References of "Demertzi, Athina"
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See detailRepeated Behavioral Assessments in Patients with Disorders of Consciousness
Wannez, Sarah ULiege; Annen, Jitka ULiege; Aubinet, Charlène ULiege et al

Conference (2016, March 04)

The Coma Recovery Scale Revised (CRS-R) is considered as the most sensitive scale to assess patients with disorders of consciousness (DOC). Guidelines recommend repeated assessments because patients might ... [more ▼]

The Coma Recovery Scale Revised (CRS-R) is considered as the most sensitive scale to assess patients with disorders of consciousness (DOC). Guidelines recommend repeated assessments because patients might suffer from consciousness fluctuations, but it is not specified how many assessments are needed. The present study included 131 patients with DOC. They have been assessed at least 6 times during a 14-days period with the CRS-R. Results show that 5 CRS-R assessments are needed to reach a reliable diagnosis, and that all the CRS-R subscales are influenced by consciousness fluctuations. We here showed that consciousness fluctuations influence the behavioral diagnosis, and that 5 assessments within a short period of time are needed to get a reliable clinical diagnosis. [less ▲]

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See detailCortical reorganization in an astronaut's brain after long-duration spaceflight.
Demertzi, Athina ULiege; Van Ombergen, Angelique; Tomilovskaya, Elena et al

in Brain Structure & Function (2016), 221(5), 2873-2876

To date, hampered physiological function after exposure to microgravity has been primarily attributed to deprived peripheral neuro-sensory systems. For the first time, this study elucidates alterations in ... [more ▼]

To date, hampered physiological function after exposure to microgravity has been primarily attributed to deprived peripheral neuro-sensory systems. For the first time, this study elucidates alterations in human brain function after long-duration spaceflight. More specifically, we found significant differences in resting-state functional connectivity between motor cortex and cerebellum, as well as changes within the default mode network. In addition, the cosmonaut showed changes in the supplementary motor areas during a motor imagery task. These results highlight the underlying neural basis for the observed physiological deconditioning due to spaceflight and are relevant for future interplanetary missions and vestibular patients. [less ▲]

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See detailCorrelation between resting state fMRI total neuronal activity and PET metabolism in healthy controls and patients with disorders of consciousness
Soddu, Andrea ULiege; Gomez, Francisco; Heine, Lizette ULiege et al

in Brain and Behavior (2016), 6(1), 1-15

Introduction: The mildly invasive 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established imaging technique to measure ‘resting state’ cerebral metabolism. This technique made ... [more ▼]

Introduction: The mildly invasive 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established imaging technique to measure ‘resting state’ cerebral metabolism. This technique made it possible to assess changes in metabolic activity in clinical applications, such as the study of severe brain injury and disorders of consciousness. Objective: We assessed the possi- bility of creating functional MRI activity maps, which could estimate the rela- tive levels of activity in FDG-PET cerebral metabolic maps. If no metabolic absolute measures can be extracted, our approach may still be of clinical use in centers without access to FDG-PET. It also overcomes the problem of recogniz- ing individual networks of independent component selection in functional mag- netic resonance imaging (fMRI) resting state analysis. Methods: We extracted resting state fMRI functional connectivity maps using independent component analysis and combined only components of neuronal origin. To assess neu- ronality of components a classification based on support vector machine (SVM) was used. We compared the generated maps with the FDG-PET maps in 16 healthy controls, 11 vegetative state/unresponsive wakefulness syndrome patients and four locked-in patients. Results: The results show a significant similarity with q = 0.75  0.05 for healthy controls and q = 0.58  0.09 for vegetative state/unresponsive wakefulness syndrome patients between the FDG- PET and the fMRI based maps. FDG-PET, fMRI neuronal maps, and the conjunction analysis show decreases in frontoparietal and medial regions in vegetative patients with respect to controls. Subsequent analysis in locked-in syndrome patients produced also consistent maps with healthy controls. Conclusions: The constructed resting state fMRI functional connectivity map points toward the possibility for fMRI resting state to estimate relative levels of activity in a metabolic map. [less ▲]

