task. Importantly, participants receiving stimulation of the opposite polarity (left anodal together with right cathodal stimulation) failed to show any change in memory performance. This is the first demonstration that visual memory can be enhanced in healthy people using non-invasive brain stimulation.

Effectiveness of Transcranial Direct Current Stimulation and Visual Illusion on Neuropathic Pain in Spinal Cord Injury

Brain : a Journal of Neurology. Sep, 2010  |  Pubmed ID: 20685806

The aim of this study was to evaluate the analgesic effect of transcranial direct current stimulation of the motor cortex and techniques of visual illusion, applied isolated or combined, in patients with neuropathic pain following spinal cord injury. In a sham controlled, double-blind, parallel group design, 39 patients were randomized into four groups receiving transcranial direct current stimulation with walking visual illusion or with control illusion and sham stimulation with visual illusion or with control illusion. For transcranial direct current stimulation, the anode was placed over the primary motor cortex. Each patient received ten treatment sessions during two consecutive weeks. Clinical assessment was performed before, after the last day of treatment, after 2 and 4 weeks follow-up and after 12 weeks. Clinical assessment included overall pain intensity perception, Neuropathic Pain Symptom Inventory and Brief Pain Inventory. The combination of transcranial direct current stimulation and visual illusion reduced the intensity of neuropathic pain significantly more than any of the single interventions. Patients receiving transcranial direct current stimulation and visual illusion experienced a significant improvement in all pain subtypes, while patients in the transcranial direct current stimulation group showed improvement in continuous and paroxysmal pain, and those in the visual illusion group improved only in continuous pain and dysaesthesias. At 12 weeks after treatment, the combined treatment group still presented significant improvement on the overall pain intensity perception, whereas no improvements were reported in the other three groups. Our results demonstrate that transcranial direct current stimulation and visual illusion can be effective in the management of neuropathic pain following spinal cord injury, with minimal side effects and with good tolerability.

Modulation of Risk-taking in Marijuana Users by Transcranial Direct Current Stimulation (tDCS) of the Dorsolateral Prefrontal Cortex (DLPFC)

Drug and Alcohol Dependence. Dec, 2010  |  Pubmed ID: 20729009

Cognitive deficits that are reported in heavy marijuana users (attention, memory, affect perception, decision-making) appear to be completely reversible after a prolonged abstinence period of about 28 days. However, it remains unclear whether the reversibility of these cognitive deficits indicates that (1) chronic marijuana use is not associated with long-lasting changes in cortical networks or (2) that such changes occur but the brain adapts to and compensates for the drug-induced changes. Therefore, we examined whether chronic marijuana smokers would demonstrate a differential pattern of response in comparison to healthy volunteers on a decision-making paradigm (Risk Task) while undergoing sham or active transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). Twenty-five chronic marijuana users who were abstinent for at least 24h were randomly assigned to receive left anodal/right cathodal tDCS of DLPFC (n=8), right anodal/left cathodal tDCS of DLPFC (n=9), or sham stimulation (n=8); results on Risk Task during sham/active tDCS were compared to healthy volunteers from a previously published dataset. Chronic marijuana users demonstrated more conservative (i.e. less risky) decision-making during sham stimulation. While right anodal stimulation of the DLPFC enhanced conservative decision-making in healthy volunteers, both right anodal and left anodal DLPFC stimulation increased the propensity for risk-taking in marijuana users. These findings reveal alterations in the decision-making neural networks among chronic marijuana users. Finally, we also assessed the effects of tDCS on marijuana craving and observed that right anodal/left cathodal tDCS of DLPFC is significantly associated with a diminished craving for marijuana.

Clinical Predictors Associated with Duration of Repetitive Transcranial Magnetic Stimulation Treatment for Remission in Bipolar Depression: a Naturalistic Study

The Journal of Nervous and Mental Disease. Sep, 2010  |  Pubmed ID: 20823731

Repetitive transcranial magnetic stimulation (rTMS) has been widely tested and shown to be effective for unipolar depression. Although it has also been investigated for bipolar depression (BD), there are only few rTMS studies with BD. Here, we investigated 56 patients with BD who received rTMS treatment until remission (defined as Hamilton Depression Rating Scores < or =7). We used simple and multiple logistic regressions to identify clinical and demographic predictors associated with duration of treatment (defined as <15 vs. >15 rTMS sessions). Age, refractoriness, number of prior depressive episodes, and severe depression at baseline were associated with a longer rTMS treatment. In the multivariate analysis, refractoriness (likelihood ratio (LR) = 4.33; p < 0.01) and baseline severity (LR = 0.18, p < 0.01) remained significant predictors. Our preliminary study showed that, in remitted patients, refractoriness and severity of index episode are associated with the need of a longer rTMS treatment; providing preliminary evidence of important factors associated with rTMS parameters adjustment.

Cardiovascular Research: New Model of Collaborative Training Program

Arquivos Brasileiros De Cardiologia. Sep, 2010  |  Pubmed ID: 20944899

Analgesia with Noninvasive Electrical Cortical Stimulation: Challenges to Find Optimal Parameters of Stimulation

Anesthesia and Analgesia. Nov, 2010  |  Pubmed ID: 20971956

Assessment and Modulation of Neural Plasticity in Rehabilitation with Transcranial Magnetic Stimulation

PM & R : the Journal of Injury, Function, and Rehabilitation. Dec, 2010  |  Pubmed ID: 21172687

Despite intensive efforts to improve outcomes after acquired brain injury, functional recovery is often limited. One reason for this limitation is the challenge in assessing and guiding plasticity after brain injury. In this context, transcranial magnetic stimulation (TMS), a noninvasive tool of brain stimulation, could play a major role. TMS has been shown to be a reliable tool for measuring plastic changes in the motor cortex associated with interventions in the motor system, such as motor training and motor cortex stimulation. In addition, as illustrated by the experience in promoting recovery from stroke, TMS is a promising therapeutic tool to minimize motor, speech, cognitive, and mood deficits. In this review, we will focus on stroke to discuss how TMS can provide insights into the mechanisms of neurologic recovery and how it can be used for measurement and modulation of plasticity after an acquired brain insult.

Clinical Effects and Brain Metabolic Correlates in Non-invasive Cortical Neuromodulation for Visceral Pain

European Journal of Pain (London, England). Jan, 2011  |  Pubmed ID: 20822942

Chronic visceral pain is frequent, extremely debilitating, and generally resistant to pharmacological treatment. It has been shown that chronic visceral inflammation, through altered afferent visceral sensory input, leads to plastic changes in the central nervous system that ultimately sustain pain. Therefore approaches aiming at modulation of brain activity are attractive candidates to control visceral pain.

Sertraline Vs. ELectrical Current Therapy for Treating Depression Clinical Trial--SELECT TDCS: Design, Rationale and Objectives

Contemporary Clinical Trials. Jan, 2011  |  Pubmed ID: 20854930

Despite significant advancements in psychopharmacology, treating major depressive disorder (MDD) is still a challenge considering the efficacy, tolerability, safety, and economical costs of most antidepressant drugs. One approach that has been increasingly investigated is modulation of cortical activity with tools of non-invasive brain stimulation - such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS). Due to its profile, tDCS seems to be a safe and affordable approach.

Cognitive, Mood, and Electroencephalographic Effects of Noninvasive Cortical Stimulation with Weak Electrical Currents

The Journal of ECT. Jun, 2011  |  Pubmed ID: 20938352

: The use of noninvasive cortical electrical stimulation with weak currents has significantly increased in basic and clinical human studies. Initial, preliminary studies with this technique have shown encouraging results; however, the safety and tolerability of this method of brain stimulation have not been sufficiently explored yet. The purpose of our study was to assess the effects of direct current (DC) and alternating current (AC) stimulation at different intensities in order to measure their effects on cognition, mood, and electroencephalogram.

Transcranial Magnetic Stimulation: a Historical Evaluation and Future Prognosis of Therapeutically Relevant Ethical Concerns

Journal of Medical Ethics. Mar, 2011  |  Pubmed ID: 21106996

Transcranial Magnetic Stimulation (TMS) is a non-invasive neurostimulatory and neuromodulatory technique increasingly used in clinical and research practices around the world. Historically, the ethical considerations guiding the therapeutic practice of TMS were largely concerned with aspects of subject safety in clinical trials. While safety remains of paramount importance, the recent US Food and Drug Administration approval of the Neuronetics NeuroStar TMS device for the treatment of specific medication-resistant depression has raised a number of additional ethical concerns, including marketing, off-label use and technician certification. This article provides an overview of the history of TMS and highlights the ethical questions that are likely arise as the therapeutic use of TMS continues to expand.

Transcranial Direct Current Stimulation: Electrode Montage in Stroke

Disability and Rehabilitation. 2011  |  Pubmed ID: 21110732

Neurophysiological and computer modelling studies have shown that electrode montage is a critical parameter to determine the neuromodulatory effects of transcranial direct current stimulation (tDCS). We tested these results clinically by systematically investigating optimal tDCS electrode montage in stroke. Ten patients received in a counterbalanced and randomised order the following conditions of stimulation (i) anodal stimulation of affected M1 (primary motor cortex) and cathodal stimulation of unaffected M1 ('bilateral tDCS'); (ii) anodal stimulation of affected M1 and cathodal stimulation of contralateral supraorbital area ('anodal tDCS'); (iii) cathodal stimulation of unaffected M1 and anodal stimulation of contralateral supraorbital area ('cathodal tDCS'); (iv) anodal stimulation of affected M1 and cathodal stimulation of contralateral deltoid muscle ('extra-cephalic tDCS') and (v) sham stimulation. We used the Jebsen-Taylor Test (JTT) as a widely accepted measure of upper limb function. Bilateral tDCS, anodal tDCS and cathodal tDCS were shown to be associated with significant improvements on the JTT. Placing the reference electrode in an extracephalic position and use of sham stimulation did not induce any significant effects. This small sham controlled cross-over clinical trial is important to provide additional data on the clinical effects of tDCS in stroke and for planning and designing future large tDCS trials in patients with stroke.

Combination of Noninvasive Brain Stimulation with Pharmacotherapy

Expert Review of Medical Devices. Jan, 2011  |  Pubmed ID: 21158538

Noninvasive brain stimulation (NIBS) techniques are being increasingly investigated as a therapeutic approach for neuropsychiatric disorders. One method is to combine NIBS with pharmacotherapy to enhance the clinical effects or avoid an increase in drug dosages to decrease the incidence of side effects. However, few studies to date have investigated the relative and combined efficacy of NIBS with pharmacotherapy. Based on a literature review of previous studies and meta-analyses for major depression, we identified four randomized, controlled trials that tested the combination of NIBS with a new drug and two trials that directly compared NIBS versus pharmacotherapy. There was no study designed to address the relative efficacy of each intervention against placebo and against combined therapy. We discuss the methods and rationale of NIBS-pharmacotherapy trials, addressing some methodological aspects, including factorial design, recruitment, blinding, blinding assessment, placebo effect and quantitative aspects, such as power analysis, statistics and interaction effects. Our review of the methodology underlying NIBS-drug trials provides insights for the further clinical research development of NIBS in major depression.

Transcranial Direct Current Stimulation in Adolescent and Adult Rasmussen's Encephalitis

Epilepsy & Behavior : E&B. Jan, 2011  |  Pubmed ID: 21167786

Rasmussen's encephalitis is a rare, progressive inflammatory disease that typically affects one cerebral hemisphere and causes intractable partial-onset seizures. Currently, the only effective therapy is hemispherectomy; however, this procedure is associated with irreversible neurological deficits. Novel therapeutic approaches to this condition are therefore necessary. One possible option that has not yet been extensively studied is electrical cathodal transcranial direct current stimulation (cTDCS). We describe the cases of two patients with atypical-onset Rasmussen's encephalitis who underwent cTDCS at 1- and 2-mA intensity for 60 minutes in four sessions (on days 0, 7, 30, and 60). No complications were recorded during their therapy. At follow-up evaluations 6 and 12 months later, one patient had a significant reduction in seizure frequency and one was seizure free. Additionally, both patients had improved levels of alertness and language. This is the first time that cTDCS has been applied in serial sessions to treat Rasmussen's encephalitis to avoid or delay surgical treatment.

Mood and Cognitive Effects of Transcranial Direct Current Stimulation in Post-stroke Depression

Neurocase. Aug, 2011  |  Pubmed ID: 21213180

Depression following stroke (PSD) affects up to 33% of patients and is associated with increased mortality. Antidepressant drugs have several side effects; therefore novel treatments are needed. Transcranial direct current stimulation (tDCS) has induced mood and cognitive gain in several neuropsychiatric conditions but has not been tested for PSD to date. Here, we report a patient with significant mood and cognitive impairment who showed marked amelioration of these symptoms following anodal stimulation (2 mA per 30 minutes per 10 days) over the left dorsolateral prefrontal cortex. We discuss the possible mechanisms of tDCS in improving PSD. This initial preliminary data is useful to encourage further controlled trials on the field.

