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Behavioural Neurology
Volume 2015, Article ID 145913, 12 pages
http://dx.doi.org/10.1155/2015/145913
Research Article

Neurophysiological Indicators of Residual Cognitive Capacity in the Minimally Conscious State

1Department of Research, Sunnaas Rehabilitation Hospital, 1450 Nesoddtangen, Norway
2Department of Psychology and Neurosurgery, University of California, Los Angeles, CA 90095-1563, USA
3Department of Psychology, University of Oslo, Postboks 1094 Blindern, 0317 Oslo, Norway
4Institute of Clinical Medicine, University of Oslo, Postboks 1171 Blindern, 0318 Oslo, Norway
5Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Postboks 4953 Nydalen, 0424 Oslo, Norway
6Regional Center of Knowledge Translation in Rehabilitation, Sunnaas Rehabilitation Hospital, 1450 Nesoddtangen, Norway
7Department of Physical Medicine and Rehabilitation, Harvard Medical School and Spaulding Rehabilitation Hospital, 300 First Avenue, Charlestown, MA 02129, USA

Received 8 July 2015; Revised 7 September 2015; Accepted 9 September 2015

Academic Editor: Juan C. Arango-Lasprilla

Copyright © 2015 Solveig L. Hauger et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. The diagnostic usefulness of electrophysiological methods in assessing disorders of consciousness (DoC) remains to be established on an individual patient level, and there is need to determine what constitutes robust experimental paradigm to elicit electrophysiological indices of covert cognitive capacity. Objectives. Two tasks encompassing active and passive conditions were explored in an event-related potentials (ERP) study. The task robustness was studied in healthy controls, and their utility to detect covert signs of command-following on an individual patient level was investigated in patients in a minimally conscious state (MCS). Methods. Twenty healthy controls and 20 MCS patients participated. The active tasks included (1) listening for a change of pitch in the subject’s own name (SON) and (2) counting SON, both contrasted to passive conditions. Midline ERPs are reported. Results. A larger P3 response was detected in the counting task compared to active listening to pitch change in the healthy controls. On an individual level, the counting task revealed a higher rate of responders among both healthy subjects and MCS patients. Conclusion. ERP paradigms involving actively counting SON represent a robust paradigm in probing for volitional cognition in minimally conscious patients and add important diagnostic information in some patients.