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See detailPain and Nociception in Disorders of Consciousness
Chatelle, Camille ULiege; LAUREYS, Steven ULiege; Demertzi, Athina ULiege

in Luis Garcia-Larrea, France; Jackson, Philip L. (Eds.) Pain and the Conscious Brain (2016)

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See detailReply: Replicability and impact of statistics in the detection of neural responses of consciousness
Naccache, Lionel; Sitt, J.D; King, J.R et al

in Brain : A Journal of Neurology (2016), 139(6), 31

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See detailA human brain network derived from coma-causing brainstem lesions
Fischer, David; Boes, A.D; Demertzi, Athina ULiege et al

in Neurology (2016), 87(23), 2427-2434

OBJECTIVE To characterize a brainstem location specific to coma-causing lesions, and its functional connectivity network. METHODS We compared 12 coma-causing brainstem lesions to 24 control brainstem ... [more ▼]

OBJECTIVE To characterize a brainstem location specific to coma-causing lesions, and its functional connectivity network. METHODS We compared 12 coma-causing brainstem lesions to 24 control brainstem lesions using voxel-based lesion-symptom mapping in a case-control design to identify a site significantly associated with coma. We next used resting-state functional connectivity from a healthy cohort to identify a network of regions functionally connected to this brainstem site. We further investigated the cortical regions of this network by comparing their spatial topography to that of known networks and by evaluating their functional connectivity in patients with disorders of consciousness. RESULTS A small region in the rostral dorsolateral pontine tegmentum was significantly associated with coma-causing lesions. In healthy adults, this brainstem site was functionally connected to the ventral anterior insula (AI) and pregenual anterior cingulate cortex (pACC). These cortical areas aligned poorly with previously defined resting-state networks, better matching the distribution of von Economo neurons. Finally, connectivity between the AI and pACC was disrupted in patients with disorders of consciousness, and to a greater degree than other brain networks. CONCLUSIONS Injury to a small region in the pontine tegmentum is significantly associated with coma. This brainstem site is functionally connected to 2 cortical regions, the AI and pACC, which become disconnected in disorders of consciousness. This network of brain regions may have a role in the maintenance of human consciousness [less ▲]

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See detailNeural correlates of consciousness in patients who have emerged from a minimally conscious state: A cross-sectional multimodal imaging study
Di Perri, Carol ULiege; Bahri, Mohamed Ali ULiege; Amico, Enrico ULiege et al

in Lancet Neurology (2016), 15

Background Between pathologically impaired consciousness and normal consciousness exists a scarcely researched transition zone, referred to as emergence from minimally conscious state, in which patients ... [more ▼]

Background Between pathologically impaired consciousness and normal consciousness exists a scarcely researched transition zone, referred to as emergence from minimally conscious state, in which patients regain the capacity for functional communication, object use, or both. We investigated neural correlates of consciousness in these patients compared with patients with disorders of consciousness and healthy controls, by multimodal imaging. Methods In this cross-sectional, multimodal imaging study, patients with unresponsive wakefulness syndrome, patients in a minimally conscious state, and patients who had emerged from a minimally conscious state, diagnosed with the Coma Recovery Scale–Revised, were recruited from the neurology department of the Centre Hospitalier Universitaire de Liège, Belgium. Key exclusion criteria were neuroimaging examination in an acute state, sedation or anaesthesia during scanning, large focal brain damage, motion parameters of more than 3 mm in translation and 3° in rotation, and suboptimal segmentation and normalisation. We acquired resting state functional and structural MRI data and ¹⁸F-fl uorodeoxyglucose (FDG) PET data; we used seed-based functional MRI (fMRI) analysis to investigate positive default mode network connectivity (within-network correlations) and negative default mode network connectivity (between-network anticorrelations). We correlated FDG-PET brain metabolism with fMRI connectivity. We used voxel- based morphometry to test the eff ect of anatomical deformations on functional connectivity. Findings We recruited a convenience sample of 58 patients (21 [36%] with unresponsive wakefulness syndrome, 24 [41%] in a minimally conscious state, and 13 [22%] who had emerged from a minimally conscious state) and 35 healthy controls between Oct 1, 2009, and Oct 31, 2014. We detected consciousness-level-dependent increases (from unresponsive wakefulness syndrome, minimally conscious state, emergence from minimally conscious state, to healthy controls) for positive and negative default mode network connectivity, brain metabolism, and grey matter volume (p<0·05 false discovery rate corrected for multiple comparisons). Positive default mode network connectivity diff ered between patients and controls but not among patient groups (F test p<0·0001). Negative default mode network connectivity was only detected in healthy controls and in those who had emerged from a minimally conscious state; patients with unresponsive wakefulness syndrome or in a minimally conscious state showed pathological between-network positive connectivity (hyperconnectivity; F test p<0·0001). Brain metabolism correlated with positive default mode network connectivity (Spearman’s r=0·50 [95% CI 0·26 to 0·61]; p<0·0001) and negative default mode network connectivity (Spearman’s r=–0·52 [–0·35 to –0·67); p<0·0001). Grey matter volume did not diff er between the studied groups (F test p=0·06). Interpretation Partial preservation of between-network anticorrelations, which are seemingly of neuronal origin and cannot be solely explained by morphological deformations, characterise patients who have emerged from a minimally conscious state. Conversely, patients with disorders of consciousness show pathological between-network correlations. Apart from a deeper understanding of the neural correlates of consciousness, these fi ndings have clinical implications and might be particularly relevant for outcome prediction and could inspire new therapeutic options. [less ▲]

