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Updated: Jun 17, 2025

Assessment and Communication for People with Disorders of Consciousness
Published on: August 1, 2017
Cognitive Motor Dissociation in Disorders of Consciousness
Yelena G Bodien1, Judith Allanson1, Paolo Cardone1
1From the Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital (Y.G.B., J.T.G.), and the Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital (B.L.E.), Charlestown, and the Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital (Y.G.B., C.C., P.K.L., A.M., W.R.S., B.L.E.), the Department of Physical Medicine and Rehabilitation, Harvard Medical School (Y.G.B., J.T.G.), and the Department of Neurology, Massachusetts General Hospital and Harvard Medical School (Y.G.B., C.C., B.L.E.), Boston - all in Massachusetts; the Department of Neurosciences, Addenbrookes Hospital (J.A.), and the Department of Clinical Neurosciences (J.A., S.C., E.K., V.C.L., J.P., E.A.S.), the Division of Neurosurgery, School of Clinical Medicine (S.C., P.F., E.K., J.P.), the Wolfson Brain Imaging Centre (V.C.L., D.M., J.P.), and the Division of Anaesthesia, Department of Medicine (D.M., E.A.S.), University of Cambridge, Cambridge, and the School of Computing, University of Kent, Canterbury (S.C.) - all in the United Kingdom; the Coma Science Group, GIGA Consciousness, University of Liege (P.C., A.B., C.C., O.G., S.L., A.T.), and Centre du Cerveau, University Hospital of Liege (P.C., A.B., C.C., O.G., A.T.), Liege, and the European Research Council Executive Agency, Brussels (C.C.) - all in Belgium; the Department of Neurology, Columbia University Irving Medical Center, New York-Presbyterian Hospital (J. Carmona, G.H., A. Velazquez, A. Vrosgou, J. Claassen), the Feil Family Brain and Mind Research Institute (M.C., J.E.H., J.D.V., N.D.S.), the Division of Medical Ethics (J.E.H., J.J.F.), and the Departments of Neurology (J.D.V., N.D.S.) and Radiology (H.U.V.), Weill Cornell Medicine, Rockefeller University Hospital (J.J.F., J.D.V., N.D.S.), and the Department of Population Health Science and Policy, Center for Biostatistics, Icahn School of Medicine at Mount Sinai (E.B.) - all in New York; Collège de France, Université Paris Sciences et Lettres (S.D.), Sorbonne Université, Paris Brain Institute-Institut du Cerveau et de la Moelle Épinière, INSERM, Centre National de la Recherche Scientifique (B.R., J.D.S., M.V., L.N.), and Assistance Publique-Hopitaux de Paris, Hôpital Pitié-Salpêtrière, Département Médico-Universitaire Neurosciences (B.R., M.V., L.N.) - all in Paris; the Departments of Physics and Astronomy (A.S.), Physiology and Pharmacology (A.M.O.), and Psychology (A.M.O.), and the Western Institute for Neuroscience (A.S., A.M.O.), University of Western Ontario, London, ON, and the CERVO Brain Research Centre, Quebec, QC (S.L.) - all in Canada; Yale Law School, New Haven, CT (J.J.F.); and the Consciousness Science Institute, Hangzhou Normal University, Hangzhou, China (S.L.).
Background:
Patients with brain injury who are unresponsive to commands may perform cognitive tasks that are detected on functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). This phenomenon, known as cognitive motor dissociation, has not been systematically studied in a large cohort of persons with disorders of consciousness.
Methods:
In this prospective cohort study conducted at six international centers, we collected clinical, behavioral, and task-based fMRI and EEG data from a convenience sample of 353 adults with disorders of consciousness. We assessed the response to commands on task-based fMRI or EEG in participants without an observable response to verbal commands (i.e., those with a behavioral diagnosis of coma, vegetative state, or minimally conscious state-minus) and in participants with an observable response to verbal commands. The presence or absence of an observable response to commands was assessed with the use of the Coma Recovery Scale-Revised (CRS-R).
Results:
Data from fMRI only or EEG only were available for 65% of the participants, and data from both fMRI and EEG were available for 35%. The median age of the participants was 37.9 years, the median time between brain injury and assessment with the CRS-R was 7.9 months (25% of the participants were assessed with the CRS-R within 28 days after injury), and brain trauma was an etiologic factor in 50%. We detected cognitive motor dissociation in 60 of the 241 participants (25%) without an observable response to commands, of whom 11 had been assessed with the use of fMRI only, 13 with the use of EEG only, and 36 with the use of both techniques. Cognitive motor dissociation was associated with younger age, longer time since injury, and brain trauma as an etiologic factor. In contrast, responses on task-based fMRI or EEG occurred in 43 of 112 participants (38%) with an observable response to verbal commands.
Conclusions:
Approximately one in four participants without an observable response to commands performed a cognitive task on fMRI or EEG as compared with one in three participants with an observable response to commands. (Funded by the James S. McDonnell Foundation and others.).
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