References of "Demertzi, Athina"
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See detailDisorders of consciousness: new advances in neuroimaging techniques
Soddu, Andrea ULg; Bruno, Marie-Aurélie ULg; VANHAUDENHUYSE, Audrey ULg et al

in Zanotti, Bruno (Ed.) Vegetative State (in press)

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See detailSedation of Patients With Disorders of Consciousness During Neuroimaging: Effects on Resting State Functional Brain Connectivity.
KIRSCH, Murielle ULg; Guldenmund, P; Ali Bahri, Mohamed et al

in Anesthesia and Analgesia (2017), 124(2),

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See detailResting-state Network-specific Breakdown of Functional Connectivity during Ketamine Alteration of Consciousness in Volunteers
BONHOMME, Vincent ULg; VANHAUDENHUYSE, Audrey ULg; Demertzi, Athina ULg et al

in Anesthesiology (2016), 125(5), 873-878

Background: Consciousness-altering anesthetic agents disturb connectivity between brain regions composing the resting-state consciousness networks (RSNs). The default mode network (DMn), executive control ... [more ▼]

Background: Consciousness-altering anesthetic agents disturb connectivity between brain regions composing the resting-state consciousness networks (RSNs). The default mode network (DMn), executive control network, salience network (SALn), auditory network, sensorimotor network (SMn), and visual network sustain mentation. Ketamine modifies consciousness differently from other agents, producing psychedelic dreaming and no apparent interaction with the environment. The authors used functional magnetic resonance imaging to explore ketamine-induced changes in RSNs connectivity. Methods: Fourteen healthy volunteers received stepwise intravenous infusions of ketamine up to loss of responsiveness. Because of agitation, data from six subjects were excluded from analysis. RSNs connectivity was compared between absence of ketamine (wake state [W1]), light ketamine sedation, and ketamine-induced unresponsiveness (deep sedation [S2]). Results: Increasing the depth of ketamine sedation from W1 to S2 altered DMn and SALn connectivity and suppressed the anticorrelated activity between DMn and other brain regions. During S2, DMn connectivity, particularly between the medial prefrontal cortex and the remaining network (effect size β [95% CI]: W1 = 0.20 [0.18 to 0.22]; S2 = 0.07 [0.04 to 0.09]), and DMn anticorrelated activity (e.g., right sensory cortex: W1 = −0.07 [−0.09 to −0.04]; S2 = 0.04 [0.01 to 0.06]) were broken down. SALn connectivity was nonuniformly suppressed (e.g., left parietal operculum: W1 = 0.08 [0.06 to 0.09]; S2 = 0.05 [0.02 to 0.07]). Executive control networks, auditory network, SMn, and visual network were minimally affected. Conclusions: Ketamine induces specific changes in connectivity within and between RSNs. Breakdown of frontoparietal DMn connectivity and DMn anticorrelation and sensory and SMn connectivity preservation are common to ketamine and propofol-induced alterations of consciousness. [less ▲]

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See detailRepeated Behavioral Assessments in Patients with Disorders of Consciousness
Wannez, Sarah ULg; Annen, Jitka ULg; Aubinet, Charlène ULg 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 ULg; 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 ULg; Gomez, Francisco; Heine, Lizette ULg 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 ULg; LAUREYS, Steven ULg; Demertzi, Athina ULg

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 ULg 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 ULg; Bahri, Mohamed Ali ULg; Amico, Enrico ULg 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 ULg; Whitfield-Gabrieli, Susan

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

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