Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Neurology. 2012 Mar 13;78(11):816-22. doi: 10.1212/WNL.0b013e318249f764. Epub 2012 Feb 29.

Relationship between etiology and covert cognition in the minimally conscious state.

Author information

  • 1Centre for Brain and Mind, University of Western Ontario, London, Canada. dcruse@uwo.ca

Abstract

OBJECTIVES:

Functional neuroimaging has shown that the absence of externally observable signs of consciousness and cognition in severely brain-injured patients does not necessarily indicate the true absence of such abilities. However, relative to traumatic brain injury, nontraumatic injury is known to be associated with a reduced likelihood of regaining overtly measurable levels of consciousness. We investigated the relationships between etiology and both overt and covert cognitive abilities in a group of patients in the minimally conscious state (MCS).

METHODS:

Twenty-three MCS patients (15 traumatic and 8 nontraumatic) completed a motor imagery EEG task in which they were required to imagine movements of their right-hand and toes to command. When successfully performed, these imagined movements appear as distinct sensorimotor modulations, which can be used to determine the presence of reliable command-following. The utility of this task has been demonstrated previously in a group of vegetative state patients.

RESULTS:

Consistent and robust responses to command were observed in the EEG of 22% of the MCS patients (5 of 23). Etiology had a significant impact on the ability to successfully complete this task, with 33% of traumatic patients (5 of 15) returning positive EEG outcomes compared with none of the nontraumatic patients (0 of 8).

CONCLUSIONS:

The overt behavioral signs of awareness (measured with the Coma Recovery Scale-Revised) exhibited by nontraumatic MCS patients appear to be an accurate reflection of their covert cognitive abilities. In contrast, one-third of a group of traumatically injured patients in the MCS possess a range of high-level cognitive faculties that are not evident from their overt behavior.

PMID:
22377810
[PubMed - indexed for MEDLINE]
PMCID:
PMC3304945
Free PMC Article

Images from this publication.See all images (1)Free text

Figure
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk