Persistent vegetative state. Review and report of electrodiagnostic studies in eight cases
P. L. Hansotia
Of 81 comatose patients studied for two years, eight entered the persistent
vegetative state (PVS), of whom four died and four survived. Clinically,
all eight showed characteristic findings of wakefulness without cognitive
function. Electrodiagnostic studies were characterized by (1)
electroencephalograms that showed a range of patterns that were unchanged
from the comatose through the vegetative state, (2) normal brainstem
auditory evoked responses, (3) median somatosensory evoked responses that
showed prolonged central conduction time, and (4) diminishing amplitude of
the N20 response. These features may serve for identifying and monitoring
patients in the PVS with a view to accurately predicting outcome.