An Estimate of Placebo Effect of Repetitive Transcranial Magnetic Stimulation in Epilepsy

Epilepsy & Behavior : E&B. Feb, 2011  |  Pubmed ID: 21216200

Low-frequency repetitive transcranial magnetic stimulation (rTMS) is emerging as a therapeutic tool in epilepsy. In recent years, several open-label trials have shown an encouraging reduction in seizure frequency in patients with epilepsy. However, the data from controlled trials are mixed with respect to antiepileptic rTMS efficacy, and the field would benefit from further carefully controlled trials. Prior to initiating new trials, it is important assess the magnitude of the placebo effect of presently used sham rTMS methods.

Sample Size Calculation in Physical Medicine and Rehabilitation: a Systematic Review of Reporting, Characteristics, and Results in Randomized Controlled Trials

Archives of Physical Medicine and Rehabilitation. Feb, 2011  |  Pubmed ID: 21272730

To assess systematically the reporting of sample size calculation in randomized controlled trials (RCTs) in 5 leading journals in the field of physical medicine and rehabilitation (PM&R).

Pharmacological and Electrical Stimulation in Chronic Disorders of Consciousness: New Insights and Future Directions

Brain Injury : [BI]. 2011  |  Pubmed ID: 21314279

Chronic disorders of consciousness are costly and challenging conditions to treat. Although recent studies that have tested pharmacological and electrical stimulation for these conditions are promising, the optimal intervention, mechanisms of action and side effects of these experimental therapies are unclear.

A Systematic Review on Reporting and Assessment of Adverse Effects Associated with Transcranial Direct Current Stimulation

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Sep, 2011  |  Pubmed ID: 21320389

Transcranial direct current stimulation (tDCS) is a non-invasive method of brain stimulation that has been intensively investigated in clinical and cognitive neuroscience. Although the general impression is that tDCS is a safe technique with mild and transient adverse effects (AEs), human data on safety and tolerability are largely provided from single-session studies in healthy volunteers. In addition the frequency of AEs and its relationship with clinical variables is unknown. With the aim of assessing tDCS safety in different conditions and study designs, we performed a systematic review and meta-analysis of tDCS clinical trials. We assessed Medline and other databases and reference lists from retrieved articles, searching for articles from 1998 (first trial with contemporary tDCS parameters) to August 2010. Animal studies, review articles and studies assessing other neuromodulatory techniques were excluded. According to our eligibility criteria, 209 studies (from 172 articles) were identified. One hundred and seventeen studies (56%) mentioned AEs in the report. Of these studies, 74 (63%) reported at least one AE and only eight studies quantified AEs systematically. In the subsample reporting AEs, the most common were, for active vs. sham tDCS group, itching (39.3% vs. 32.9%, p>0.05), tingling (22.2% vs. 18.3%, p>0.05), headache (14.8% vs. 16.2%, p>0.05), burning sensation (8.7% vs. 10%, p>0.05) and discomfort (10.4% vs. 13.4%, p>0.05). Meta-analytical techniques could be applied in only eight studies for itching, but no definite results could be obtained due to between-study heterogeneity and low number of studies. Our results suggested that some AEs such as itching and tingling were more frequent in the tDCS active group, although this was not statistically significant. Although results suggest that tDCS is associated with mild AEs only, we identified a selective reporting bias for reporting, assessing and publishing AEs of tDCS that hinders further conclusions. Based on our findings, we propose a revised adverse effects questionnaire to be applied in tDCS studies in order to improve systematic reporting of tDCS-related AEs.

Effect of Mild Cognitive Impairment on Balance

Journal of the Neurological Sciences. Jun, 2011  |  Pubmed ID: 21420690

To investigate the effect of mild cognitive impairment (MCI) on balance.

Limits to Clinical Trials in Surgical Areas

Clinics (São Paulo, Brazil). 2011  |  Pubmed ID: 21437453

Randomized clinical trials are considered to be the gold standard of evidence-based medicine nowadays. However, it is important that we point out some limitations of randomized clinical trials relating to surgical interventions. There are limitations that affect the external and internal validity of many surgical study designs. Some limitations can be bypassed, but can make it more difficult for the study to be carried out. Other limitations cannot be bypassed. When it is intended to extrapolate the result of a randomized clinical trial, the premise is that the performed or to be performed intervention will be similar wherever applied and/or for every doctor using it. However, no matter how standardized the technique may be, the results are not similar for all surgeons, which implies a significant limitation to surgical randomized clinical trials concerning external validity. When considering the various limitations presented for performing surgical trials capable of generating scientific evidence within the patterns currently proposed in the evidence level classifications of medical publications, it is necessary to rethink whether those scientific evidence levels are similarly applicable to surgical works and to nonsurgical trials. We currently live in a time of supposed ''inferiority'' of surgical scientific works under the optics of the current quality criteria for a ''suitable'' clinical trial.

Collaborative Teaching and Learning: a Model for Building Capacity and Partnerships to Address NTDs

PLoS Neglected Tropical Diseases. 2011  |  Pubmed ID: 21468316

Transcranial DC Stimulation in Fibromyalgia: Optimized Cortical Target Supported by High-resolution Computational Models

The Journal of Pain : Official Journal of the American Pain Society. May, 2011  |  Pubmed ID: 21497140

In this study we aimed to determine current distribution and short-term analgesic effects of transcranial direct current stimulation (tDCS) in fibromyalgia using different electrode montages. For each electrode montage, clinical effects were correlated with predictions of induced cortical current flow using magnetic resonance imaging-derived finite element method head model. Thirty patients were randomized into 5 groups (Cathodal-M1 [primary motor cortex], Cathodal-SO [supra-orbital area], Anodal-M1, Anodal-SO, and Sham) to receive tDCS application (2 mA, 20 minutes) using an extracephalic montage. Pain was measured using a visual numerical scale (VNS), pressure pain threshold (PPT), and a body diagram (BD) evaluating pain area. There was significant pain reduction in cathodal-SO and anodal-SO groups indexed by VNS. For PPT there was a trend for a similar effect in anodal-SO group. Computer simulation indicated that the M1-extracephalic montage produced dominantly temporo-parietal current flow, consistent with lack of clinical effects with this montage. Conversely, the SO-extracephalic montage produced current flow across anterior prefrontal structures, thus supporting the observed analgesic effects. Our clinical and modeling findings suggest that electrode montage, considering both electrodes, is critical for the clinical effects of M1-tDCS as electric current needs to be induced in areas associated with the pain matrix. These results should be taken into consideration for the design of pain tDCS studies. PERSPECTIVE: Results in this article support that electrode montage is a critical factor to consider for the clinical application of tDCS for pain control, as there is an important correlation between the location of induced electrical current and tDCS-induced analgesic effects.

Clinical Trial Design in Non-invasive Brain Stimulation Psychiatric Research

International Journal of Methods in Psychiatric Research. Jun, 2011  |  Pubmed ID: 21538653

Major depressive disorder (MDD) trials - investigating either non-pharmacological or pharmacological interventions - have shown mixed results. Many reasons explain this heterogeneity, but one that stands out is the trial design due to specific challenges in the field. We aimed therefore to review the methodology of non-invasive brain stimulation (NIBS) trials and provide a framework to improve clinical trial design. We performed a systematic review for randomized, controlled MDD trials whose intervention was transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) in MEDLINE and other databases from April 2002 to April 2008. We created an unstructured checklist based on CONSORT guidelines to extract items such as power analysis, sham method, blinding assessment, allocation concealment, operational criteria used for MDD, definition of refractory depression and primary study hypotheses. Thirty-one studies were included. We found that the main methodological issues can be divided in to three groups: (1) issues related to phase II/small trials, (2) issues related to MDD trials and, (3) specific issues of NIBS studies. Taken together, they can threaten study validity and lead to inconclusive results. Feasible solutions include: estimating the sample size a priori; measuring the degree of refractoriness of the subjects; specifying the primary hypothesis and statistical tests; controlling predictor variables through stratification randomization methods or using strict eligibility criteria; adjusting the study design to the target population; using adaptive designs and exploring NIBS efficacy employing biological markers. In conclusion, our study summarizes the main methodological issues of NIBS trials and proposes a number of alternatives to manage them.

Obsessive Compulsive Disorder As a Functional Interhemispheric Imbalance at the Thalamic Level

Medical Hypotheses. Sep, 2011  |  Pubmed ID: 21737205

Obsessive Compulsive Disorder (OCD) involves failures in two main inhibitory processes, namely cognitive (obsessions) and behavioral (compulsions). Recent research has supported two cortical-subcortical pathways on OCD pathogenesis: (a) the frontostriatal loop (dorsolateral-caudate-striatum-thalamus) responsible for impairments of behavioral inhibition; (b) the orbitofrontal loop (orbitofrontal, medial prefrontal and cingulate) responsible for impairments with cognitive inhibitory processes. These failures in both cognitive and motor inhibitory systems may mediate several neuropsychological deficits in these patients, namely memory, attention, planning and decision making. But are those deficits related to specific hemispheric effects, namely functional imbalance between hemispheres? In this article we hypothesize that: (1) OCD patients have an inter-hemispheric functional imbalance, probably due to inadequate filtering at the thalamic level; (2) the restoration of inter-hemispheric balance, will be correlative to symptomatic improvement.

Auditory Event-related Potentials (P3) and Cognitive Changes Induced by Frontal Direct Current Stimulation in Alcoholics According to Lesch Alcoholism Typology

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Jul, 2011  |  Pubmed ID: 21781352

Frontal lobe dysfunction is a hallmark of alcohol dependence. Recent studies have shown that a simple but powerful technique of cortical modulation - transcranial direct current stimulation (tDCS) - can induce significant cognitive changes. We therefore aimed to assess the clinical and electrophysiological (as indexed by P3) effects of tDCS of left dorsolateral prefrontal cortex (DLPFC) in different types of alcoholic patients according to Lesch's typology. We enrolled 49 alcoholic subjects, aged between 18 and 75 yr, during the subacute abstinence period to participate in this study. Subjects underwent event-related potential (ERP) registration of alcohol-related and neutral sounds before, during and after active tDCS (1 mA, 35 cm2, during 10 min) or sham procedure in a counterbalanced and randomized order. Frontal assessment battery (FAB) and five items of the Obsessive Compulsive Drinking Scale were applied at the beginning and at the end of each experimental session. ERP analysis showed an increase in the mean amplitude of P3 associated with alcohol-related sounds after tDCS. This effect was not seen for neutral sounds. This change was more pronounced in Lesch IV alcoholics. Secondary exploratory analysis showed a significant improvement of FAB performance after active tDCS compared to sham tDCS in Lesch IV alcoholics only. We showed clinical and electrophysiological evidence of tDCS-induced frontal activity enhancement that was specific for Lesch IV alcoholics. Given that frontal dysfunction may contribute to the loss of control over drinking behaviour, local increase in frontal activity induced by tDCS might have a beneficial clinical impact in the future.

Neurophysiological and Behavioral Effects of TDCS Combined with Constraint-induced Movement Therapy in Poststroke Patients

Neurorehabilitation and Neural Repair. Nov-Dec, 2011  |  Pubmed ID: 21803933

Recovery of motor function after stroke may depend on a balance of activity in the neural network involving the affected and the unaffected motor cortices.

The Past, Present and Future of Clinical Research

Clinics (São Paulo, Brazil). 2011  |  Pubmed ID: 21808853

Translational Research in Transcranial Direct Current Stimulation (tDCS): a Systematic Review of Studies in Animals

Reviews in the Neurosciences. 2011  |  Pubmed ID: 21819264

Recent therapeutic human studies testing transcranial direct current stimulation (tDCS) has shown promising results, although many questions remain unanswered. Translational research with experimental animals is an appropriate framework for investigating its mechanisms of action that are still undetermined. Nevertheless, animal and human studies are often discordant. Our aim was to review tDCS animal studies, examining and comparing their main findings with human studies. We performed a systematic review in Medline and other databases, screening for animal studies in vivo that delivered tDCS. Studies in vitro and using other neuromodulatory techniques were excluded. We extracted data according to Animal Research: Reporting In Vivo Experiments (ARRIVE) guidelines for reporting in vivo animal research. Thus, we collected data on sample characteristics (size, gender, weight and specimen) and methodology (experimental procedures, experimental animals, housing and husbandry, as well as analysis). We also collected data on methods for delivering tDCS (location, size, current and current density of electrodes and electrode montage), experimental effects (polarity-, intensity- and after-effects) and safety. Only 12 of 48 potentially eligible studies met our inclusion criteria and were reviewed. Quality assessment reporting was only moderate and studies were heterogeneous regarding tDCS montage methodology, position of active and reference electrodes, and current density used. Nonetheless, almost all studies demonstrated that tDCS had positive immediate and long-lasting effects. Vis-à-vis human trials, animal studies applied higher current densities (34.2 vs. 0.4 A/m(2), respectively), preferred extra-cephalic positions for reference electrodes (60% vs. 10%, respectively) and used electrodes with different sizes more often. Potential implications for translational tDCS research are discussed.

