seconds-administration-guidelines-fast-tool-to-assess-consciousness

SECONDs Administration Guidelines: A Fast Tool to Assess Consciousness in Brain-injured Patients

Establishing an accurate diagnosis is crucial for patients with disorders of consciousness (DoC) following a severe brain injury. The Coma Recovery ...

University of Liège

University Hospital of Liège

Transcranial direct current stimulation (tDCS) was recently shown to promote recovery of voluntary signs of consciousness in some patients in minimally conscious state (MCS). However, it remains unclear why clinical improvement is only observed in a subgroup of patients.

Clinical Response to tDCS Depends on Residual Brain Metabolism and Grey Matter Integrity in Patients With Minimally Conscious State.

Positron Emission Tomography: Basic Principles, New Applications, and Studies Under Anesthesia.

To assess the effects of repeated transcranial direct current stimulation (tDCS) sessions on the level of consciousness in chronic patients in minimally conscious state (MCS).

Controlled clinical trial of repeated prefrontal tDCS in patients with chronic minimally conscious state.

Visual pursuit is a key marker of residual consciousness in patients with disorders of consciousness (DOC). Currently, its assessment relies on subjective clinical decisions. In this study, we explore the variability of such clinical assessments, and present an easy-to-use device composed of cameras and video processing algorithms that could help the clinician to improve the detection of visual pursuit in a clinical context. Visual pursuit was assessed by an experienced research neuropsychologist on 31 patients with DOC and on 23 healthy subjects, while the device was used to simultaneously record videos of both one eye and the mirror. These videos were then scored by three researchers: the experienced research neuropsychologist who did the clinical assessment, another experienced research neuropsychologist, and a neurologist. For each video, a consensus was decided between the three persons, and used as the gold standard of the presence or absence of visual pursuit. Almost 10% of the patients were misclassified at the bedside according to their consensus. An automatic classifier analyzed eye and mirror trajectories, and was able to identify patients and healthy subjects with visual pursuit, in total agreement with the consensus on video. In conclusion, our device can be used easily in patients with DOC while respecting the current guidelines of visual pursuit assessment. Our results suggest that our material and our classification method can identify patients with visual pursuit, as well as the three researchers based on video recordings can.

Objective assessment of visual pursuit in patients with disorders of consciousness: an exploratory study.

Different behavioural signs of consciousness can distinguish patients with an unresponsive wakefulness syndrome from patients in minimally conscious state (MCS). The Coma Recovery Scale-Revised (CRS-R) is the most sensitive scale to differentiate the different altered states of consciousness and eleven items detect the MCS. The aim of this study is to document the prevalence of these items. We analysed behavioural assessments of 282 patients diagnosed in MCS based on the CRS-R. Results showed that some items are particularly frequent among patients in MCS, namely fixation, visual pursuit, and reproducible movement to command, which were observed in more than 50% of patients. These responses were also the most probably observed items when the patients only showed one sign of consciousness. On the other hand, some items were rarely or never observed alone, e.g., object localisation (reaching), object manipulation, intelligible verbalisation, and object recognition. The results also showed that limiting the CRS-R assessment to the five most frequently observed items (i.e., fixation, visual pursuit, reproducible movement to command, automatic motor response and localisation to noxious stimulation) detected 99% of the patients in MCS. If clinicians have only limited time to assess patients with disorders of consciousness, we suggest to evaluate at least these five items of the CRS-R.

Prevalence of coma-recovery scale-revised signs of consciousness in patients in minimally conscious state.

Visual pursuit should be tested with a mirror in patients with disorders of consciousness. This stimulus was indeed more efficient than a person or an object, and the auto-referential aspect was supposed to be the key feature. The present study tested the hypothesis that the mirror was more efficient because of its self-aspect.

Mirror efficiency in the assessment of visual pursuit in patients in minimally conscious state.

Resistance to eye opening (REO) is a commonly encountered phenomenon in clinical practice. We aim to investigate whether REO is a sign of consciousness or a reflex in severely brain-injured patients.

Resistance to eye opening in patients with disorders of consciousness.

