Olivia Gosseries
Research interests
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InterestsMRI, EEG, TMS, locked in syndrome, minimally conscious state, vegetative state, Coma, clinical assesment
Publications
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3.00Impact points
Corticospinal excitability in patients with anoxic, traumatic, and non-traumatic diffuse brain injury.
Brain stimulation. 04/2012;
BACKGROUND: Transcranial magnetic stimulation (TMS) have been frequently used to explore changes in motor cortex excitability in stroke and traumatic brain injury, while the extent of motor cortex reorganization in patients with diffuse non-traumatic brain injury remains largely unknown. OBJECTIVE/H... [more] BACKGROUND: Transcranial magnetic stimulation (TMS) have been frequently used to explore changes in motor cortex excitability in stroke and traumatic brain injury, while the extent of motor cortex reorganization in patients with diffuse non-traumatic brain injury remains largely unknown. OBJECTIVE/HYPOTHESIS: It was hypothesized that the motor cortex excitability would be decreased and would correlate to the severity of brain injury and level of functioning in patients with anoxic, traumatic, and non-traumatic diffuse brain injury. METHODS: TMS was applied to primary motor cortices of 19 patients with brain injury (5 traumatic and 14 non-traumatic causes; on average four months after insult), and 9 healthy controls. The test parameters included resting motor threshold (RMT), short intracortical inhibition (SICI), intracortical facilitation (ICF), and short latency afferent inhibition (SAI). Excitability parameters were correlated to the severity of brain injury measured with Glasgow Coma Scale and the level of functioning assessed using the Ranchos Los Amigos Levels of Cognitive Functioning Assessment Scale and Functional Independence Measure. RESULTS: The patient group revealed a significantly decreased SICI and SAI compared to healthy controls with the amount of SICI correlated significantly to the severity of brain injury. Other electrophysiological parameters did not differ between the groups and did not exhibit any significant relationship with clinical functional scores. CONCLUSIONS: The present study demonstrated the impairment of the cortical inhibitory circuits in patients with brain injury of traumatic and non-traumatic aetiology. Moreover, the significant correlation was found between the amount of SICI and the severity of brain injury.
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Brain Connectivity in Disorders of Consciousness.
Brain connectivity. 04/2012;
Abstract The last 10 years witnessed a considerable increase in our knowledge of brain function in survivors to severe brain injuries with disorders of consciousness (DOC). At the same time, a growing interest developed for the use of functional neuroimaging as a new diagnostic tool in these patient... [more] Abstract The last 10 years witnessed a considerable increase in our knowledge of brain function in survivors to severe brain injuries with disorders of consciousness (DOC). At the same time, a growing interest developed for the use of functional neuroimaging as a new diagnostic tool in these patients. In this context, particular attention has been devoted to connectivity studies-as these, more than measures of brain metabolism, may be more appropriate to capture the dynamics of large populations of neurons. Here, we will review the pros and cons of various connectivity methods as potential diagnostic tools in brain-damaged patients with DOC. We will also discuss the relevance of the study of the level versus the contents of consciousness in this context.
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1.88Impact points
Metabolic activity in external and internal awareness networks in severely brain-damaged patients.
Journal of rehabilitation medicine : official journal of the UEMS European Board of Physical and Rehabilitation Medicine. 02/2012;
Objective: An extrinsic cerebral network (encompassing lateral frontoparietal cortices) related to external/sensory awareness and an intrinsic midline network related to internal/self-awareness have been identified recently. This study measured brain metabolism in both networks in patients with seve... [more] Objective: An extrinsic cerebral network (encompassing lateral frontoparietal cortices) related to external/sensory awareness and an intrinsic midline network related to internal/self-awareness have been identified recently. This study measured brain metabolism in both networks in patients with severe brain damage. Design: Prospective [18F]-fluorodeoxyglucose-positron emission tomography and Coma Recovery Scale-Revised assessments in a university hospital setting. Subjects: Healthy volunteers and patients in vegetative state/unresponsive wakefulness syndrome (VS/UWS), minimally conscious state (MCS), emergence from MCS (EMCS), and locked-in syndrome (LIS). Results: A total of 70 patients were included in the study: 24 VS/UWS, 28 MCS, 10 EMCS, 8 LIS and 39 age-matched controls. VS/UWS showed metabolic dysfunction in extrinsic and intrinsic networks and thalami. MCS showed dysfunction mostly in intrinsic network and thalami. EMCS showed impairment in posterior cingulate/retrosplenial cortices. LIS showed dysfunction only in infratentorial regions. Coma Recovery Scale-Revised total scores correlated with metabolic activity in both extrinsic and part of the intrinsic network and thalami. Conclusion: Progressive recovery of extrinsic and intrinsic awareness network activity was observed in severely brain-damaged patients, ranging from VS/UWS, MCS, EMCS to LIS. The predominance of intrinsic network impairment in MCS could reflect altered internal/self-awareness in these patients, which is difficult to quantify at the bedside.
