Publications of Olivier BODART
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See detailSimplified Evaluation of CONsciousness Disorders (SECONDs) in individuals with severe brain injury: A validation study
Aubinet, Charlène ULiege; Cassol, Helena ULiege; BODART, Olivier ULiege et al

in Annals of Physical and Rehabilitation Medicine (2021), 64(5), 101432

Background 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 ... [more ▼]

Background 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. Objective. We aimed to validate a new faster tool to assess consciousness in individuals with DoC. Methods This prospective validation study introduces the Simplified Evaluation of CONsciousness Disorders (SECONDs), a tool composed of 8 items: arousal, localization to pain, visual fixation, visual pursuit, oriented behaviors, command-following, and communication (both intentional and functional). A total of 57 individuals with DoC were assessed on 2 consecutive days by 3 blinded examiners: one CRS-R and one SECONDs were performed on 1 day, whereas 2 SECONDs were performed on the other day. A Mann-Whitney U test was used to compare the duration of administration of the SECONDs versus the CRS-R, and weighted Fleiss’ kappa coefficients were used to assess inter-/intra-rater reliability as well as concurrent validity. Results In the 57 participants, the SECONDs was about 2.5 times faster to administer than the CRS-R. The comparison of the CRS-R versus the SECONDs on the same day or the best of the 3 SECONDs led to “substantial” or “almost perfect” agreement (kappa coefficients ranging from 0.78 to 0.85). Intra-/inter-rater reliability also showed almost perfect agreement (kappa coefficients from 0.85 to 0.91 and 0.82 to 0.85, respectively). Conclusions The SECONDs appears to be a fast, reliable and easy-to-use scale to diagnose DoC and may be a good alternative to other scales in clinical settings where time constraints preclude a more thorough assessment. [less ▲]

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See detailEvaluation of the effect of analgesic treatment on signs of nociception-related behaviors during physiotherapy in patients with disorders of consciousness: a pilot crossover randomized controlled trial
Bonin, Estelle ULiege; Binda Fossati, Mariachiara Luisella ULiege; Filippini, Maddalena et al

in Pain (2021)

Neuro-orthopedic disorders are common in patients with disorders of consciousness (DOC) and can lead to potential pain. However, the patients' inability to communicate makes pain detection and management ... [more ▼]

Neuro-orthopedic disorders are common in patients with disorders of consciousness (DOC) and can lead to potential pain. However, the patients' inability to communicate makes pain detection and management very challenging for clinicians. In this crossover randomized double-blind placebo-controlled study, we investigated the effects of an analgesic treatment on the presence of nociception-related behaviors. At baseline, the Nociception Coma Scale-Revised (NCS-R) was performed in 3 conditions: a non-noxious stimulation, a noxious stimulation, and during a physiotherapy session. Patients with a NCS-R total score during physiotherapy equal or above the score observed after the noxious stimulation could participate to the clinical trial, as well as patients with a score above 5. They received an analgesic treatment and a placebo on 2 consecutive days in a randomized order followed by an assessment with the NCS-R. Of the 18 patients, 15 displayed signs of potential pain during physiotherapy. Patients showed higher NCS-R scores during physiotherapy compared with the other conditions, suggesting that mobilizations were potentially painful. Of these 15 patients, 10 met the criteria to participate in the placebo-controlled trial. We did not find any effect of analgesic treatment on the NCS-R scores. This study highlights that physiotherapy may be potentially painful for patients with DOC, while analgesic treatments did not reduced NCS-R scores. Therefore, careful monitoring with appropriate assessment and treatment before and during mobilization should become a priority in clinical settings. Future studies should focus on the development of assessment tools sensitive to analgesic dosage to manage pain in DOC. [less ▲]

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See detailSECONDs administration guidelines: A fast tool for assessing consciousness in brain-injured patients
Sanz, Leandro ULiege; Aubinet, Charlène ULiege; Cassol, Helena ULiege et al

in Journal of Visualized Experiments (2021), (168), 61968

Establishing an accurate diagnosis is crucial for patients with disorders of consciousness (DoC) following a severe brain injury. The Coma Recovery Scale-Revised (CRS-R) is the recommended behavioral ... [more ▼]

