References of "Cologan, Victor"
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See detailSleep in the unresponsive wakefulness syndrome and minimally conscious state
Cologan, Victor ULg; Drouot, Xavier; Parapatics, Silvia et al

in Journal of Neurotrauma (2013), 30(5), 339-346

The goal of our study was to investigate different aspects of sleep, namely the sleep-wake cycle and sleep stages, in the vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally ... [more ▼]

The goal of our study was to investigate different aspects of sleep, namely the sleep-wake cycle and sleep stages, in the vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state (MCS). 24h polysomnography was performed in 20 patients in a UWS (n=10) or in a MCS (n=10) due to brain injury. The data were first tested for the presence of a sleep-wake cycle and the observed sleep patterns were compared to standard scoring criteria. Sleep spindles, slow waves sleep and rapid eye movement sleep were quantified and their clinical value was investigated. According to our results, an electrophysiological sleep-wake cycle was identified in 5 MCS and 3 VS/UWS patients. Sleep stages did not always match the standard scoring criteria which therefore needed to be adapted. Sleep spindles were more present in patients who clinically improved within 6 months. Slow wave sleep was present in 8 MCS and 3 VS/UWS patients but never in the ischemic etiology. Rapid eye movement sleep, and therefore dreaming which is a form of consciousness, was present in all MCS and 3 VS/UWS patients. In conclusion, the presence of alternating periods of eyes-open/eyes-closed cycles does not necessarily imply preserved electrophysiological sleep architecture in the UWS and MCS, contrary to previous definition. The investigation of sleep is a little studied yet simple and informative way to evaluate the integrity of residual brain function in patients with disorders of consciousness with possible clinical diagnostic and prognostic implications. [less ▲]

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See detailSleep in Patients with Disorders of Consciousness
Cologan, Victor ULg

Book published by Lambert Academic Publishing (2013)

Sleep is a complex and essential activity for the preservation of the brain and for the general health of an individual. The nature of sleep is therefore of major importance for brain injured patients ... [more ▼]

Sleep is a complex and essential activity for the preservation of the brain and for the general health of an individual. The nature of sleep is therefore of major importance for brain injured patients with disorders of consciousness. However the standard definition of sleep is not relevant for this clinical population and it is thus necessary to adapt the standard method of sleep analysis. In this book we review the specialized literature and present our own original study of sleep in the unresponsive wakefulness syndrome and minimally conscious state. We describe the wide variety of sleep patterns possible in these patients who often no longer retain their sleep-wake cycle. In particular we shed light on the fact that standard sleep stages can differentiate the minimally conscious state from the unresponsive wakefulness syndrome and that they predict possible behavioral improvements within a period of 6 months. This new and promising field of research should be especially useful to neurologists and researchers who wish to improve the clinical evaluation and the care of their patients as well as improving the understanding of the neural correlations of vigilance and consciousness. [less ▲]

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See detailLe sommeil chez les patients en état de conscience altéré
Cologan, Victor ULg

Doctoral thesis (2012)

Cet ouvrage décrit les études réalisées sur le sommeil des patients cérébro-lésés en état de conscience altérés et présente nos travaux effectués chez les patient en état végétatif et en état de ... [more ▼]

Cet ouvrage décrit les études réalisées sur le sommeil des patients cérébro-lésés en état de conscience altérés et présente nos travaux effectués chez les patient en état végétatif et en état de conscience minimale. Les conclusions supportent l'intérêt neurophysiologique mais aussi diagnostique et pronostique de l'examen du sommeil chez ces patients. [less ▲]

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See detailResting-state EEG study of comatose patients: a connectivity and frequency analysis to find differences between vegetative and minimally conscious states.
Lehembre, Remy ULg; Bruno, Marie-Aurélie ULg; Vanhaudenhuyse, Audrey ULg et al

in Functional Neurology (2012), 27(1), 41-47

The aim of this study was to look for differences in the power spectra and in EEG connectivity measures between patients in the vegetative state (VS/UWS) and patients in the minimally conscious state (MCS ... [more ▼]