Prolonged Visual Memory Enhancement After Direct Current Stimulation in Alzheimer's Disease

Brain Stimulation. Jul, 2011  |  Pubmed ID: 21840288

BACKGROUND: Immediately after patients with Alzheimer's disease (AD) receive a single anodal transcranial direct current stimulation (tDCS) session their memory performance improves. Whether multiple tDCS sessions improve memory performance in the longer term remains unclear. OBJECTIVE: In this study we aimed to assess memory changes after five consecutive sessions of anodal tDCS applied over the temporal cortex in patients with AD. METHODS: A total of 15 patients were enrolled in two centers. Cognitive functions were evaluated before and after therapeutic tDCS. tDCS was delivered bilaterally through two scalp anodal electrodes placed over the temporal regions and a reference electrode over the right deltoid muscle. The stimulating current was set at 2 mA intensity and was delivered for 30 minutes per day for 5 consecutive days. RESULTS: After patients received tDCS, their performance in a visual recognition memory test significantly improved. We found a main effect of tDCS on memory performance, i.e., anodal stimulation improved it by 8.99% from baseline, whereas sham stimulation decreased it by 2.62%. tDCS failed to influence differentially general cognitive performance measures or a visual attention measure. CONCLUSIONS: Our findings show that after patients with AD receive anodal tDCS over the temporal cerebral cortex in five consecutive daily sessions their visual recognition memory improves and the improvement persists for at least 4 weeks after therapy. These encouraging results provide additional support for continuing to investigate anodal tDCS as an adjuvant treatment for patients with AD.

Reversal of TMS-induced Motor Twitch by Training is Associated with a Reduction in Excitability of the Antagonist Muscle

Journal of Neuroengineering and Rehabilitation. 2011  |  Pubmed ID: 21861922

A single session of isolated repetitive movements of the thumb can alter the response to transcranial magnetic stimulation (TMS), such that the related muscle twitch measured post-training occurs in the trained direction. This response is attributed to transient excitability changes in primary motor cortex (M1) that form the early part of learning. We investigated; (1) whether this phenomenon might occur for movements at the wrist, and (2) how specific TMS activation patterns of opposing muscles underlie the practice-induced change in direction.

TMS Suppression of Right Pars Triangularis, but Not Pars Opercularis, Improves Naming in Aphasia

Brain and Language. Dec, 2011  |  Pubmed ID: 21864891

This study sought to discover if an optimum 1 cm(2) area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.

Task-specific Effects of TDCS-induced Cortical Excitability Changes on Cognitive and Motor Sequence Set Shifting Performance

PloS One. 2011  |  Pubmed ID: 21909415

In this study, we tested the effects of transcranial Direct Current Stimulation (tDCS) on two set shifting tasks. Set shifting ability is defined as the capacity to switch between mental sets or actions and requires the activation of a distributed neural network. Thirty healthy subjects (fifteen per site) received anodal, cathodal and sham stimulation of the dorsolateral prefrontal cortex (DLPFC) or the primary motor cortex (M1). We measured set shifting in both cognitive and motor tasks. The results show that both anodal and cathodal single session tDCS can modulate cognitive and motor tasks. However, an interaction was found between task and type of stimulation as anodal tDCS of DLPFC and M1 was found to increase performance in the cognitive task, while cathodal tDCS of DLPFC and M1 had the opposite effect on the motor task. Additionally, tDCS effects seem to be most evident on the speed of changing sets, rather than on reducing the number of errors or increasing the efficacy of irrelevant set filtering.

Atherosclerosis and Dementia: a Cross-sectional Study with Pathological Analysis of the Carotid Arteries

Stroke; a Journal of Cerebral Circulation. Dec, 2011  |  Pubmed ID: 21940957

Previous ultrasound-based studies have shown an association between carotid artery atherosclerosis and dementia. Our aim was to investigate this association using postmortem examination.

Non-invasive Brain Stimulation to Assess and Modulate Neuroplasticity in Alzheimer's Disease

Neuropsychological Rehabilitation. Oct, 2011  |  Pubmed ID: 21942868

Alzheimer's disease (AD) is a neurodegenerative and progressive disease related to a gradual decline in cognitive functions such as memory, attention, perceptual-spatial abilities, language, and executive functions. Recent evidence has suggested that interventions promoting neural plasticity can induce significant cognitive gains especially in subjects at risk of or with mild AD. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are non-invasive techniques that can induce significant and long-lasting changes in focal and non-focal neuroplasticity. In this review, we present initial preliminary evidence that TMS and tDCS can enhance performance in cognitive functions typically impaired in AD. Also, we reviewed the initial six studies on AD that presented early findings showing cognitive gains such as in recognition memory and language associated with TMS and tDCS treatment. In addition, we showed that TMS has also been used to assess neuroplasticity changes in AD supporting the notion that cortical excitability is changed in AD due to the neurodegenerative process. Due to the safe profile, cost of these tools, and initial clinical trials results, further studies are warranted in order to replicate and extend the initial findings of rTMS and tDCS as cognitive enhancers in AD. Further trials should explore different targets of stimulation along with different paradigms of stimulation including combination with behavioural interventions.

Manic Psychosis After Sertraline and Transcranial Direct-current Stimulation

The Journal of Neuropsychiatry and Clinical Neurosciences. 2011  |  Pubmed ID: 21948925

Polarity-dependent Transcranial Direct Current Stimulation Effects on Central Auditory Processing

PloS One. 2011  |  Pubmed ID: 21966519

Given the polarity dependent effects of transcranial direct current stimulation (tDCS) in facilitating or inhibiting neuronal processing, and tDCS effects on pitch perception, we tested the effects of tDCS on temporal aspects of auditory processing. We aimed to change baseline activity of the auditory cortex using tDCS as to modulate temporal aspects of auditory processing in healthy subjects without hearing impairment. Eleven subjects received 2mA bilateral anodal, cathodal and sham tDCS over auditory cortex in a randomized and counterbalanced order. Subjects were evaluated by the Random Gap Detection Test (RGDT), a test measuring temporal processing abilities in the auditory domain, before and during the stimulation. Statistical analysis revealed a significant interaction effect of time vs. tDCS condition for 4000 Hz and for clicks. Post-hoc tests showed significant differences according to stimulation polarity on RGDT performance: anodal improved 22.5% and cathodal decreased 54.5% subjects' performance, as compared to baseline. For clicks, anodal also increased performance in 29.4% when compared to baseline. tDCS presented polarity-dependent effects on the activity of the auditory cortex, which results in a positive or negative impact in a temporal resolution task performance. These results encourage further studies exploring tDCS in central auditory processing disorders.

Top Down Prefrontal Affective Modulation of Tinnitus with Multiple Sessions of TDCS of Dorsolateral Prefrontal Cortex

Brain Stimulation. Oct, 2011  |  Pubmed ID: 22019079

Most forms of tinnitus are attributable to reorganization and hyperactivity in the auditory central nervous system with coactivation of nonauditory brain structures. One such nonauditory brain area is the dorsolateral prefrontal cortex (DLPFC), which is important for the integration of sensory and emotional aspects of tinnitus. Based on extensive evidence that transcranial direct current stimulation can induce significant effects on DLPFC-related cognitive function, we aimed to investigate whether left or right anodal DLFPC tDCS is associated with modulation of tinnitus. We conducted a double-blind, placebo-controlled cross-over study in which 15 subjects with tinnitus were randomly assigned to receive active and sham anodal tDCS over left (n = 8) or right DLPFC (n = 7) for six sessions in a counterbalanced order; the cathode electrode was placed in the contralateral DLPFC. The results demonstrate that both active conditions-irrespective of the anodal position-can decrease tinnitus annoyance but it is not associated with improvements in tinnitus intensity when comparing pre-tDCS versus post-tDCS as well as comparing sham-tDCS versus real tDCS. Also, we show that the anode electrode placed over the left DLPFC modulates depression when comparing pre-tDCS versus post-tDCS as well as comparing sham-tDCS versus real tDCS. In addition, we also show that the anode electrode placed over the right DLPFC modulates anxiety when comparing pre-tDCS versus post-tDCS. This latter effect does not remain when we compare sham-tDCS versus real tDCS. This study further supports the involvement of the prefrontal cortex in the neural network associated with tinnitus, and also provides initial evidence for a potential brain stimulation site for tinnitus treatment in association with other treatments that can reduce tinnitus intensity.

Responding to Unfair Offers Made by a Friend: Neuroelectrical Activity Changes in the Anterior Medial Prefrontal Cortex

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience. Oct, 2011  |  Pubmed ID: 22031902

When receiving unfair monetary offers from another person, the most common response is punishment. Existing literature on the Ultimatum Game indicates that individuals frequently refuse unfair offers even when this results in a loss for themselves. Here, we present behavioral and neurophysiological evidence demonstrating that friendship substantially modifies this response. When the proposer was a friend rather than an unknown person, unfair offers were less frequently rejected and the medial frontal negativity (MFN) typically associated with unfair offers was reversed to positive polarity. The underlying generators were located in inferior-mesial and right inferior- and medial-lateral frontal regions (BA10 and BA11). These findings highlight the fundamental role of the anterior prefrontal cortex in interpersonal economic interaction and, particularly, present new evidence on the effects of social distance on the MFN.

Clinical Research with Transcranial Direct Current Stimulation (tDCS): Challenges and Future Directions

Brain Stimulation. Apr, 2011  |  Pubmed ID: 22037126

BACKGROUND: Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. In the past 10 years, tDCS physiologic mechanisms of action have been intensively investigated giving support for the investigation of its applications in clinical neuropsychiatry and rehabilitation. However, new methodologic, ethical, and regulatory issues emerge when translating the findings of preclinical and phase I studies into phase II and III clinical studies. The aim of this comprehensive review is to discuss the key challenges of this process and possible methods to address them. METHODS: We convened a workgroup of researchers in the field to review, discuss, and provide updates and key challenges of tDCS use in clinical research. MAIN FINDINGS/DISCUSSION: We reviewed several basic and clinical studies in the field and identified potential limitations, taking into account the particularities of the technique. We review and discuss the findings into four topics: (1) mechanisms of action of tDCS, parameters of use and computer-based human brain modeling investigating electric current fields and magnitude induced by tDCS; (2) methodologic aspects related to the clinical research of tDCS as divided according to study phase (ie, preclinical, phase I, phase II, and phase III studies); (3) ethical and regulatory concerns; and (4) future directions regarding novel approaches, novel devices, and future studies involving tDCS. Finally, we propose some alternative methods to facilitate clinical research on tDCS.

Efficacy of Transcranial Direct Current Stimulation Coupled with a Multidisciplinary Rehabilitation Program for the Treatment of Fibromyalgia

The Open Rheumatology Journal. 2011  |  Pubmed ID: 22046206

Pain control in fibromyalgia patients is limited no matter the therapeutic regimens used. Recent data have shown that daily sessions of anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) in patients with fibromyalgia (FM) are associated with reduction of pain perception.

Assessment and Treatment of Pain with Non-invasive Cortical Stimulation

Restorative Neurology and Neuroscience. Jan, 2011  |  Pubmed ID: 22124038

Purpose: There remains an unmet clinical need for the development of new therapeutic approaches for the treatment of pain. Recent findings have confirmed significant changes in the pain-related neural networks among patients with chronic pain, opening novel possibilities for investigation. Two non-invasive techniques (transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS)) have emerged as interesting, effective, and promising modalities for pain relief. Methods: Here we review the clinical efficacy of these techniques for the treatment of pain through an updated systematic meta-analysis on the effects of primary motor cortex stimulation on pain and we discuss potential mechanisms of action based on insights from brain stimulation studies. Our meta-analysis includes 18 studies, which together show that non-invasive brain stimulation is associated with an effect size of -0.86 (95% C.I., -1.54, -0.19) on a standardized pain scale ranging from 0 (no pain) to 10 (worst pain possible). Results and Conclusions: Besides its use as a therapeutic tool, non-invasive brain stimulation can also be used to measure cortical reactivity and plasticity in chronic pain. Such measurements could potentially be used as biomarkers for the dysfunctional chronic pain-related neural network and might be helpful in measuring the efficacy of interventions designed for chronic pain.

