References of "Laureys, Steven"
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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 detailLocked-in syndrome after stroke
Charland-Verville, Vanessa ULg; Bruno, Marie-Aurélie ULg; Laureys, Steven ULg

Conference (2013, April)

The development of intensive care has considerably increased the number of patients surviving severe brain damage. In clinical practice, traumatic and non-traumatic coma is a frequent problem and the main ... [more ▼]

The development of intensive care has considerably increased the number of patients surviving severe brain damage. In clinical practice, traumatic and non-traumatic coma is a frequent problem and the main preoccupations of relatives and physicians is the neurologic recovery that may range from absence of cognitive and motor impairments to severe disability or death. The American Congress of Rehabilitation Medicine defined Locked-In Syndrome (LIS) with the presence of sustained eye opening, intact cognitive function, aphonia or severe hypophonia, quadriplegia or quadriparesis and a primery and elementary code of communication that use vertical or lateral eye movement or blinking of the upper eyelid. LIS is typically caused by a ventral pontine lesion of the brainstem. LIS infrequently occurs in children and in adults and patients may wrongly be considered as being in a coma or in vegetative state/unresponsive wakefulness state. In order to avoid this misdiagnosis, our group developed active paradigms in which participants are instructed to voluntarily direct their attention to a target stimulus. Limitations of communication make quality of life assessments in LIS patients particularly difficult. Some physicians who take care of acute LIS or healthy individual may consider that the quality of life of a LIS is very limited. However, studies have shown that patients with severe diseases or motor impairments do not necessarily self-report a poor quality of life. [less ▲]

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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 detailBrain function in coma
Charland-Verville, Vanessa ULg; Laureys, Steven ULg

Conference (2013, February)

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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 detailDisorders of consciousness and neuroimaging techniques
Charland-Verville, Vanessa ULg; Demertzi, Athina ULg; VANHAUDENHUYSE, Audrey ULg et al

Scientific conference (2013, January)

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See detailProbing command following in patients with disorders of consciousness using a brain-computer interface.
Lule, Dorothee; Noirhomme, Quentin ULg; Kleih, Sonja C. et al

in Clinical Neurophysiology (2013), 124(1), 101-6

OBJECTIVE: To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and ... [more ▼]

OBJECTIVE: To determine if brain-computer interfaces (BCIs) could serve as supportive tools for detecting consciousness in patients with disorders of consciousness by detecting response to command and communication. METHODS: We tested a 4-choice auditory oddball EEG-BCI paradigm on 16 healthy subjects and 18 patients in a vegetative state/unresponsive wakefulness syndrome, in a minimally conscious state (MCS), and in locked-in syndrome (LIS). Subjects were exposed to 4 training trials and 10 -12 questions. RESULTS: Thirteen healthy subjects and one LIS patient were able to communicate using the BCI. Four of those did not present with a P3. One MCS patient showed command following with the BCI while no behavioral response could be detected at bedside. All other patients did not show any response to command and could not communicate with the BCI. CONCLUSION: The present study provides evidence that EEG based BCI can detect command following in patients with altered states of consciousness and functional communication in patients with locked-in syndrome. However, BCI approaches have to be simplified to increase sensitivity. SIGNIFICANCE: For some patients without any clinical sign of consciousness, a BCI might bear the potential to employ a "yes-no" spelling device offering the hope of functional interactive communication. [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. Ethical and Legal Issues in Neurology (2013)

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 detailPain perception in disorders of consciousness: Neuroscience, clinical care, and ethics in dialogue
Demertzi, Athina ULg; Racine, Eric; Bruno, Marie-Aurélie ULg et al

in Neuroethics (2013), 6(1), 37-50

Pain, suffering and positive emotions in patients in vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious states (MCS) pose clinical and ethical challenges. Clinically, we ... [more ▼]

Pain, suffering and positive emotions in patients in vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious states (MCS) pose clinical and ethical challenges. Clinically, we evaluate behavioural responses after painful stimulation and also emotionally-contingent behaviours (e.g., smiling). Using stimuli with emotional valence, neuroimaging and electrophysiology technologies can detect subclinical remnants of preserved capacities for pain <br />which might influence decisions about treatment limitation. To date, no data exist as to how healthcare providers think about end-of-life options (e.g., withdrawal of artificial nutrition and hydration) in the presence or absence of pain in non-communicative patients. Here, we aimed to better clarify this issue by re-analyzing previously published data on pain <br />perception (Prog Brain Res 2009 177, 329–38) and end-of-life decisions (J Neurol 2010 258, 1058–65) in patients with disorders of consciousness. In a sample of 2259 European healthcare professionals we found that, for VS/UWS more respondents agreed with treatment withdrawal when they considered that VS/UWS patients did not feel pain (77%) as compared to those who thought VS/UWS did feel pain (59%). This interaction was influenced by religiosity and professional <br />background. For MCS, end-of-life attitudes were not influenced by opinions on pain perception. Within a contemporary ethical context we discuss (1) the evolving scientific understandings of pain perception and their relationship to existing clinical and ethical guidelines; (2) the discrepancies of attitudes within (and between) healthcare providers and their consequences for <br />treatment approaches, and (3) the implicit but complex relationship between pain perception and attitudes toward life-sustaining treatments. [less ▲]

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