Proteomic and imaging markers have been widely studied as potential biomarkers for diagnosis, monitoring and prognosis of Alzheimer's disease. In this study, we used Alzheimer Disease Neuroimaging Initiative dataset and performed parallel independent component analysis on cross sectional and longitudinal proteomic and imaging data in order to identify the best proteomic model for diagnosis, monitoring and prediction of Alzheimer disease (AD). We used plasma proteins measurement and imaging data from AD and healthy controls (HC) at the baseline and 1year follow-up. Group comparisons at baseline and changes over 1year were calculated for proteomic and imaging data. The results were fed into parallel independent component analysis in order to identify proteins that were associated with structural brain changes cross sectionally and longitudinally. Regression model was used to find the best model that can discriminate AD from HC, monitor AD and to predict MCI converters from non-converters. We showed that five proteins are associated with structural brain changes in the brain. These proteins could discriminate AD from HC with 57% specificity and 89% sensitivity. Four proteins whose change over 1year were associated with brain structural changes could discriminate AD from HC with sensitivity of 93%, and specificity of 92%. This model predicted MCI conversion to AD in 2years with 94% accuracy. This model has the highest accuracy in prediction of MCI conversion to AD within the ADNI-1 dataset. This study shows that combination of selected plasma protein levels and MR imaging is a useful method in identifying potential biomarker.
Abstinence-based therapy (ABT) and methadone maintenance therapy (MMT) are common methods of treatment in heroin dependence as both suppress subjective feeling of drug craving. However, it is not clear whether the neural basis of craving suppression is similar in both types of treatments. In this study, we compared brain activation during pictorial presentation of heroin-related cues in ABT and MMT groups to understand the neural basis of drug craving in these groups.
To compare the potential of five functional magnetic resonance imaging (fMRI) language paradigms in activating language areas in Persian-speaking volunteers in order to optimize these tasks for clinically useful protocol.
Manifestations of dyslexia depend on language systems and scripts. This study explored the prevalence and clinical features of developmental dyslexia among monolingual Persian students and provided insights on mechanisms involved in reading Persian.
There is a paucity of neuroimaging data in pediatric-onset obsessive-compulsive disorder (OCD). This multimodal neuroimaging study aimed to identify structural gray (GM) and white matter (WM) microstructure changes in pediatric OCD.
We aimed to investigate changes in the verbal recognition memory network in patients with early Parkinsons disease (PD) without overt recognition memory alteration. Verbal recognition memory was assessed in 24 PD patients in early stages of the disease and a control group of 24 healthy subjects during fMRI data acquisition. Participants were presented with a list of 35 words before imaging, and later during fMRI scanning they were required to recognize these previously presented words. Both model-based (FEAT) and model-free (MELODIC) analyses of the fMRI data were carried out with FSL software. Memory was also assessed by means of Reys Auditory Verbal Learning Test (RAVLT). PD patients showed no difference in the fMRI recognition memory task and recognition memory assessed by the RAVLT compared to healthy controls. Model-based analysis did not show significant differences between groups. On the other hand, model-free analysis identified components that fitted the task-model and were common to all the participants, as well as components that differed between PD and healthy controls. PD patients showed decreased task-related activations in areas involved in the recognition memory network and decreased task-related deactivations in the default mode network in comparison with controls. In conclusion, model-free fMRI analysis detected alterations in functional cerebral networks involved in a verbal memory task in PD patients without evident recognition memory deficit.
To identify neuropsychological and structural brain changes using a combination of high-resolution structural and diffusion tensor imaging in pediatric bipolar disorder (PBD) with psychosis (presence of delusions and or hallucinations).