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1.88Impact points
Metabolic activity in external and internal awareness networks in severely brain-damaged patients
Journal of Rehabilitation Medicine. 02/2012;
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9.49Impact points
Recovery of cortical effective connectivity and recovery of consciousness in vegetative patients.
Brain : a journal of neurology. 01/2012;
Patients surviving severe brain injury may regain consciousness without recovering their ability to understand, move and communicate. Recently, electrophysiological and neuroimaging approaches, employing simple sensory stimulations or verbal commands, have proven useful in detecting higher order pro... [more] Patients surviving severe brain injury may regain consciousness without recovering their ability to understand, move and communicate. Recently, electrophysiological and neuroimaging approaches, employing simple sensory stimulations or verbal commands, have proven useful in detecting higher order processing and, in some cases, in establishing some degree of communication in brain-injured subjects with severe impairment of motor function. To complement these approaches, it would be useful to develop methods to detect recovery of consciousness in ways that do not depend on the integrity of sensory pathways or on the subject's ability to comprehend or carry out instructions. As suggested by theoretical and experimental work, a key requirement for consciousness is that multiple, specialized cortical areas can engage in rapid causal interactions (effective connectivity). Here, we employ transcranial magnetic stimulation together with high-density electroencephalography to evaluate effective connectivity at the bedside of severely brain injured, non-communicating subjects. In patients in a vegetative state, who were open-eyed, behaviourally awake but unresponsive, transcranial magnetic stimulation triggered a simple, local response indicating a breakdown of effective connectivity, similar to the one previously observed in unconscious sleeping or anaesthetized subjects. In contrast, in minimally conscious patients, who showed fluctuating signs of non-reflexive behaviour, transcranial magnetic stimulation invariably triggered complex activations that sequentially involved distant cortical areas ipsi- and contralateral to the site of stimulation, similar to activations we recorded in locked-in, conscious patients. Longitudinal measurements performed in patients who gradually recovered consciousness revealed that this clear-cut change in effective connectivity could occur at an early stage, before reliable communication was established with the subject and before the spontaneous electroencephalogram showed significant modifications. Measurements of effective connectivity by means of transcranial magnetic stimulation combined with electroencephalography can be performed at the bedside while by-passing subcortical afferent and efferent pathways, and without requiring active participation of subjects or language comprehension; hence, they offer an effective way to detect and track recovery of consciousness in brain-injured patients who are unable to exchange information with the external environment.
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2.14Impact points
From armchair to wheelchair: How patients with a locked-in syndrome integrate bodily changes in experienced identity.
Consciousness and cognition. 11/2011; 21(1):431-7.
Different sort of people are interested in personal identity. Philosophers frequently ask what it takes to remain oneself. Caregivers imagine their patients' experience. But both philosophers and caregivers think from the armchair: they can only make assumptions about what it would be like to wa... [more] Different sort of people are interested in personal identity. Philosophers frequently ask what it takes to remain oneself. Caregivers imagine their patients' experience. But both philosophers and caregivers think from the armchair: they can only make assumptions about what it would be like to wake up with massive bodily changes. Patients with a locked-in syndrome (LIS) suffer a full body paralysis without cognitive impairment. They can tell us what it is like. Forty-four chronic LIS patients and 20 age-matched healthy medical professionals answered a 15-items questionnaire targeting: (A) global evaluation of identity, (B) body representation and (C) experienced meaning in life. In patients, self-reported identity was correlated with B and C. Patients differed with controls in C. These results suggest that the paralyzed body remains a strong component of patients' experienced identity, that patients can adjust to objectives changes perceived as meaningful and that caregivers fail in predicting patients' experience.
