References of "Laureys, Steven"
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See detailQue mesure la neuro-imagerie fonctionnelle: IRMf, TEP & MEG?
Gosseries, Olivia ULg; Demertzi, Athina ULg; Noirhomme, Quentin ULg et al

in Revue Médicale de Liège (2008), 63(5-6), 231-7

Functional cerebral imaging techniques allow the in vivo study of human cognitive and sensorimotor functions in physiological or pathological conditions. In this paper, we review the advantages and ... [more ▼]

Functional cerebral imaging techniques allow the in vivo study of human cognitive and sensorimotor functions in physiological or pathological conditions. In this paper, we review the advantages and limitations of functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and magnetoencephalography (MEG). fMRI and PET measure haemodynamic changes induced by regional changes in neuronal activity. These techniques have a high spatial resolution (a few millimeters), but a poor temporal resolution (a few seconds to several minutes). Electroencephalogram (EEG) and MEG measure the neuronal electrical or magnetic activity with a high temporal resolution (i.e., milliseconds) albeit with a poorer spatial resolution (i.e., a few millimeters to one centimeter). The combination of these different neuroimaging techniques allows studying different components of the brain's activity (e.g., neurovascular coupling, electromagnetic activity) with both a high temporal and spatial resolution. [less ▲]

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See detailMeasuring the effect of amantadine in chronic anoxic minimally conscious state.
Schnakers, Caroline ULg; Hustinx, Roland ULg; Vandewalle, Gilles ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2), 225-7

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See detailBlink to visual threat does not herald consciousness in the vegetative state.
Vanhaudenhuyse, Audrey ULg; Giacino, J.; Schnakers, Caroline ULg et al

in Neurology (2008), 71(17), 1374-5

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See detailQuelle vie apres le Locked-In syndrome?
Bruno, Marie-Aurélie ULg; Pellas, F.; Bernheim, J. L. et al

in Revue Médicale de Liège (2008), 63(5-6), 445-51

The Locked-In Syndrome (LIS) is classically caused by an anterior pontine vascular lesion and characterized by quadriplegia and anarthria with preserved consciousness and intellectual functioning. We here ... [more ▼]

The Locked-In Syndrome (LIS) is classically caused by an anterior pontine vascular lesion and characterized by quadriplegia and anarthria with preserved consciousness and intellectual functioning. We here review the definition, etiologies, diagnosis and prognosis of LIS patients and briefly discuss the few studies on their quality of life and the challenging end-of-life decisions that can be encountered. Some clinicians may consider that LIS is worse than being in a vegetative or in a minimally conscious state. However, preliminary data from chronic LIS survivors show a surprisingly preserved self-scored quality of life and requests of treatment withdrawal or euthanasia, though not absent, are infrequent. [less ▲]

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See detailA french validation study of the Coma Recovery Scaled-Revised (CRS-R)
Schnakers, Caroline ULg; Majerus, Steve ULg; Giacino, Joseph et al

in Brain Injury (2008), 22(10), 786-792

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See detailIntrinsic brain activity in altered states of consciousness: how conscious is the default mode of brain function?
Boly, Mélanie ULg; Phillips, Christophe ULg; Tshibanda, Luaba ULg et al

in Annals of the New York Academy of Sciences (2008), 1129

Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships ... [more ▼]

Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships has been challenged. That altered states of consciousness are a privileged way to study the relationships between spontaneous brain activity and behavior is proposed, and common resting-state brain activity features observed in various states of altered consciousness are reviewed. Early positron emission tomography studies showed that states of extremely low or high brain activity are often associated with unconsciousness. However, this relationship is not absolute, and the precise link between global brain metabolism and awareness remains yet difficult to assert. In contrast, voxel-based analyses identified a systematic impairment of associative frontoparieto-cingulate areas in altered states of consciousness, such as sleep, anesthesia, coma, vegetative state, epileptic loss of consciousness, and somnambulism. In parallel, recent functional magnetic resonance imaging studies have identified structured patterns of slow neuronal oscillations in the resting human brain. Similar coherent blood oxygen level-dependent (BOLD) systemwide patterns can also be found, in particular in the default-mode network, in several states of unconsciousness, such as coma, anesthesia, and slow-wave sleep. The latter results suggest that slow coherent spontaneous BOLD fluctuations cannot be exclusively a reflection of conscious mental activity, but may reflect default brain connectivity shaping brain areas of most likely interactions in a way that transcends levels of consciousness, and whose functional significance remains largely in the dark. [less ▲]

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See detailCognitive Event-Related Potentials in Comatose and Post-Comatose States
Vanhaudenhuyse, Audrey ULg; Laureys, Steven ULg; Perrin, F.

in Neurocritical Care (2008), 8(2), 262-70

We review the interest of cognitive event-related potentials (ERPs) in comatose, vegetative, or minimally conscious patients. Auditory cognitive ERPs are useful to investigate residual cognitive functions ... [more ▼]

