References of "Laureys, Steven"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAutomated analysis of background EEG and reactivity during therapeutic hypothermia in comatose patients after cardiac arrest
Noirhomme, Quentin ULg; Lehembre, Rémy; Lugo, Zulay et al

in Clinical EEG and Neuroscience : Official Journal of the EEG and Clinical Neuroscience Society (ENCS) (2014)

Visual analysis of electroencephalography (EEG) background and reactivity during therapeutic hypothermia provides important outcome information, but is time-consuming and not always consistent between ... [more ▼]

Visual analysis of electroencephalography (EEG) background and reactivity during therapeutic hypothermia provides important outcome information, but is time-consuming and not always consistent between reviewers. Automated EEG analysis may help quantify the brain damage. Forty-six comatose patients in therapeutic hypothermia, after cardiac arrest, were included in the study. EEG background was quantified with burst-suppression ratio (BSR) and approximate entropy, both used to monitor anesthesia. Reactivity was detected through change in the power spectrum of signal before and after stimulation. Automatic results obtained almost perfect agreement (discontinuity) to substantial agreement (background reactivity) with a visual score from EEG-certified neurologists. Burst-suppression ratio was more suited to distinguish continuous EEG background from burst-suppression than approximate entropy in this specific population. Automatic EEG background and reactivity measures were significantly related to good and poor outcome. We conclude that quantitative EEG measurements can provide promising information regarding current state of the patient and clinical outcome, but further work is needed before routine application in a clinical setting. [less ▲]

Detailed reference viewed: 63 (15 ULg)
Full Text
Peer Reviewed
See detailA vibrotactile P300-based BCI for consciousness detection and communication
Lugo, Zulay; Rodriguez, Javi; Lechner, Alexander et al

in Clinical EEG and Neuroscience : Official Journal of the EEG and Clinical Neuroscience Society (ENCS) (2014)

Brain–computer interface (BCI) has been used for many years for communication in severely disabled patients. BCI based on electrophysiological signals has enabled communication, using auditory or visual ... [more ▼]

Brain–computer interface (BCI) has been used for many years for communication in severely disabled patients. BCI based on electrophysiological signals has enabled communication, using auditory or visual stimuli to elicit event-related potentials (ERPs). The aim of this study was to determine whether patients with locked-in syndrome (LIS) could elicit a P300 wave, using a vibrotactile oddball paradigm for establishing somatosensory BCI-based communication. Six chronic LIS patients performed 2electroencephalography (EEG)-based vibrotactile P300 oddball tasks. After a simple mental counting task of the target stimuli, participants were instructed to answer 5 questions by counting the vibration on either the right wrist for “yes” or the left wrist for “no.” All participants were able to elicit a P300 wave using the vibrotactile oddball paradigm BCI task. In the counting task, 4 patients got accuracies of 100% (average above chance). In the communication task, one patient achieved 100% accuracy (average above chance). We have shown the feasibility of eliciting a P300 response using vibrotactile stimulation in patients with LIS. The present study provides evidence that this approach can be used for EEG-based BCI communications in this patient group. This is the first study to prove the feasibility of a BCI based on somatosensory (vibratory) stimulation in a group of braininjured patients. Furthermore, this approach could be used for the detection of consciousness in non-communicating patients due to severe brain injuries. [less ▲]

Detailed reference viewed: 70 (4 ULg)
Full Text
Peer Reviewed
See detailHow electroencephalography serves the anesthesiologist.
Marchant, Nicolas ULg; Sanders, Robert; Sleigh, Jamie et al

in Clinical EEG and neuroscience (2014), 45(1), 22-32

Major clinical endpoints of general anesthesia, such as the alteration of consciousness, are achieved through effects of anesthetic agents on the central nervous system, and, more precisely, on the brain ... [more ▼]

Major clinical endpoints of general anesthesia, such as the alteration of consciousness, are achieved through effects of anesthetic agents on the central nervous system, and, more precisely, on the brain. Historically, clinicians and researchers have always been interested in quantifying and characterizing those effects through recordings of surface brain electrical activity, namely electroencephalography (EEG). Over decades of research, the complex signal has been dissected to extract its core substance, with significant advances in the interpretation of the information it may contain. Methodological, engineering, statistical, mathematical, and computer progress now furnishes advanced tools that not only allow quantification of the effects of anesthesia, but also shed light on some aspects of anesthetic mechanisms. In this article, we will review how advanced EEG serves the anesthesiologist in that respect, but will not review other intraoperative utilities that have no direct relationship with consciousness, such as monitoring of brain and spinal cord integrity. We will start with a reminder of anesthestic effects on raw EEG and its time and frequency domain components, as well as a summary of the EEG analysis techniques of use for the anesthesiologist. This will introduce the description of the use of EEG to assess the depth of the hypnotic and anti-nociceptive components of anesthesia, and its clinical utility. The last part will describe the use of EEG for the understanding of mechanisms of anesthesia-induced alteration of consciousness. We will see how, eventually in association with transcranial magnetic stimulation, it allows exploring functional cerebral networks during anesthesia. We will also see how EEG recordings during anesthesia, and their sophisticated analysis, may help corroborate current theories of mental content generation. [less ▲]

Detailed reference viewed: 18 (2 ULg)
Full Text
Peer Reviewed
See detailFunctional neuroanatomy of disorders of consciousness
Di Perri, Carol; Stender, Johan; Laureys, Steven ULg et al

in CAVANNA, Andrea (Ed.) Epilepsy and behavior Alteration of Counsciousness in Epilepsy (2014)

Our understanding of the mechanisms of loss and recovery of consciousness, following severe brain injury or during anesthesia, is changing rapidly. Recent neuroimaging studies have shown that patients ... [more ▼]

Our understanding of the mechanisms of loss and recovery of consciousness, following severe brain injury or during anesthesia, is changing rapidly. Recent neuroimaging studies have shown that patients with chronic disorders of consciousness and subjects undergoing general anesthesia present a complex dysfunctionality in the architecture of brain connectivity. At present, the global hallmark of impaired consciousness appears to be amultifaceted dysfunctional connectivity pattern with both within-network loss of connectivity in awidespread frontoparietal network and between-network hyperconnectivity involving other regions such as the insula and ventral tegmental area. Despite ongoing efforts, the mechanisms underlying the emergence of consciousness after severe brain injury are not thoroughly understood. Important questions remain unanswered:What triggers the connectivity impairment leading to disorders of consciousness? Why do some patients recover from coma, while others with apparently similar brain injuries do not? Understanding these mechanisms could lead to a better comprehension of brain function and, hopefully, lead to new therapeutic strategies in this challenging patient population. [less ▲]

Detailed reference viewed: 30 (5 ULg)
See detailPreserved Covert Cognition in Noncommunicative Patients With Severe Brain Injury?
schnakers, caroline; Giacino, Joseph T; Løvstad, Marianne et al

in Neurorehabilitation and Neural Repair (2014)

Detailed reference viewed: 23 (10 ULg)
Full Text
Peer Reviewed
See detailNociception coma scale-revised scores correlate with metabolism in the anterior cingulate cortex.
Chatelle, Camille ULg; Thibaut, Aurore ULg; Bruno, Marie-Aurelie et al

in Neurorehabilitation and neural repair (2014), 28(2), 149-52

BACKGROUND: . The Nociception Coma Scale-Revised (NCS-R) was recently validated to assess possible pain perception in patients with disorders of consciousness. OBJECTIVE: . To identify correlations ... [more ▼]

BACKGROUND: . The Nociception Coma Scale-Revised (NCS-R) was recently validated to assess possible pain perception in patients with disorders of consciousness. OBJECTIVE: . To identify correlations between cerebral glucose metabolism and NCS-R total scores. METHODS: . [18F]-fluorodeoxyglucose positron emission tomography, NCS-R, and Coma Recovery Scale-Revised assessments were performed in 49 patients with disorders of consciousness. RESULTS: . We identified a significant positive correlation between NCS-R total scores and metabolism in the posterior part of the anterior cingulate cortex, known to be involved in pain processing. No other cluster reached significance. No significant effect of clinical diagnosis (vegetative/unresponsive vs minimally conscious states), etiology or interval since insult was observed. CONCLUSIONS: . Our data support the hypothesis that the NCS-R total scores are related to cortical processing of nociception and may constitute an appropriate behavioral tool to assess, monitor, and treat possible pain in brain-damaged noncommunicative patients with disorders of consciousness. Future studies using event-related functional magnetic resonance imaging should investigate the correlation between NCS-R scores and brain activation in response to noxious stimulation at the single-subject level. [less ▲]