The aims of this study were to i) identify substantia nigra subregions i.e. pars reticulata (SNr) and pars compacta (SNc), in human, and ii) to assess volumetric changes in these subregions in the diagnosis of Parkinsons disease. Current MR imaging techniques are unable to distinguish SNr and SNc. Segmentation of these regions may be clinically useful in Parkinsons disease (PD) as substantia nigra is invariably affected in PD. We acquired quantitative T1 as well as diffusion tensor imaging (DTI) data from ten healthy subjects and ten PD patients. For each subject, the left and right SN were manually outlined on T1 images and then classified into two discrete regions based on the characteristics of their connectivity with the rest of the brain using an automated clustering method on the DTI data. We identified two regions in each subjects SN: an internal region that is likely to correspond with SNc because it was mainly connected with posterior striatum, pallidum, anterior thalamus, and prefrontal cortex; and an external region that corresponds with SNr because it was chiefly connected with posterior thalamus, ventral thalamus, and motor cortex. Volumetric study of these regions in PD patients showed a general atrophy in PD particularly in the right SNr. This pilot study showed that automated DTI-based parcellation of SN subregions may provide a useful tool for in-vivo identification of SNc and SNr and might therefore assist to detect changes that occur in patients with PD.
Olfactory dysfunction is known to occur before the appearance of the classical motor signs in Parkinsons disease (PD) and diffusion tensor imaging (DTI) studies in PD have reported fractional anisotropy (FA) reductions in the early disease stages. We aimed to investigate the relationship between olfactory dysfunction and white matter (WM) FA of central olfactory areas in early PD. Twenty-four patients at Hoehn and Yahr stages I and II and 24 healthy controls matched by age, gender and years of education participated in this study. DTI was acquired at a 3 Tesla scanner and odor identification was assessed using the University of Pennsylvania Smell Identification Test (UPSIT). We performed FA voxelwise group comparisons in the central olfactory structures using tract-based spatial statistics (TBSS) and correlation analyses between FA values in these central olfactory areas and UPSIT scores. Patients with severe microsmia (UPSIT between 19 and 25) and anosmia (UPSIT lower or equal to 18) had lower FA values than PD patients with mild/moderate or no olfactory dysfunction (UPSIT between 26 and 40) and healthy controls in the WM adjacent to gyrus rectus. In addition, patients with anosmia had reduced FA in the WM surrounding primary olfactory areas in comparison with healthy controls. FA values in the WM adjacent to primary olfactory cortex and right gyrus rectus correlated with UPSIT scores in the PD group. This study demonstrates, for the first time, that microstructural WM reductions are present in the central olfactory system of early stage PD patients and that these reductions are associated with reduced ability to smell.
Neural correlates of single word reading with the use of a functional MRI (fMRI) scan have been widely studied in different languages. These study patterns of cortical activation differ in different languages. In this report we used a similar technique to study cortical activation when reading single Persian words.
Functional MRI studies on patients with multiple sclerosis (MS) have demonstrated widespread cortical reorganization of the motor network. However, few functional studies have addressed cortical plasticity in patients with clinically isolated syndrome (CIS). The activity of the lower limb motor system, despite its highlighted involvement in patients with CIS and MS, has been little studied. Thus, brain activation was compared in CIS patients with clinically intact motor systems with that in healthy control participants while they were performing motor tasks with four limbs. A total of 26 right-handed patients with CIS with clinically intact motor systems and 28 right-handed age and sex-matched controls participated in the functional MRI (fMRI) motor task. Patients with CIS showed greater activation in the ipsilateral secondary somatosensory cortex, cingulate gyrus and precuneus cortex while performing the ankle movement task compared to healthy controls. In the finger-tapping task, patients with CIS showed greater activity in the contralateral thalamus, ipsilateral premotor and superior temporal gyrus. In addition, the left inferior frontal gyrus was activated more in patients with CIS, regardless of the hand used. Therefore, despite having clinically intact motor systems, patients with CIS had different motor networks. All novel recruited regions were adjacent to the somatotopy of the primary motor areas of the limbs. Our finding confirm that brain reorganization precedes clinical manifestation, as no patient had any clinical manifestation that suggested involvement of the motor system.
