References of "Laureys, Steven"
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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 ▲]

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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 ▲]

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See detailDynamic change of global and local information processing in Propofol-induced loss and recovery of consciousness
Monti, Martin; Lutkenoff, Evan; Rubinov, Mikail et al

in PLoS Computational Biology (2013), 9

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See detailA Comparison of Two Spelling Brain-Computer Interfaces Based on Visual P3 and SSVEP in Locked-In Syndrome
Combaz, Adrien; Chatelle, Camille ULg; Robben, Arne et al

in PLoS ONE (2013), 8(9), 73691

Objectives: We study the applicability of a visual P3-based and a Steady State Visually Evoked Potentials (SSVEP)-based Brain-Computer Interfaces (BCIs) for mental text spelling on a cohort of patients ... [more ▼]

Objectives: We study the applicability of a visual P3-based and a Steady State Visually Evoked Potentials (SSVEP)-based Brain-Computer Interfaces (BCIs) for mental text spelling on a cohort of patients with incomplete Locked-In Syndrome (LIS). Methods: Seven patients performed repeated sessions with each BCI. We assessed BCI performance, mental workload and overall satisfaction for both systems. We also investigated the effect of the quality of life and level of motor impairment on the performance. Results: All seven patients were able to achieve an accuracy of 70% or more with the SSVEP-based BCI, compared to 3 patients with the P3-based BCI, showing a better performance with the SSVEP BCI than with the P3 BCI in the studied cohort. Moreover, the better performance of the SSVEP-based BCI was accompanied by a lower mental workload and a higher overall satisfaction. No relationship was found between BCI performance and level of motor impairment or quality of life. Conclusion:Our results show a better usability of the SSVEP-based BCI than the P3-based one for the sessions performed by the tested population of locked-in patients with respect to all the criteria considered. The study shows the advantage of developing alternative BCIs with respect to the traditional matrix-based P3 speller using different designs and signal modalities such as SSVEPs to build a faster, more accurate, less mentally demanding and more satisfying BCI by testing both types of BCIs on a convenience sample of LIS patients. [less ▲]

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See detailPalliative sedation: Why we should be more concerned about the risks that patients experience an uncomfortable death
Deschepper, R; Laureys, Steven ULg; Hachimi-Idrissi, S et al

in Pain (2013), Vol 154

[No abstract available]

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See detailChanges in Effective Connectivity by Propofol Sedation
Gomez Jaramillo, Francisco Albeiro ULg; Phillips, Christophe ULg; Soddu, Andrea ULg et al

in PLoS ONE (2013), 8(8), 71370

Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent ... [more ▼]

Mechanisms of propofol-induced loss of consciousness remain poorly understood. Recent fMRI studies have shown decreases in functional connectivity during unconsciousness induced by this anesthetic agent. Functional connectivity does not provide information of directional changes in the dynamics observed during unconsciousness. The aim of the present study was to investigate, in healthy humans during an auditory task, the changes in effective connectivity resulting from propofol induced loss of consciousness. We used Dynamic Causal Modeling for fMRI (fMRI-DCM) to assess how causal connectivity is influenced by the anesthetic agent in the auditory system. Our results suggest that the dynamic observed in the auditory system during unconsciousness induced by propofol, can result in a mixture of two effects: a local inhibitory connectivity increase and a decrease in the effective connectivity in sensory cortices. [less ▲]

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See detailA theoretically based index of consciousness independent of sensory processing and behavior
Casali, AG; Gosseries, Olivia ULg; Rosanova, M et al

in Science Translational Medicine (2013), 5

One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the subject's ability to interact with ... [more ▼]

One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the subject's ability to interact with the external environment. Theoretical considerations suggest that consciousness depends on the brain's ability to support complex activity patterns that are, at once, distributed among interacting cortical areas (integrated) and differentiated in space and time (information-rich). We introduce and test a theory-driven index of the level of consciousness called the perturbational complexity index (PCI). PCI is calculated by (i) perturbing the cortex with transcranial magnetic stimulation (TMS) to engage distributed interactions in the brain (integration) and (ii) compressing the spatiotemporal pattern of these electrocortical responses to measure their algorithmic complexity (information). We test PCI on a large data set of TMS-evoked potentials recorded in healthy subjects during wakefulness, dreaming, nonrapid eye movement sleep, and different levels of sedation induced by anesthetic agents (midazolam, xenon, and propofol), as well as in patients who had emerged from coma (vegetative state, minimally conscious state, and locked-in syndrome). PCI reliably discriminated the level of consciousness in single individuals during wakefulness, sleep, and anesthesia, as well as in patients who had emerged from coma and recovered a minimal level of consciousness. PCI can potentially be used for objective determination of the level of consciousness at the bedside [less ▲]