Detailed reference viewed: 50 (14 ULg)
Full Text
Peer Reviewed
See detailAssessment of visual fixatio in vegetative and minimally conscious states
Di, Haibo; Nie, Yunzhi; Hu, Xiaohu et al

in BMC Neurology (2014), 14(147),

Background: Visual fixation plays a key role in the differentiation between vegetative state/unresponsive wakefulness (VS/UWS) syndrome and minimally conscious state (MCS). However, the use of different ... [more ▼]

Background: Visual fixation plays a key role in the differentiation between vegetative state/unresponsive wakefulness (VS/UWS) syndrome and minimally conscious state (MCS). However, the use of different stimuli changes the frequency of visual fixation occured in patients, thereby possibly affecting the accuracy of the diagnosis. In order to establish a standardized assessment of visual fixation in patients in disorders of consciousness (DOC), we compared the frequency of visual fixation elicited by mirror,a ball and a light. Method: Visual fixation was assessed in eighty-one post-comatose patients diagnosed with a MCS or VS/UWS. Occurrence of fixation to different stimuli was analysis used Chi-square testing. Result: 40 (49%) out of the 81 patients showed fixation to visual stimuli. Among those, significantly more patients (39, 48%) had visual fixation elicited by mirror compared to a ball (23, 28%) and mirror compared to a light (20, 25%).Conclusion: The use of a mirror during the assessment of visual fixation showed higher positive response rate, compared to other stimuli in eliciting a visual fixating response. Therefore, fixation elicited by a mirror can be a very sensitive and accurate test to differentiate the two disorders of consciousness. [less ▲]

Detailed reference viewed: 13 (6 ULg)
Full Text
Peer Reviewed
See detailPain issues in disorders of consciousness
Chatelle, Camille ULg; Thibaut, Aurore ULg; Wythe, John et al

in Brain Injury (2014), 28(9), 1202-1208

Background: The assessment of pain and nociception in non-communicative patients with disorders of consciousness (DOC) is a real challenge for clinicians. It is, therefore, important to develop sensitive ... [more ▼]

Background: The assessment of pain and nociception in non-communicative patients with disorders of consciousness (DOC) is a real challenge for clinicians. It is, therefore, important to develop sensitive standardized tools usable at the bedside. Objectives: This review aims to provide an overview of the current knowledge about pain processing and assessment in patients with DOC. Methods: A search was performed on PubMed using MeSH terms including vegetative state, unresponsive wakefulness syndrome, minimally conscious state, consciousness disorders, pain, nociception, neuroimaging and pain assessment. Results: Neuroimaging studies investigating pain processing in patients with DOC and their implication for clinicians are reviewed. Current works on the development of standardized and sensitive tools for assessing nociception are described. Conclusion: The suggested pain perception capacity highlighted by neuroimaging studies in patients in a MCS and in some patients in a VS/UWS supports the idea that these patients need analgesic treatment and monitoring. The first tool which has been developed to assess nociception and pain in patients with DOC is the NCS. Its revised version represents a rapid, standardized and sensitive scale which can be easily implemented in a clinical setting. Complementary pain assessments are also under validation in order to offer more options to clinicians. [less ▲]

Detailed reference viewed: 35 (0 ULg)
Full Text
Peer Reviewed
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 & Metabolism (2014)

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 ▲]

Detailed reference viewed: 20 (0 ULg)
Peer Reviewed
See detailPositron emission tomography imaging in altered states of consciousness: Coma, sleep and hypnosis
Thibaut, Aurore ULg; Chatelle, Camille ULg; Stender, Johan et al

in Dierckx, Rudi; Otte, Andreas; Vries, Erik (Eds.) et al PET and SPECT in Neurology (2014)

Positron emission tomography (PET) allows studies of cerebral metabolism and blood flow and has been widely used to investigate physiological mechanisms underlying altered states of consciousness. The aim ... [more ▼]

