[en] Differentiation of the minimally conscious state (MCS) and the unresponsive wakefulness syndrome (UWS) is a persistent clinical challenge [1]. Based on positron emission tomography (PET) studies with [18F]-fluorodeoxyglucose (FDG) during sleep and anesthesia, the global cerebral metabolic rate of glucose has been proposed as an indicator of consciousness [2, 3]. Likewise, FDG-PET may contribute to the clinical diagnosis of disorders of consciousness (DOCs) [4, 5]. However, current methods are non-quantitative and have important drawbacks deriving from visually guided assessment of relative changes in brain metabolism [4]. We here used FDG-PET to measure resting state brain glucose metabolism in 131 DOC patients to identify objective quantitative metabolic indicators and predictors of awareness. Quantitation of images was performed by normalizing to extracerebral tissue. We show that 42% of normal cortical activity represents the minimal energetic requirement for the presence of conscious awareness. Overall, the cerebral metabolic rate accounted for the current level, or imminent return, of awareness in 94% of the patient population, suggesting a global energetic threshold effect, associated with the reemergence of consciousness after brain injury. Our data further revealed that regional variations relative to the global resting metabolic level reflect preservation of specific cognitive or sensory modules, such as vision and language comprehension. These findings provide a simple and objective metabolic marker of consciousness, which can readily be implemented clinically. The direct correlation between brain metabolism and behavior further suggests that DOCs can fundamentally be understood as pathological neuroenergetic conditions and provide a unifying physiological basis for these syndromes.
Disciplines :
Neurology
Author, co-author :
Stender, Johan; BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Nørre Allé 10, Copenhagen, Denmark, Cyclotron Research Center and Department of Neurology, CHU Sart Tilman, University of Liège, Avenue de l'hôpital 11, Liège, Belgium
Mortensen, Kristian Nygaard; BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Nørre Allé 10, Copenhagen, Denmark
Thibaut, Aurore ; Université de Liège - ULiège > GIGA Consciousness: Coma Science Group
Darkner, Sune; Department of Computer Science, University of Copenhagen, Universitetsparken 5, Copenhagen, Denmark
Laureys, Steven ; Université de Liège - ULiège > GIGA Consciousness: Coma Science Group
Gjedde, Albert; BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Nørre Allé 10, Copenhagen, Denmark
Kupers, Ron; BRAINlab, Department of Neuroscience & Pharmacology, Panum Institute, University of Copenhagen, Nørre Allé 10, Copenhagen, Denmark, Department of Radiology & Biomedical Imaging, Yale University, 300 Cedar Street, New Haven, CT, United States
Language :
English
Title :
The Minimal Energetic Requirement of Sustained Awareness after Brain Injury
Publication date :
2016
Journal title :
Current Biology
ISSN :
0960-9822
eISSN :
1879-0445
Publisher :
Cell Press
Volume :
26
Issue :
11
Pages :
1494-1499
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
University of Copenhage F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE] JSMF - James S McDonnell Foundation [US-MO] BAEF - Belgian American Educational Foundation [BE] WBI - Wallonie-Bruxelles International [BE] FEDER - Fonds Européen de Développement Régional [BE] ASE - Agence Spatiale Européenne [FR] the Wallonia-Brussels Federation Concerted Research Action Belgian interuniversity attraction pole
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