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See detailConsciousness and responsiveness: Lessons from anaesthesia and the vegetative state
Boly, M; Sanders, RD; Mashour, GA et al

in Current Opinion in Anaesthesiology (2013), Vol 26

PURPOSE OF REVIEW: The aim of this article is to review recent behavioural and neuroimaging studies in anaesthesia and the vegetative state. RECENT FINDINGS: These studies highlight possible dissociations ... [more ▼]

PURPOSE OF REVIEW: The aim of this article is to review recent behavioural and neuroimaging studies in anaesthesia and the vegetative state. RECENT FINDINGS: These studies highlight possible dissociations between consciousness and responsiveness in both these states. SUMMARY: We discuss future avenues of research in the field, in order to improve the detection of awareness during anaesthesia and the vegetative state using neuroimaging and neurophysiologic techniques. [less ▲]

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See detailAbnormal corticospinal excitability in patients with disorders of consciousness
Lapitskaya, Natallia; Gosseries, Olivia ULg; DE PASQUA, Victor ULg et al

in Brain Stimulation (2013), Volume 6

Background: Transcranial magnetic stimulation (TMS) has been frequently used to explore changes in the human motor cortex in different conditions, while the extent of motor cortex reorganization in ... [more ▼]

Background: Transcranial magnetic stimulation (TMS) has been frequently used to explore changes in the human motor cortex in different conditions, while the extent of motor cortex reorganization in patients in vegetative state (VS) (now known as unresponsive wakefulness syndrome, UWS) and minimally conscious (MCS) states due to severe brain damage remains largely unknown. Objective/hypothesis: It was hypothesized that cortical motor excitability would be decreased and would correlate to the level of consciousness in patients with disorders of consciousness. Methods: Corticospinal excitability was assessed in 47 patients (24 VS/UWS and 23 MCS) and 14 healthy controls. The test parameters included maximal peak-to-peak M-wave (Mmax), F-wave persistence, peripheral and central motor conduction times, sensory (SEP) and motor evoked (MEP) potential latencies and amplitudes, resting motor threshold (RMT), stimulus/response curves, and short latency afferent inhibition (SAI). TMS measurements were correlated to the level of consciousness (assessed using the Coma Recovery Scale-Revised). Results: On average, the patient group had lower Mmax, lower MEP and SEP amplitudes, higher RMTs, narrower stimulus/response curves, and reduced SAI compared to the healthy controls (P < 0.05). The SAI alterations were correlated to the level of consciousness (P < 0.05). Conclusions: The findings demonstrated the impairment of the cortical inhibitory circuits in patients with disorders of consciousness. Moreover, the significant relationship was found between cortical inhibition and clinical consciousness dysfunction. [less ▲]

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See detailBrain dead yet mind alive: A positron emission tomography case study of brain metabolism in Cotard’s syndrome
Charland-Verville, Vanessa ULg; Bruno, Marie-Aurélie ULg; Bahri, Mohamed Ali ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2013), 49(7), 1997-1999

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See detailCharacteristics of Near-Death Experiences Memories as Compared to Real and Imagined Events Memories
Thonnard, Marie ULg; Charland-Verville, Vanessa ULg; Brédart, Serge ULg et al

in PLoS ONE (2013), 8(3),

Since the dawn of time, Near-Death Experiences (NDEs) have intrigued and, nowadays, are still not fully explained. Since reports of NDEs are proposed to be imagined events, and since memories of imagined ... [more ▼]