Positron emission tomography (PET) allows studies of cerebral metabolism and blood flow and has been widely used to investigate physiological mechanisms underlying altered states of consciousness. The aim of this chapter is to review the current literature on brain metabolism during physiological or pathological loss of consciousness including studies on disorders of consciousness arising from severe brain injury (vegetative/unresponsive or minimally conscious states), and related non-pathological conditions such as sleep and hypnotic states. Identifying brain areas specifically involved in conscious processing, these studies have contributed to our understanding of the underlying physiology of consciousness. The precuneal and cingulate cortices, for example, seem to be key areas for maintaining consciousness awareness. Other areas such as hypothalamus, amygdala or the temporo-occipital cortex seem to play a role in different states of unconsciousness such as rapid eye movement sleep and hypnosis. PET studies permit a better comprehension of the loss of consciousness, and focus the implication of specific neural areas and networks in pathologically (vegetative/unresponsive or minimally conscious states), physiologically (sleep), and hypnotically altered states of consciousness. [less ▲]

Detailed reference viewed: 33 (8 ULg)
Full Text
See detailCerebral functional connectivity periodically (de)synchronizes with anatomical constraints
Liegeois, Raphaël ULg; Sepulchre, Rodolphe ULg; LAUREYS, Steven ULg

E-print/Working paper (2014)

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber ... [more ▼]

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber tractography. Instead of a static analysis based on the correlation between SC and the FC averaged over the entire fMRI time series, we propose a dynamic analysis, based on the time evolution of the correlation between SC and a suitably windowed FC. Assessing the statistical significance of the time series against random phase permutations, our data show a pronounced peak of significance for time window widths around 20-30 TR (40-60 sec). Using the appropriate window width, we show that FC patterns oscillate between phases of high modularity, primarily shaped by anatomy, and phases of low modularity, primarily shaped by inter-network connectivity. Building upon recent results in dynamic FC, this emphasizes the potential role of SC as a transitory architecture between different highly connected resting state FC patterns. Finally, we show that networks implied in consciousness-related processes, such as the default mode network (DMN), contribute more to these brain-level fluctuations compared to other networks, such as the motor or somatosensory networks. This suggests that the fluctuations between FC and SC are capturing mind-wandering effects. [less ▲]

Detailed reference viewed: 17 (5 ULg)
Full Text
Peer Reviewed
See detailMultiple fMRI system-level baseline connectivity is disrupted in patients with consciousness alterations
Demertzi, Athina ULg; Gomez, Francisco; Crone, Julia-Sophia et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2014), 52

Introduction: In healthy conditions, group-level fMRI resting state analyses identify ten resting state networks (RSNs) of cognitive relevance. Here, we aim to assess the tennetwork model in severely ... [more ▼]

Introduction: In healthy conditions, group-level fMRI resting state analyses identify ten resting state networks (RSNs) of cognitive relevance. Here, we aim to assess the tennetwork model in severely brain-injured patients suffering from disorders of consciousness and to identify those networks which will be most relevant to discriminate between patients and healthy subjects. Methods: 300 fMRI volumes were obtained in 27 healthy controls and 53 patients in minimally conscious state (MCS), vegetative state/unresponsive wakefulness syndrome (VS/ UWS) and coma. Independent component analysis (ICA) reduced data dimensionality. The ten networks were identified by means of a multiple template-matching procedure and were tested on neuronality properties (neuronal vs non-neuronal) in a data-driven way. Univariate analyses detected between-group differences in networks’ neuronal properties and estimated voxel-wise functional connectivity in the networks, which were significantly less identifiable in patients. A nearest-neighbor “clinical” classifier was used to determine the networks with high between-group discriminative accuracy. Results: Healthy controls were characterized by more neuronal components compared to patients in VS/UWS and in coma. Compared to healthy controls, fewer patients in MCS and VS/UWS showed components of neuronal origin for the left executive control network, default mode network (DMN), auditory, and right executive control network. The “clinical” classifier indicated the DMN and auditory network with the highest accuracy (85.3%) in discriminating patients from healthy subjects. [less ▲]

Detailed reference viewed: 70 (8 ULg)
Full Text
Peer Reviewed
See detailAssessment of Patient Comfort During Palliative Sedation: Is it always Reliable?
Deschepper, R; Bilsen, J; Laureys, Steven ULg

in Annual Update in Intensive Care and Emergency Medicine (2014)

"When death knocks at the door of our ward, we do not easily open the door”, an intensivist once said. In the intensive care unit (ICU) and emergency department, care is strongly focused on cure and ... [more ▼]