Patients with prolonged disorders of consciousness (DoC) after severe brain injury may present residual behavioral and cognitive functions. Yet the bedside assessment of these functions is compromised by patients' multiple impairments. Standardized behavioral scales such as the  (CRS-R) have been developed to diagnose DoC, but there is also a need for neuropsychological measurement in these patients. The  (CAVE) was therefore recently created. In this study, we describe five patients in minimally conscious state (MCS) or emerging from the MCS (EMCS). Their cognitive profiles, derived from the CRS-R and CAVE, are presented alongside their neuroimaging results using structural magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET). Scores on the CAVE decreased along with the CRS-R total score, establishing a consistent behavioral/cognitive profile for each patient. Out of these five cases, the one with highest CRS-R and CAVE performance had the least extended cerebral hypometabolism. All patients showed structural and functional brain impairments that were consistent with their behavioral/cognitive profile as based on previous literature. For instance, the presence of visual and motor residual functions was respectively associated with a relative preservation of occipital and motor cortex/cerebellum metabolism. Moreover, residual language comprehension skills were found in the presence of preserved temporal and angular cortex metabolism. Some patients also presented structural impairment of hippocampus, suggesting the presence of memory impairments. Our results suggest that brain-behavior relationships might be observed even in severely brain-injured patients and they highlight the importance of developing new tools to assess residual cognition and language in MCS and EMCS patients. Indeed, a better characterization of their cognitive profile will be helpful in preparation of rehabilitation programs and daily routines.

Brain, Behavior, and Cognitive Interplay in Disorders of Consciousness: A Multiple Case Study.

Meditation-induced modulation of brain response to transcranial magnetic stimulation.

The recovery of patients with disorders of consciousness is a real challenge, especially at the chronic stage. After a severe brain injury, patients can regain some slight signs of consciousness, while not being able to functionally communicate. This entity is called the minimally conscious state (MCS), which has been divided into MCS- and MCS+, respectively based on the absence or presence of language-related signs of consciousness. In this series of cases we aimed to describe retrospectively the longitudinal recovery of specific language-related behaviors using neuroimaging measurement in severely brain-injured patients. Among 209 chronic MCS patients admitted to our center from 2008 to 2018, 19 were assessed at two time points by means of behavioral and neuroimaging assessments. Three of them met our inclusion criteria and were diagnosed as MCS- during their first stay and had recovered command-following when they were reassessed (i.e., MCS+). As compared to their first assessments, when the three patients were in a MCS+, they showed less hypometabolism and/or higher gray matter volume in brain regions such as the precuneus and thalamus, as well as the left caudate and temporal/angular cortices known to be involved in various aspects of semantics. According to these preliminary results, the reappearance of language-related behaviors was concomitant with the recovery of metabolism and gray matter in neural regions that have been associated with self-consciousness and language processing. Prospective studies should be conducted to deepen our understanding of the neural correlates of the recovery of language-related behaviors in chronic MCS.

Reappearance of Command-Following Is Associated With the Recovery of Language and Internal-Awareness Networks: A Longitudinal Multiple-Case Report.

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in elderly people. Although studies suggested that visual hallucinations may be caused by brain damage in the visual system in CBS patients, alterations in specific brain regions in the occipital cortex have not been studied. Functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI; without hallucinations) in CBS patients, has never been explored. We aimed to investigate brain structural and functional changes in a patient with CBS, as compared with late blind (LB) and normally sighted subjects. We employed voxel-based morphometry and cortical thickness analyses to investigate alterations in grey matter characteristics, and rs-fMRI to study changes in functional brain connectivity. Decreased grey matter volume was observed in the middle occipital gyrus and in the cuneus in the CBS patient, and in the middle occipital gyrus and in the lingual gyrus within LB subjects, compared to their respective control groups. Reductions in cortical thickness in associative and multimodal cortices were observed in the CBS patient when comparing with LB subjects. The precuneus exhibited increased functional connectivity with the secondary visual cortex in the CBS patient compared to the controls. In contrast, LB patients showed decreased functional connectivity compared to sighted controls between the DMN and the temporo-occipital fusiform gyrus, a region known to support hallucinations. Our findings suggest a reorganization of the functional connectivity between regions involved in self-awareness and in visual and salience processing in CBS that may contribute to the appearance of visual hallucinations.

Resting-state functional connectivity and cortical thickness characterization of a patient with Charles Bonnet syndrome.

The Nociception Coma Scale-Revised (NCS-R) was developed to help assess pain in patients with disorders of consciousness (DOC). Several studies have shown its sensitivity in assessing response to acute noxious stimuli. However, they failed to determine a reliable cut-off score that could be used to infer pain processing in these patients. This retrospective cross-sectional study aimed to determine a NCS-R cut-off score supporting preserved neural basis for pain experience, based on brain metabolism preservation as measured by fluorodeoxyglucose positron emission tomography (FDG-PET). We included patients in unresponsive wakefulness syndrome (UWS) confirmed by the FDG-PET and examined the NCS-R total scores. As the highest score was 4, we defined the cut-off to be 5 and compared the brain metabolism of these patients to matched patients with DOC and a NCS-R cut-off score ≥5 (ie, potential pain), as well as healthy subjects. We found a higher global cerebral metabolism in healthy subjects compared to both patient groups and also in patients with potential pain compared with FDG-PET confirmed UWS. We observed a preserved metabolism in the left insula in patients with potential pain compared with FDG-PET confirmed UWS. PERSPECTIVES: Our data suggest that using the cut-off score of 5 could be helpful to improve pain management in patients with DOC. Future studies should focus on patients showing scores below this cut-off to better characterize their profile and improve care.