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See detailIntrinsic brain activity and consciousness
Demertzi, Athina ULiege; Whitfield-Gabrieli, Susan

in Laureys, Steven; Gosseries, Olivia; Tononi, Giulio (Eds.) The Neurology of Consciousness (2016)

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See detailIntrinsic fMRI functional architecture differentiates single patients after severe brain injury
Demertzi, Athina ULiege; Antonopoulos, Georgios ULiege; Heine, Lizette ULiege et al

Poster (2015)

Background: Resting state acquisitions are by definition appropriate to assess non-communicating subjects. We here assessed the clinical relevance of systems-level resting state fMRI in patients with ... [more ▼]

Background: Resting state acquisitions are by definition appropriate to assess non-communicating subjects. We here assessed the clinical relevance of systems-level resting state fMRI in patients with disorders of consciousness with the aim to promote single-patient diagnostics. Methods: Seventy three patients in minimally conscious state (MCS), vegetative state/unresponsive wakefulness syndrome (VS/UWS) and coma were scanned in 3 different centers. The main analysis was performed on the dataset coming from one centre (Liège, 51 patients; 26 MCS, 19 VS/UWS, 6 coma; 16 traumatic, 32 non-traumatic, 3 mixed; 35 patients assessed >1 month post-insult) for whom the clinical diagnosis with the Coma Recovery Scale-Revised (CRS-R) was congruent with positron emission tomography scanning. Using a multiple-seed correlation approach, group-level functional connectivity was investigated for the default mode, frontoparietal, salience, auditory, sensorimotor and visual networks. Between-group inferential statistics and machine learning were used to identify each network’s capacity to discriminate between patients in MCS and VS/UWS. Data from 22 patients independently scanned in two other centres (Salzburg: 10 MCS, 5 VS/UWS; New York: 5 MCS, 1 VS/UWS, 1 emerged from MCS) were used to validate the classification with the indetified features. Results: CRS-R total scores correlated with key regions of each network reflecting their involvement in consciousness-related processes. Although all networks had a high discriminative capacity (>80%) for separating patients in MCS and VS/UWS, the auditory network was ranked the most highly. Specifically, bilateral auditory and visual cortices of the auditory network were more functionally connected in patients in MCS compared to VS/UWS. Connectivity values in these three regions discriminated congruently 20 out of 22 independently assessed patients. Conclusions: These findings highlight the significance of preserved multisensory integration and top-down processing in minimal consciousness which are seemingly supported by auditory-visual crossmodal connectivity, and promote the clinical utility of the resting paradigm for single-patient diagnostics. [less ▲]

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See detailHypnosis modulates behavioural measures and subjective ratings about external and internal awareness
Demertzi, Athina ULiege; VANHAUDENHUYSE, Audrey ULiege; Noirhomme, Quentin ULiege et al

in Journal of Physiology - Paris (2015), 109(4), 173-179

In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects’ behalf. With the aim to characterize the ... [more ▼]