Decision-making and recognition of emotions are often impaired in patients with Parkinsons disease (PD). The orbitofrontal cortex (OFC) and the amygdala are critical structures subserving these functions. This study was designed to test whether there are any structural changes in these areas that might explain the impairment of decision-making and recognition of facial emotions in early PD. We used the Iowa Gambling Task (IGT) and the Ekman 60 faces test which are sensitive to the integrity of OFC and amygdala dysfunctions in 24 early PD patients and 24 controls. High-resolution structural magnetic resonance images (MRI) were also obtained. Group analysis using voxel-based morphometry (VBM) showed significant and corrected (P < 0.05 FEW-small volume correction) gray matter (GM) loss in the right amygdala and bilaterally in the OFC in PD patients. Volumetric analyses were also performed but did not yield significant differences between groups. Left lateral GM volume in OFC showed a slight correlation with the IGT, and bilateral OFC GM was strongly correlated with Ekman test performance in PD patients. We conclude that: (i) impairment in decision-making and recognition of facial emotions occurs at the early stages of PD, (ii) these neuropsychological deficits are accompanied by degeneration of OFC and amygdala, and (iii) bilateral OFC reductions are associated with impaired recognition of emotions, and GM volume loss in left lateral OFC is related to decision-making impairment in PD.
Use of reliable screening and diagnostic tests for assessment of cognitive abilities in neurological patients is rapidly increasing in clinical practice. This is due to the increase in the prevalence of dementias and the raised awareness of cognitive impairment in neurological disorders. Two well-known bedside screening tests for dementias among the English-speaking population are the Mini Mental State Examination (MMSE) and Addenbrookes Cognitive Examination (ACE). However, such tests have not been developed for the Persian-speaking population, which is estimated at 120 million worldwide. In this study we developed the Persian ACE and MMSE, adopted from the English version. We also assessed the sensitivity and specificity of these tests in the identification of Alzheimers disease (AD) and mild cognitive impairment (MCI). We found that the Persian ACE at a cutoff point of 84, has a sensitivity of 93% and a specificity of 91% in discriminating MCI from a normal population; at 78, the test has a sensitivity of 73% and a specificity of 93% in differentiating MCI from AD, and at a similar cutoff point has a sensitivity of 100% and specificity of 96% in discriminating AD from a normal population. We conclude that the Persian ACE is a valuable tool in clinical practice in the Persian-speaking population.
The pattern of degenerative changes in the brain white matter (WM) in aging, mild cognitive impairment (MCI), and Alzheimers disease (AD) has been under debate. Methods of image analysis are an important factor affecting the outcomes of various studies. Here we used diffusion tensor imaging (DTI) to obtain fractional anisotropy (FA) measures of the WM in healthy young (n = 8), healthy elderly (n = 22), MCI (n = 8), and AD patients (n = 16). We then applied "tract-based spatial statistics" (TBSS) to study the effects of aging, MCI, and AD on WM integrity. Our results show that changes in WM integrity (that is, decreases in FA) are different between healthy aging and AD: in healthy older subjects compared with healthy young subjects decreased FA was primarily observed in frontal, parietal, and subcortical areas whereas in AD, compared with healthy older subjects, decreased FA was only observed in the left anterior temporal lobe. This different pattern of decreased anatomical connectivity in normal aging and AD suggests that AD is not merely accelerated aging.
Alzheimers disease (AD) is associated with neuronal loss not only in the hippocampus and amygdala but also in the thalamus. Anterodorsal, centromedial, and pulvinar nuclei are the main sites of degeneration in AD. Here we combined shape analysis and diffusion tensor imaging (DTI) tractography to study degeneration in AD in the thalamus and its connections. Structural and diffusion tensor MRI scans were obtained from 16 AD patients and 22 demographically similar healthy volunteers. The thalamus, hippocampus, and amygdala were automatically segmented using our locally developed algorithm, and group comparisons were carried out for each surface vertex. We also employed probabilistic diffusion tractography to obtain connectivity measures between individual thalamic voxels and hippocampus/amygdala voxels and to segment the internal medullary lamina (IML). Shape analysis showed significant bilateral regional atrophy in the dorsal-medial part of the thalamus in AD patients compared to controls. Probabilistic tractography demonstrated that these regions are mainly connected with the hippocampus, temporal, and prefrontal cortex. Intrathalamic FA comparisons showed reductions in the anterodorsal region of thalamus. Intrathalamic tractography from this region revealed that the IML was significantly smaller in AD patients than in controls. We suggest that these changes can be attributed to the degeneration of the anterodorsal and intralaminar nuclei, respectively. In addition, based on previous neuropathological reports, ventral and dorsal-medial shape change in the thalamus in AD patients is likely to be driven by IML atrophy. This combined shape and connectivity analysis provides MRI evidence of regional thalamic degeneration in AD.