Establishing an accurate diagnosis is crucial for patients with disorders of consciousness (DoC) following a severe brain injury. The Coma Recovery Scale-Revised (CRS-R) is the recommended behavioral scale for assessing the level of consciousness among these patients, but its long administration duration is a major hurdle in clinical settings. The Simplified Evaluation of CONsciousness Disorders (SECONDs) is a shorter scale that was developed to tackle this issue. It consists of six mandatory items, observation, command-following, visual pursuit, visual fixation, oriented behaviors, and arousal, and two conditional items, communication and localization to pain. The score ranges between 0 and 8 and corresponds to a specific diagnosis (i.e., coma, unresponsive wakefulness syndrome, minimally conscious state minus/plus, or emergence from the minimally conscious state). A first validation study on patients with prolonged DoC showed high concurrent validity and intra- and inter-rater reliability. The SECONDs requires less training than the CRS-R and its administration lasts about 7 minutes (interquartile range: 5-9 minutes). An additional index score allows the more precise tracking of a patient’s behavioral fluctuation or evolution over time. The SECONDs is therefore a fast and valid tool for assessing the level of consciousness in patients with severe brain injury. It can easily be used by healthcare staff and implemented in time-constrained clinical settings, such as intensive care units, to help decrease misdiagnosis rates and to optimize treatment decisions. These administration guidelines provide detailed instructions for administering the SECONDs in a standardized and reproducible manner, which is an essential requirement for achieving a reliable diagnosis. [less ▲]

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See detailDecreased evoked slow-activity after tDCS in disorders of consciousness
Mensen, Armand; BODART, Olivier ULiege; Thibaut, Aurore ULiege et al

in Frontiers in Systems Neuroscience (2020), 14(62),

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 ... [more ▼]

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. [less ▲]

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See detailGeneral Anesthesia: A Probe to Explore Consciousness
BONHOMME, Vincent ULiege; STAQUET, Cécile ULiege; Montupil, Javier ULiege et al

in Frontiers in Systems Neuroscience (2019)

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See detailEvaluation of the effect of TDCS on TMS-EEG responses in patients with disorders of consciousness
Mensen, Armand ULiege; BODART, Olivier ULiege; Thibaut, Aurore ULiege et al

in Frontiers in Neuroscience (2018, June 21)

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See detailPCI & Auditory ERPs for the diagnosis of disorders of consciousness: a EEG-based methods comparison study
Blandiaux, Séverine ULiege; Raimondo, Federico ULiege; Wolff, Audrey ULiege et al

Conference (2018, June 15)

INTRODUCTION Diagnosing the level of consciousness in patients suffering from severe brain lesions is still a major challenge. EEG-based systems can help discriminate conscious from unconscious patients ... [more ▼]

INTRODUCTION Diagnosing the level of consciousness in patients suffering from severe brain lesions is still a major challenge. EEG-based systems can help discriminate conscious from unconscious patients. This study aims to confront the results from two of the most reliable methods: the Perturbational Complexity Index (PCI) which is based on Transcranial Magnetic Stimulation (TMS-EEG), and a recent machine learning approach using EEG-extracted markers from a standardized oddball auditory stimulation paradigm (EEG-ERP). METHODS Patients presenting either an unresponsive wakefulness syndrome (UWS), a minimally conscious state (MCS) or an emergence of MCS (EMCS) underwent both TMS-EEG and EEG-ERP. We computed PCI value by compressing the spatiotemporal pattern of cortical responses to the perturbation of the cortex with TMS. For EEG-ERP, we extracted 60 markers corresponding to quantification of power spectrum and complexity in individual EEG sensors and information sharing between them. Using machine-learning, we predicted the individual probability of being (minimally) conscious. RESULTS PCI and EEG markers, when considered categorically (i.e. UWS vs MCS), were consistent for all UWS and EMCS patients, whereas the results for MCS patients showed less consistency. Nevertheless, we found a significant correlation between PCI values and the probability of being conscious with the multivariate classifier. CONCLUSION PCI correlated positively with the combination of EEG markers in severely brain-injured patients. These findings imply that EEG signatures of consciousness can be reliably extracted from different contexts and combined into coherent predictive models, encouraging future efforts in large-scale data-driven clinical neuroscience. [less ▲]

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See detailGlobal structural integrity and effective connectivity in patients with disorders of consciousness
BODART, Olivier ULiege; Amico, Enrico; Gomez, Francisco et al

in Brain Stimulation (2018)

