References of "Laureys, Steven"
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See detailHierarchical clustering of brain activity during human nonrapid eye movement sleep.
Boly, Mélanie ULg; Perlbarg, V; Marrelec, G et al

in Proceedings of the National Academy of Sciences of the United States of America (2012)

Consciousness is reduced during nonrapid eye movement (NREM) sleep due to changes in brain function that are still poorly understood. Here, we tested the hypothesis that impaired consciousness during NREM ... [more ▼]

Consciousness is reduced during nonrapid eye movement (NREM) sleep due to changes in brain function that are still poorly understood. Here, we tested the hypothesis that impaired consciousness during NREM sleep is associated with an increased modularity of brain activity. Cerebral connectivity was quantified in resting-state functional magnetic resonance imaging times series acquired in 13 healthy volunteers during wakefulness and NREM sleep. The analysis revealed a modification of the hierarchical organization of large-scale networks into smaller independent modules during NREM sleep, independently from EEG markers of the slow oscillation. Such modifications in brain connectivity, possibly driven by sleep ultraslow oscillations, could hinder the brain's ability to integrate information and account for decreased consciousness during NREM sleep. [less ▲]

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See detailLe Sommeil dans l'Etat Végétatif et de Conscience Minimale
Cologan, Victor ULg; Drouot, Xavier; Parapatics, Silvia et al

Poster (2011, November)

Présentation des résultats de l'étude du sommeil chez les patients cérébrolésés en état de conscience altéré.

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See detailWachkoma: medizinische Grundlagen und neurowissenschaftliche Revolution
Demertzi, Athina ULg; Schabus; Weilhart, K. et al

in Jox, R.; Borasio, G. D.; Kühlmeyer, K. (Eds.) Leben im Koma Interdisziplinäre Perspektiven auf das Problem des Wachkomas (2011)

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See detailDesign of a novel covert SSVEP-based BCI
Lesenfants, Damien ULg; Partoune, Nicolas; Soddu, Andrea ULg et al

in Proceedings of the 5th International Brain-Computer Interface Conference 2011 (2011, September 22)

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See detailDésordres de la conscience : aspects éthiques.
Demertzi, Athina ULg; Gosseries, Olivia ULg; Bruno, Marie-Aurélie ULg et al

in Schnakers, Caroline; LAUREYS, Steven (Eds.) Comas et états de conscience altérée (2011)

L’apparition de la ventilation mécanique dans les années cinquante et le développement des soins intensifs dans les années soixante ont permis à de nombreux patients de survivre à de graves lésions ... [more ▼]

L’apparition de la ventilation mécanique dans les années cinquante et le développement des soins intensifs dans les années soixante ont permis à de nombreux patients de survivre à de graves lésions cérébrales. Bien que ces avancées technologiques soient étonnantes, de nombreux patients vont alors se retrouver dans des états cliniques critiques peu rencontrés auparavant (1). L’impact éthique de ces états d’inconscience se reflète lors de la rédaction des premiers comités de bioéthique et lors de l’apparition du concept d’acharnement thérapeutique. En 1968, le comité spécial de l’école médicale de Harvard a publié un article essentiel redéfinissant la mort comme étant un coma irréversible et une perte permanente de toutes les fonctions cérébrales (2). Le comité, composé de dix médecins, d’un théologien, d’un avocat et d’un historien des sciences, a débattu des questions médicales, juridiques et sociétales quant à la prise en charge des patients en mort cérébrale. Nous donnerons ici un bref aperçu des principales questions éthiques liées à la notion de conscience et à la prise en charge médicale des patients atteints de troubles de la conscience (TDC) tels que le coma, l’état végétatif et l’état de conscience minimale. Nous mettrons également l’accent sur le problème de la gestion de la douleur et des prises de décision en fin de vie. [less ▲]

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See detailHypnotic modulation of resting state fMRI default mode and extrinsic network connectivity
Demertzi, Athina ULg; Soddu, Andrea ULg; FAYMONVILLE, Marie-Elisabeth ULg et al

in Progress in Brain Research (2011), 193

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 ... [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. [less ▲]

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See detailAutomated EEG entropy measurements in coma, vegetative state/unresponsive wakefulness syndrome and minimally conscious state
Gosseries, Olivia ULg; Schnakers, Caroline ULg; LEDOUX, Didier ULg et al

in Functional Neurology (2011)