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2.90Impact points
Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients.
Journal of neurology. 11/2011;
Patients in a minimally conscious state (MCS) show restricted signs of awareness but are unable to communicate. We assessed cerebral glucose metabolism in MCS patients and tested the hypothesis that this entity can be subcategorized into MCS- (i.e., patients only showing nonreflex behavior such as v... [more] Patients in a minimally conscious state (MCS) show restricted signs of awareness but are unable to communicate. We assessed cerebral glucose metabolism in MCS patients and tested the hypothesis that this entity can be subcategorized into MCS- (i.e., patients only showing nonreflex behavior such as visual pursuit, localization of noxious stimulation and/or contingent behavior) and MCS+ (i.e., patients showing command following).Patterns of cerebral glucose metabolism were studied using [(18)F]-fluorodeoxyglucose-PET in 39 healthy volunteers (aged 46 ± 18 years) and 27 MCS patients of whom 13 were MCS- (aged 49 ± 19 years; 4 traumatic; 21 ± 23 months post injury) and 14 MCS+ (aged 43 ± 19 years; 5 traumatic; 19 ± 26 months post injury). Results were thresholded for significance at false discovery rate corrected p < 0.05.We observed a metabolic impairment in a bilateral subcortical (thalamus and caudate) and cortical (fronto-temporo-parietal) network in nontraumatic and traumatic MCS patients. Compared to MCS-, patients in MCS+ showed higher cerebral metabolism in left-sided cortical areas encompassing the language network, premotor, presupplementary motor, and sensorimotor cortices. A functional connectivity study showed that Broca's region was disconnected from the rest of the language network, mesiofrontal and cerebellar areas in MCS- as compared to MCS+ patients.The proposed subcategorization of MCS based on the presence or absence of command following showed a different functional neuroanatomy. MCS- is characterized by preserved right hemispheric cortical metabolism interpreted as evidence of residual sensory consciousness. MCS+ patients showed preserved metabolism and functional connectivity in language networks arguably reflecting some additional higher order or extended consciousness albeit devoid of clinical verbal or nonverbal expression.
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1.81Impact points
Transcranial magnetic stimulation-evoked EEG/cortical potentials in physiological and pathological aging.
Neuroreport. 08/2011; 22(12):592-7.
The frontal cortex undergoes macrostructural and microstructural changes across the lifespan. These changes can be entirely physiological, such as the ones occurring in elderly individuals who are cognitively intact, or pathological, such as the ones occurring in patients with Alzheimer's diseas... [more] The frontal cortex undergoes macrostructural and microstructural changes across the lifespan. These changes can be entirely physiological, such as the ones occurring in elderly individuals who are cognitively intact, or pathological, such as the ones occurring in patients with Alzheimer's disease. Here, we use simultaneous electroencephalography (EEG) and transcranial magnetic stimulation (TMS) to study how the excitability of the frontal cortex changes during healthy and pathological aging. Hence, we compared the TMS-evoked EEG potentials collected in healthy elderly individuals with the ones collected in healthy young individuals, and in patients with Alzheimer's disease. We have shown that the EEG response to TMS of the left superior frontal cortex is not affected by physiological aging but is markedly altered by cognitive impairment.
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9.49Impact points
Electrophysiological correlates of behavioural changes in vigilance in vegetative state and minimally conscious state.
Brain : a journal of neurology. 08/2011; 134(Pt 8):2222-32.