Background Previous studies have separately reported impaired functional, structural, and effective connectivity in patients with disorders of consciousness (DOC). The perturbational complexity index (PCI ... [more ▼]

Background Previous studies have separately reported impaired functional, structural, and effective connectivity in patients with disorders of consciousness (DOC). The perturbational complexity index (PCI) is a transcranial magnetic stimulation (TMS) derived marker of effective connectivity. The global fractional anisotropy (FA) is a marker of structural integrity. Little is known about how these parameters are related to each other. Objective We aimed at testing the relationship between structural integrity and effective connectivity. Methods We assessed 23 patients with severe brain injury more than 4 weeks post-onset, leading to DOC or locked-in syndrome, and 14 healthy subjects. We calculated PCI using repeated single pulse TMS coupled with high-density electroencephalography, and used it as a surrogate of effective connectivity. Structural integrity was measured using the global FA, derived from diffusion weighted imaging. We used linear regression modelling to test our hypothesis, and computed the correlation between PCI and FA in different groups. Results Global FA could predict 74% of PCI variance in the whole sample and 56% in the patients' group. No other predictors (age, gender, time since onset, behavioural score) improved the models. FA and PCI were correlated in the whole population (r = 0.86, p < 0.0001), the patients, and the healthy subjects subgroups. Conclusion We here demonstrated that effective connectivity correlates with structural integrity in brain-injured patients. Increased structural damage level decreases effective connectivity, which could prevent the emergence of consciousness. [less ▲]

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See detailNeuronal surface antibody-mediated encephalopathy as manifestation of chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation
Pirotte, Michelle ULiege; Forte, Florence ULiege; Lutteri, Laurence ULiege et al

in Journal of Neuroimmunology (2018), 323

Although it remained controversial for a long time, central nervous system (CNS) involvement of graft-versus-host disease (GVHD) is now becoming recognized as a real nosological entity. Previous case ... [more ▼]

Although it remained controversial for a long time, central nervous system (CNS) involvement of graft-versus-host disease (GVHD) is now becoming recognized as a real nosological entity. Previous case reports have suggested heterogeneous clinical presentations and it is not excluded that the whole spectrum of manifestations has not yet been fully described. Here, we report the case of a 58-year-old man with chronic GVHD who developed a rapidly ingravescent encephalopathy. There was no evidence for CNS immune-mediated lesions on conventional imaging nor for cellular infiltration in the cerebrospinal fluid. Serum analyses revealed the presence of anti-neuronal antibodies directed against anti-contactin-associated protein 2 (anti-Caspr2), a protein associated with voltage-gated potassium neuronal channels. Functional imaging with 2-deoxy-2-[fluorine-18] fluoro- D-glucose integrated with computed tomography (18F-FDG PET-CT) demonstrated diffuse cortical and subcortical hypometabolism. The patient was treated with a combination of immunosuppressive agents (corticosteroids, cyclophosphamide and rituximab) and progressively recovered normal neurocognitive functions. Taken together, these data suggest that CNS-GVHD may manifest as a reversible antibody-mediated functional encephalopathy. This report suggests for the first time the interest of screening for anti-neuronal antibodies and functional imaging with brain 18F-FDG PET-CT in diagnosing this severe complication of allogeneic hematopoietic cell transplantation (alloHSCT). © 2018 Elsevier B.V. [less ▲]

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See detailResistance to eye opening in patients with disorders of consciousness
van Ommen, H. J.; Thibaut, Aurore ULiege; VANHAUDENHUYSE, Audrey ULiege et al

in Journal of Neurology (2018)

Introduction: 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 ... [more ▼]

Introduction: 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. Methods: We recorded REO in chronic patients with disorders of consciousness during a multimodal diagnostic assessment. REO evaluations were performed daily in each patient and clinical diagnosis of unresponsive wakefulness syndrome (UWS), minimally conscious state with (MCS+) or without (MCS−) preserved language processing was made using the Coma Recovery Scale-Revised (CRS-R). Results: Out of 150 consecutive patients, 79 patients fit inclusion criteria. REO was seen in 19 patients (24.1%). At the group level, there was a significant relationship between the presence of REO and the level of consciousness. We also observed a difference in the repeatability of REO between patients in UWS, MCS− and MCS+. Out of 23 patients in UWS, six showed REO, in whom five showed atypical brain patterns activation. Conclusion: Our findings suggest a voluntary basis for REO and stress the need for multiple serial assessments of REO in these patients, especially since most patients show fluctuating levels of consciousness. © 2018 Springer-Verlag GmbH Germany, part of Springer Nature [less ▲]

