References of "Laureys, Steven"
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See detailCortical reorganization in an astronaut's brain after long-duration spaceflight.
Demertzi, Athina ULg; Van Ombergen, Angelique; Tomilovskaya, Elena et al

in Brain Structure & Function (2015)

To date, hampered physiological function after exposure to microgravity has been primarily attributed to deprived peripheral neuro-sensory systems. For the first time, this study elucidates alterations in ... [more ▼]

To date, hampered physiological function after exposure to microgravity has been primarily attributed to deprived peripheral neuro-sensory systems. For the first time, this study elucidates alterations in human brain function after long-duration spaceflight. More specifically, we found significant differences in resting-state functional connectivity between motor cortex and cerebellum, as well as changes within the default mode network. In addition, the cosmonaut showed changes in the supplementary motor areas during a motor imagery task. These results highlight the underlying neural basis for the observed physiological deconditioning due to spaceflight and are relevant for future interplanetary missions and vestibular patients. [less ▲]

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See detailCognitive auditory evoked potentials in coma: can you hear me?
Piarulli, Andrea; Charland-Verville, Vanessa ULg; Laureys, Steven ULg

in Brain : A Journal of Neurology (2015), 138(Pt5), 1129-1137

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See detailCerebral FDG uptake changes with supraorbital transcutaneous electrical stimulation for episodic migraine prevention
D'Ostilio, Kevin ULg; Thibaut, Aurore ULg; Laureys, Steven ULg et al

Conference (2015, May)

Background: A recent multicentre RCT has shown that supraorbital transcutaneous stimulation (STS) targeting branches of the ophtalmic nerve with the Cefaly® device is effective as a preventive therapy for ... [more ▼]

Background: A recent multicentre RCT has shown that supraorbital transcutaneous stimulation (STS) targeting branches of the ophtalmic nerve with the Cefaly® device is effective as a preventive therapy for migraine (Schoenen et al., Neurology 2013). However, the mechanisms of action in the central nervous system remain unknown. Here, we conducted voxel-based analyses of [18]FDG-PET to evaluate metabolic changes immediately after the first STS session and after 3 months of treatment in patients with migraine. Methods: Twenty-eight subjects participated in the experiment: 14 patients with episodic migraine (ICHD3 beta criteria) and 14 age-matched controls. Healthy volunteers underwent only one [18]FDG-PET scan whereas patients were scanned at baseline, directly after a first session of STS and after 3 months of daily treatment. Results: Compliant patients showed a significant decrease in the number of attacks (p = 0.03). When compared to controls, patients (n = 14) at baseline were hypometabolic in the fronto-temporal regions (p < 0.001), especially in the orbitofrontal (OFC) and perigenual anterior cingulate cortex. OFC hypometabolism was not correlated with medication intake. In compliant patients, daily STS for 3 months was followed by a normalization of the fronto-temporal hypometabolism (p< 0.001; OFC: pFWE<0.01). Conclusion: Our study suggests that the OFC is hypoactive in episodic migraine. STS with the Cefaly° device is able to normalize this hypoactivity. This indicates that STS exerts its beneficial effect via slow neuromodulatory mechanisms, as also previously shown for percutaneous occipital nerve stimulation in refractory cluster headache (Magis et al., BMC Neurology 2011). [less ▲]

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See detailThalamic and extrathalamic mechanisms of consciousness after severe brain injury.
Lutkenhoff, Evan; Chiang, Jeffrey; TSHIBANDA, Luaba ULg et al

in Annals of Neurology (2015)

Abstract OBJECTIVE: What mechanisms underlie the loss and recovery of consciousness after severe brain injury? We sought to establish, in the largest cohort of patients with disorders of consciousness ... [more ▼]