The existence of normal sleep in patients in a vegetative state is still a matter of debate. Previous electrophysiological sleep studies in patients with disorders of consciousness did not differentiate patients in a vegetative state from patients in a minimally conscious state. Using high-density e... [more] The existence of normal sleep in patients in a vegetative state is still a matter of debate. Previous electrophysiological sleep studies in patients with disorders of consciousness did not differentiate patients in a vegetative state from patients in a minimally conscious state. Using high-density electroencephalographic sleep recordings, 11 patients with disorders of consciousness (six in a minimally conscious state, five in a vegetative state) were studied to correlate the electrophysiological changes associated with sleep to behavioural changes in vigilance (sustained eye closure and muscle inactivity). All minimally conscious patients showed clear electroencephalographic changes associated with decreases in behavioural vigilance. In the five minimally conscious patients showing sustained behavioural sleep periods, we identified several electrophysiological characteristics typical of normal sleep. In particular, all minimally conscious patients showed an alternating non-rapid eye movement/rapid eye movement sleep pattern and a homoeostatic decline of electroencephalographic slow wave activity through the night. In contrast, for most patients in a vegetative state, while preserved behavioural sleep was observed, the electroencephalographic patterns remained virtually unchanged during periods with the eyes closed compared to periods of behavioural wakefulness (eyes open and muscle activity). No slow wave sleep or rapid eye movement sleep stages could be identified and no homoeostatic regulation of sleep-related slow wave activity was observed over the night-time period. In conclusion, we observed behavioural, but no electrophysiological, sleep wake patterns in patients in a vegetative state, while there were near-to-normal patterns of sleep in patients in a minimally conscious state. These results shed light on the relationship between sleep electrophysiology and the level of consciousness in severely brain-damaged patients. We suggest that the study of sleep and homoeostatic regulation of slow wave activity may provide a complementary tool for the assessment of brain function in minimally conscious state and vegetative state patients.
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29.75Impact points
Preserved feedforward but impaired top-down processes in the vegetative state.
Science (New York, N.Y.). 05/2011; 332(6031):858-62.
Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation... [more] Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of consciousness in severely brain-damaged patients, than frontoparietal responses. We measured effective connectivity during a mismatch negativity paradigm and found that the only significant difference between patients in a vegetative state and controls was an impairment of backward connectivity from frontal to temporal cortices. This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception.
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2.13Impact points
Comparison of the Full Outline of UnResponsiveness and Glasgow Liege Scale/Glasgow Coma Scale in an intensive care unit population.
Neurocritical care. 04/2011; 15(3):447-53.
The Full Outline of UnResponsiveness (FOUR) has been proposed as an alternative for the Glasgow Coma Scale (GCS)/Glasgow Liège Scale (GLS) in the evaluation of consciousness in severely brain-damaged patients. We compared the FOUR and GLS/GCS in intensive care unit patients who were admitted in a co... [more] The Full Outline of UnResponsiveness (FOUR) has been proposed as an alternative for the Glasgow Coma Scale (GCS)/Glasgow Liège Scale (GLS) in the evaluation of consciousness in severely brain-damaged patients. We compared the FOUR and GLS/GCS in intensive care unit patients who were admitted in a comatose state. FOUR and GLS evaluations were performed in randomized order in 176 acutely (<1 month) brain-damaged patients. GLS scores were transformed in GCS scores by removing the GLS brainstem component. Inter-rater agreement was assessed in 20% of the studied population (N = 35). A logistic regression analysis adjusted for age, and etiology was performed to assess the link between the studied scores and the outcome 3 months after injury (N = 136). GLS/GCS verbal component was scored 1 in 146 patients, among these 131 were intubated. We found that the inter-rater reliability was good for the FOUR score, the GLS/GCS. FOUR, GLS/GCS total scores predicted functional outcome with and without adjustment for age and etiology. 71 patients were considered as being in a vegetative/unresponsive state based on the GLS/GCS. The FOUR score identified 8 of these 71 patients as being minimally conscious given that these patients showed visual pursuit. The FOUR score is a valid tool with good inter-rater reliability that is comparable to the GLS/GCS in predicting outcome. It offers the advantage to be performable in intubated patients and to identify non-verbal signs of consciousness by assessing visual pursuit, and hence minimal signs of consciousness (11% in this study), not assessed by GLS/GCS scales.
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0.64Impact points
[Neuroimaging technique: a diagnostic tool to detect altered states of consciousness].
Médecine sciences : M/S. 02/2011; 27(1):77-81.
Vegetative and minimally conscious states diagnosis remained a major clinical challenge. New paradigms such as measurement of the global cerebral metabolism, the structural and functional integrity of fronto-parietal network, or the spontaneous activity in resting state have been shown to be helpful... [more] Vegetative and minimally conscious states diagnosis remained a major clinical challenge. New paradigms such as measurement of the global cerebral metabolism, the structural and functional integrity of fronto-parietal network, or the spontaneous activity in resting state have been shown to be helpful to disentangle vegetative from minimally conscious patients. Active neuroimagery paradigms also allow detecting voluntary and conscious activity in non-communicative patients. The implementation of these methods in clinical routine could permit to reduce the current high rate of misdiagnosis (40%).
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2.67Impact points
Assessment of consciousness with electrophysiological and neurological imaging techniques.
Current opinion in critical care. 01/2011; 17(2):146-51.
Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. ... [more] Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. Increasing evidence from functional neuroimaging and electrophysiology demonstrates some residual cognitive processing in a subgroup of patients who clinically fail to show any response to commands, leading to the recent proposal of 'unresponsive wakefulness syndrome' as an alternative name for patients previously coined 'vegetative' or 'apallic'. Consciousness can be viewed as the emergent property of the collective behavior of widespread thalamocortical frontoparietal network connectivity. Data from physiological, pharmacological and pathological alterations of consciousness provide evidence in favor of this hypothesis. Increasing our understanding of the neural correlates of consciousness is helping clinicians to do a better job in terms of diagnosis, prognosis and finally treatment and drug development for these severely brain-damaged patients. The current challenge remains to continue translating this research from the bench to the bedside. Only well controlled large multicentric neuroimaging and electrophysiology studies will enable to identify which paraclinical diagnostic or prognostic test is necessary for our routine evidence-based assessment of individuals with disorders of consciousness.
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1.95Impact points
Disorders of consciousness: what's in a name?
NeuroRehabilitation. 01/2011; 28(1):3-14.
Following a coma, some patients may "awaken" without voluntary interaction or communication with the environment. More than 40 years ago this condition was coined coma vigil or apallic syndrome and later became worldwide known as "persistent vegetative state". About 10 years ago ... [more] Following a coma, some patients may "awaken" without voluntary interaction or communication with the environment. More than 40 years ago this condition was coined coma vigil or apallic syndrome and later became worldwide known as "persistent vegetative state". About 10 years ago it became clear that some of these patients who failed to recover verbal or non-verbal communication did show some degree of consciousness--a condition called "minimally conscious state". Some authors questioned the usefulness of differentiating unresponsive "vegetative" from minimally conscious patients but subsequent functional neuroimaging studies have since objectively demonstrated differences in residual cerebral processing and hence, we think, conscious awareness. These neuroimaging studies have also demonstrated that a small subset of unresponsive "vegetative" patients may show unambiguous signs of consciousness and command following inaccessible to bedside clinical examination. These findings, together with negative associations intrinsic to the term "vegetative state" as well as the diagnostic errors and their potential effect on the treatment and care for these patients gave rise to the recent proposal for an alternative neutral and more descriptive name: unresponsive wakefulness syndrome. We here give an overview of PET and (functional) MRI studies performed in these challenging patients and stress the need for a separate ICD-9-CM diagnosis code and MEDLINE MeSH entry for "minimally conscious state" as the lack of clear distinction between vegetative state/unresponsive wakefulness syndrome and minimally conscious state may encumber scientific studies in the field of disorders of consciousness.
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2.90Impact points
Attitudes towards end-of-life issues in disorders of consciousness: a European survey.
Journal of neurology. 01/2011; 258(6):1058-65.
Previous European surveys showed the support of healthcare professionals for treatment withdrawal [i.e., artificial nutrition and hydration (ANH) in chronic vegetative state (VS) patients]. The recent definition of minimally conscious state (MCS), and possibly research advances (e.g., functional neu... [more] Previous European surveys showed the support of healthcare professionals for treatment withdrawal [i.e., artificial nutrition and hydration (ANH) in chronic vegetative state (VS) patients]. The recent definition of minimally conscious state (MCS), and possibly research advances (e.g., functional neuroimaging), may have lead to uncertainty regarding potential residual perception and may have influenced opinions of healthcare professionals. The aim of the study was to update the end-of-life attitudes towards VS and to determine the end-of-life attitudes towards MCS. A 16-item questionnaire related to consciousness, pain and end-of-life issues in chronic (i.e., >1 year) VS and MCS and locked-in syndrome was distributed among attendants of medical and scientific conferences around Europe (n = 59). During a lecture, the items were explained orally to the attendants who needed to provide written yes/no responses. Chi-square tests and logistic regression analyses identified differences and associations for age, European region, religiosity, profession, and gender. We here report data on items concerning end-of-life issues on chronic VS and MCS. Responses were collected from 2,475 participants. For chronic VS (>1 year), 66% of healthcare professionals agreed to withdraw treatment and 82% wished not to be kept alive (P < 0.001). For chronic MCS (>1 year), less attendants agreed to withdraw treatment (28%, P < 0.001) and wished not to be kept alive (67%, P < 0.001). MCS was considered worse than VS for the patients in 54% and for their families in 42% of the sample. Respondents' opinions were associated with geographic region and religiosity. Our data show that end-of-life opinions differ for VS as compared to MCS. The introduction of the diagnostic criteria for MCS has not substantially changed the opinions on end-of-life issues on permanent VS. Additionally, the existing legal ambiguity around MCS may have influenced the audience to draw a line between expressing preferences for self versus others, by implicitly recognizing that the latter could be a step on the slippery slope to legalize euthanasia. Given the observed individual variability, we stress the importance of advance directives and identification of proxies when discussing end-of-life issues in patients with disorders of consciousness.
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2.01Impact points
Hypnotic modulation of resting state fMRI default mode and extrinsic network connectivity.
Progress in brain research. 01/2011; 193:309-22.
Resting state fMRI (functional magnetic resonance imaging) acquisitions are characterized by low-frequency spontaneous activity in a default mode network (encompassing medial brain areas and linked to self-related processes) and an anticorrelated "extrinsic" system (encompassing lateral fr... [more] Resting state fMRI (functional magnetic resonance imaging) acquisitions are characterized by low-frequency spontaneous activity in a default mode network (encompassing medial brain areas and linked to self-related processes) and an anticorrelated "extrinsic" system (encompassing lateral frontoparietal areas and modulated via external sensory stimulation). In order to better determine the functional contribution of these networks to conscious awareness, we here sought to transiently modulate their relationship by means of hypnosis. We used independent component analysis (ICA) on resting state fMRI acquisitions during normal wakefulness, under hypnotic state, and during a control condition of autobiographical mental imagery. As compared to mental imagery, hypnosis-induced modulation of resting state fMRI networks resulted in a reduced "extrinsic" lateral frontoparietal cortical connectivity, possibly reflecting a decreased sensory awareness. The default mode network showed an increased connectivity in bilateral angular and middle frontal gyri, whereas its posterior midline and parahippocampal structures decreased their connectivity during hypnosis, supposedly related to an altered "self" awareness and posthypnotic amnesia. In our view, fMRI resting state studies of physiological (e.g., sleep or hypnosis), pharmacological (e.g., sedation or anesthesia), and pathological modulation (e.g., coma or related states) of "intrinsic" default mode and anticorrelated "extrinsic" sensory networks, and their interaction with other cerebral networks, will further improve our understanding of the neural correlates of subjective awareness.
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2.01Impact points
Multimodal neuroimaging in patients with disorders of consciousness showing "functional hemispherectomy".
Progress in brain research. 01/2011; 193:323-33.
Beside behavioral assessment of patients with disorders of consciousness, neuroimaging modalities may offer objective paraclinical markers important for diagnosis and prognosis. They provide information on the structural location and extent of brain lesions (e.g., morphometric MRI and diffusion tens... [more] Beside behavioral assessment of patients with disorders of consciousness, neuroimaging modalities may offer objective paraclinical markers important for diagnosis and prognosis. They provide information on the structural location and extent of brain lesions (e.g., morphometric MRI and diffusion tensor imaging (DTI-MRI) assessing structural connectivity) but also their functional impact (e.g., metabolic FDG-PET, hemodynamic fMRI, and EEG measurements obtained in "resting state" conditions). We here illustrate the role of multimodal imaging in severe brain injury, presenting a patient in unresponsive wakefulness syndrome (UWS; i.e., vegetative state, VS) and in a "fluctuating" minimally conscious state (MCS). In both cases, resting state FDG-PET, fMRI, and EEG showed a functionally preserved right hemisphere, while DTI showed underlying differences in structural connectivity highlighting the complementarities of these neuroimaging methods in the study of disorders of consciousness.
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Assessment and detection of pain in noncommunicative severely brain-injured patients.
Expert review of neurotherapeutics. 11/2010; 10(11):1725-31.
Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their feelings and potential perception of pain. However, recent studies suggest that patients in a minimall... [more] Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their feelings and potential perception of pain. However, recent studies suggest that patients in a minimally conscious state can experience pain to some extent. Pain monitoring in these patients is hence of medical and ethical importance. In this article, we will focus on the possible use of behavioral scales for the assessment and detection of pain in noncommunicative patients.
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0.61Impact points
[The Sensory Modality Assessment and Rehabilitation Technique (SMART): a behavioral assessment scale for disorders of consciousness].
Revue neurologique. 03/2010; 166(8-9):675-82.
Difficulties in detecting bedside signs of consciousness in non-communicative patients still lead to a high rate of misdiagnosis illustrating the need to employ standardized behavioral assessment scales. The Sensory Modality Assessment and Rehabilitation Technique (SMART) is a behavioral assessment ... [more] Difficulties in detecting bedside signs of consciousness in non-communicative patients still lead to a high rate of misdiagnosis illustrating the need to employ standardized behavioral assessment scales. The Sensory Modality Assessment and Rehabilitation Technique (SMART) is a behavioral assessment scale of consciousness that assesses responses to multimodal sensory stimulation in disorders of consciousness. These stimulations can also be considered to have therapeutic value. We here review the different components and use of the SMART assessment and discuss its validity, reliability, and robustness in clinical practice. The scale has a high intra- and inter-observer reliability thanks to a detailed procedure description. However, in the absence of objective gold standards in the assessment of consciousness, it is currently difficult to make strong claims about its validity. A comparison between SMART and other standardized and validated coma-scales is proposed. In our view, SMART is an interesting tool for monitoring patients with altered states of consciousness subsequent to coma. Currently, we await studies on its concurrent validity as compared to other validated behavioral assessment scales and on the effect of SMART stimulations on patient outcome.
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2.11Impact points
Visual fixation in the vegetative state: an observational case series PET study.
BMC neurology. 01/2010; 10:35.
Assessment of visual fixation is commonly used in the clinical examination of patients with disorders of consciousness. However, different international guidelines seem to disagree whether fixation is compatible with the diagnosis of the vegetative state (i.e., represents "automatic" subco... [more] Assessment of visual fixation is commonly used in the clinical examination of patients with disorders of consciousness. However, different international guidelines seem to disagree whether fixation is compatible with the diagnosis of the vegetative state (i.e., represents "automatic" subcortical processing) or is a sufficient sign of consciousness and higher order cortical processing. We here studied cerebral metabolism in ten patients with chronic post-anoxic encephalopathy and 39 age-matched healthy controls. Five patients were in a vegetative state (without fixation) and five presented visual fixation but otherwise showed all criteria typical of the vegetative state. Patients were matched for age, etiology and time since insult and were followed by repeated Coma Recovery Scale-Revised (CRS-R) assessments for at least 1 year. Sustained visual fixation was considered as present when the eyes refixated a moving target for more than 2 seconds as defined by CRS-R criteria. Patients without fixation showed metabolic dysfunction in a widespread fronto-parietal cortical network (with only sparing of the brainstem and cerebellum) which was not different from the brain function seen in patients with visual fixation. Cortico-cortical functional connectivity with visual cortex showed no difference between both patient groups. Recovery rates did not differ between patients without or with fixation (none of the patients showed good outcome). Our findings suggest that sustained visual fixation in (non-traumatic) disorders of consciousness does not necessarily reflect consciousness and higher order cortical brain function.
Following (23)
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Didier Ledoux
CHU de Liege - Belgium -
Andrea Pigorini
University of Milan -
Steven Laureys
Université de Liège -
Marie Thonnard
Université de Liège -
Victor Cologan
Université de Liège
