Willful modulation of brain activity in disorders of consciousness.
BACKGROUND
The differential diagnosis of disorders of consciousness is challenging. The rate of misdiagnosis is approximately 40%, and new methods are required to complement bedside testing, particularly if the patient's capacity to show behavioral signs of awareness is diminished.


METHODS
At two major referral centers in Cambridge, United Kingdom, and Liege, Belgium, we performed a study involving 54 patients with disorders of consciousness. We used functional magnetic resonance imaging (MRI) to assess each patient's ability to generate willful, neuroanatomically specific, blood-oxygenation-level-dependent responses during two established mental-imagery tasks. A technique was then developed to determine whether such tasks could be used to communicate yes-or-no answers to simple questions.


RESULTS
Of the 54 patients enrolled in the study, 5 were able to willfully modulate their brain activity. In three of these patients, additional bedside testing revealed some sign of awareness, but in the other two patients, no voluntary behavior could be detected by means of clinical assessment. One patient was able to use our technique to answer yes or no to questions during functional MRI; however, it remained impossible to establish any form of communication at the bedside.


CONCLUSIONS
These results show 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. This technique may be useful in establishing basic communication with patients who appear to be unresponsive.
Medical Research Council Cognition and Brain Sciences Unit, Cambridge, United Kingdom.
Martin M
MM
Monti
Audrey
A
Vanhaudenhuyse
Martin R
MR
Coleman
Melanie
M
Boly
John D
JD
Pickard
Luaba
L
Tshibanda
Adrian M
AM
Owen
Steven
S
Laureys
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001364:Awareness; D001921:Brain / Q000378:metabolism*; D003142:Communication; D005260:Female; D006801:Humans; D007092:Imagination; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes; D008875:Middle Aged; D018458:Persistent Vegetative State / Q000175:diagnosis / Q000378:metabolism / Q000523:psychology*; D055815:Young Adult