Isokinetic Muscle Strength and Knee Function Associated with Double Femoral Pin Fixation and Fixation with Interference Screw in Anterior Cruciate Ligament Reconstruction

Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. Feb, 2012  |  Pubmed ID: 21710112

Intensive scheduling in sports requires athletes to resume physical activity shortly after injury. The purpose of this study was to investigate early isokinetic muscle strength and knee function on bone-patellar tendon-bone (BPTB) ACL reconstruction with double femoral pin fixation or interference screw technique.

Comparison of Visual Field Training for Hemianopia With Active Versus Sham Transcranial Direct Cortical Stimulation

Neurorehabilitation and Neural Repair. Jan, 2012  |  Pubmed ID: 22291042

BACKGROUND: Vision Restoration Therapy (VRT) aims to improve visual field function by systematically training regions of residual vision associated with the activity of suboptimal firing neurons within the occipital cortex. Transcranial direct current stimulation (tDCS) has been shown to modulate cortical excitability. OBJECTIVE: Assess the possible efficacy of tDCS combined with VRT. METHODS: The authors conducted a randomized, double-blind, demonstration-of-concept pilot study where participants were assigned to either VRT and tDCS or VRT and sham. The anode was placed over the occipital pole to target both affected and unaffected lobes. One hour training sessions were carried out 3 times per week for 3 months in a laboratory. Outcome measures included objective and subjective changes in visual field, recording of visual fixation performance, and vision-related activities of daily living (ADLs) and quality of life (QOL). RESULTS: Although 12 participants were enrolled, only 8 could be analyzed. The VRT and tDCS group demonstrated significantly greater expansion in visual field and improvement on ADLs compared with the VRT and sham group. Contrary to expectations, subjective perception of visual field change was greater in the VRT and sham group. QOL did not change for either group. The observed changes in visual field were unrelated to compensatory eye movements, as shown with fixation monitoring. CONCLUSIONS: The combination of occipital cortical tDCS with visual field rehabilitation appears to enhance visual functional outcomes compared with visual rehabilitation alone. TDCS may enhance inherent mechanisms of plasticity associated with training.

Enhancement of Selective Attention by TDCS: Interaction with Interference in a Sternberg Task

Neuroscience Letters. Feb, 2012  |  Pubmed ID: 22327036

Transcranial Direct Current Stimulation (tDCS) enhances performance on working memory tasks. However, such effects may be dependent on modulation of specific aspects of working memory. We therefore tested the hypothesis that tDCS improves selective attention in the context of a Sternberg task. Subjects had to maintain a memory set while responding to distracter stimuli. Probes consisted of one item from the memory set, and one item that could have been presented as a distracter. TDCS was found to improve reaction time significantly only when the incorrect choice had been a distracter stimulus. The results thus support the notion that tDCS effects on working memory might be mediated by a specific effect on selective attention.

BDNF As an Effect Modifier for Gender Effects on Pain Thresholds in Healthy Subjects

Neuroscience Letters. Apr, 2012  |  Pubmed ID: 22395087

BDNF is an important marker of neuronal plasticity. It has also been associated with pain processing. Increased BDNF levels are observed in chronic pain syndromes. In order to understand the role of BDNF associated with other factors such as gender on experimental pain we aimed to determine whether experimental heat or pressure pain threshold is correlated with brain derived neurotrophic factor (BDNF) level, gender and age. Heat pain threshold and pressure pain threshold were measured in 49 healthy volunteers (27 females). The multivariate linear regression models (on heat and pressure pain thresholds) revealed a significant effect of gender (p=0.001 for both models), serum BDNF (p<0.004 for both models) and interaction between BDNF and gender (<0.001 for both models). In fact, when adjusting for BDNF levels and age, heat and pressure pain thresholds were significantly reduced in women as compared to men (p<0.001 for both models). These effects were not observed when gender was analyzed alone. These finding suggests that experimental heat and pressure pain threshold is gender-related and BDNF dependent. In fact BDNF has a facilitatory effect on pain threshold in females but has an opposite effect in males; supporting the notion that BDNF is an effect modifier of the gender effects on pain threshold in healthy subjects.

Dissociation of Motor Task-induced Cortical Excitability and Pain Perception Changes in Healthy Volunteers

PloS One. 2012  |  Pubmed ID: 22470548

There is evidence that interventions aiming at modulation of the motor cortex activity lead to pain reduction. In order to understand further the role of the motor cortex on pain modulation, we aimed to compare the behavioral (pressure pain threshold) and neurophysiological effects (transcranial magnetic stimulation (TMS) induced cortical excitability) across three different motor tasks.

Clinical Effects of Scalp Electrical Acupuncture in Stroke: a Sham-controlled Randomized Clinical Trial

Journal of Alternative and Complementary Medicine (New York, N.Y.). Apr, 2012  |  Pubmed ID: 22489807

The majority of individuals who survive a stroke are disabled because of persisting neurological impairments. The objective of this study was to evaluate the efficacy of subcutaneous electrical stimulation of the scalp in spontaneous functional recovery of patients with chronic ischemic stroke, by evaluating clinical, neurological, and functional findings.

TDCS-induced Analgesia and Electrical Fields in Pain-related Neural Networks in Chronic Migraine

Headache. Sep, 2012  |  Pubmed ID: 22512348

We investigated in a sham-controlled trial the analgesic effects of a 4-week treatment of transcranial direct current stimulation (tDCS) over the primary motor cortex in chronic migraine. In addition, using a high-resolution tDCS computational model, we analyzed the current flow (electric field) through brain regions associated with pain perception and modulation.

Effects of Motor Cortex Modulation and Descending Inhibitory Systems on Pain Thresholds in Healthy Subjects

The Journal of Pain : Official Journal of the American Pain Society. May, 2012  |  Pubmed ID: 22515945

Pain modulation can be achieved using neuromodulatory tools that influence various levels of the nervous system. Transcranial direct current stimulation (tDCS), for instance, has been shown to reduce chronic pain when applied to the primary motor cortex. In contrast to this central neuromodulatory technique, diffuse noxious inhibitory controls (DNIC) refers to endogenous analgesic mechanisms that decrease pain following the introduction of heterotopic noxious stimuli. We examined whether combining top-down motor cortex modulation using anodal tDCS with a bottom-up DNIC induction paradigm synergistically increases the threshold at which pain is perceived. The pain thresholds of 15 healthy subjects were assessed before and after administration of active tDCS, sham tDCS, cold-water-induced DNIC, and combined tDCS and DNIC. We found that both tDCS and the DNIC paradigm significantly increased pain thresholds and that these approaches appeared to have additive effects. Increase in pain threshold following active tDCS was positively correlated with baseline N-acetylaspartate in the cingulate cortex and negatively correlated with baseline glutamine levels in the thalamus as measured by magnetic resonance spectroscopy. These results suggest that motor cortex modulation may have a greater analgesic effect when combined with bottom-up neuromodulatory mechanisms, presenting new avenues for modulation of pain using noninvasive neuromodulatory approaches.

Transcranial Direct Current Stimulation for the Treatment of Major Depressive Disorder: a Summary of Preclinical, Clinical and Translational Findings

Progress in Neuro-psychopharmacology & Biological Psychiatry. Oct, 2012  |  Pubmed ID: 22651961

Major depressive disorder (MDD) is a common psychiatric illness, with 6-12% lifetime prevalence. It is also among the five most disabling diseases worldwide. Current pharmacological treatments, although relatively effective, present important side effects that lead to treatment discontinuation. Therefore, novel treatment options for MDD are needed. Here, we discuss the recent advancements of one new neuromodulatory technique--transcranial direct current stimulation (tDCS)--that has undergone intensive research over the past decade with promising results. tDCS is based on the application of weak, direct electric current over the scalp, leading to cortical hypo- or hyper-polarization according to the specified parameters. Recent studies have shown that tDCS is able to induce potent changes in cortical excitability as well as to elicit long-lasting changes in brain activity. Moreover, tDCS is a technique with a low rate of reported side effects, relatively easy to apply and less expensive than other neuromodulatory techniques--appealing characteristics for clinical use. In the past years, 4 of 6 phase II clinical trials and one recent meta-analysis have shown positive results in ameliorating depression symptoms. tDCS has some interesting, unique aspects such as noninvasiveness and low rate of adverse effects, being a putative substitutive/augmentative agent for antidepressant drugs, and low-cost and portability, making it suitable for use in clinical practice. Still, further phase II and phase III trials are needed as to better clarify tDCS role in the therapeutic arsenal of MDD.

After-effects of Consecutive Sessions of Transcranial Direct Current Stimulation (tDCS) in a Rat Model of Chronic Inflammation

Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale. Aug, 2012  |  Pubmed ID: 22752510

Transcranial direct current stimulation (tDCS) induces cortical excitability changes in animals and humans that can last beyond the duration of stimulation. Preliminary evidence suggests that tDCS may have an analgesic effect; however, the timing of these effects, especially when associated with consecutive sessions of stimulation in a controlled animal experiment setting, has yet to be fully explored. To evaluate the effects of tDCS in inflammatory chronic pain origin immediately and 24 h after the last treatment session, complete Freund's adjuvant (CFA) was injected (100 μl) in the right footpad to induce inflammation. On the 15th day after CFA injection, rats were divided into two groups: tDCS (n = 9) and sham (n = 9). The tDCS was applied for 8 days. The hot plate and Von Frey tests were applied immediately and 24 h after the last tDCS session. Eight 20-min sessions of 500 μA anodal tDCS resulted in antinociceptive effects as assessed by the hot plate test immediately (P = 0.04) and 24 h after the last tDCS session (P = 0.006), for the active tDCS group only. There was increased withdrawal latency in the Von Frey test at 24 h after the last session (P = 0.01). Our findings confirm the hypothesis that tDCS induces significant, long-lasting, neuroplastic effects and expands these findings to a chronic pain model of peripheral inflammation, thus supporting the exploration of this technique in conditions associated with chronic pain and peripheral inflammation, such as osteoarthritis.

Analgesic Effects of Noninvasive Brain Stimulation in Rodent Animal Models: a Systematic Review of Translational Findings

Neuromodulation : Journal of the International Neuromodulation Society. Jul, 2012  |  Pubmed ID: 22759345

Noninvasive brain stimulation (NIBS) interventions have demonstrated promising results in the clinical treatment of pain, according to several preliminary trials, although the results have been mixed. The limitations of clinical research on NIBS are the insufficient understanding of its mechanisms of action, a lack of adequate safety data, and several disparities with regard to stimulation parameters, which have hindered the generalizability of such studies. Thus, experimental animal research that allows the use of more invasive interventions and creates additional control of independent variables and confounders is desirable. To this end, we systematically reviewed animal studies investigating the analgesic effects of NIBS. In addition, we also explored the investigation of NIBS in animal models of stroke as to compare these findings with NIBS animal pain research.

High-resolution Modeling Assisted Design of Customized and Individualized Transcranial Direct Current Stimulation Protocols

Neuromodulation : Journal of the International Neuromodulation Society. Jul, 2012  |  Pubmed ID: 22780230

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity currents facilitating or inhibiting spontaneous neuronal activity. tDCS is attractive since dose is readily adjustable by simply changing electrode number, position, size, shape, and current. In the recent past, computational models have been developed with increased precision with the goal to help customize tDCS dose. The aim of this review is to discuss the incorporation of high-resolution patient-specific computer modeling to guide and optimize tDCS.

Bench to Clinical Translational Applications of Noninvasive Brain Stimulation

Neuromodulation : Journal of the International Neuromodulation Society. Jul, 2012  |  Pubmed ID: 22882243

Noninvasive Brain Stimulation to Modulate Neuroplasticity in Traumatic Brain Injury

Neuromodulation : Journal of the International Neuromodulation Society. Jul, 2012  |  Pubmed ID: 22882244

To review the use of noninvasive brain stimulation (NBS) as a therapeutic tool to enhance neuroplasticity following traumatic brain injury (TBI).

