References of "Di Perri, Carol"
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See detailMultifaceted Brain Networks Reconfiguration in Disorders of Consciousness Uncovered by Co-Activation Patterns
Di Perri, Carol ULiege; Amico, Enrico; Heine, Lizette ULiege et al

in Human Brain Mapping (in press)

Introduction: Given that recent research has shown that functional connectivity is not a static phenomenon, we aim to investigate the dynamic properties of the default mode network’s (DMN) connectivity in ... [more ▼]

Introduction: Given that recent research has shown that functional connectivity is not a static phenomenon, we aim to investigate the dynamic properties of the default mode network’s (DMN) connectivity in patients with disorders of consciousness. Methods: Resting-state fMRI volumes of a convenience sample of 17 patients in unresponsive wakefulness syndrome (UWS) and controls were reduced to a spatiotemporal point process by selecting critical time points in the posterior cingulate cortex (PCC). Spatial clustering was performed on the extracted PCC time frames to obtain 8 different co-activation patterns (CAPs). We investigated spatial connectivity patterns positively and negatively correlated with PCC using both CAPs and standard stationary method. We calculated CAPs occurrences and the total number of frames. Results: Compared to controls, patients showed (i) decreased within-network positive correlations and between-network negative correlations, (ii) emergence of “pathological” within-network negative correlations and between-network positive correlations (better defined with CAPs), and (iii) “pathological” increases in within-network positive correlations and between-network negative correlations (only detectable using CAPs). Patients showed decreased occurrence of DMN-like CAPs (1–2) compared to controls. No between-group differences were observed in the total number of frames Conclusion: CAPs reveal at a more fine-grained level the multifaceted spatial connectivity reconfiguration following the DMN disruption in UWS patients, which is more complex than previously thought and suggests alternative anatomical substrates for consciousness. BOLD fluctuations do not seem to differ between patients and controls, suggesting that BOLD response represents an intrinsic feature of the signal, and therefore that spatial configuration is more important for consciousness than BOLD activation itself. [less ▲]

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See detailA method for independent component graph analysis of resting-state fMRI. Brain and Behavior 2017, in press
Ribeiro de Paula, Demetrius; Ziegler, Erik; Abeyasinghe, P et al

in Brain and Behavior (in press)

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See detailMultimodal imaging analysis in Charles Bonnet Syndrome: a case report
Martial, Charlotte ULiege; Di Perri, Carol ULiege; Larroque, Stephen ULiege et al

Poster (2017, June)

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in psychologically normal elderly people. Previous studies have suggested ... [more ▼]

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in psychologically normal elderly people. Previous studies have suggested that visual hallucinations may be caused by brain damage in the visual system. However, in the case of CBS, specific brain regions in the occipital cortex have not been clearly determined and functional neuroimaging remains relatively unexplored. To our knowledge, functional connectivity by means of resting-state magnetic resonance imaging (MRI) has never been investigated in patients with CBS. We here aimed to investigate structural imaging, brain metabolism and functional connectivity in a patient with CBS. Resting-state functional and structural MRI were acquired in an 85-year-old patient with CBS and 12 age- and gender-matched normally sighted controls. Cognitive functioning was measured by behavioral assessment. A seed-based resting state fMRI was performed to investigate the default mode network (DMN), the executive control network and the visual networks connectivity. A voxel-based morphometry (VBM) analysis was employed to investigate the grey matter volume. Cortical and subcortical grey matter thickness were further investigated. Finally, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was also acquired to observe regional glucose uptake by comparing standard uptake values (SUVs). Increased functional connectivity was found between the DMN and the temporo-occipital fusiform cortex, as well as between the secondary visual cortex and the left frontal cortex, in the CBS patient compared to controls. The patient also demonstrated increased functional connectivity between the primary visual cortex and the left supramarginal gyrus and between the associative visual cortex and the superior temporal gyrus/angular gyrus, as compared to controls. Decreased grey matter volume was observed in the lateral occipital cortex/angular gyrus in our patient as compared to controls. Diminished grey matter thickness values were observed in the lateral geniculate nucleus compared to healthy controls. FDG-PET results confirmed previous work and showed bilateral hypometabolism in the occipital cortex (mean SUV reduction of 5.36%, p<0.001). Our results suggest that structural alterations in visual system in CBS are associated with compensatory/adaptive changes in functional connectivity that involve regions known to support hallucinations of faces in CBS patients. We suggest that this functional connectivity reorganization following visual structural damage may contribute to visual hallucinations. These findings might shed light on the pathophysiology underlining this rare condition. [less ▲]

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See detailClinical sub-categorization of minimally conscious state according to resting functional connectivity
Aubinet, Charlène ULiege; Heine, Lizette ULiege; Martial, Charlotte ULiege et al

Conference (2017, March 31)

Introduction: Patients in a minimally conscious state (MCS) have been subcategorized in MCS plus and MCS minus, respectively with and without command following capacity. Here we aim to characterize ... [more ▼]

