References of "Laureys, Steven"
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See detailConsciousness: And Disorders of Consciousness
Heine, Lizette ULg; Demertzi, Athina ULg; Laureys, Steven ULg et al

in Toga, Arthur W (Ed.) Brain mapping : an encyclopedic reference (2015)

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See detailDetecting Levels of Consciousness
Demertzi, Athina ULg; Laureys, Steven ULg

in Levy, N; Clausen, J (Eds.) Handbook of Neuroethics (2015)

Patients with disordered consciousness due to brain injury pose medical and ethical challenges. Rates of clinical misdiagnosis of “vegetative”/unresponsive, minimally conscious and locked-in syndrome ... [more ▼]

Patients with disordered consciousness due to brain injury pose medical and ethical challenges. Rates of clinical misdiagnosis of “vegetative”/unresponsive, minimally conscious and locked-in syndrome states remain challengingly high. Clinical misdiagnosis raises profound ethical concerns in terms of medical management, treatment of pain, and end-of-life decisions. Therefore, valid diagnosis is of utmost importance in clinical settings. A number of neuroimaging and electrophysiology studies now suggest that some behaviorally “vegetative state” patients may nevertheless show atypical cortical activation during resting state conditions; in some cases, they are able to follow commands or even communicate through willfully modified brain activity. Advances in investigating disorders of consciousness with neuroimaging techniques promise to lead to a more accurate understanding of individual patients’ cognitive abilities and to shed light on the gray zones of these clinical conditions. The formulation of an ethical framework which will strike a balance between the protection of these patients and further research on disorders of consciousness is an ethical, clinical, and scientific demand. [less ▲]

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See detailImaging correlation in non-communicating patients
Heine, Lizette ULg; Di Perri, Carol ULg; Soddu, Andrea ULg et al

in Rossetti, A.O; Laureys, Steven (Eds.) Clinical Neurophysiology in Disorders of Consciousness-Brain Function Monitoring in the ICU and beyond (2015)

The diagnosis and medical management of patients with acute or chronic disorders of consciousness (DOC) are challenging. Motor-independent functional neuroimaging technologies are increasingly employed to ... [more ▼]

The diagnosis and medical management of patients with acute or chronic disorders of consciousness (DOC) are challenging. Motor-independent functional neuroimaging technologies are increasingly employed to study covert cognitive processes in the absence of behavioural reports. Studies with functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) performed in this patient population have utilized active, passive and restingstate paradigms. Active paradigms refer to mental imagery tasks that measure wilful modulation of brain signal in specific brain areas, aiming to detect command-following. Passive paradigms are used to measure brain responses to external sensory stimulation (e.g. auditory, somatosensory and visual). Alternatively, in resting-state paradigms, spontaneous brain function is assessed while subjects receive no external stimulation and are instructed to let their mind wander. Independently from each other, these methods have shown differences between healthy controls and patients, as well as among patients with DOC. However, these techniques cannot yet be used in clinical settings before robust information at the single-subject level will be provided: it is expected that multimodal research will improve the single-patient diagnosis, shed light on the prognostic biomarkers, and eventually promote the medical management of patients with consciousness alterations. [less ▲]

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See detailThinking on patients’ behalf: attitudes of healthcare providers towards medico-ethical issues in non-communicating patients
Demertzi, Athina ULg; Laureys, Steven ULg

in Sturma, D; Honnefelder, L; Fuchs, M (Eds.) Yearbook for Science and Ethics (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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See detailDetection of response to command using voluntary control of breathing in disorders of consciousness
Charland-Verville, Vanessa ULg; Lesenfants, Damien; Sela, Lee et al

in Frontiers in Human Neuroscience (2014), 8(1020),

BACKGROUND: Detecting signs of consciousness in patients in a vegetative state/unresponsive wakefulness syndrome (UWS/VS) or minimally conscious state (MCS) is known to be very challenging. Plotkin et al ... [more ▼]