Abstract OBJECTIVE: What mechanisms underlie the loss and recovery of consciousness after severe brain injury? We sought to establish, in the largest cohort of patients with disorders of consciousness (DOC) to date, the link between gold standard clinical measures of awareness and wakefulness, and specific patterns of local brain pathology-thereby possibly providing a mechanistic framework for patient diagnosis, prognosis, and treatment development. METHODS: Structural T1-weighted magnetic resonance images were collected, in a continuous sample of 143 severely brain-injured patients with DOC (and 96 volunteers), across 2 tertiary expert centers. Brain atrophy in subcortical regions (bilateral thalamus, basal ganglia, hippocampus, basal forebrain, and brainstem) was assessed across (1) healthy volunteers and patients, (2) clinical entities (eg, vegetative state, minimally conscious state), (3) clinical measures of consciousness (Coma Recovery Scale-Revised), and (4) injury etiology. RESULTS: Compared to volunteers, patients exhibited significant atrophy across all structures (p < 0.05, corrected). Strikingly, we found almost no significant differences across clinical entities. Nonetheless, the clinical measures of awareness and wakefulness upon which differential diagnosis rely were systematically associated with tissue atrophy within thalamic and basal ganglia nuclei, respectively; the basal forebrain was atrophied in proportion to patients' response to sensory stimulation. In addition, nontraumatic injuries exhibited more extensive thalamic atrophy. INTERPRETATION: These findings provide, for the first time, a grounding in pathology for gold standard behavior-based clinical measures of consciousness, and reframe our current models of DOC by stressing the different links tying thalamic mechanisms to willful behavior and extrathalamic mechanisms to behavioral (and electrocortical) arousal. Ann Neurol 2015. [less ▲]

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See detailImpact of Aphasia on Consciousness Assessment: A Cross-Sectional Study.
Schnakers, C; Bessou, H; Rubi-Fessen, I et al

in Neurorehabilitation & Neural Repair (2015), 29

BACKGROUND: . Previous findings suggest that language disorders may occur in severely brain-injured patients and could interfere with behavioral assessments of consciousness. However, no study ... [more ▼]

BACKGROUND: . Previous findings suggest that language disorders may occur in severely brain-injured patients and could interfere with behavioral assessments of consciousness. However, no study investigated to what extent language impairment could affect patients' behavioral responses. OBJECTIVE: . To estimate the impact of receptive and/or productive language impairments on consciousness assessment. METHODS: . Twenty-four acute and subacute stroke patients with different types of aphasia (global, n = 11; Broca, n = 4; Wernicke, n = 3; anomic, n = 4; mixed, n = 2) were recruited in neurology and neurosurgery units as well as in rehabilitation centers. The Coma Recovery Scale-Revised (CRS-R) was administered. RESULTS: . We observed that 25% (6 out of 24) of stroke patients with a diagnosis of aphasia and 54% (6 out of 11) of patients with a diagnosis of global aphasia did not reach the maximal CRS-R total score of 23. An underestimation of the consciousness level was observed in 3 patients with global aphasia who could have been misdiagnosed as being in a minimally conscious state, even in the absence of any documented period of coma. More precisely, lower subscores were observed on the communication, motor, oromotor, and arousal subscales. CONCLUSION: . Consciousness assessment may be complicated by the co-occurrence of severe language deficits. This stresses the importance of developing new tools or identifying items in existing scales, which may allow the detection of language impairment in severely brain-injured patients. [less ▲]

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See detailNear-Death Experiences in patients with locked-in syndrome: Not always a blissful journey
Charland-Verville, Vanessa ULg; Lugo, Zulay; Jourdan, Jean-Pierre et al

in Consciousness & Cognition (2015), 34

Memories of Near-Death Experiences (NDEs) most often are recounted as emotionally positive events. At present, no satisfactory explanatory model exists to fully account for the rich phenomenology of NDEs ... [more ▼]

Memories of Near-Death Experiences (NDEs) most often are recounted as emotionally positive events. At present, no satisfactory explanatory model exists to fully account for the rich phenomenology of NDEs following a severe acute brain injury. The particular population of patients with locked-in syndrome (LIS) provides a unique opportunity to study NDEs following infratentorial brain lesions. We here retrospectively characterized the content of NDEs in 8 patients with LIS caused by an acute brainstem lesion (i.e., ‘‘LIS NDEs’’) and 23 NDE experiencers after coma with supratentorial lesions (i.e., ‘‘classical NDEs’’). Compared to ‘‘classical NDEs’’, ‘‘LIS NDEs’’ less frequently experienced a feeling of peacefulness or well-being. It could be hypothesized that NDEs containing less positive emotions might have a specific neuroanatomical substrate related to impaired pontine/paralimbic connectivity or alternatively might be related to the emotional distress caused by the presence of conscious awareness in a paralyzed body. [less ▲]

