Auditory brain-stem and middle- and long-latency evoked potentials in coma.

Twenty-five patients in coma, each with a Glasgow Coma Scale measure less than or equal to five, were studied within the first three days of hospitalization with auditory brain-stem and middle- and long-latency evoked potentials. Survival was related to the simultaneous preservation of long- and middle-latency and brain-stem evoked potentials. The preservation of just middle-latency and/or brain-stem components did not correlate with survival. However, if the group of patients in coma due to head trauma was analyzed separately, survival could be related to the results of the brain-stem evoked potentials. There was no relationship between survival and the results of the initial clinical neurological examination. In patients who survived, there was no pattern of evoked potential preservation that related to the quality of survival.