We review the interest of cognitive event-related potentials (ERPs) in comatose, vegetative, or minimally conscious patients. Auditory cognitive ERPs are useful to investigate residual cognitive functions, such as echoic memory (MMN), acoustical and semantic discrimination (P300), and incongruent language detection (N400). While early ERPs (such as the absence of cortical responses on somatosensory-evoked potentials) predict bad outcome, cognitive ERPs (MMN and P300) are indicative of recovery of consciousness. In coma-survivors, cognitive potentials are more frequently obtained when using stimuli that are more ecologic or have an emotional content (such as the patient's own name) than when using classical sine tones. [less ▲]

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See detailLes échelles d’évaluation des états de conscience altérée
Ledoux, Didier ULg; Piret, Sonia ULg; Boveroux, Pierre ULg et al

in Réanimation (2008), 17

L’évaluation de l’état de conscience revêt une importance clinique considé- rable. En effet, déterminer avec précision la sévérité de l’altération de conscience permet non seulement d’établir un pronostic ... [more ▼]

L’évaluation de l’état de conscience revêt une importance clinique considé- rable. En effet, déterminer avec précision la sévérité de l’altération de conscience permet non seulement d’établir un pronostic vital et fonctionnel mais aussi de suivre plus efficacement l’évolution clinique des patients avec lésion cérébrale et d’optimaliser l’utilisation des ressources disponibles. Dans cet article, nous passons en revue les principales échelles d’évaluation des états de conscience altérée. Nous nous intéressons particu- lièrement à instrument récemment publié, l’échelle «Full Outline of UnResponsiveness» (FOUR). En effet, cette dernière constitue une avancée considérable dans l’évaluation cli- nique des patients présentant un état de conscience altérée. Parmi les apports de cette échelle, on notera sa contribution au diagnostic d’un locked-in syndrome, d’un état de conscience minimale ou encore d’un état de mort cérébrale. Nous pensons qu’en rai- son de son apport à l’examen clinique durant la phase initiale d’un état de conscience altérée, l’échelle FOUR devrait être préférée à la désormais classique échelle de Glasgow. [less ▲]

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See detailBrain function in physiologically, pharmacologically, and pathologically altered states of consciousness
Boveroux, Pierre ULg; Bonhomme, Vincent ULg; Vanhaudenhuyse, Audrey ULg et al

in International Anesthesiology Clinics (2008), 46(3), 131-146

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See detailWhat is it like to be vegetative or minimally conscious?
Laureys, Steven ULg; Boly, Mélanie ULg

in Current Opinion in Neurology (2007), 20(6), 609-613

Purpose of review Patients in a vegetative or minimally conscious state continue to pose problems in terms of diagnosis, prognosis and treatment. Despite recent waves of international media attention ... [more ▼]

Purpose of review Patients in a vegetative or minimally conscious state continue to pose problems in terms of diagnosis, prognosis and treatment. Despite recent waves of international media attention following Terri Schiavo's death and the 'miracle recovery' of Terry Wallis, research efforts aimed at increasing our knowledge about brain function in these conditions remain scarce and must address a series of difficulties, including financial and ethical barriers. Here we review current possibilities and limitations of clinical and para-clinical assessment of chronic disorders of consciousness. Recent findings During the past year the field has witnessed publication of significant, yet isolated, case reports in top-ranking journals, including Science and Nature. Such milestone reports and other impressive recent technological advances in the study of vegetative and minimally conscious patients reveal enthralling areas of science that must find their way to clinical medical reality. Summary Consciousness is a subjective experience whose study has remained within the purview of philosophy for millennia. That has finally changed, and empirical evidence from functional neuroimaging offers a genuine glimpse at a solution to the infamous mind-body conundrum. New technological and scientific advances offer the neurological community unique ways to improve our understanding and management of vegetative and minimally conscious patients. [less ▲]

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See detailSelf-consciousness in non-communicative patients
Laureys, Steven ULg; Perrin, F.; Brédart, Serge ULg

in Consciousness & Cognition (2007), 16(3), 722-741742-5

The clinical and para-clinical examination of residual self-consciousness in non-communicative severely brain damaged patients (i.e., coma, vegetative state and minimally conscious state) remains ... [more ▼]

The clinical and para-clinical examination of residual self-consciousness in non-communicative severely brain damaged patients (i.e., coma, vegetative state and minimally conscious state) remains exceptionally challenging. Passive presentation of the patient's own name and own face are known to be effective attention-grabbing stimuli when clinically assessing consciousness at the patient's bedside. Event-related potential and functional neuroimaging studies using such self-referential stimuli are currently being used to disentangle the cognitive hierarchy of self-processing. We here review neuropsychological, neuropathological, electrophysiological and neuroimaging studies using the own name and own face paradigm obtained in conscious waking, sleep, pharmacological coma, pathological coma and related disorders of consciousness. Based on these results we discuss what we currently do and do not know about the functional significance of the neural network involved in "automatic" and "conscious" self-referential processing. (c) 2007 Elsevier Inc. All rights reserved. [less ▲]

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See detailBaseline brain activity fluctuations predict somatosensory perception in humans
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2007), 104(29), 12187-12192