BACKGROUND: Detecting signs of consciousness in patients in a vegetative state/unresponsive wakefulness syndrome (UWS/VS) or minimally conscious state (MCS) is known to be very challenging. Plotkin et al. (2010) recently showed the possibility of using a breathing-controlled communication device in patients with locked in syndrome. We here aim to test a breathing-based "sniff controller" that could be used as an alternative diagnostic tool to evaluate response to command in severely brain damaged patients with chronic disorders of consciousness (DOC). METHODS: Twenty-five DOC patients were included. Patients' resting breathing-amplitude was measured during a 5 min resting condition. Next, they were instructed to end the presentation of a music sequence by sniffing vigorously. An automated detection of changes in breathing amplitude (i.e., >1.5 SD of resting) ended the music and hence provided positive feedback to the patient. RESULTS: None of the 11 UWS/VS patients showed a sniff-based response to command. One out of 14 patients with MCS was able to willfully modulate his breathing pattern to answer the command on 16/19 trials (accuracy 84%). Interestingly, this patient failed to show any other motor response to command. DISCUSSION: We here illustrate the possible interest of using breathing-dependent response to command in the detection of residual cognition in patients with DOC after severe brain injury. [less ▲]

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See detailNear-Death Experiences in patients with locked-in syndrome
Charland-Verville, Vanessa ULg; Lugo Ramirez, Zulay del Rosario ULg; Jourdan, Jean-Pierre et al

Poster (2014, October 04)

Near-Death Experiences (NDEs) are classically associated with positive emotions like peacefulness, happiness and joy [1-3]. To date, few negative NDEs reports have been documented [4]. Although NDEs ... [more ▼]

Near-Death Experiences (NDEs) are classically associated with positive emotions like peacefulness, happiness and joy [1-3]. To date, few negative NDEs reports have been documented [4]. Although NDEs classically arise in the context of an acute severe brain damage, their associated memories are reported as being phenomenologically very rich and detailed [5]. To date, no satisfactory explanatory model exits to fully account for the rich phenomenology of NDEs following a severe acute brain injury [6]. Neurobiological hypotheses include cerebral hypoxia [7, 8] and temporal lobe dysfunctions [9] to account for some of the features occurring during NDEs. However, it has been recently shown that anoxic/hypoxic, traumatic and other supratentorial brain lesions do not seem to influence the content of a NDE when assessed with a standardized tool (i.e., Greyson NDE scale; [1]). Due to their particular brain lesion (i.e., pontine brainstem), locked-in syndrome (LIS) patients provide a unique opportunity to further investigate the neural correlates of NDEs. We here aimed at retrospectively characterizing the content of NDEs in patients with LIS having suffered from an acute brainstem lesion (cerebrovascular accident (CVA) or trauma; i.e., “LIS NDEs”) and to compare these experiences to those collected in a cohort of matched NDE experiencers after coma with supratentorial lesions (CVA or trauma; i.e., “classical NDEs”). [less ▲]

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See detailSwallowing in disorders of consciousness
Bicego, Aminata; Lejoly, Kelly ULg; Maudoux, Audrey et al

in Revue Neurologique (2014), 170(10),

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See detailNeurophysiology of hypnosis
VANHAUDENHUYSE, Audrey ULg; Laureys, Steven ULg; Faymonville, Marie-Elisabeth ULg

in Clinical Neurophysiology (2014), 44

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that ... [more ▼]

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that hypnotic processes modify internal (self awareness) as well as external (environmental awareness) brain networks. Brain mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical as well as subcortical areas including anterior cingulate and prefrontal cortices, basal ganglia and thalami. Combined with local anesthesia and conscious sedation in patients undergoing surgery, hypnosis is associated with improved peri- and postoperative comfort of patients and surgeons. Finally, hypnosis can be considered as a useful analogue for simulating conversion and dissociation symptoms in healthy subjects, permitting better characterization of these challenging disorders by producing clinically similar experiences. [less ▲]

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