The substantia nigra contains dopaminergic cells that project to the striatum and are affected by the neurodegenerative process that appears in Parkinsons disease (PD). For accurate differential diagnosis and for disease monitoring the availability of a sensitive and non-invasive biomarker for Parkinsons disease would be essential. Although there has been notable progress in studying correlates of nigral degeneration by means of magnetic resonance imaging (MRI) in the past decade, MRI and analysis techniques that allow accurate high-resolution mapping of the SN within a clinically acceptable acquisition time are still elusive. The main purpose of the preliminary study was to evaluate the potential role of the driven equilibrium single pulse observation of T1 (DESPOT1) method for delineation of the SN and differentiation of PD patients from healthy control subjects (n=10 in each group). We also investigated whether additional measures that can be obtained with diffusion tensor imaging (DTI) can further improve the MRI-guided discrimination between PD patients and controls. Our results show that the DESPOT1 method allows for a clear visualisation of the SN as a whole. Volumetric comparisons between ten PD patients and ten healthy subjects revealed significantly smaller volumes in patients for both the left and the right sides when the whole SN was considered. Combining SN volumetry and its connectivity with the thalamus improved the classification sensitivity to 100% and specificity to 80% for PD (discriminant function analysis with leave-one-out cross validation). Combining DESPOT1 imaging and DTI could therefore serve as a diagnostic marker for idiopathic Parkinsons disease in the future.
Considerable clinical and radiological overlap between vascular dementia (VaD) and Alzheimer disease (AD) often makes the diagnosis difficult. Diffusion-tensor imaging studies showed that fractional anisotropy (FA) could be a useful marker for white matter changes. This study aimed to identify regional FA changes to identify a biomarker that could be used to differentiate VaD from AD.
In this study we segment the hippocampus according to functional connectivity assessed from resting state functional magnetic resonance images in healthy subjects and in patients with Alzheimers disease (AD). We recorded the resting FMRI signal from 16 patients and 22 controls. We used seed-based functional correlation analyses to calculate partial correlations of all voxels in the hippocampus relative to characteristic regional signal changes in the thalamus, the prefrontal cortex (PFC) and the posterior cingulate cortex (PCC), while controlling for ventricular CSF and white matter signals. Group comparisons were carried out controlling for age, gender, hippocampal volume and brain volume. The strength of functional connectivity in each region also was correlated with neuropsychological measures. We found that the hippocampus can be segmented into three distinct functional subregions (head, body, and tail), according to the relative connectivity with PFC, PCC and thalamus, respectively. The AD group showed stronger hippocampus-PFC and weaker hippocampus-PCC functional connectivity, the magnitudes of which correlated with MMSE in both cases. The results are consistent with an adaptive role of the PFC in the context of progression of dysfunction in PCC during earlier stages of AD. Extension of our approach could integrate regional volume measures for the hippocampus with their functional connectivity patterns in ways that should increase sensitivity for assessment of AD onset and progression.
Cognitive dysfunction is common in multiple sclerosis (MS) and validated batteries are limited in languages other than English. We aimed to translate, cross-culturally adapt, validate, and assess reliability of Minimal Assessment of Cognitive Function in MS (MACFIMS) in Persian. The MACFIMS is a well-constructed battery in the MS literature. The battery was adapted to Persian in accordance with available guidelines. A total of 158 MS patients and 90 controls underwent neuropsychological assessment. For reliability assessment the battery was re-administered in a subset of 41 patients after a short interval using alternate forms to mitigate practice effects (approximately 10 days). Patients performed significantly worse than controls in all cognitive tests, supporting discriminant validity of our adapted battery. Approximately half of patients (46.2%) showed cognitive impairment as defined by the impairment in two or more tests. The Symbol Digit Modalities Test was the most robust test by ROC analysis. All tests showed acceptable to good level of reliability. This is the first validation of gold-standard cognitive testing in Persian. The Persian MACFIMS shows nearly the same psychometrics as its English counterpart.
Related JoVE Video
Journal of Visualized Experiments
What is Visualize?
JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.
How does it work?
We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.
Video X seems to be unrelated to Abstract Y...
In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.