Bilateral Temporal Cortex Transcranial Direct Current Stimulation Worsens Male Performance in a Multisensory Integration Task

Neuroscience Letters. Oct, 2012  |  Pubmed ID: 22985520

Somatosensory integration is a critical cognitive function for human social interaction. Though somatosensory integration has been highly explored in cognitive studies; only a few studies have explored focal modulation of cortical excitability using a speech perception paradigm. In the current study, we aimed to investigate the effects of tDCS applied over the temporal cortex of healthy subjects during a go-no-go task in which stimuli were shapes and non-words. Twenty-eight subjects were randomized to receive cathodal, anodal or sham tDCS bilaterally over the superior temporal cortex (the reference electrode was on deltoid) in a counterbalanced order. The effects on judgment of congruency between shapes and non-words in healthy volunteers were measured by a go-no-go task. Our findings show a significant modification of performance according to the polarity of stimulation, task and subject gender. We found that men performed worse on the no-go condition for congruent stimuli during cathodal tDCS. For reaction time, on the other hand, there was a similar effect for anodal and cathodal stimulation. There were significantly faster responses on incongruent trials during both anodal and cathodal tDCS. Along with previous literature showing gender differences in tasks associated with speech perception, the findings of this study provide additional evidence suggesting that men may have a more focal and restricted neural processing in this multisensory integration task.

Cross-cultural Adaptation and Validation of the Brazilian Portuguese Version of the Pain Catastrophizing Scale

Pain Medicine (Malden, Mass.). Nov, 2012  |  Pubmed ID: 23036076

Catastrophizing is a maladaptive response to pain and is one of the factors that contribute to the chronicity of some pain syndromes. The Pain Catastrophizing Scale (PCS) assists both treatment planning and outcome assessment. Its use is limited in Portuguese-speaking countries because of the lack of a validated translated version. We conducted the validation of the Brazilian Portuguese (BP)-PCS and explored its psychometric properties. This study reports the internal consistency, factor structure, and its capability to discriminate pain reported by patients with specific chronic pain conditions.

Reversal of Chronic Stress-induced Pain by Transcranial Direct Current Stimulation (tDCS) in an Animal Model

Brain Research. Dec, 2012  |  Pubmed ID: 23063889

Transcranial direct current stimulation (tDCS) has been suggested as a therapeutic tool for pain syndromes. Although initial results in human subjects are encouraging, it still remains unclear whether the effects of tDCS can reverse maladaptive plasticity associated with chronic pain. To investigate this question, we tested whether tDCS can reverse the specific behavioral effects of chronic stress in the pain system, and also those indexed by corticosterone and interleukin-1β levels in serum and TNFα levels in the hippocampus, in a well-controlled rat model of chronic restraint stress (CRS). Forty-one adult male Wistar rats were divided into two groups control and stress. The stress group was exposed to CRS for 11 weeks for the establishment of hyperalgesia and mechanical allodynia as shown by the hot plate and von Frey tests, respectively. Rats were then divided into four groups control, stress, stress+sham tDCS and stress+tDCS. Anodal or sham tDCS was applied for 20min/day over 8 days and the tests were repeated. Then, the animals were killed, blood collected and hippocampus removed for ELISA testing. This model of CRS proved effective to induce chronic pain, as the animals exhibited hyperalgesia and mechanical allodynia. The hot plate test showed an analgesic effect, and the von Frey test, an anti-allodynic effect after the last tDCS session, and there was a significant decrease in hippocampal TNFα levels. These results support the notion that tDCS reverses the detrimental effects of chronic stress on the pain system and decreases TNFα levels in the hippocampus.

Exploring a Long-term Global Approach for Musculoskeletal Ultrasound Training: WORLD-MUSCULUS

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. Nov, 2012  |  Pubmed ID: 23069862

The Long-term Impact of Physical and Emotional Trauma: the Station Nightclub Fire

PloS One. 2012  |  Pubmed ID: 23077593

Survivors of physical and emotional trauma experience enduring occupational, psychological and quality of life impairments. Examining survivors from a large fire provides a unique opportunity to distinguish the impact of physical and emotional trauma on long-term outcomes. The objective is to detail the multi-dimensional long-term effects of a large fire on its survivor population and assess differences in outcomes between survivors with and without physical injury.

Feasibility of Focal Transcranial DC Polarization with Simultaneous EEG Recording: Preliminary Assessment in Healthy Subjects and Human Epilepsy

Epilepsy & Behavior : E&B. Nov, 2012  |  Pubmed ID: 23123281

We aimed to investigate the feasibility of an experimental system for simultaneous transcranial DC stimulation (tDCS) and EEG recording in human epilepsy. We report tolerability of this system in a cross-over controlled trial with 15 healthy subjects and preliminary effects of its use, testing repeated tDCS sessions, in two patients with drug-refractory Continuous Spike-Wave Discharges During Slow Sleep (CSWS). Our system combining continuous recording of the EEG with tDCS allows detailed evaluation of the interictal activity during the entire process. Stimulation with 1 mA was well-tolerated in both healthy volunteers and patients with refractory epilepsy. The large reduction in interictal epileptiform EEG discharges in the two subjects with epilepsy supports further investigation of tDCS using this combined method of stimulation and monitoring in epilepsy. Continuous monitoring of epileptic activity throughout tDCS improves safety and allows detailed evaluation of epileptic activity changes induced by tDCS in patients.

Immediate Effects of TDCS on the μ-opioid System of a Chronic Pain Patient

Frontiers in Psychiatry / Frontiers Research Foundation. 2012  |  Pubmed ID: 23130002

We developed a unique protocol where transcranial direct current stimulation (tDCS) of the motor cortex is performed during positron emission tomography (PET) scan using a μ-opioid receptor (μOR) selective radiotracer, [(11)C]carfentanil. This is one of the most important central neuromechanisms associated with pain perception and regulation. We measured μOR non-displaceable binding potential (μOR BP(ND)) in a trigeminal neuropathic pain patient (TNP) without creating artifacts, or posing risks to the patient (e.g., monitoring of resistance). The active session directly improved in 36.2% the threshold for experimental cold pain in the trigeminal allodynic area, mandibular branch, but not the TNP patient's clinical pain. Interestingly, the single active tDCS application considerably decreased μORBP(ND) levels in (sub)cortical pain-matrix structures compared to sham tDCS, especially in the posterior thalamus. Suggesting that the μ-opioidergic effects of a single tDCS session are subclinical at immediate level, and repetitive sessions are necessary to revert ingrained neuroplastic changes related to the chronic pain. To our knowledge, we provide data for the first time in vivo that there is possibly an instant increase of endogenous μ-opioid release during acute motor cortex neuromodulation with tDCS.

The Influence of Femoral Tunnel Position in Single-bundle ACL Reconstruction on Functional Outcomes and Return to Sports

Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. Nov, 2012  |  Pubmed ID: 23132410

PURPOSE: The purpose of this study was to radiographically investigate the influence of femoral tunnel placement in ACL reconstruction on early outcomes and return to sports due to anatomic and nonanatomic positioning. METHODS: A prospective study was conducted from 2008 to 2010, with 86 athletes who underwent ACL reconstruction between anteromedial (AM) footprint and high AM position. Knee functional outcomes (IKDC objective and subjective, Tegner score, and Lysholm scale) return to sports and complications were analyzed at 6- and 12-month follow-up. RESULTS: At follow-up, it was observed that tunnel projection along Blumensaat's line was correlated with functional outcomes on Tegner scale (at 6 and 12 months) and IKDC subjective (at 12 months). There was a significant difference in mean tunnel projection along Blumensaat's line when analyzing return to sports (73 ± 1.4 and 79 ± 1.7 %, respectively, for projections on return vs. no return to sports, p = 0.02) and complications (73 ± 1.3 vs. 78 ± 1.6 %, respectively, for projections on no complications vs. complications, p = 0.03). No differences were stated on coronal view. These correlations between tunnel positioning on functional outcomes could not be explained by demographic or baseline characteristics. CONCLUSION: The clinical relevance of this study is that tunnel positioning along AM footprint and high AM position represented by tunnel projection along Blumensaat's line is associated with early return to sports on previous Tegner level and better functional outcome in athletes. LEVEL OF EVIDENCE: III.

The Effects of Cross-hemispheric Dorsolateral Prefrontal Cortex Transcranial Direct Current Stimulation (tDCS) on Task Switching

Brain Stimulation. Nov, 2012  |  Pubmed ID: 23142550

BACKGROUND: Task switching, defined as the ability to flexibly switch between tasks in the face of goal shifting, is a central mechanism in cognitive control. Task switching is thought to involve both prefrontal cortex (PFC) and parietal regions. Our previous work has shown that it is possible to modulate set shifting tasks using 1 mA tDCS on both the left dorsolateral prefrontal cortex and the left primary motor area. However, it remains unclear whether the effects of PFC tDCS on task switching are hemisphere-dependent. OBJECTIVES: We aimed to test the effects of three types of cross-hemispheric tDCS over the PFC (left anode-right cathode [LA-RC], left cathode-right anode [LC-RA] and sham stimulation) on participants' performance (reaction time) and accuracy (correct responses) in two task-switching paradigms (i.e., letter/digit naming and vowel-consonant/parity tasks). METHODS: Sixteen participants received cross-hemispheric tDCS over the PFC in two task-switching paradigms. RESULTS: The results show that cross-hemispheric tDCS over the PFC modulates task-switching ability in both paradigms. Our results were task and hemisphere-specific, such that in the letter/digit naming task, LA-RC tDCS increased switching performance, whereas LC-RA tDCS improved accuracy. On the other hand, in the vowel-consonant/parity task, LA-RC improved accuracy, and decreased switching performance. CONCLUSIONS: Our findings confirm the notion that involvement of the PFC on task switching depends critically on laterality, implying the existence of different roles for the left hemisphere and the right hemisphere in task switching.

Neurochemical Correlates of Cognitive Dysfunction in Patients with Leukoaraiosis: a Proton Magnetic Resonance Spectroscopy Study

Neurological Research. Dec, 2012  |  Pubmed ID: 23146302

Leukoaraiosis (LA) is a common radiological finding in the elderly and may reflect cerebral small vessel disease (SVD). Although SVD has been identified as a major cause of vascular cognitive impairment or vascular dementia, the mechanisms for this association remain unclear. We therefore aimed to measure brain metabolites in LA using proton magnetic resonance spectroscopy ((1)H-MRS) as to determine the relationship between cognitive function and neurochemical white matter profile.

Rapid Therapeutic Response to Anodal TDCS of Right Dorsolateral Prefrontal Cortex in Acute Mania

Brain Stimulation. Nov, 2012  |  Pubmed ID: 23158877

Systematic Review of Parameters of Stimulation, Clinical Trial Design Characteristics, and Motor Outcomes in Non-invasive Brain Stimulation in Stroke

Frontiers in Psychiatry / Frontiers Research Foundation. 2012  |  Pubmed ID: 23162477

Introduction/Objectives: Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation are two powerful non-invasive neuromodulatory therapies that have the potential to alter and evaluate the integrity of the corticospinal tract. Moreover, recent evidence has shown that brain stimulation might be beneficial in stroke recovery. Therefore, investigating and investing in innovative therapies that may improve neurorehabilitative stroke recovery are next steps in research and development. Participants/Materials and Methods: This article presents an up-to-date systematic review of the treatment effects of rTMS and tDCS on motor function. A literary search was conducted, utilizing search terms "stroke" and "transcranial stimulation." Items were excluded if they failed to: (1) include stroke patients, (2) study motor outcomes, or (3) include rTMS/tDCS as treatments. Other exclusions included: (1) reviews, editorials, and letters, (2) animal or pediatric populations, (3) case reports or sample sizes ≤2 patients, and (4) primary outcomes of dysphagia, dysarthria, neglect, or swallowing. Results: Investigation of PubMed English Database prior to 01/01/2012 produced 695 applicable results. Studies were excluded based on the aforementioned criteria, resulting in 50 remaining studies. They included 1314 participants (1282 stroke patients and 32 healthy subjects) evaluated by motor function pre- and post-tDCS or rTMS. Heterogeneity among studies' motor assessments was high and could not be accounted for by individual comparison. Pooled effect sizes for the impact of post-treatment improvement revealed consistently demonstrable improvements after tDCS and rTMS therapeutic stimulation. Most studies provided limited follow-up for long-term effects. Conclusion: It is apparent from the available studies that non-invasive stimulation may enhance motor recovery and may lead to clinically meaningful functional improvements in the stroke population. Only mild to no adverse events have been reported. Though results have been positive results, the large heterogeneity across articles precludes firm conclusions.