The aim of this study was to look for differences in the power spectra and in EEG connectivity measures between patients in the vegetative state (VS/UWS) and patients in the minimally conscious state (MCS). The EEG of 31 patients was recorded and analyzed. Power spectra were obtained using modern multitaper methods. Three connectivity measures (coherence, the imaginary part of coherency and the phase lag index) were computed. Of the 31 patients, 21 were diagnosed as MCS and 10 as VS/UWS using the Coma Recovery Scale-Revised (CRS-R). EEG power spectra revealed differences between the two conditions. The VS/UWS patients showed increased delta power but decreased alpha power compared with the MCS patients. Connectivity measures were correlated with the CRS-R diagnosis; patients in the VS/UWS had significantly lower connectivity than MCS patients in the theta and alpha bands. Standard EEG recorded in clinical conditions could be used as a tool to help the clinician in the diagnosis of disorders of consciousness. [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 detailLe sommeil chez les patients en état de conscience altérée
Cologan, Victor ULg

in Sommeil et Vigilance (2011, November), 20

Cet article offre un résumé des études sur le sommeil menées chez les patients dans le coma, en état végétatif, avec un syndrome "locked-in" et après récupération. Il illustre l'importance de tester le ... [more ▼]

Cet article offre un résumé des études sur le sommeil menées chez les patients dans le coma, en état végétatif, avec un syndrome "locked-in" et après récupération. Il illustre l'importance de tester le fonctionnement du sommeil chez le patient blessé au cerveau afin de contriburer à son évaluation clinique. [less ▲]

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See detailLe sommeil chez le patient en état de conscience altéré
Cologan, Victor ULg

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

En dépit des progrès de la médecine, la prise en charge des patients récupérant d'un coma constitue toujours un réel challenge. Depuis plus d'une dizaine d'années, les membres du Coma Science Group n'ont ... [more ▼]

En dépit des progrès de la médecine, la prise en charge des patients récupérant d'un coma constitue toujours un réel challenge. Depuis plus d'une dizaine d'années, les membres du Coma Science Group n'ont cessé de travailler sur cette thématique que ce soit à des fins scientifiques ou cliniques. Cet ouvrage est le fruit de leur travail. L'objectif est d'offrir aux cliniciens comme aux chercheurs un moyen de développer une expertise dans un domaine en perpétuel développement. Outre les aspects diagnostiques, pronostiques et éthiques, cet ouvrage aborde non seulement les techniques d'évaluations (comportementales, électrophysiologiques et par neuro-imagerie) et de traitements qui aideront à la prise en charge du patient, mais également les techniques en cours de validation (l’apprentissage par machine, les interfaces cerveau-ordinateur, la stimulation magnétique transcrânienne ou intracrânienne) qui susciteront d'autres pistes de recherche. [less ▲]

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See detailSleep in Disorders of Consciousness
Schabus, Manuel; Cologan, Victor ULg; Weihart, K et al

Poster (2010, September)

Résultats préliminaires de l'étude du sommeil chez les patients cérébrolésés en état de conscience altéré.

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See detailL'électroencéphalographie dans l'étude de la conscience
Cologan, Victor ULg

Conference (2010, March 17)

Présentation au grand public de l'étude électrophysiologique du patient cérébrolésé, en particulier par les techniques d'électroencéphalographie.

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See detailSleep in disorders of consciousness
Cologan, Victor ULg; Schabus, Manuel; LEDOUX, Didier ULg et al

in Sleep Medicine Reviews (2010), 14(2), 97-105

From a behavioral as well as neurobiological point of view, sleep and consciousness are intimately connected. A better understanding of sleep cycles and sleep architecture of patients suffering from ... [more ▼]

From a behavioral as well as neurobiological point of view, sleep and consciousness are intimately connected. A better understanding of sleep cycles and sleep architecture of patients suffering from disorders of consciousness (DOC) might therefore improve the clinical care for these patients as well as our understanding of the neural correlations of consciousness. Defining sleep in severely brain-injured patients is however problematic as both their electrophysiological and sleep patterns differ in many ways from healthy individuals. This paper discusses the concepts involved in the study of sleep of patients suffering from DOC and critically assesses the applicability of standard sleep criteria in these patients. <br /><br />The available literature on comatose and vegetative states as well as that on locked-in and related states following traumatic or non-traumatic severe brain injury will be reviewed. A wide spectrum of sleep disturbances ranging from almost normal patterns to severe loss and architecture disorganization are reported in cases of DOC and some patterns correlate with diagnosis and prognosis. At the present time the interactions of sleep and consciousness in brain-injured patients are a little studied subject but, the authors suggest, a potentially very interesting field of research. [less ▲]