Since the dawn of time, Near-Death Experiences (NDEs) have intrigued and, nowadays, are still not fully explained. Since reports of NDEs are proposed to be imagined events, and since memories of imagined event have, on average, fewer phenomenological characteristics than real events memories, we here compared phenomenological characteristics of NDEs reports with memories of imagined and real events. We included three groups of coma survivors (8 patients with NDE as defined by the Greyson NDE scale, 6 patients without NDE but with memory of their coma, 7 patients without memories of their coma) and a group of 18 age-matched healthy volunteers. Five types of memories were assessed using Memory Characteristics Questionnaire (MCQ – Johnson et al., 1988): target memory (NDE for NDE memory group, coma memory for coma memory group, and first childhood memory for no memory and control groups), old and recent real event memories and old and recent imagined event memories. Since NDEs are known to have high emotional content, participants were requested to choose the most emotionally salient memories for both real and imagined recent and old event memories. Results showed that, in NDE memories group, NDE memories have more characteristics than memories of imagined and real events (p<0.02). NDE memories contain more self-referential and emotional information and have better clarity than memories of coma (all p<0.02). The present study showed that NDE memories contain more characteristics than real event memories and coma memories. Thus, this suggests that they cannot be considered as imagined event memories. On the contrary, their physiological origins could lead them to be really perceived although not lived in the reality. Further work is needed to better understand this phenomenon. [less ▲]

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See detailAssessment of localisation to auditory stimulation in post-comatose states: Use the patient's own name
Cheng, L; Gosseries, Olivia ULg; Ying, L et al

in BMC Neurology (2013), Vol 13

Background: At present, there is no consensus on how to clinically assess localisation to sound in patients recovering from coma. We here studied auditory localisation using the patient's own name as ... [more ▼]

Background: At present, there is no consensus on how to clinically assess localisation to sound in patients recovering from coma. We here studied auditory localisation using the patient's own name as compared to a meaningless sound (i.e., ringing bell).Methods: Eighty-six post-comatose patients diagnosed with a vegetative state/unresponsive wakefulness syndrome or a minimally conscious state were prospectively included. Localisation of auditory stimulation (i.e., head or eyes orientation toward the sound) was assessed using the patient's own name as compared to a ringing bell. Statistical analyses used binomial testing with bonferroni correction for multiple comparisons.Results: 37 (43%) out of the 86 studied patients showed localisation to auditory stimulation. More patients (n=34, 40%) oriented the head or eyes to their own name as compared to sound (n=20, 23%; p<0.001).Conclusions: When assessing auditory function in disorders of consciousness, using the patient's own name is here shown to be more suitable to elicit a response as compared to neutral sound [less ▲]

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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 detailDisorders of consciousness: Are we ready for a paradigm shift? - Authors' reply
Jox, RJ; Bernat, JL; Laureys, Steven ULg et al

in Lancet (2013), Vol 12

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See detailActigraphy assessments of circadian sleep-wake cycles in the Vegetative and Minimally Conscious States
Cruse, Damian; Thibaut, Aurore ULg; Demertzi, Athina ULg et al

in BMC Neuroscience (2013), 11(18),

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See detailConsciousness supporting networks
Demertzi, Athina ULg; Soddu, Andrea ULg; Laureys, Steven ULg

in Current Opinion in Neurobiology (2013), 23(2), 239244

Functional neuroimaging shows that patients with disorders of consciousness exhibit disrupted system-level functional connectivity. Unresponsive/’’vegetative state’’ patients preserve wakefulness networks ... [more ▼]

Functional neuroimaging shows that patients with disorders of consciousness exhibit disrupted system-level functional connectivity. Unresponsive/’’vegetative state’’ patients preserve wakefulness networks of brainstem and basal forebrain but the cerebral networks accounting for external perceptual awareness and internal self-related mentation are disrupted. Specifically, the ‘external awareness’ network encompassing lateral fronto-temporo-parietal cortices bilaterally, and the ‘internal awareness’ network including midline anterior cingulate/mesiofrontal and posterior cingulate/ precuneal cortices, are functionally disconnected. By contrast, patients in minimally conscious state ‘minus’, who show nonreflex behaviors, are characterized by right-lateralized recovery of the external awareness network. Similarly, patients who evolve to minimally conscious state ‘plus’ and respond to commands recover the dominant left-lateralized language network. Now, the use of active experimental paradigms targeting at detecting motor-independent signs of awareness or even establishing communication with these patients, challenge these two clinical boundaries. Such advances are naturally accompanied by legitimate neuroscientific and ethical queries demanding our attention on the medical implementations of this new knowledge. [less ▲]