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold ... [more ▼]

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold standard for assessing consciousness but previous studies have shown a high rate of misdiagnosis. This study aimed to investigate the usefulness of electroencephalography (EEG) entropy measurements in differentiating unconscious (coma or vegetative) from minimally conscious patients. Left fronto-temporal EEG recordings (10-minute resting state epochs) were prospectively obtained in 56 patients and 16 age-matched healthy volunteers. Patients were assessed in the acute (≤1 month post-injury;n=29) or chronic (>1 month post-injury; n=27) stage. The etiology was traumatic in 23 patients. Automated online EEG entropy calculations (providing an arbitrary value ranging from 0 to 91) were compared with behavioral assessments (Coma Recovery Scale-Revised) and outcome. EEG entropy correlated with Coma Recovery Scale total scores (r=0.49). Mean EEG entropy values were higher in minimally conscious (73±19; mean and standard deviation) than in vegetative/unresponsive wakefulness syndrome patients (45±28). Receiver operating characteristic analysis revealed an entropy cut-off value of 52 differentiating acute unconscious from minimally conscious patients (sensitivity 89% and specificity 90%). In chronic patients, entropy measurements offered no reliable diagnostic information. EEG entropy measurements did not allow prediction of outcome. User-independent time-frequency balanced spectral EEG entropy measurements seem to constitute an interesting diagnostic – albeit not prognostic – tool for assessing neural network complexity in disorders of consciousness in the acute setting. Future studies are needed before using this tool in routine clinical practice, and these should seek to improve automated EEG quantification paradigms in order to reduce the remaining false negative and false positive findings. [less ▲]

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See detailWhen the nursing workload measurement among comatose patients becomes a reality …
THONON, Olivier ULg; BOULANGER, Jean-Marie ULg; BAKAY, Tahar ULg et al

Poster (2011, May)

The neurologic unit of the Academic Hospital of Liège is composed of 30 beds. This is one of reference's centers for detection and differentiation of the comatose patients. With the mediatization of the ... [more ▼]

The neurologic unit of the Academic Hospital of Liège is composed of 30 beds. This is one of reference's centers for detection and differentiation of the comatose patients. With the mediatization of the Pr S. Laureys's findings, our reference's center accommodate more and more comatose patients from different European countries. With the arrival and the increase of these comatose patients, the nurses had the feeling of an increase workload by report to all others neurologic patients. The purpose of this overview is initially to be able to measure the nursing workload among comatose patients and to demonstrate that this one, within a neurology unit of an academic Belgian hospital, is heavier than that of other patients suffering from neurologic affections. [less ▲]

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See detailThe ethics in disorders of consciousness
Demertzi, Athina ULg; LAUREYS, Steven ULg; Bruno, Marie-Aurélie ULg

in Vincent, J. L. (Ed.) Annual Update in Intensive Care and Emergency Medicine (2011)

The introduction of the mechanical ventilator in the 1950s and the development of intensive care in the 1960s permitted many patients to sustain their vegetative functions and survive severe injuries ... [more ▼]

The introduction of the mechanical ventilator in the 1950s and the development of intensive care in the 1960s permitted many patients to sustain their vegetative functions and survive severe injuries. Despite such advances, in many cases patients were found to suffer from altered states of consciousness which had never been encountered before as these patients would normally have died from apnea [1]. The imminent ethical impact of these profound states of unconsciousness was reflected in the composition of the first bioethical committees discussing the redefinition of life and the concept of therapeutic obstinacy. In 1968, the Ad Hoc Committee of Harvard Medical School published a milestone paper for the redefinition of death as irreversible coma and brain failure [2]. The committee was comprised of ten physicians, a theologian, a lawyer and a historian of science, betokening the medical, legal and societal debates that were to follow. We will here give a brief overview of some ethical issues related to the concept of consciousness and the medical management of patients with disorders of consciousness, such as comatose, vegetative and minimally conscious states that may be encountered in the intensive care setting. We will emphasize the problem of pain management and end-of life decision-making. [less ▲]

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See detailResting-state activity in the tinnitus brain
Maudoux, Audrey ULg; LEFEBVRE, Philippe ULg; CABAY, Jean-Evrard ULg et al

Conference (2011, March)

