Auditory brain-stem responses in brain death.

Auditory brain-stem responses were measured by far-field recording techniques in 27 patients fulfilling the criteria of brain death. The responses were either absent or consisted of the presence of just the initial component (Wave I). Wave I, when present, was of normal amplitude but prolonged in latency. Four patients were followed over several days from a state of coma with evidence of preserved brain-stem and cerebral functions to a clinical state compatible with brain death. Auditory brain-stem responses were initially intact and then showed a decrease in amplitude and a prolongation of latency of the later components until finally Wave I was alone. Auditory brain-stem responses are an objective measure of one of the sensory pathways traversing the brain-stem and can be used to evaluate the functional states of the brain-stem in patients in whom the question of brain death has been raised.