Using functional MRI, researchers have found some brain activation, awareness, and cognition in a handful of patients in a vegetative or minimally conscious state, according to research published online February 3 by the New England Journal of Medicine.
The study comes from the University of Cambridge in the U.K. and the University of Liège in Belgium. The lead author was Martin Monti, Ph.D., from the University of Cambridge.
In the study, 54 patients with severe brain injury (23 patients in a vegetative state and 31 patients in a minimally conscious state) underwent functional MRI to evaluate their performance on motor and spatial imagery tasks.
Functional MRI helped assess each patient's ability to generate willful, neuroanatomically specific, blood-oxygenation-level-dependent responses during two established mental-imagery tasks.
While in the functional MRI scanner, all patients were asked to imagine standing still on a tennis court and to swing an arm as if hitting the ball. Patients also were asked to imagine navigating the streets of a familiar city or to imagine walking from room to room in their home and to visualize all that they would see if they were there.
Before each of these imaging sessions, participants were asked a yes-or-no question, such as "Do you have any brothers?" and instructed to respond by using one type of mental imagery -- either motor imagery or spatial imagery -- for "yes" and the other for "no."
Among the 54 patients, the researchers found five patients who showed considerable activation in the supplementary motor area. In four of the five patients, the scans associated with spatial imagery, as compared with motor imagery, showed activation in the parahippocampal gyrus.
Activity within the two regions of interest was sustained for 30 seconds and was associated with the delivery of the verbal cues. The results for the patients in a vegetative state closely matched results among healthy control subjects in the study.
The researchers concluded that "a small proportion of patients in a vegetative or minimally conscious state have brain activation reflecting some awareness and cognition. Careful clinical examination will result in reclassification of the state of consciousness in some of these patients."
They speculated that the technique "may be useful in establishing basic communication with patients who appear to be unresponsive."
By Wayne Forrest
AuntMinnie.com staff writer
February 4, 2010
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