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See detailComa and disorders of consciousness
Bruno, Marie-Aurélie ULg; Laureys, Steven ULg; Demertzi, Athina ULg

in Handbook of Clinical Neurology (2013), Vol 118

Patients in coma, vegetative state/unresponsive wakefulness syndrome, and in minimally conscious states pose medical, scientific, and ethical challenges. As patients with disorders of consciousness are by ... [more ▼]

Patients in coma, vegetative state/unresponsive wakefulness syndrome, and in minimally conscious states pose medical, scientific, and ethical challenges. As patients with disorders of consciousness are by definition unable to communicate, the assessment of pain, quality of life, and end-of-life preferences in these conditions can only be approached by adopting a third-person perspective. Surveys of healthcare workers' attitudes towards pain and end of life in disorders of consciousness shed light on the background of clinical reality, where no standard medical-legal framework is widely accepted. On the other hand, patients with locked-in syndrome, who are severely paralyzed but fully conscious, can inform about subjective quality of life in serious disability and help us to understand better the underlying factors influencing happiness in disease. In the medico-legal arena, such ethical issues may be resolved by previously drafted advance directives and, when absent, by surrogate representation. Lately, functional medical imaging and electrophysiology provide alternative means to communicate with these challenging patients and will potentially mediate to extract responses of medical-ethical content. Eventually, the clinical translation of these advanced technologies in the medical routine is of paramount importance for the promotion of medical management of these challenging patients [less ▲]

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See detailLooking for the self in pathological unconsciousness.
Demertzi, Athina ULg; Vanhaudenhuyse, Audrey ULg; Brédart, Serge ULg et al

in Frontiers in Human Neuroscience (2013), 7

There is an intimate relationship between consciousness and the notion of self. By studying patients with disorders of consciousness, we are offered with a unique lesion approach to tackle the neural ... [more ▼]

There is an intimate relationship between consciousness and the notion of self. By studying patients with disorders of consciousness, we are offered with a unique lesion approach to tackle the neural correlates of self in the absence of subjective reports. Studies employing neuroimaging techniques point to the critical involvement of midline anterior and posterior cortices in response to the passive presentation of self-referential stimuli, such as the patient’s own name and own face. Also, resting state studies show that these midline regions are severely impaired as a function of the level of consciousness. Theoretical frameworks combining all this progress surpass the functional localization of self-related cognition and suggest a dynamic system-level approach to the phenomenological complexity of subjectivity. Importantly for non-communicating patients suffering from disorders of consciousness, the clinical translation of these technologies will allow medical professionals and families to better comprehend these disorders and plan efficient medical management for these patients. [less ▲]

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See detailA multiscale method for a robust detection of the default mode network.
Baquero, Katherine; Gómez, Francisco; Cifuentes, Christian et al

Poster (2013)

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See detailLa stimulation transcranienne a courant continu : un nouvel outil de neurostimulation.
Thibaut, Aurore ULg; Chatelle, Camille ULg; Gosseries, Olivia ULg et al

in Revue Neurologique (2013), 169

Transcranial direct current stimulation (tDCS) is a safe method to modulate cortical excitability. Anodal stimulation can improve the stimulated area's functions whereas cathodal stimulation reduces them ... [more ▼]

Transcranial direct current stimulation (tDCS) is a safe method to modulate cortical excitability. Anodal stimulation can improve the stimulated area's functions whereas cathodal stimulation reduces them. Currently, a lot of clinical trials have been conducted to study the effect of tDCS on post-stroke motor and language deficits, in depression, chronic pain, memory impairment and tinnitus in order to decrease symptoms. Results showed that, if an effect is observed with tDCS, it does not persist over time. Current studies suggest that direct current stimulation is a promising technique that helps to improve rehabilitation after stroke, to enhance cognitive deficiencies, to reduce depression and to relieve chronic pain. Moreover, it is a safe, simple and cheap device that could be easily integrated in a rehabilitation program. [less ▲]

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