"When death knocks at the door of our ward, we do not easily open the door”, an intensivist once said. In the intensive care unit (ICU) and emergency department, care is strongly focused on cure and resuscitation. Notwithstanding the technological progress made in intensive and emergency medicine, a substantial number of the patients admitted to the ICU cannot be saved. In these cases, it is important to make a timely shift from curative efforts to palliative care, so that futile and burdensome interventions can be avoided. When death becomes imminent, a major concern of the family members and caregivers is to assure maximal comfort during the dying process. A central aspect of good end-of-life care is to keep the patient, as much as possible, free of pain and other kinds of distress. However, many critically ill patients often suffer from symptoms such as pain and delirium. More than 50 % of critically ill patients in the ICU experience moderate to severe pain and pain in critically ill patients often remains untreated [1]. [less ▲]

Detailed reference viewed: 24 (0 ULg)
Full Text
Peer Reviewed
See detailDisorders of consciousness after acquired brain injury: the state of the science
Giacino, Joseph T; Fins, Joseph J; Laureys, Steven ULg et al

in Nature Reviews Neurology (2014)

The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain ... [more ▼]

The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest. [less ▲]

Detailed reference viewed: 86 (6 ULg)
Peer Reviewed
See detailNeuroimaging in Disorders of Consciousness
Bodart, Olivier ULg; Charland-Verville, Vanessa ULg; Laureys, Steven ULg et al

in Filippi, M. (Ed.) Oxford Textbook of Clinical Neurology (2014)

Detailed reference viewed: 49 (12 ULg)
Full Text
Peer Reviewed
See detailAmantadine, Apomorphine and Zolpidem in the Treatment of Disorders of Consciousness
Gosseries, Olivia ULg; Charland-Verville, Vanessa ULg; Thonnard, Marie ULg et al

in Current Pharmaceutical Design (2014), 20

Survivors of severe brain injuries may end up in a state of 'wakeful unresponsiveness' or in a minimally conscious state. Pharmacological treatments of patients with disorders of consciousness aim to ... [more ▼]

Survivors of severe brain injuries may end up in a state of 'wakeful unresponsiveness' or in a minimally conscious state. Pharmacological treatments of patients with disorders of consciousness aim to improve arousal levels and recovery of consciousness. We here provide a systematic overview of the therapeutic effects of amantadine, apomorphine and zolpidem in patients recovering from coma. Evidence from clinical trials using these commonly prescribed pharmacological agents suggests positive changes in the neurological status in patients, leading sometimes to dramatic improvements. These findings are discussed in the context of current hypotheses of these agents' therapeutic mechanisms on cerebral function. In order to enhance our understanding of the underlying pathophysiological mechanisms of these drugs, we suggest combining sensitive and specific behavioral tools with neuroimaging and electrophysiological measures in large randomized, double-blind, placebo-controlled experimental designs. We conclude that the pharmacokinetics and pharmacodynamics of amantadine, apomorphine and zolpidem need further exploration to determine which treatment would provide a better neurological outcome regarding the patient's etiology, diagnosis, time since injury and overall condition. [less ▲]

Detailed reference viewed: 158 (11 ULg)
Full Text
Peer Reviewed
See detailOn the statistical assessment of small sample classification
Noirhomme, Quentin ULg; Lesenfants, Damien ULg; Gomez, Francisco et al

Conference (2013, December)

Classifiers start to be used in medical application to infer diagnosis. Their results are assessed through either a binomial or a permutation test. Distributions built from classification of random data ... [more ▼]

Classifiers start to be used in medical application to infer diagnosis. Their results are assessed through either a binomial or a permutation test. Distributions built from classification of random data with cross-validation, did not follow the theoretical binomial distribution, showing that binomial test was not conservative enough. A permutation test is thus recommended. [less ▲]

Detailed reference viewed: 26 (1 ULg)
Full Text
Peer Reviewed
See detailCommon resting brain dynamics indicate a possible mechanism underlying zolpidem response in severe brain injury
Williams, Shawniqua; Conte, Mary; Goldfine, Andrew et al

in eLife (2013)

Zolpidem produces paradoxical recovery of speech, cognitive and motor functions in select subjects with severe brain injury but underlying mechanisms remain unknown. In three diverse patients with known ... [more ▼]