In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects’ behalf. With the aim to characterize the behavioural counterpart of external and internal awareness in a modified subjective condition, we used hypnosis during which subjects remain fully responsive. Eleven right-handed subjects reached a satisfactory level of hypnotisability as evidenced by subjective reports on arousal, absorption and dissociation. Compared to normal wakefulness, in hypnosis (a) participants’ self-ratings for internal awareness increased and self-ratings for external awareness decreased, (b) the two awareness components tended to anticorrelate less and the switches between external and internal awareness self-ratings were less frequent, and (c) participants’ reaction times were higher and lapses in key presses were more frequent. The identified imbalance between the two components of awareness is considered as of functional relevance to subjective (meta)cognition, possibly mediated by allocated attentional properties brought about by hypnosis. Our results highlight the presence of a cognitive counterpart in resting state, indicate that the modified contents of awareness are measurable behaviourally, and provide leverage for investigations of more challenging altered conscious states, such as anaesthesia, sleep and disorders of consciousness. [less ▲]

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See detailBeyond the gaze: Communicating in chronic locked-in syndrome
Lugo, Z.R; Bruno, Marie-Aurelie; Gosseries, Olivia ULiege et al

in Brain Injury (2015), 29

OBJECTIVE Locked-in syndrome (LIS) usually follows a brainstem stroke and is characterized by paralysis of all voluntary muscles (except eyes' movements or blinking) and lack of speech with preserved ... [more ▼]

OBJECTIVE Locked-in syndrome (LIS) usually follows a brainstem stroke and is characterized by paralysis of all voluntary muscles (except eyes' movements or blinking) and lack of speech with preserved consciousness. Several tools have been developed to promote communication with these patients. The aim of the study was to evaluate the current status regarding communication in a cohort of LIS patients. DESIGN A survey was conducted in collaboration with the French Association of Locked-in syndrome (ALIS). SUBJECTS AND METHODS Two hundred and four patients, members of ALIS, were invited to fill in a questionnaire on communication issues and clinical evolution (recovery of verbal language and movements, presence of visual and/or auditory deficits). RESULTS Eighty-eight responses were processed. All respondents (35% female, mean age = 52 ± 12 years, mean time in LIS = 10 ± 6 years) reported using a yes/no communication code using mainly eyes' movements and 62% used assisting technology; 49% could communicate through verbal language and 73% have recovered some functional movements within the years. CONCLUSION The results highlight the possibility to recover non-eye dependent communication, speech production and some functional movement in the majority of chronic LIS patients. [less ▲]

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See detailConsciousness: And Disorders of Consciousness
Heine, Lizette ULiege; Demertzi, Athina ULiege; Laureys, Steven ULiege et al

in Toga, Arthur W (Ed.) Brain mapping : an encyclopedic reference (2015)

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See detailDetecting Levels of Consciousness
Demertzi, Athina ULiege; Laureys, Steven ULiege

in Levy, N; Clausen, J (Eds.) Handbook of Neuroethics (2015)

Patients with disordered consciousness due to brain injury pose medical and ethical challenges. Rates of clinical misdiagnosis of “vegetative”/unresponsive, minimally conscious and locked-in syndrome ... [more ▼]

Patients with disordered consciousness due to brain injury pose medical and ethical challenges. Rates of clinical misdiagnosis of “vegetative”/unresponsive, minimally conscious and locked-in syndrome states remain challengingly high. Clinical misdiagnosis raises profound ethical concerns in terms of medical management, treatment of pain, and end-of-life decisions. Therefore, valid diagnosis is of utmost importance in clinical settings. A number of neuroimaging and electrophysiology studies now suggest that some behaviorally “vegetative state” patients may nevertheless show atypical cortical activation during resting state conditions; in some cases, they are able to follow commands or even communicate through willfully modified brain activity. Advances in investigating disorders of consciousness with neuroimaging techniques promise to lead to a more accurate understanding of individual patients’ cognitive abilities and to shed light on the gray zones of these clinical conditions. The formulation of an ethical framework which will strike a balance between the protection of these patients and further research on disorders of consciousness is an ethical, clinical, and scientific demand. [less ▲]

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