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See detailMeditation-induced modulation of brain response to transcranial magnetic stimulation
BODART, Olivier ULiege; Fecchio, M.; Massimini, Marcello et al

in Brain Stimulation (2018), 11(6), 1397-1400

[No abstract available]

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See detailSleep-like cortical OFF-periods disrupt causality and complexity in the brain of unresponsive wakefulness syndrome patients
Rosanova, Mario; Fecchio, M.; Casarotto, Silvia et al

in Nature Communications (2018), 9(1),

Unresponsive wakefulness syndrome (UWS) patients may retain intact portions of the thalamocortical system that are spontaneously active and reactive to sensory stimuli but fail to engage in complex causal ... [more ▼]

Unresponsive wakefulness syndrome (UWS) patients may retain intact portions of the thalamocortical system that are spontaneously active and reactive to sensory stimuli but fail to engage in complex causal interactions, resulting in loss of consciousness. Here, we show that loss of brain complexity after severe injuries is due to a pathological tendency of cortical circuits to fall into silence (OFF-period) upon receiving an input, a behavior typically observed during sleep. Spectral and phase domain analysis of EEG responses to transcranial magnetic stimulation reveals the occurrence of OFF-periods in the cortex of UWS patients (N = 16); these events never occur in healthy awake individuals (N = 20) but are similar to those detected in healthy sleeping subjects (N = 8). Crucially, OFF-periods impair local causal interactions, and prevent the build-up of global complexity in UWS. Our findings link potentially reversible local events to global brain dynamics that are relevant for pathological loss and recovery of consciousness. © 2018, The Author(s). [less ▲]

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See detailA TMS–EEG contribution to the multimodal assessment of brain connectivity and consciousness
BODART, Olivier ULiege

Doctoral thesis (2017)

Patients with chronic disorders of consciousness make a challenging population. On the clinical side, establishing an accurate diagnosis is arduous, as the signs of consciousness can be subtle, or even ... [more ▼]

Patients with chronic disorders of consciousness make a challenging population. On the clinical side, establishing an accurate diagnosis is arduous, as the signs of consciousness can be subtle, or even undetectable behaviourally. Both the families and the caregivers need truthful information to make tough decisions about the patient’s management. Transcranial magnetic stimulation, coupled with high-density electroencephalography, is a promising technique to improve our diagnostic ability. The perturbational complexity index derived from this technique is able to distinguish between unconscious and conscious conditions. Its specificity remains to be determined. On the scientific side, the long-standing quest to discover the neural correlates of consciousness is still ongoing. Patients with disorders of consciousness have structural brain damage, and several areas may lose their ability to causally interact in complex patterns with long distance structure. The relation between this ability and structural integrity remains undetermined, despite a vast amount of neuroimaging studies on several networks and connectivities in this population. Our objectives are i) to cross-validate the perturbational complexity index with other neuroimaging techniques, and to determine its specificity, and ii) to determine the relation between global structural integrity and the brain global ability to sustain complex long-range interactions. To do so, we first combined transcranial magnetic stimulation with fluoro-deoxyglucose positron emission tomography, a validated technique studying the brain metabolism, in a population of patients behaviourally characterized by repeated assessments with the gold standard scale, the coma recovery scale – revised. To meet our second objective, we computed and compared the perturbational complexity index and the global fractional anisotropy, a magnetic resonance imaging marker of structural integrity, in patients and in healthy subjects. We found an excellent congruence between electrophysiological and metabolic results in our first study, even in behaviourally unconscious patients showing indirect signs of consciousness. In our second study, we demonstrated that structural integrity largely correlated with the perturbational complexity index, and did not depend on the time since onset or the aetiology. This confirms the diagnostic value of transcranial magnetic stimulation and the perturbational complexity index. It is not only sensitive at the single subject level, but also highly specific. It can detect covert signs of consciousness, as confirmed by other neuroimaging techniques. As such, it could be integrated in diagnostic algorithms and improve their accuracy, leading to better management of these patients. Moreover, the brain’s ability to sustain complex long-range interactions is highly dependant on the global structural integrity. By looking further in detail at the local correlation between these two parameters, our understanding of the emergence of consciousness from fixed structure with variable connectivity would improve. This would be one step forward in the quest for the neural correlates of consciousness. [less ▲]