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See detailA survey on self-assessed well-being in a cohort of chronic locked-in syndrome patients: happy majority, miserable minority
Bruno, Marie-Aurélie ULg; Bernheim, Jan; LEDOUX, Didier ULg et al

in BMJ Open (2011), 1

Objectives Locked-in syndrome (LIS) consists of anarthria and quadriplegia while consciousness is preserved. Classically, vertical eye movements or blinking allow coded communication. Given appropriate ... [more ▼]

Objectives Locked-in syndrome (LIS) consists of anarthria and quadriplegia while consciousness is preserved. Classically, vertical eye movements or blinking allow coded communication. Given appropriate medical care, patients can survive for decades. We studied the self-reported quality of life in chronic LIS patients.Design 168 LIS members of the French Association for LIS were invited to answer a questionnaire on medical history, current status and end-of-life issues. They self-assessed their global subjective well-being with the Anamnestic Comparative Self-Assessment (ACSA) scale, whose +5 and −5 anchors were their memories of the best period in their life before LIS and their worst period ever, respectively.Results 91 patients (54%) responded and 26 were excluded because of missing data on quality of life. 47 patients professed happiness (median ACSA +3) and 18 unhappiness (median ACSA −4). Variables associated with unhappiness included anxiety and dissatisfaction with mobility in the community, recreational activities and recovery of speech production. A longer time in LIS was correlated with happiness. 58% declared they did not wish to be resuscitated in case of cardiac arrest and 7% expressed a wish for euthanasia.Conclusions Our data stress the need for extra palliative efforts directed at mobility and recreational activities in LIS and the importance of anxiolytic therapy. Recently affected LIS patients who wish to die should be assured that there is a high chance they will regain a happy meaningful life. End-of-life decisions, including euthanasia, should not be avoided, but a moratorium to allow a steady state to be reached should be proposed. [less ▲]

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See detailNeural plasticity lessons from disorders of consciousness
Demertzi, Athina ULg; Schnakers, Caroline ULg; Soddu, Andrea ULg et al

in Frontiers in Psychology (2011), 1

Communication and intentional behavior are supported by the brain?s integrity at a structural and a functional level. When widespread loss of cerebral connectivity is brought about as a result of a severe ... [more ▼]

Communication and intentional behavior are supported by the brain?s integrity at a structural and a functional level. When widespread loss of cerebral connectivity is brought about as a result of a severe brain injury, in many cases patients are not capable of conscious interactive behavior and are said to suffer from disorders of consciousness (e.g., coma, vegetative state /unresponsive wakefulness syndrome, minimally conscious states). This lesion paradigm has offered not only clinical insights, as how to improve diagnosis, prognosis and treatment, but also put forward scientific opportunities to study the brain?s plastic abilities. We here review interventional and observational studies performed in severely brain-injured patients with regards to recovery of consciousness. The study of the recovered conscious brain (spontaneous and/or after surgical or pharmacologic interventions), suggests a link between some specific brain areas and the capacity of the brain to sustain conscious experience, challenging at the same time the notion of fixed temporal boundaries in rehabilitative processes. Altered functional connectivity, cerebral structural reorganization as well as behavioral amelioration after invasive treatments will be discussed as the main indices for plasticity in these challenging patients. The study of patients with chronic disorders of consciousness may, thus, provide further insights not only at a clinical level (i.e., medical management and rehabilitation) but also from a scientific-theoretical perspective (i.e., the brain?s plastic abilities and the pursuit of the neural correlate of consciousness). [less ▲]

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See detailResting state activity in patients with disorders of consciousness.
Soddu, Andrea ULg; Vanhaudenhuyse, Audrey ULg; Demertzi, Athena et al

in Functional Neurology (2011), 26(1), 37-43

Recent advances in the study of spontaneous brain activity have demonstrated activity patterns that emerge with no task performance or sensory stimulation; these discoveries hold promise for the study of ... [more ▼]