Analgesic and Sedative Effects of Melatonin in Temporomandibular Disorders: A Double-Blind, Randomized, Parallel-Group, Placebo-Controlled Study

Journal of Pain and Symptom Management. Nov, 2012  |  Pubmed ID: 23195393

CONTEXT: The association between myofascial temporomandibular disorder (TMD) and nonrestorative sleep supports the investigation of therapies that can modulate the sleep/wake cycle. In this context, melatonin becomes an attractive treatment option for myofascial TMD pain. OBJECTIVES: To investigate the effects of melatonin on pain (primary aim) and sleep (secondary aim) as compared with placebo in a double-blind, randomized, parallel-group trial. METHODS: Thirty-two females, aged 20-40 years, with myofascial TMD pain were randomized into placebo or melatonin (5mg) treatment groups for a period of four weeks. RESULTS: There was a significant interaction (time vs. group) for the main outcomes of pain scores as indexed by the visual analogue scale and pressure pain threshold (analysis of variance; P<0.05 for these analyses). Post hoc analysis showed that the treatment reduced pain scores by -44% (95% CI -57%, -26%) compared with placebo, and it also increased the pressure pain threshold by 39% (95% CI 14%, 54%). The use of analgesic doses significantly decreased with time (P<0.01). The daily analgesic doses decreased by -66% (95% CI -94%, -41%) when comparing the two groups. Additionally, melatonin improved sleep quality, but its effect on pain was independent of the effect on sleep quality. CONCLUSION: This study provides additional evidence supporting the analgesic effects of melatonin on pain scores and analgesic consumption in patients with mild-to-moderate chronic myofascial TMD pain. Furthermore, melatonin improves sleep quality but its effect on pain appears to be independent of changes in sleep quality.

Neurobiological Effects of Transcranial Direct Current Stimulation: a Review

Frontiers in Psychiatry / Frontiers Research Foundation. 2012  |  Pubmed ID: 23293607

Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation technique that is affordable and easy to operate compared to other neuromodulation techniques. Anodal stimulation increases cortical excitability, while the cathodal stimulation decreases it. Although tDCS is a promising treatment approach for chronic pain as well as for neuropsychiatric diseases and other neurological disorders, several complex neurobiological mechanisms that are not well understood are involved in its effect. The purpose of this systematic review is to summarize the current knowledge regarding the neurobiological mechanisms involved in the effects of tDCS. The initial search resulted in 171 articles. After applying inclusion and exclusion criteria, we screened 32 full-text articles to extract findings about the neurobiology of tDCS effects including investigation of cortical excitability parameters. Overall, these findings show that tDCS involves a cascade of events at the cellular and molecular levels. Moreover, tDCS is associated with glutamatergic, GABAergic, dopaminergic, serotonergic, and cholinergic activity modulation. Though these studies provide important advancements toward the understanding of mechanisms underlying tDCS effects, further studies are needed to integrate these mechanisms as to optimize clinical development of tDCS.

Modulation of Untruthful Responses with Non-invasive Brain Stimulation

Frontiers in Psychiatry / Frontiers Research Foundation. 2012  |  Pubmed ID: 23550273

Deceptive abilities have long been studied in relation to personality traits. More recently, studies explored the neural substrates associated with deceptive skills suggesting a critical role of the prefrontal cortex. Here we investigated whether non-invasive brain stimulation over the dorsolateral prefrontal cortex (DLPFC) could modulate generation of untruthful responses about subject's personal life across contexts (i.e., deceiving on guilt-free questions on daily activities; generating previously memorized lies about past experience; and producing spontaneous lies about past experience), as well as across modality responses (verbal and motor responses). Results reveal that real, but not sham, transcranial direct current stimulation (tDCS) over the DLPFC can reduce response latency for untruthful over truthful answers across contexts and modality responses. Also, contexts of lies seem to incur a different hemispheric laterality. These findings add up to previous studies demonstrating that it is possible to modulate some processes involved in generation of untruthful answers by applying non-invasive brain stimulation over the DLPFC and extend these findings by showing a differential hemispheric contribution of DLPFCs according to contexts.

Polarity- and Valence-dependent Effects of Prefrontal Transcranial Direct Current Stimulation on Heart Rate Variability and Salivary Cortisol

Psychoneuroendocrinology. Jan, 2013  |  Pubmed ID: 22626867

Recent evidence has supported the notion that the hypothalamic-pituitary-adrenal (HPA) and the sympatho-adreno-medullary (SAM) systems are modulated by cortical structures such as the prefrontal cortex. This top-down modulation may play a major role in the neuroendocrine changes associated with stressful events. We aimed to investigate further this hypothesis by modulating directly prefrontal cortex excitability using transcranial direct current stimulation (tDCS) - a non-invasive, neuromodulatory tool that induces polarity-dependent changes in cortical excitability - and measuring effects on salivary cortisol and heart rate variability as proxies of the HPA and SAM systems. Twenty healthy participants with no clinical and neuropsychiatric conditions were randomized to receive bifrontal tDCS (left anodal/right cathodal or left cathodal/right anodal) or sham stimulation, in a within-subject design. During each stimulation session, after a resting period, subjects were shown images with neutral or negative valence. Our findings showed that excitability enhancing left anodal tDCS induced a decrease in cortisol levels. This effect is more pronounced during emotional negative stimuli. Moreover, vagal activity was higher during left anodal tDCS and emotional negative stimuli, as compared to sham stimulation and neutral images. We also observed an association between higher mood scores, higher vagal activation and lower cortisol levels for anodal stimulation. Subjective mood and anxiety evaluation revealed no specific changes after stimulation. Our findings suggest that tDCS induced transient, polarity specific modulatory top-down effects with anodal tDCS leading to a down-regulation of HPA and SAM systems. Further research using tDCS and neuroendocrine markers should explore the mechanisms of stress regulation in healthy and clinical samples.

Bone Loss in Chronic Hemiplegia: a Longitudinal Cohort Study

Journal of Clinical Densitometry : the Official Journal of the International Society for Clinical Densitometry. Apr, 2013  |  Pubmed ID: 22677198

The purpose of this study was to evaluate hemiplegic stroke patients in terms of long-term changes in bone mineral density and related factors. We conducted a longitudinal cohort study, involving 57 first-stroke patients (40 males) with chronic hemiplegia (for more than 12mo), at a university rehabilitation center in the city of São Paulo, Brazil. Bone loss, body composition, lean mass, and fat mass were evaluated at 2 time points (mean interval, 16mo). Bone loss was significantly greater in paretic forearms than in nonparetic forearms (p=0.001) and in patients having suffered strokes more recently (p=0.015). We found no difference between paretic and nonparetic femurs. Femoral bone loss was significantly greater in patients using anticoagulants or anticonvulsants (p=0.025) and in those with greater spasticity (p=0.040), regardless of the time since stroke. Our results provide additional evidence that hemiplegic stroke patients have progressive bone loss and that such bone loss is more common in the arms than in the legs. Patients with poststroke hemiplegia should be densitometric monitored mainly in paretic arm and treated for bone loss, with attention to the determinants identified in this study.

Epidural Direct Current Stimulation over the Left Medial Prefrontal Cortex Facilitates Spatial Working Memory Performance in Rats

Brain Stimulation. May, 2013  |  Pubmed ID: 22878259

Extensive evidence supports the notion that modulation of PFC excitability using low-intensity electrical stimulation is a promising modality for treating neuropsychiatric diseases and improving cognitive function.

Cranial Electrotherapy Stimulation and Transcranial Pulsed Current Stimulation: a Computer Based High-resolution Modeling Study

NeuroImage. Jan, 2013  |  Pubmed ID: 23041337

The field of non-invasive brain stimulation has developed significantly over the last two decades. Though two techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS)--are becoming established tools for research in neuroscience and for some clinical applications, related techniques that also show some promising clinical results have not been developed at the same pace. One of these related techniques is cranial electrotherapy stimulation (CES), a class of transcranial pulsed current stimulation (tPCS). In order to understand further the mechanisms of CES, we aimed to model CES using a magnetic resonance imaging (MRI)-derived finite element head model including cortical and also subcortical structures. Cortical electric field (current density) peak intensities and distributions were analyzed. We evaluated different electrode configurations of CES including in-ear and over-ear montages. Our results confirm that significant amounts of current pass the skull and reach cortical and subcortical structures. In addition, depending on the montage, induced currents at subcortical areas, such as midbrain, pons, thalamus and hypothalamus are of similar magnitude than that of cortical areas. Incremental variations of electrode position on the head surface also influence which cortical regions are modulated. The high-resolution modeling predictions suggest that details of electrode montage influence current flow through superficial and deep structures. Finally we present laptop based methods for tPCS dose design using dominant frequency and spherical models. These modeling predictions and tools are the first step to advance rational and optimized use of tPCS and CES.

The Reporting of Blinding in Physical Medicine and Rehabilitation Randomized Controlled Trials: A Systematic Review

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. May, 2013  |  Pubmed ID: 23150143

Objective: To conduct a systematic review evaluating the reporting of blinding in randomized controlled trials published in the field of Physical Medicine and Rehabilitation over two time periods. Data sources: We searched MEDLINE via PubMed for all randomized controlled trials published in American Journal of Physical Medicine and Rehabilitation, Archives of Physical Medicine and Rehabilitation, Clinical Rehabilitation, Disability and Rehabilitation and (Scandinavian) Journal of Rehabilitation Medicine in the years 2000 and 2010. Study selection: We initially identified 222 articles, and 139 (62.6%) met our selection criteria. Data extraction: Two independent investigators collected data regarding study characteristics and blinding from each article. Consistency of data extraction was evaluated. Data synthesis: When comparing articles from 2010 and 2000, the former showed significantly higher rates for reporting of blinding, explicitly describing key persons' blinding status, and discussing the absence of blinding as a study limitation. There was a trend for lower reporting among trials with positive outcomes. No improvement was observed in other CONSORT-enforced parameters. Conclusions: Although the reporting of blinding in Physical Medicine and Rehabilitation randomized controlled trials shows some improvement over the past decade, it still does not fulfill current recommendations. Given its critical role in determining internal validity, stricter enforcement of CONSORT guidelines is needed.


International Journal of Neural Systems. Feb, 2013  |  Pubmed ID: 23273124

Bifrontal TDCS Prevents Implicit Learning Acquisition in Antidepressant-free Patients with Major Depressive Disorder

Progress in Neuro-psychopharmacology & Biological Psychiatry. Jun, 2013  |  Pubmed ID: 23274503

The findings for implicit (procedural) learning impairment in major depression are mixed. We investigated this issue using transcranial direct current stimulation (tDCS), a method that non-invasively increases/decreases cortical activity. Twenty-eight age- and gender-matched, antidepressant-free depressed subjects received a single-session of active/sham tDCS. We used a bifrontal setup - anode and cathode over the left and the right dorsolateral prefrontal cortex (DLPFC), respectively. The probabilistic classification-learning (PCL) task was administered before and during tDCS. The percentage of correct responses improved during sham; although not during active tDCS. Procedural or implicit learning acquisition between tasks also occurred only for sham. We discuss whether DLPFC activation decreased activity in subcortical structures due to the depressive state. The deactivation of the right DLPFC by cathodal tDCS can also account for our results. To conclude, active bifrontal tDCS prevented implicit learning in depressive patients. Further studies with different tDCS montages and in other samples are necessary.

Site-specific Effects of Mental Practice Combined with Transcranial Direct Current Stimulation on Motor Learning

The European Journal of Neuroscience. Mar, 2013  |  Pubmed ID: 23279569

Mental practice can induce significant neural plasticity and result in motor performance improvement if associated with motor imagery tasks. Given the effects of transcranial direct current stimulation (tDCS) on neuroplasticity, the current study tested whether tDCS, using different electrode montages, can increase the neuroplastic effects of mental imagery on motor learning. Eighteen healthy right-handed adults underwent a randomised sham-controlled crossover experiment to receive mental training combined with either sham or active anodal tDCS of the right primary motor cortex (M1), right supplementary motor area, right premotor area, right cerebellum or left dorsolateral prefrontal cortex (DLPFC). Motor performance was assessed by a blinded rater using: non-dominant handwriting time and legibility, and mentally trained task at baseline (pre) and immediately after (post) mental practice combined with tDCS. Active tDCS significantly enhances the motor-imagery-induced improvement in motor function as compared with sham tDCS. There was a specific effect for the site of stimulation such that effects were only observed after M1 and DLPFC stimulation during mental practice. These findings provide new insights into motor imagery training and point out that two cortical targets (M1 and DLPFC) are significantly associated with the neuroplastic effects of mental imagery on motor learning. Further studies should explore a similar paradigm in patients with brain lesions.