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See detailCerebral responses and role of the prefrontal cortex in conditioned pain modulation: an fMRI study in healthy subjects
Bogdanov, Volodymyr; Vigano, Alessandro; Noirhomme, Quentin ULg et al

in Behavioural Brain Research (2015)

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See detailConsciousness and complexity during unresponsiveness induced by propofol, xenon, and ketamine
Sarasso, S.; Boly, M.; Napolitani, M. et al

in Current Biology (2015), 25(23), 3099-3105

A common endpoint of general anesthetics is behavioral unresponsiveness [1], which is commonly associated with loss of consciousness. However, subjects can become disconnected from the environment while ... [more ▼]

A common endpoint of general anesthetics is behavioral unresponsiveness [1], which is commonly associated with loss of consciousness. However, subjects can become disconnected from the environment while still having conscious experiences, as demonstrated by sleep states associated with dreaming [2]. Among anesthetics, ketamine is remarkable [3] in that it induces profound unresponsiveness, but subjects often report ketamine dreams upon emergence from anesthesia [4-9]. Here, we aimed at assessing consciousness during anesthesia with propofol, xenon, and ketamine, independent of behavioral responsiveness. To do so, in 18 healthy volunteers, we measured the complexity of the cortical response to transcranial magnetic stimulation (TMS) - an approach that has proven helpful in assessing objectively the level of consciousness irrespective of sensory processing and motor responses [10]. In addition, upon emergence from anesthesia, we collected reports about conscious experiences during unresponsiveness. Both frontal and parietal TMS elicited a low-amplitude electroencephalographic (EEG) slow wave corresponding to a local pattern of cortical activation with low complexity during propofol anesthesia, a high-amplitude EEG slow wave corresponding to a global, stereotypical pattern of cortical activation with low complexity during xenon anesthesia, and a wakefulness-like, complex spatiotemporal activation pattern during ketamine anesthesia. Crucially, participants reported no conscious experience after emergence from propofol and xenon anesthesia, whereas after ketamine they reported long, vivid dreams unrelated to the external environment. These results are relevant because they suggest that brain complexity may be sensitive to the presence of disconnected consciousness in subjects who are considered unconscious based on behavioral responses. © 2015 Elsevier Ltd All rights reserved. [less ▲]

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See detailBehavioural Diagnosis of Disorders of Consciousness
Thibaut, Aurore ULg; Di Perri, Carol ULg; Bodart, Olivier ULg et al

in Rossetti, Andrea; Laureys, Steven (Eds.) Clinical Neurophysiology in Disorders of Consciousness (2015)

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

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

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See detailClinical Response to tDCS Depends on Residual Brain Metabolism and Grey Matter Integrity in Patients With Minimally Conscious State.
Thibaut, Aurore ULg; Di Perri, Carol; Chatelle, Camille ULg et al

in Brain stimulation (2015), 8(6), 1116-23

BACKGROUND: 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 ... [more ▼]

BACKGROUND: 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. OBJECTIVES: In this retrospective study, we investigated the relationship between tDCS responsiveness and neuroimaging data from MCS patients. METHODS: Structural Magnetic Resonance Imaging (MRI), Fluorodeoxyglucose Positron emission tomography (FDG-PET) and clinical electroencephalography (EEG) were acquired in 21 sub-acute and chronic MCS patients (8 tDCS responders) who subsequently (<48 h) received left dorsolateral prefrontal (DLPF) tDCS in a double-blind randomized cross-over trial. The behavioral data have been published elsewhere (Thibaut et al., Neurology, 2014). RESULTS: Grey matter atrophy was observed in non-responders as compared with responders in the left DLPF cortex, the medial-prefrontal cortex, the cingulate cortex, the hippocampi, part of the rolandic regions, and the left thalamus. FDG-PET showed hypometabolism in non-responders as compared with responders in the left DLPF cortex, the medial-prefrontal cortex, the precuneus, and the thalamus. EEG did not show any difference between the two groups. CONCLUSION: Our findings suggest that the transient increase of signs of consciousness following left DLPF tDCS in patients in MCS require grey matter preservation and residual metabolic activity in cortical and subcortical brain areas known to be involved in attention and working memory. These results further underline the critical role of long-range cortico-thalamic connections in consciousness recovery, providing important information for guidelines on the use of tDCS in disorders of consciousness. [less ▲]