Recent advances in the study of spontaneous brain activity have demonstrated activity patterns that emerge with no task performance or sensory stimulation; these discoveries hold promise for the study of higher-order associative network functionality. Additionally, such advances are argued to be relevant in pathological states, such as disorders of consciousness (DOC), i.e., coma, vegetative and minimally conscious states. Recent studies on resting state activity in DOC, measured with functional magnetic resonance imaging (fMRI) techniques, show that functional connectivity is disrupted in the task-negative or the default mode network. However, the two main approaches employed in the analysis of resting state functional connectivity data (i.e., hypothesis-driven seed-voxel and data-driven independent component analysis) present multiple methodological difficulties, especially in non-collaborative DOC patients. Improvements in motion artifact removal and spatial normalization are needed before fMRI resting state data can be used as proper biomarkers in severe brain injury. However, we anticipate that such developments will boost clinical resting state fMRI studies, allowing for easy and fast acquisitions and ultimately improve the diagnosis and prognosis in the absence of DOC patients' active collaboration in data acquisition. [less ▲]

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See detailBrain functional integration decreases during propofol-induced loss of consciousness.
Schrouff, Jessica ULg; Perlbarg, Vincent; Boly, Mélanie ULg et al

in NeuroImage (2011), 57(1), 198-205

Consciousness has been related to the amount of integrated information that the brain is able to generate. In this paper, we tested the hypothesis that the loss of consciousness caused by propofol ... [more ▼]

Consciousness has been related to the amount of integrated information that the brain is able to generate. In this paper, we tested the hypothesis that the loss of consciousness caused by propofol anesthesia is associated with a significant reduction in the capacity of the brain to integrate information. To assess the functional structure of the whole brain, functional integration and partial correlations were computed from fMRI data acquired from 18 healthy volunteers during resting wakefulness and propofol-induced deep sedation. Total integration was significantly reduced from wakefulness to deep sedation in the whole brain as well as within and between its constituent networks (or systems). Integration was systematically reduced within each system (i.e., brain or networks), as well as between networks. However, the ventral attentional network maintained interactions with most other networks during deep sedation. Partial correlations further suggested that functional connectivity was particularly affected between parietal areas and frontal or temporal regions during deep sedation. Our findings suggest that the breakdown in brain integration is the neural correlate of the loss of consciousness induced by propofol. They stress the important role played by parietal and frontal areas in the generation of consciousness. [less ▲]

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See detailPropofol anesthesia and sleep: a high-density EEG study.
Murphy, Michael; Bruno, Marie-Aurélie ULg; Riedner, Brady A et al

in Sleep (2011), 34(3), 283-91

STUDY OBJECTIVES: The electrophysiological correlates of anesthetic sedation remain poorly understood. We used high-density electroencephalography (hd-EEG) and source modeling to investigate the cortical ... [more ▼]

STUDY OBJECTIVES: The electrophysiological correlates of anesthetic sedation remain poorly understood. We used high-density electroencephalography (hd-EEG) and source modeling to investigate the cortical processes underlying propofol anesthesia and compare them to sleep. DESIGN: 256-channel EEG recordings in humans during propofol anesthesia. SETTING: Hospital operating room. PATIENTS OR PARTICIPANTS: 8 healthy subjects (4 males) INTERVENTIONS: N/A MEASUREMENTS AND RESULTS: Initially, propofol induced increases in EEG power from 12-25 Hz. Loss of consciousness (LOC) was accompanied by the appearance of EEG slow waves that resembled the slow waves of NREM sleep. We compared slow waves in propofol to slow waves recorded during natural sleep and found that both populations of waves share similar cortical origins and preferentially propagate along the mesial components of the default network. However, propofol slow waves were spatially blurred compared to sleep slow waves and failed to effectively entrain spindle activity. Propofol also caused an increase in gamma (25-40 Hz) power that persisted throughout LOC. Source modeling analysis showed that this increase in gamma power originated from the anterior and posterior cingulate cortices. During LOC, we found increased gamma functional connectivity between these regions compared to the wakefulness. CONCLUSIONS: Propofol anesthesia is a sleep-like state and slow waves are associated with diminished consciousness even in the presence of high gamma activity. CITATION: Murphy M; Bruno MA; Riedner BA; Boveroux P; Noirhomme Q; Landsness EC; Brichant JF; Phillips C; Massimini M; Laureys S; Tononi G; Boly M. Propofol anesthesia and sleep: a high-density EEG study. SLEEP 2011;34(3):283-291. [less ▲]

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See detailPronostic des patients récupérant du coma
Bruno, Marie-Aurélie ULg; Ledoux, Didier; Vanhaudenhuyse, Audrey ULg et al

in Schnakers, Caroline; Laureys, Steven (Eds.) Coma et états de conscience altérée (2011)

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