A Feasibility Study Assessing Cortical Plasticity in Chronic Neuropathic Pain Following Burn Injury

Journal of Burn Care & Research : Official Publication of the American Burn Association. Jan-Feb, 2013  |  Pubmed ID: 23292595

The aim of this article is to evaluate the neuroplastic changes associated with chronic neuropathic pain following burn injury and modulation feasibility using transcranial direct current stimulation (tDCS). This is a crossover, double-blinded case series involving three patients with chronic neuropathic pain following burn injury. Participants were randomly assigned to undergo single sessions of both sham and active anodal tDCS over the primary motor cortex, contralateral to the most painful site. Excitability of the motor cortex was assessed before and after each stimulation session with the use of transcranial magnetic stimulation. An overall decrease in cortical excitability was seen after active tDCS only, as characterized by a decrease in intracortical facilitation and amplitude of motor evoked potentials and an increase in intracortical inhibition. Clinical outcomes did not change after a single session of tDCS. Results are consistent with previous studies showing that patients with chronic neuropathic pain have defective intracortical inhibition. This case series shows early evidence that chronic pain following burn injury may share similar central neural mechanisms, which could be modulated using tDCS.

Effects of Sensory Behavioral Tasks on Pain Threshold and Cortical Excitability

PloS One. 2013  |  Pubmed ID: 23301010

Transcutaneous electrical stimulation has been proven to modulate nervous system activity, leading to changes in pain perception, via the peripheral sensory system, in a bottom up approach. We tested whether different sensory behavioral tasks induce significant effects in pain processing and whether these changes correlate with cortical plasticity.

Safety of Repeated Transcranial Direct Current Stimulation in Impaired Skin: a Case Report

The Journal of ECT. Jun, 2013  |  Pubmed ID: 23303424

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique based on the application of a weak, direct electric current via 2 or more electrodes (anode and cathode) over the scalp. One concern when applying tDCS is skin burn. It has been suggested that skin lesions are related to changes in the local dermal homeostasis, and therefore, caution is warranted in patients with skin diseases (Loo et al [Int J Neuropsychopharmacol. 2011;14:425-426]). In this context, we believe that it would be useful for this emerging field of tDCS to report the preliminary safety of repeated application of tDCS in a patient with vitiligo, an autoimmune disorder characterized by depigmentation sites of the skin or mucous membranes. We report the case of a 31-year-old male patient with schizophrenia who underwent 10-daily tDCS sessions. He has had generalized vitiligo since childhood, and despite previous treatment, no current dermatologic follow-up was being carried out. Depigmentation sites were evident in different areas, particularly under the anodal area. We found that repeated anodal tDCS in 1 patient did not lead to skin lesions when applied over a vitiligo skin area. Some of the procedures that we used to buffer changes in skin temperature may have contributed to prevent tDCS-induced skin damage. Nevertheless, the exact conditions that lead to skin lesion are still unknown. Given the growing use and testing of tDCS, continuous assessment and reporting of local adverse effects are still warranted especially in conditions with increased risk of skin lesions such as in dermatologic conditions, skin burns, and previous skin damage.

Acute Working Memory Improvement After TDCS in Antidepressant-free Patients with Major Depressive Disorder

Neuroscience Letters. Mar, 2013  |  Pubmed ID: 23370288

Based on previous studies showing that transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique that employs weak, direct currents to induce cortical-excitability changes, might be useful for working memory (WM) enhancement in healthy subjects and also in treating depressive symptoms, our aim was to evaluate whether tDCS could acutely enhance WM in depressed patients. Twenty-eight age- and gender-matched, antidepressant-free depressed subjects received a single-session of active/sham tDCS in a randomized, double-blind, parallel design. The anode was positioned over the left and the cathode over the right dorsolateral prefrontal cortex. The n-back task was used for assessing WM and it was performed immediately before and 15min after tDCS onset. We found that active vs. sham tDCS led to an increase in the rate of correct responses. We also used signal detection theory analyses to show that active tDCS increased both discriminability, i.e., the ability to discriminate signal (correct responses) from noise (false alarms), and response criterion, indicating a lower threshold to yield responses. All effect sizes were large. In other words, one session of tDCS acutely enhanced WM in depressed subjects, suggesting that tDCS can improve "cold" (non affective-loaded) working memory processes in MDD. Based on these findings, we discuss the effects of tDCS on WM enhancement in depression. We also suggest that the n-back task could be used as a biomarker in future tDCS studies investigating prefrontal activity in healthy and depressed samples.

The Sertraline Vs. Electrical Current Therapy for Treating Depression Clinical Study: Results from a Factorial, Randomized, Controlled Trial

JAMA Psychiatry (Chicago, Ill.). Apr, 2013  |  Pubmed ID: 23389323

Transcranial direct current stimulation (tDCS) trials for major depressive disorder (MDD) have shown positive but mixed results.

Focal Modulation of the Primary Motor Cortex in Fibromyalgia Using 4×1-ring High-definition Transcranial Direct Current Stimulation (HD-tDCS): Immediate and Delayed Analgesic Effects of Cathodal and Anodal Stimulation

The Journal of Pain : Official Journal of the American Pain Society. Apr, 2013  |  Pubmed ID: 23415877

Fibromyalgia is a prevalent chronic pain syndrome characterized by altered pain and sensory processing in the central nervous system, which is often refractory to multiple therapeutic approaches. Given previous evidence supporting analgesic properties of noninvasive brain stimulation techniques in this condition, this study examined the effects of a novel, more focal method of transcranial direct current stimulation (tDCS), using the 4×1-ring configuration of high-definition (HD)-tDCS, on overall perceived pain in fibromyalgia patients. In this patient- and assessor-blind, sham-controlled, crossover trial, 18 patients were randomized to undergo single 20-minute sessions of anodal, cathodal, and sham HD-tDCS at 2.0 mA in a counterbalanced fashion. The center electrode was positioned over the left primary motor cortex. Pain scales and sensory testing were assessed before and after each intervention. A finite element method brain model was generated to predict electric field distribution. We found that both active stimulation conditions led to significant reduction in overall perceived pain as compared to sham. This effect occurred immediately after cathodal HD-tDCS and was evident for both anodal and cathodal HD-tDCS 30 minutes after stimulation. Furthermore, active anodal stimulation induced a significant bilateral increase in mechanical detection thresholds. These interventions proved well tolerated in our patient population.

Transcranial Direct Current Stimulation (tDCS) for Catatonic Schizophrenia: a Case Study

Schizophrenia Research. May, 2013  |  Pubmed ID: 23434501

Response to the Letter to the Editor by Berger

Journal of Rehabilitation Medicine : Official Journal of the UEMS European Board of Physical and Rehabilitation Medicine. Feb, 2013  |  Pubmed ID: 23495381

Transcranial Direct Current Stimulation: Challenges, Opportunities, and Impact on Psychiatry and Neurorehabilitation

Frontiers in Psychiatry / Frontiers Research Foundation. 2013  |  Pubmed ID: 23544030

Transcranial Direct Current Stimulation (tDCS) for the Treatment of Persistent Visual and Auditory Hallucinations in Schizophrenia: A Case Study

Brain Stimulation. Apr, 2013  |  Pubmed ID: 23602026

Methods to Focalize Noninvasive Electrical Brain Stimulation: Principles and Future Clinical Development for the Treatment of Pain

Expert Review of Neurotherapeutics. May, 2013  |  Pubmed ID: 23621302


Depression and Anxiety. Apr, 2013  |  Pubmed ID: 23625554

BACKGROUND: Transcranial direct current stimulation (tDCS) is a promising nonpharmacological therapy for major depression. In the Sertraline versus Electrical Current Therapy for Treating Depression Clinical Trial (SELECT-TDCS) trial, phase-I (Brunoni et al., JAMA Psychiatry, 2013) we found that tDCS is effective for the acute episode. Here, we describe tDCS effects during phases II (crossover) and III (follow-up) of this trial (NCTs: 01149889 and 01149213). METHODS: Phase II (n = 25) was the open-label, crossover phase in which phase-I nonresponders who had received sham-tDCS received a 10-day course of active-tDCS. In phase-III (n = 42), all active-tDCS responders (>50% Montgomery-Asberg Depression Rating Scale (MADRS) improvement or MADRS ≤ 12) were enrolled to a 24-week, follow-up phase in which a maximum of nine tDCS sessions were performed-every other week for 3 months and, thereafter, once a month for the subsequent 3 months-sessions would be interrupted earlier whether the subject relapsed. TDCS was applied at 2 mA/30 min, with the anode over the left and the cathode over the right dorsolateral prefrontal cortex. Relapse was the outcome measure. RESULTS: In phase-II, 52% of completers responded to tDCS. In phase-III, the mean response duration was 11.7 weeks. The survival rate per Kaplan-Meier analysis was 47%. Patients with treatment-resistant depression presented a much lower 24-week survival rate as compared to nonrefractory patients (10% vs. 77%, OR = 5.52; P < .01). Antidepressant use (sertraline 50 mg/day, eight patients) was not a predictor of relapse. TDCS was well tolerated and with few side effects. CONCLUSION: Continuation tDCS protocols should be optimized as to prevent relapse among tDCS responders, particularly for patients with baseline treatment-resistant depression.

Paraspinal Stimulation Combined With Trigger Point Needling and Needle Rotation for the Treatment of Myofascial Pain: A Randomized Sham-controlled Clinical Trial

The Clinical Journal of Pain. Apr, 2013  |  Pubmed ID: 23629597

BACKGROUND:: There are different types and parameters of dry needling (DN) that can affect its efficacy in the treatment of pain that have not been assessed properly. OBJECTIVE:: To test the hypothesis that either multiple deep intramuscular stimulation therapy multiple deep intramuscular stimulation therapy (MDIMST) or TrP lidocaine injection (LTrP-I) is more effective than a placebo-sham for the treatment of myofascial pain syndrome (MPS) and that MDIMST is more effective than LTrP-I for improving pain relief, sleep quality, and the physical and mental state of the patient. METHODS:: Seventy-eight females aged 20 to 40 who were limited in their ability to perform active and routine activities due to MPS in the previous 3 months were recruited. The participants were randomized into 1 of the 3 groups as follows: placebo-sham, LTrP-I, or MDIMST. The treatments were provided twice weekly over 4 weeks using standardized MDIMST and LTrP-I protocols. RESULTS:: There was a significant interaction (time vs. group) for the main outcomes. Compared with the sham-treated group, MDIMST and LTrP-I administration improved pain scores based on a visual analog scale, the pain pressure threshold (P<0.001 for all analyses), and analgesic use (P<0.01 for all analyses). In addition, when comparing the active groups for these outcomes, MDIMST resulted in better improvement than LTrP-I (P<0.01 for all analyses). In addition, both active treatments had a clinical effect, as assessed by a sleep diary and by the SF-12 physical and mental health scores. CONCLUSIONS:: This study highlighted the greater efficacy of MDIMST over the placebo-sham and LTrP-I and indicated that both active treatments are more effective than placebo-sham for MPS associated with limitations in active and routine activities.

Therapeutic Time Window of Noninvasive Brain Stimulation for Pain Treatment: Inhibition of Maladaptive Plasticity with Early Intervention

Expert Review of Medical Devices. May, 2013  |  Pubmed ID: 23668706

Neuromodulatory effects of noninvasive brain stimulation (NIBS) have been extensively studied in chronic disorders such as major depression, chronic pain and stroke. However, few studies have explored the use of these techniques in acute conditions. A possible use of NIBS in acute disorders is to prevent or reverse ongoing maladaptive plastic alterations, seemingly responsible for treatment refractoriness and detrimental behavioral changes. In this review, the authors discuss the potential role of NIBS in blocking maladaptive plasticity using the transition of acute to chronic pain in conditions such as postsurgical pain, central poststroke pain, pain after spinal cord injury and pain after traumatic brain injury as a model. The authors also present suggestions for clinical trial design using NIBS in the acute stage of illnesses.

Non-invasive Brain Stimulation and the Autonomic Nervous System

Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology. May, 2013  |  Pubmed ID: 23684898

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are non-invasive methods of brain stimulation (NIBS) that can induce significant effects on cortical and subcortical neural networks. Both methods are relatively safe if appropriate guidelines are followed, and both can exert neuromodulatory effects that may be applied to the investigation of the autonomic nervous system (ANS). In addition, ANS measures can shed important light onto the neurobiologic mechanisms of NIBS. Here we present a systematic review on studies testing NIBS and ANS simultaneously. We structure our findings into four broad (not mutually exclusive) categories: (i) studies in which ANS function was modified by NIBS versus those in which it was not; (ii) studies in which NIBS was used to understand ANS function, (iii) studies in which ANS was used to understand NIBS mechanisms and (iv) NIBS/ANS studies conducted in healthy subjects versus those in patients with neuropsychiatric diseases. Forty-four articles were identified and no conclusive evidence of the effects of NIBS on ANS was observed, mainly because of the heterogeneity of included studies. Based on a comprehensive summary of this literature we propose how NIBS might be further developed to enhance our understanding of the cortical mechanisms of autonomic regulation and perhaps to modulate autonomic activity for therapeutic purposes.