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See detailThalamic volume as a biomarker for Disorders Of Consciousness. Progress in Biomedical Optics and Imaging
Rubeaux, M; Mahalingam, J; Gomez, F et al

in Proceedings of SPIE (2015)

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See detailAn empirical classification scheme for detection of impossible and improbable CRS-R subscore combinations
Chatelle, Camille ULg; Bodien, Yelena Guller; Carlowicz, Cecilia et al

Poster (2015)

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See detailInterfaces cerveau-ordinateur, locked-in syndrome et troubles de la conscience.
Lesenfants, Damien; Chatelle, Camille ULg; Laureys, Steven ULg et al

in Medecine sciences : M/S (2015), 31(10), 904-11

Detecting signs of consciousness in patients with severe brain injury constitutes a real challenge for clinicians. The current gold standard in clinical diagnosis is the behavioral scale relying on motor ... [more ▼]

Detecting signs of consciousness in patients with severe brain injury constitutes a real challenge for clinicians. The current gold standard in clinical diagnosis is the behavioral scale relying on motor abilities, which are often impaired or nonexistent in these patients. In this context, brain-computer interfaces (BCIs) could offer a potential complementary tool to detect signs of consciousness whilst bypassing the usual motor pathway. In addition to complementing behavioral assessments and potentially reducing error rate, BCIs could also serve as a communication tool for paralyzed but conscious patients, e.g., suffering from Locked-In Syndrome. In this paper, we report on recent work conducted by the Coma Science Group on BCI technology, aiming to optimize diagnosis and communication in patients with disorders of consciousness and Locked-In syndrome. [less ▲]

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See detailBrain computer interface for assessing consciousness in severely brain-injured patients
Chatelle, Camille ULg; Lesenfants, Damien; Bodien, Yelena G et al

in Rosetti, Andrea; LAUREYS, Steven (Eds.) Clinical Neurophysiology in Disorders of Consciousness (2015)

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See detailQuantitative rates of brain glucose metabolism distinguish minimally conscious from vegetative state patients.
Stender, Johan; Kupers, Ron; Rodell, Anders et al

in Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism (2015), 35(1), 58-65

The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc ... [more ▼]

The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS (n=14), MCS (n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers (n=29). Global cortical CMRglc in VS/UWS and MCS averaged 42% and 55% of normal, respectively. Differences between VS/UWS and MCS were most pronounced in the frontoparietal cortex, at 42% and 60% of normal. In brainstem and thalamus, metabolism declined equally in the two conditions. In EMCS, metabolic rates were indistinguishable from those of MCS. Ordinal logistic regression predicted that patients are likely to emerge into MCS at CMRglc above 45% of normal. Receiver-operating characteristics showed that patients in MCS and VS/UWS can be differentiated with 82% accuracy, based on cortical metabolism. Together these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients. [less ▲]

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See detailTotal connectivity: a marker of dynamical functional connectivity applied to consciousness
Liegeois, Raphaël ULg; Phillips, Christophe ULg; Bahri, Mohamed Ali ULg et al

Poster (2015)

In the last years functional connectivity (FC) has become one of the most popular tools to explore and characterize information contained in fMRI =me series. The classical hypothesis on FC consists of ... [more ▼]

In the last years functional connectivity (FC) has become one of the most popular tools to explore and characterize information contained in fMRI =me series. The classical hypothesis on FC consists of considering it as constant (or static) over the whole fMRI time series. However, it has been emphasized recently that FC should be treated as a dynamical quantity, for example by using sliding windows of the fMRI time courses in order to compute a dynamical FC. We propose a comprehensive marker of FC based on an auto-regressive (AR) model of fMRI time series capturing its static and dynamic properties. We call it total connectivity and we illustrate the benefits of our approach on data of patients undergoing four different states of consciousness. [less ▲]

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