Nociception Coma Scale-Revised Allows to Identify Patients With Preserved Neural Basis for Pain Experience.

To investigate the influence of the presence of a tracheostomy tube to assess pain with the Nociception Coma Scale-Revised (NCS-R) in patients with disorders of consciousness (DOC).

Can the Nociception Coma Scale-Revised Be Used in Patients With a Tracheostomy?

The Coma Recovery Scale-Revised (CRS-R) is the gold standard to assess severely brain-injured patients with prolonged disorders of consciousness (DoC). However, the amount of time needed to complete this examination may limit its use in clinical settings.

Simplified Evaluation of CONsciousness Disorders (SECONDs) in individuals with severe brain injury: a validation study.

Due to life-saving medical advances, the diagnosis and treatment of disorders of consciousness (DOC) has become a more commonly occurring clinical issue. One recently developed intervention option has been non-invasive transcranial direct current stimulation. This dichotomy of patient responders may be better understood by investigating the mechanism behind the transcranial direct current stimulation (tDCS) intervention. The combination of transcranial magnetic stimulation and electroencephalography (TMS-EEG) has been an important diagnostic tool in DOC patients. We therefore examined the neural response using TMS-EEG both before and after tDCS in seven DOC patients (four diagnosed as in a minimally conscious state and three with unresponsive wakefulness syndrome). tDCS was applied over the dorsolateral prefrontal cortex, while TMS pulses were applied to the premotor cortex. None of the seven patients showed relevant behavioral change after tDCS. We did, however, find that the overall evoked slow activity was reduced following tDCS intervention. We also found a positive correlation between the strength of the slow activity and the amount of high-frequency suppression. However, there was no significant pre-post tDCS difference in high frequencies. In the resting-state EEG, we observed that both the incidence of slow waves and the positive slope of the wave were affected by tDCS. Taken together, these results suggest that the tDCS intervention can reduce the slow-wave activity component of bistability, but this may not directly affect high-frequency activity. We hypothesize that while reduced slow activity may be necessary for the recovery of neural function, especially consciousness, this alone is insufficient.

Article	Year
Clinical Response to tDCS Depends on Residual Brain Metabolism and Grey Matter Integrity in Patients With Minimally Conscious State. Brain stimulation\| PubMed ID: 26471400	2015
Positron Emission Tomography: Basic Principles, New Applications, and Studies Under Anesthesia. International anesthesiology clinics\| PubMed ID: 26655512	2016
Controlled clinical trial of repeated prefrontal tDCS in patients with chronic minimally conscious state. Brain injury\| PubMed ID: 28281845	2017
Objective assessment of visual pursuit in patients with disorders of consciousness: an exploratory study. Journal of neurology\| PubMed ID: 28364295	2017
Prevalence of coma-recovery scale-revised signs of consciousness in patients in minimally conscious state. Neuropsychological rehabilitation\| PubMed ID: 28399715	2018
Mirror efficiency in the assessment of visual pursuit in patients in minimally conscious state. Brain injury\| PubMed ID: 28980847	2017
Resistance to eye opening in patients with disorders of consciousness. Journal of neurology\| PubMed ID: 29623396	2018
Brain, Behavior, and Cognitive Interplay in Disorders of Consciousness: A Multiple Case Study. Frontiers in neurology\| PubMed ID: 30154755	2018
Meditation-induced modulation of brain response to transcranial magnetic stimulation. Brain stimulation\| PubMed ID: 30205950	2018
Reappearance of Command-Following Is Associated With the Recovery of Language and Internal-Awareness Networks: A Longitudinal Multiple-Case Report. Frontiers in systems neuroscience\| PubMed ID: 30863288	2019
Resting-state functional connectivity and cortical thickness characterization of a patient with Charles Bonnet syndrome. PloS one\| PubMed ID: 31318888	2019
Nociception Coma Scale-Revised Allows to Identify Patients With Preserved Neural Basis for Pain Experience. The journal of pain\| PubMed ID: 31733361	2020
Can the Nociception Coma Scale-Revised Be Used in Patients With a Tracheostomy? Archives of physical medicine and rehabilitation\| PubMed ID: 31765612	2020
Simplified Evaluation of CONsciousness Disorders (SECONDs) in individuals with severe brain injury: a validation study. Annals of physical and rehabilitation medicine\| PubMed ID: 32992025	2020
Decreased Evoked Slow-Activity After tDCS in Disorders of Consciousness. Frontiers in systems neuroscience\| PubMed ID: 33100977	2020

Sarah Wannez

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