Effects of Non-pharmacological Pain Treatments on Brain States

Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology. May, 2013  |  Pubmed ID: 23706958

OBJECTIVE: To (1) evaluate the effects of a single session of four non-pharmacological pain interventions, relative to a sham tDCS procedure, on pain and electroencephalogram- (EEG-) assessed brain oscillations, and (2) determine the extent to which procedure-related changes in pain intensity are associated with changes in brain oscillations. METHODS: 30 individuals with spinal cord injury and chronic pain were given an EEG and administered measures of pain before and after five procedures (hypnosis, meditation, transcranial direct current stimulation [tDCS], neurofeedback, and a control sham tDCS procedure). RESULTS: Each procedure was associated with a different pattern of changes in brain activity, and all active procedures were significantly different from the control procedure in at least three bandwidths. Very weak and mostly non-significant associations were found between changes in EEG-assessed brain activity and pain. CONCLUSIONS: Different non-pharmacological pain treatments have distinctive effects on brain oscillation patterns. However, changes in EEG-assessed brain oscillations are not significantly associated with changes in pain, and therefore such changes do not appear useful for explaining the benefits of these treatments. SIGNIFICANCE: The results provide new findings regarding the unique effects of four non-pharmacological treatments on pain and brain activity.

Motor and Parietal Cortex Stimulation for Phantom Limb Pain and Sensations

Pain. Apr, 2013  |  Pubmed ID: 23707312

Limb amputation may lead to chronic painful sensations referred to as the absent limb, ie phantom limb pain (PLP), which is likely subtended by maladaptive plasticity. The present study investigated whether transcranial direct current stimulation (tDCS), a noninvasive technique of brain stimulation that can modulate neuroplasticity, can reduce PLP. In 2 double-blind, sham-controlled experiments in subjects with unilateral lower or upper limb amputation, we measured the effects of a single session of tDCS (2mA, 15min) of the primary motor cortex (M1) and of the posterior parietal cortex (PPC) on PLP, stump pain, nonpainful phantom limb sensations and telescoping. Anodal tDCS of M1 induced a selective short-lasting decrease of PLP, whereas cathodal tDCS of PPC induced a selective short-lasting decrease of nonpainful phantom sensations; stump pain and telescoping were not affected by parietal or by motor tDCS. These findings demonstrate that painful and nonpainful phantom limb sensations are dissociable phenomena. PLP is associated primarily with cortical excitability shifts in the sensorimotor network; increasing excitability in this system by anodal tDCS has an antalgic effect on PLP. Conversely, nonpainful phantom sensations are associated to a hyperexcitation of PPC that can be normalized by cathodal tDCS. This evidence highlights the relationship between the level of excitability of different cortical areas, which underpins maladaptive plasticity following limb amputation and the phenomenology of phantom limb, and it opens up new opportunities for the use of tDCS in the treatment of PLP.

Enhancement of Affective Processing Induced by Bifrontal Transcranial Direct Current Stimulation in Patients With Major Depression

Neuromodulation : Journal of the International Neuromodulation Society. May, 2013  |  Pubmed ID: 23710817

OBJECTIVE: Our aim was to evaluate whether one single section of transcranial direct current stimulation (tDCS), a neuromodulatory technique that noninvasively modifies cortical excitability, could induce acute changes in the negative attentional bias in patients with major depression. SUBJECTS AND METHODS: Randomized, double-blind, sham-controlled, parallel design enrolling 24 age-, gender-matched, drug-free, depressed subjects. Anode and cathode were placed over the left and right dorsolateral prefrontal cortex. We performed a word Emotional Stroop Task collecting the response times (RTs) for positive-, negative-, and neutral-related words. The emotional Stroop effect for negative vs. neutral and vs. positive words was used as the measure of attentional bias. RESULTS: At baseline, RTs were significantly slower for negative vs. positive words. We found that active but not sham tDCS significantly modified the negative attentional bias, abolishing slower RT for negative words. CONCLUSION: Active but not sham tDCS significantly modified the negative attentional bias. These findings add evidence that a single tDCS session transiently induces potent changes in affective processing, which might be one of the mechanisms of tDCS underlying mood changes.

Targeted Therapies Using Electrical and Magnetic Neural Stimulation for the Treatment of Chronic Pain in Spinal Cord Injury

NeuroImage. May, 2013  |  Pubmed ID: 23727533

BACKGROUND: Chronic neuropathic pain is one of the most common and disabling symptoms in individuals with spinal cord injury (SCI). Over two-thirds of subjects with SCI suffer from chronic pain influencing quality of life, rehabilitation, and recovery. Given the refractoriness of chronic pain to most pharmacological treatments, the majority of individuals with SCI report worsening of this condition over time. Moreover, only 4-6% of patients in this cohort report improvement. Novel treatments targeting mechanisms associated with pain-maladaptive plasticity, such as electromagnetic neural stimulation, may be desirable to improve outcomes. To date, few, small clinical trials have assessed the effects of invasive and noninvasive nervous system stimulation on pain after SCI. OBJECTIVE: We aimed to review initial efficacy, safety and potential predictors of response by assessing the effects of neural stimulation techniques to treat SCI pain. SEARCH STRATEGY: A literature search was performed using the PubMed database including studies using the following targeted stimulation strategies: transcranial Direct Current Stimulation (tDCS), High Definition tDCS (HD-tDCS), repetitive Transcranial Magnetical Stimulation (rTMS), Cranial Electrotherapy Stimulation (CES), Transcutaneous Electrical Nerve Stimulation (TENS), Spinal Cord Stimulation (SCS) and Motor Cortex Stimulation (MCS), published prior to June of 2012. We included studies from 1998 to 2012. RESULTS: Eight clinical trials and one naturalistic observational study (nine studies in total) met the inclusion criteria. Among the clinical trials, three studies assessed the effects of tDCS, two of CES, two of rTMS and one of TENS. The naturalistic study investigated the analgesic effects of SCS. No clinical trials for epidural motor cortex stimulation (MCS) or HD-tDCS were found. Parameters of stimulation and also clinical characteristics varied significantly across studies. Three out of eight studies showed larger effects sizes (0.73, 0.88 and 1.86 respectively) for pain reduction. Classical neuropathic pain symptoms such as dysesthesia (defined as an unpleasant burning sensation in response to touch), allodynia (pain due to a non-painful stimulus), pain in paroxysms, location of SCI in thoracic and lumbar segments and pain in the lower limbs seem to be associated with a positive response to neural stimulation. No significant adverse effects were reported in these studies. CONCLUSIONS: Chronic pain in SCI is disabling and resistant to common pharmacologic approaches. Electrical and magnetic neural stimulation techniques have been developed to offer a potential tool in the management of these patients. Although some of these techniques are associated with large standardized mean differences to reduce pain, we found an important variability in these results across studies. There is a clear need for the development of methods to decrease treatment variability and increase response to neural stimulation for pain treatment. We discuss potential methods such as neuroimaging or EEG-guided neural stimulation and the development of better surrogate markers of response such as TMS-indexed cortical plasticity.

Heart Rate Variability is a Trait Marker of Major Depressive Disorder: Evidence from the Sertraline Vs. Electric Current Therapy to Treat Depression Clinical Study

The International Journal of Neuropsychopharmacology / Official Scientific Journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). Jun, 2013  |  Pubmed ID: 23759172

Decreased heart rate variability (HRV) is a cardiovascular predictor of mortality. Recent debate has focused on whether reductions in HRV in major depressive disorder (MDD) are a consequence of the disorder or a consequence of pharmacotherapy. Here we report on the impact of transcranial direct current stimulation (tDCS), a non-pharmacological intervention, vs. sertraline to further investigate this issue. The employed design was a double-blind, randomized, factorial, placebo-controlled trial. One hundred and eighteen moderate-to-severe, medication-free, low-cardiovascular risk depressed patients were recruited for this study and allocated to either active/sham tDCS (10 consecutive sessions plus two extra sessions every other week) or placebo/sertraline (50 mg/d) for 6 wk. Patients were age and gender-matched to healthy controls from a concurrent cohort study [the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)]. The impact of disorder, treatment and clinical response on HRV (root mean square of successive differences and high frequency) was examined. Our findings confirmed that patients displayed decreased HRV relative to controls. Furthermore, HRV scores did not change following treatment with either a non-pharmacological (tDCS) or pharmacological (sertraline) intervention, nor did HRV increase with clinical response to treatment. Based on these findings, we discuss whether reduced HRV is a trait-marker for MDD, which may predispose patients to a host of conditions and disease even after response to treatment. Our findings have important implications for our understanding of depression pathophysiology and the relationship between MDD, cardiovascular disorders and mortality.

Je Pense Donc Je Fais: Transcranial Direct Current Stimulation Modulates Brain Oscillations Associated with Motor Imagery and Movement Observation

Frontiers in Human Neuroscience. 2013  |  Pubmed ID: 23761755

Motor system neural networks are activated during movement imagery, observation and execution, with a neural signature characterized by suppression of the Mu rhythm. In order to investigate the origin of this neurophysiological marker, we tested whether transcranial direct current stimulation (tDCS) modifies Mu rhythm oscillations during tasks involving observation and imagery of biological and non-biological movements. We applied tDCS (anodal, cathodal, and sham) in 21 male participants (mean age 23.8 ± 3.06), over the left M1 with a current of 2 mA for 20 min. Following this, we recorded the EEG at C3, C4, and Cz and surrounding C3 and C4 electrodes. Analyses of C3 and C4 showed significant effects for biological vs. non-biological movement (p = 0.005), and differential hemisphere effects according to the type of stimulation (p = 0.04) and type of movement (p = 0.02). Analyses of surrounding electrodes revealed significant interaction effects considering type of stimulation and imagery or observation of biological or non-biological movement (p = 0.03). The main findings of this study were (1) Mu desynchronization during biological movement of the hand region in the contralateral hemisphere after sham tDCS; (2) polarity-dependent modulation effects of tDCS on the Mu rhythm, i.e., anodal tDCS led to Mu synchronization while cathodal tDCS led to Mu desynchronization during movement observation and imagery (3) specific focal and opposite inter-hemispheric effects, i.e., contrary effects for the surrounding electrodes during imagery condition and also for inter-hemispheric electrodes (C3 vs. C4). These findings provide insights into the cortical oscillations during movement observation and imagery. Furthermore, it shows that tDCS can be highly focal when guided by a behavioral task.

The Relationship Between Cortical Excitability and Pain Catastrophizing in Myofascial Pain

The Journal of Pain : Official Journal of the American Pain Society. Jun, 2013  |  Pubmed ID: 23810270

Pain catastrophizing regularly occurs in chronic pain patients. It has been suggested that pain catastrophizing is a stable, person-based construct. These findings highlight the importance of investigating catastrophizing in conceptualizing specific approaches for pain management. One important area of investigation is the mechanism underlying pain catastrophizing. Therefore, this study explored the relationship between a neurophysiological marker of cortical excitability, as assessed by transcranial magnetic stimulation, and catastrophizing, as assessed by the Brazilian Portuguese Pain Catastrophizing Scale, in patients with chronic myofascial pain syndrome. The Pain Catastrophizing Scale is a robust questionnaire used to examine rumination, magnification and helplessness that are associated with the experience of pain. We include 24 women with myofascial pain syndrome. The Brazilian Portuguese Pain Catastrophizing Scale and cortical excitability were assessed. Functional and behavioral aspects of pain were evaluated with a version of the Profile of Chronic Pain scale and by multiple pain measurements (eg, pain intensity, pressure pain threshold, and other quantitative sensory measurements). Intracortical facilitation was found to be significantly associated with pain catastrophizing (β = .63, P = .001). Our results did not suggest that these findings were influenced by other factors, such as age or medication use. Furthermore, short intracortical inhibition showed a significant association with pressure pain threshold (β = .44, P = .04). This study elaborates on previous findings indicating a relationship between cortical excitability and catastrophizing. The present findings suggest that glutamatergic activity may be associated with mechanisms underlying pain catastrophizing; thus, the results highlight the need to further investigate the neurophysiological mechanisms associated with pain and catastrophizing.

Biological Markers in Noninvasive Brain Stimulation Trials in Major Depressive Disorder: A Systematic Review

The Journal of ECT. Jul, 2013  |  Pubmed ID: 23845938

The therapeutic effects of transcranial magnetic stimulation (TMS) and transcranial direct current stimulation in patients with major depression have shown promising results; however, there is a lack of mechanistic studies using biological markers (BMs) as an outcome. Therefore, our aim was to review noninvasive brain stimulation trials in depression using BMs.

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