Introduction: Patients in a minimally conscious state (MCS) have been subcategorized in MCS plus and MCS minus, respectively with and without command following capacity. Here we aim to characterize differences in MCS plus as compared to MCS minus by means of functional connectivity (FC). Method: Resting state functional magnetic resonance imagery (fMRI) was acquired in 292 MCS patients and a seed-based analysis was conducted on a convenience sample of 19 MCS patients (10 MCS plus and 9 MCS minus) and 35 healthy controls. We investigated the left and right frontoparietal networks (FPN), the auditory network and the default mode network (DMN). We employed a ROI-to-ROI analysis to investigate the inter-hemispheric connectivity and we investigated inter-group differences in grey and white matter volume by means of voxel-based morphometry. Results: We found a higher FC in MCS plus as compared to MCS minus in the left FPN, specifically between the left dorso-lateral prefrontal cortex and the left temporo-occipital fusiform cortex (TOFC). The FC of auditory network, right FPN and DMN, inter-hemispheric connectivity and structure of grey and white matter did not show differences between patients groups. Discussion: Our results suggest that the clinical sub-categorization of MCS is sustained by FC differences in a language-related executive control network. MCS plus and MCS minus patients are not differentiated by networks involved in auditory processing, perception of surroundings and internal thoughts, nor by differences in inter-hemispheric connectivity and in morphology. [less ▲]

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See detailCharacterization of minimally conscious state minus and plus according to resting functional connectivity
Aubinet, Charlène ULiege; Heine, Lizette; Martial, Charlotte ULiege et al

Scientific conference (2017, February 01)

The minimally conscious state (MCS) has been sub-categorized in MCS plus and MCS minus, i.e. respectively with and without command following capacity. Here we aimed at characterizing differences in MCS ... [more ▼]

The minimally conscious state (MCS) has been sub-categorized in MCS plus and MCS minus, i.e. respectively with and without command following capacity. Here we aimed at characterizing differences in MCS plus as compared to MCS minus by means of functional connectivity (FC). Resting state functional magnetic resonance imagery (fMRI) was acquired in 292 MCS patients and a seed-based analysis was conducted on a convenience sample of 19 MCS patients (10 MCS plus and 9 MCS minus) and 35 healthy controls. We investigated the left and right frontoparietal networks (FPN), the auditory network and the default mode network (DMN). We employed a ROI-to-ROI analysis and a voxel-based morphometry in order to investigate the inter-hemispheric connectivity and the grey and white matter volume, respectively. A significantly higher FC was found in MCS plus as compared to MCS minus in the left FPN, specifically between the left dorso-lateral prefrontal cortex and the left temporo-occipital fusiform cortex (TOFC). The FC of auditory network, right FPN and DMN, inter-hemispheric connectivity and structure of grey and white matter did not show differences between patients groups. The clinical sub-categorization of MCS is therefore sustained by FC differences in a language-related executive control network. These patient groups are not differentiated by networks involved in auditory processing, perception of surroundings and internal thoughts, nor by differences in inter-hemispheric connectivity and in morphology. [less ▲]

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

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

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See detailMapping the functional connectome traits of levels of consciousness
Amico, Enrico; Marinazzo, Daniele; Di Perri, Carol ULiege et al

in NeuroImage (2017)

Examining task-free functional connectivity (FC) in the human brain offers insights on how spontaneous integration and segregation of information relate to human cognition, and how this organization may ... [more ▼]

Examining task-free functional connectivity (FC) in the human brain offers insights on how spontaneous integration and segregation of information relate to human cognition, and how this organization may be altered in different conditions, and neurological disorders. This is particularly relevant for patients in disorders of consciousness (DOC) following severe acquired brain damage and coma, one of the most devastating conditions in modern medical care. We present a novel data-driven methodology, connICA, which implements Independent Component Analysis (ICA) for the extraction of robust independent FC patterns (FC-traits) from a set of individual functional connectomes, without imposing any a priori data stratification into groups. We here apply connICA to investigate associations between network-traits derived from task-free FC and cognitive features that define levels of consciousness. Three main independent FC-traits were identified and linked to consciousness-related clinical features. The first one represents the functional configuration of an "awake resting" brain, and is associated to the level of arousal. The second FC-trait reflects the disconnection of the visual and sensory-motor connectivity patterns and relates to the ability of communicating with the external environment. The third FC-trait isolates the connectivity pattern encompassing the fronto-parietal and the default-mode network areas as well as the interaction between left and right hemisphere, which are also associated to the awareness of the self and its surroundings. Each FC-trait represents a distinct functional process with a role in the degradation of conscious states in functional brain networks, shedding further light on the functional subcircuits that get disrupted in severe brain-damage. [less ▲]

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See detailFunctional Connectivity Substrates for tDCS Response in Minimally Conscious State Patients
Cavaliere, Carlo ULiege; Aiello, Marco; Di Perri, Carol ULiege et al

in Frontiers in Cellular Neuroscience (2016)

Transcranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half ... [more ▼]

Transcranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half of minimally conscious state (MCS) patients. Although the rising evidences about its possible role in the treatment of many neurological and psychiatric conditions exist, no evidences exist about brain functional connectivity substrates underlying tDCS response. We retrospectively evaluated resting state functional Magnetic Resonance Imaging (fMRI) of 16 sub-acute and chronic MCS patients (6 tDCS responders) who successively received a single left dorsolateral prefrontal cortex (DLPFC) tDCS in a double-blind randomized cross-over trial. A seed-based approach for regions of left extrinsic control network (ECN) and default-mode network (DMN) was performed. tDCS responders showed an increased left intra-network connectivity for regions co-activated with left DLPFC, and significantly with left inferior frontal gyrus. Non-responders (NR) MCS patients showed an increased connectivity between left DLPFC and midline cortical structures, including anterior cingulate cortex and precuneus. Our findings suggest that a prior high connectivity with regions belonging to ECN can facilitate transitory recovery of consciousness in a subgroup of MCS patients that underwent tDCS treatment. Therefore, resting state-fMRI could be very valuable in detecting the neuronal conditions necessary for tDCS to improve behavior in MCS. [less ▲]

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See detailFunction–structure connectivity in patients with severe brain injury as measured by MRI-DWI and FDG-PET
Annen, Jitka ULiege; Heine, Lizette ULiege; Ziegler, Erik et al

in Human Brain Mapping (2016), 37(11), 3707-3720

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See detailSleep, Coma, Vegetative and Minimally 4 Conscious States
Di Perri, Carol ULiege; Cavaliere, Carlo; Bodart, Olivier ULiege et al

in Sleep Disorders Medicine (2016)

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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 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 detailRecovery of language comprehension in the minimally conscious state studied by FDG-PET
Wannez, Sarah ULiege; Thibaut, Aurore ULiege; Vitali-Roscini, Gaia et al

Poster (2015, June 21)

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See detailImaging correlation in non-communicating patients
Heine, Lizette ULiege; Di Perri, Carol ULiege; Soddu, Andrea ULiege et al

in Rossetti, A.O; Laureys, Steven (Eds.) Clinical Neurophysiology in Disorders of Consciousness-Brain Function Monitoring in the ICU and beyond (2015)

The diagnosis and medical management of patients with acute or chronic disorders of consciousness (DOC) are challenging. Motor-independent functional neuroimaging technologies are increasingly employed to ... [more ▼]

The diagnosis and medical management of patients with acute or chronic disorders of consciousness (DOC) are challenging. Motor-independent functional neuroimaging technologies are increasingly employed to study covert cognitive processes in the absence of behavioural reports. Studies with functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) performed in this patient population have utilized active, passive and restingstate paradigms. Active paradigms refer to mental imagery tasks that measure wilful modulation of brain signal in specific brain areas, aiming to detect command-following. Passive paradigms are used to measure brain responses to external sensory stimulation (e.g. auditory, somatosensory and visual). Alternatively, in resting-state paradigms, spontaneous brain function is assessed while subjects receive no external stimulation and are instructed to let their mind wander. Independently from each other, these methods have shown differences between healthy controls and patients, as well as among patients with DOC. However, these techniques cannot yet be used in clinical settings before robust information at the single-subject level will be provided: it is expected that multimodal research will improve the single-patient diagnosis, shed light on the prognostic biomarkers, and eventually promote the medical management of patients with consciousness alterations. [less ▲]

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See detailBehavioural Diagnosis of Disorders of Consciousness
Thibaut, Aurore ULiege; Di Perri, Carol ULiege; Bodart, Olivier ULiege et al

in Rossetti, Andrea; Laureys, Steven (Eds.) Clinical Neurophysiology in Disorders of Consciousness (2015)

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See detailTechnology-based assessment in patients with disorders of consciousness
Di Perri, Carol ULiege; Heine, Lizette ULiege; Amico, Enrico ULiege et al

in Annali dell'Istituto Superiore di Sanita (2014), 50(3), 209-220

INTRODUCTION A number of studies highlight the difficulty in forming a diagnosis for patients with disorders of consciousness when this is established merely on behavioral assessments. BACKGROUND Positron ... [more ▼]

INTRODUCTION A number of studies highlight the difficulty in forming a diagnosis for patients with disorders of consciousness when this is established merely on behavioral assessments. BACKGROUND Positron emission tomography (PET), functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and electroencephalography combined with transcranial magnetic stimulation (TMS-EEG) techniques are promoting the clinical characterization of this challenging population. With such technology-based "objective" tools, patients are also differentially able to follow simple commands and in some cases even communicate through modified brain activity. Consequently, the vegetative state and minimally conscious state have been revised and new nosologies have been proposed, namely the unresponsive wakefulness syndrome, the minimally conscious state plus and minus, and the functional locked-in syndrome. AIM To our mind, an integration of different technical modalities is important to gain a holistic vision of the underlying pathophysiology of disorders of consciousness in general and to promote single-patient medical management in particular. [less ▲]

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