Zolpidem produces paradoxical recovery of speech, cognitive and motor functions in select subjects with severe brain injury but underlying mechanisms remain unknown. In three diverse patients with known zolpidem responses we identify a distinctive pattern of EEG dynamics that suggests a mechanistic model. In the absence of zolpidem, all subjects show a strong low frequency oscillatory peak ∼6–10 Hz in the EEG power spectrum most prominent over frontocentral regions and with high coherence (∼0.7–0.8) within and between hemispheres. Zolpidem administration sharply reduces EEG power and coherence at these low frequencies. The ∼6–10 Hz activity is proposed to arise from intrinsic membrane properties of pyramidal neurons that are passively entrained across the cortex by locally-generated spontaneous activity. Activation by zolpidem is proposed to arise from a combination of initial direct drug effects on cortical, striatal, and thalamic populations and further activation of underactive brain regions induced by restoration of cognitively-mediated behaviors. [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
Peer Reviewed
See detailElectroencephalographic profiles for differentiation of disorders of consciousness.
Malinowska, U; Chatelle, Camille ULg; Bruno, Marie-Aurélie ULg et al

in BioMedical Engineering OnLine (2013), 12

BACKGROUND: Electroencephalography (EEG) is best suited for long-term monitoring of brain functions in patients with disorders of consciousness (DOC). Mathematical tools are needed to facilitate efficient ... [more ▼]

BACKGROUND: Electroencephalography (EEG) is best suited for long-term monitoring of brain functions in patients with disorders of consciousness (DOC). Mathematical tools are needed to facilitate efficient interpretation of long-duration sleep-wake EEG recordings. METHODS: Starting with matching pursuit (MP) decomposition, we automatically detect and parametrize sleep spindles, slow wave activity, K-complexes and alpha, beta and theta waves present in EEG recordings, and automatically construct profiles of their time evolution, relevant to the assessment of residual brain function in patients with DOC. RESULTS: Above proposed EEG profiles were computed for 32 patients diagnosed as minimally conscious state (MCS, 20 patients), vegetative state/unresponsive wakefulness syndrome (VS/UWS, 11 patients) and Locked-in Syndrome (LiS, 1 patient). Their interpretation revealed significant correlations between patients' behavioral diagnosis and: (a) occurrence of sleep EEG patterns including sleep spindles, slow wave activity and light/deep sleep cycles, (b) appearance and variability across time of alpha, beta, and theta rhythms. Discrimination between MCS and VS/UWS based upon prominent features of these profiles classified correctly 87 % of cases. CONCLUSIONS: Proposed EEG profiles offer user-independent, repeatable, comprehensive and continuous representation of relevant EEG characteristics, intended as an aid in differentiation between VS/UWS and MCS states and diagnostic prognosis. To enable further development of this methodology into clinically usable tests, we share user-friendly software for MP decomposition of EEG (http://braintech.pl/svarog) and scripts used for creation of the presented profiles (attached to this article). [less ▲]

Detailed reference viewed: 50 (7 ULg)
Full Text
Peer Reviewed
See detailLimbic hyperconnectivity in the vegetative state
Di Perri, C; Bastianello, S; Bartsch, AJ et al

in Neurology (2013), Vol 81

Objective: To investigate functional connectivity between the default mode network (DMN) and other networks in disorders of consciousness. Methods: We analyzedMRI data from 11 patients in a vegetative ... [more ▼]

Objective: To investigate functional connectivity between the default mode network (DMN) and other networks in disorders of consciousness. Methods: We analyzedMRI data from 11 patients in a vegetative state and 7 patients in a minimally conscious state along with age- And sex-matched healthy control subjects. MRI data analysis included nonlinear spatial normalization to compensate for disease-related anatomical distortions. We studied brain connectivity data from resting-state MRI temporal series, combining noninferential (independent component analysis) and inferential (seed-based general linear model) methods. Results: In DMN hypoconnectivity conditions, a patient's DMN functional connectivity shifts and paradoxically increases in limbic structures, including the orbitofrontal cortex, insula, hypothalamus, and the ventral tegmental area. Conclusions: Concurrently with DMN hypoconnectivity, we report limbic hyperconnectivity in patients in vegetative and minimally conscious states. This hyperconnectivity may reflect the persistent engagement of residual neural activity in self-reinforcing neural loops, which, in turn, could disrupt normal patterns of connectivity. [less ▲]

Detailed reference viewed: 13 (0 ULg)