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means ... [more ▼]

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means of thulium-yttrium/aluminum- garnet laser and event-related functional MRI, we tested whether variability in perception of identical stimuli relates to differences in prestimulus, baseline brain activity. Results indicate a positive relationship between conscious perception of low-intensity somatosensory stimuli and immediately preceding levels of baseline activity in medial thalamus and the lateral frontoparietal network, respectively, which are thought to relate to vigilance and "external monitoring." Conversely, there was a negative correlation between subsequent reporting of conscious perception and baseline activity in a set of regions encompassing posterior cingulate/ precuneus and temporoparietal cortices, possibly relating to introspection and self-oriented processes. At nociceptive levels of stimulation, pain-intensity ratings positively correlated with baseline fluctuations in anterior cingulate cortex in an area known to be involved in the affective dimension of pain. These results suggest that baseline brain-activity fluctuations may profoundly modify our conscious perception of the external world. [less ▲]

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See detailWhen thoughts become action: An fMRI paradigm to study volitional brain activity in non-communicative brain injured patients
Boly, Mélanie ULg; Coleman, M. R.; Davis, M. H. et al

in NeuroImage (2007), 36(3), 979-992

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the ... [more ▼]

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the neural correlates of consciousness, even a normal activation in response to passive sensory stimulation cannot be considered as proof of the presence of awareness in these patients. In contrast, predicted activation in response to the instruction to perform a mental imagery task would provide evidence of voluntary task-dependent brain activity, and hence of consciousness, in non-communicative patients. However, no data yet exist to indicate which imagery instructions would yield reliable single subject activation. The aim of the present study was to establish such a paradigm in healthy volunteers. Two exploratory experiments evaluated the reproducibility of individual brain activation elicited by four distinct mental imagery tasks. The two most robust mental imagery tasks were found to be spatial navigation and motor imagery. In a third experiment, where these two tasks were directly compared, differentiation of each task from one another and from rest periods was assessed blindly using a priori criteria and was correct for every volunteer. The spatial navigation and motor imagery tasks described here permit the identification of volitional brain activation at the single subject level, without a motor response. Volunteer as well as patient data [Owen, A. M., Coleman, M.R., Boly, M., Davis, M.H., Laureys, S., Pickard J.D., 2006. Detecting awareness in the vegetative state. Science 313, 1402] strongly suggest that this' paradigm may provide a method for assessing the presence of volitional brain activity, and thus of consciousness, in non-communicative brain-injured patients. (c) 2007 Elsevier Inc. All rights reserved. [less ▲]

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See detailfMRI study of hypnosis-induced analgesia
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 38-39

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See detailCerebral resting state fluctuations predict somatosensory perception
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 42

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See detailEffect of dementia severity and age on posterior cingulate cortex metabolism in Alzheimer's disease
Withofs, Nadia ULg; Salmon, Eric ULg; Hallet, Claude ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 146

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See detailEyes open, brain shut
Laureys, Steven ULg

in Scientific American (2007), 296(5), 84-89

Recent progress in medical care has greatly increased the number of people who survive acute brain damage. Doctors can save the lives of many patients who suffer trauma to the brain or a lack of oxygen ... [more ▼]

Recent progress in medical care has greatly increased the number of people who survive acute brain damage. Doctors can save the lives of many patients who suffer trauma to the brain or a lack of oxygen, but if the damage is severe, the victim will-slip into a coma, individuals in this condition do not open their eyes; at best, they will show some reflex movements to the limbs. [less ▲]

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See detailCerebral response to patient's own name in the vegetative and minimally conscious states
Di, H. B.; Yu, S. M.; Weng, X. C. et al

in Neurology (2007), 68(12), 895-899

Background: A challenge in the management of severely brain- damaged patients with altered states of consciousness is the differential diagnosis between the vegetative state ( VS) and the minimally ... [more ▼]

Background: A challenge in the management of severely brain- damaged patients with altered states of consciousness is the differential diagnosis between the vegetative state ( VS) and the minimally conscious state ( MCS), especially for the gray zone separating these clinical entities. Objective: To evaluate the differences in brain activation in response to presentation of the patient's own name spoken by a familiar voice ( SON- FV) in patients with VS and MCS. Methods: By using fMRI, we prospectively studied residual cerebral activation to SON- FV in seven patients with VS and four with MCS. Behavioral evaluation was performed by means of standardized testing up to 3 months post- fMRI. Results: Two patients with VS failed to show any significant cerebral activation. Three patients with VS showed SON- FV induced activation within the primary auditory cortex. Finally, two patients with VS and all four patients with MCS not only showed activation in primary auditory cortex but also in hierarchically higher order associative temporal areas. These two patients with VS showing the most widespread activation subsequently showed clinical improvement to MCS observed 3 months after their fMRI scan. Conclusion: The cerebral responses to patient's own name spoken by a familiar voice as measured by fMRI might be a useful tool to preclinically distinguish minimally conscious state - like cognitive processing in some patients behaviorally classified as vegetative. [less ▲]

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