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See detailTracking dynamic interactions between structural and functional connectivity: a TMS/EEG-dMRI study
Amico, Enrico; BODART, Olivier ULiege; Rosanova, Mario et al

in Brain Connectivity (2017)

Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography ... [more ▼]

Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography (TMS/hd-EEG), TMS pulses revealed electrophysiological signatures of different cortical modules in health and disease. However, the neural underpinnings of these signatures remain unclear. Here, by applying multimodal analyses of cortical response to TMS recordings and diffusion magnetic resonance imaging (dMRI) tractography, we investigated the relationship between functional and structural features of different cortical modules in a cohort of awake healthy volunteers. For each subject we computed directed functional connectivity interactions between cortical areas from the source reconstructed TMS/hd- EEG recordings and correlated them with the correspondent structural connectivity matrix extracted from dMRI tractography, in three different frequency bands (alpha, beta, gamma) and two sites of stimulation (left precuneus and left premotor). Each stimulated area appeared to mainly respond to TMS by being functionally elicited in specific frequency bands, i.e. beta for precuneus and gamma for premotor. We also observed a temporary decrease in the whole-brain correlation between directed functional connectivity and structural connectivity after TMS in all frequency bands. Notably, when focusing on the stimulated areas only, we found that the structurefunction correlation significantly increases over time in the premotor area contralateral to TMS. Our study points out the importance of taking into account the major role played by different cortical oscillations when investigating the mechanisms for integration and segregation of information in the human brain. [less ▲]

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See detailAn unusual cause of diplopia
BODART, Olivier ULiege; MALAISE, Denis ULiege; Horta, Alexia ULiege et al

in Acta Neurologica Belgica (2016)

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See detailChronic disorders of consciousness
Thibaut, Aurore ULiege; BODART, Olivier ULiege; Laureys, Steven ULiege et al

in Canavero, Sergio (Ed.) Surgical Principles of Therapeutic Cortical Stimulation (2015)

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See detailThe Glasgow Coma Scale: time for critical reappraisal?
Laureys, Steven ULiege; Bodart, Olivier ULiege; Gosseries, Olivia ULiege

in Lancet Neurology (2014), Vol 13

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See detailPredicting outcome from subacute unresponsive wakefulness syndrome or vegetative state
BODART, Olivier ULiege; LAUREYS, Steven ULiege

in Critical Care (2014), 18(2), 132

Predicting recovery of consciousness in patients who survive their coma but evolve to a vegetative state (recently coined unresponsive wakefulness syndrome) remains a challenge. Most previous prognostic ... [more ▼]

Predicting recovery of consciousness in patients who survive their coma but evolve to a vegetative state (recently coined unresponsive wakefulness syndrome) remains a challenge. Most previous prognostic studies have focused on the acute coma phase. A novel outcome scale (combining behavioural, aetiology, electroencephalographic, sleep electroencephalographic and somatosensory evoked potential data) has been proposed for patients in subacute unresponsive wakefulness syndrome. The scale’s clinical application awaits validation in a larger population. [less ▲]

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See detailComa and disorders of consciousness: scientific advances and practical considerations for clinicians
Bodart, Olivier ULiege; Laureys, Steven ULiege; Gosseries, Olivia ULiege

in Seminars in Neurology (2013), 33

Recently, neuroscientists and clinicians have seen the rapid evolution of diagnoses in disorders of consciousness. The unresponsive wakefulness syndrome–vegetative state, the minimally conscious state ... [more ▼]

Recently, neuroscientists and clinicians have seen the rapid evolution of diagnoses in disorders of consciousness. The unresponsive wakefulness syndrome–vegetative state, the minimally conscious state plus and minus, and the functional locked-in syndrome have been defined using new neuroimaging techniques. Diffusion tensor imaging, positron emission tomography, functional magnetic resonance imaging, electroen- cephalography, and transcranial magnetic stimulation techniques have all promoted important discoveries in the field of disorders of consciousness. This has led to a better understanding of these patients’ condition and to the development of new prognosis, therapeutic, and communication tools. However, low sensitivity and artifacts problems need to be solved to bring these new technologies to the single-patient level; they also need to be studied in larger scale and randomized control trials. In addition, new ethics questions have arisen and need to be investigated. [less ▲]

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