Article (Scientific journals)
Reduction in inter-hemispheric connectivity in disorders of consciousness.
Ovadia-Caro, Smadar; Nir, Yuval; Soddu, Andrea et al.
2012In PLoS ONE, 7 (5), p. 37238
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Keywords :
Adult; Aged; Brain/physiopathology; Brain Mapping; Consciousness Disorders/physiopathology; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Nerve Net/physiopathology; Neural Pathways/physiopathology
Abstract :
[en] Clinical diagnosis of disorders of consciousness (DOC) caused by brain injury poses great challenges since patients are often behaviorally unresponsive. A promising new approach towards objective DOC diagnosis may be offered by the analysis of ultra-slow (<0.1 Hz) spontaneous brain activity fluctuations measured with functional magnetic resonance imaging (fMRI) during the resting-state. Previous work has shown reduced functional connectivity within the "default network", a subset of regions known to be deactivated during engaging tasks, which correlated with the degree of consciousness impairment. However, it remains unclear whether the breakdown of connectivity is restricted to the "default network", and to what degree changes in functional connectivity can be observed at the single subject level. Here, we analyzed resting-state inter-hemispheric connectivity in three homotopic regions of interest, which could reliably be identified based on distinct anatomical landmarks, and were part of the "Extrinsic" (externally oriented, task positive) network (pre- and postcentral gyrus, and intraparietal sulcus). Resting-state fMRI data were acquired for a group of 11 healthy subjects and 8 DOC patients. At the group level, our results indicate decreased inter-hemispheric functional connectivity in subjects with impaired awareness as compared to subjects with intact awareness. Individual connectivity scores significantly correlated with the degree of consciousness. Furthermore, a single-case statistic indicated a significant deviation from the healthy sample in 5/8 patients. Importantly, of the three patients whose connectivity indices were comparable to the healthy sample, one was diagnosed as locked-in. Taken together, our results further highlight the clinical potential of resting-state connectivity analysis and might guide the way towards a connectivity measure complementing existing DOC diagnosis.
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Author, co-author :
Ovadia-Caro, Smadar
Nir, Yuval
Soddu, Andrea ;  Université de Liège - ULiège > Centre de recherches du cyclotron
Ramot, Michal
Hesselmann, Guido
Vanhaudenhuyse, Audrey  ;  Université de Liège - ULiège > Centre de recherches du cyclotron
Dinstein, Ilan
Tshibanda, Jean-Flory L.
Boly, Mélanie ;  Université de Liège - ULiège > Département des sciences cliniques > Neurologie
Harel, Michal
Laureys, Steven  ;  Université de Liège - ULiège > Centre de recherches du cyclotron
Malach, Rafael
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Title :
Reduction in inter-hemispheric connectivity in disorders of consciousness.
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Public Library of Science, United States - California
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Peer Reviewed verified by ORBi
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since 07 January 2013


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