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See detailSleep in the vegetative and minimally conscious states
Cologan, Victor ULg; Schabus, Manuel; Maquet, Pierre ULg et al

Poster (2009, June)

Résultats préliminaires de l'étude du sommeil chez les patients cérébrolésés en état de conscience altéré.

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See detailSleep: Implications for Theories of Dreaming and Consciousness
Dang Vu, Thien Thanh ULg; Schabus, Manuel; Cologan, Victor ULg et al

in Banks, William (Ed.) Encyclopedia of Consciousness (2009)

This article discusses the relationships between sleep and consciousness.

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See detailYou are only coming through in waves: wakefulness variability and assessment in patients with impaired consciousness
Bekinschtein, Tristan; Cologan, Victor ULg; Dahmen, Brigitte et al

in Progress in Brain Research (2009), 177

The vegetative state (VS) is defined as a condition of wakefulness without awareness. Being awake and being asleep are two behavioral and physiological manifestations of the daily cycles of vigilance and ... [more ▼]

The vegetative state (VS) is defined as a condition of wakefulness without awareness. Being awake and being asleep are two behavioral and physiological manifestations of the daily cycles of vigilance and metabolism. International guidelines for the diagnosis of VS propose that a patient fulfills criteria for wakefulness if he/she exhibits cycles of eye closure and eye opening giving the impression of a preserved sleep–wake cycle. We argue that these criteria are insufficient and we suggest guidelines to address wakefulness in a more comprehensive manner in this complex and heterogeneous group of patients. Four factors underlying wakefulness, as well as their interactions, are considered: arousal/ responsiveness, circadian rhythms, sleep cycle, and homeostasis. The first refers to the arousability and capacity to, consciously or not, respond to external stimuli. The second deals with the circadian clock as a synchronizer of physiological functions to environmental cyclic changes. The third evaluates general sleep patterns, while homeostasis refers to the capacity of the body to regulate its internal state and maintain a stable condition. We present examples of reflex responses, activity rhythms, and electroencephalographic (EEG) measurements from patients with disorders of consciousness (DOC) to illustrate these factors of wakefulness. If properly assessed, they would help in the evaluation of consciousness by informing when and in which context the patient is likely to exhibit maximal responsiveness. This evaluation has the potential to improve diagnosis and treatment and may also add prognostic value to the multimodal assessment in DOC. [less ▲]

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See detailEvaluation comportementale et par neuroimagerie fonctionnelle des patients en état végétatif
Vanhaudenhuyse, Audrey ULg; Schnakers, Caroline ULg; Boly, Mélanie ULg et al

in Revue Médicale de Liège (2007), 62 Spec No

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The ... [more ▼]

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The gold standard remains the Glasgow Coma Scale (GCS, Teasdale and Jennet, 1974), with the Glasgow Liege Scale (GLS, Born, 1988) adding standardized assessment of brainstem reflexes. New sensible behavioral assessment tools for use in the acute neurocritical care setting include the Full Outline of UnResponsiveness (FOUR, Wijdicks et al., 2005). The Coma Recovery Scale-Revised (CRS-R, Giacino and Kalmar, 2004) specifically tests the diagnostic criteria differentiating vegetative from minimally conscious patients. Detecting signs of consciousness also depends on the employed methodology. We showed that for the assesment of the presence of visual pursuit, using a moving mirror is better suited than using a moving object or person. The clinical diagnosis can be confirmed by cerebral positron emission tomography studies objectively quantifying residual metabolic activity in vegetative and minimally conscious patients. Ongoing studies evaluate the prognostic value of functional magnetic resonance imaging studies in these challenging patient populations. [less ▲]

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