Return to alertness after brain-stem hemorrhage. A case with evoked potential and roentgenographic evidence of bilateral tegmental damage.

After a 65-year-old man had received anticoagulation therapy for brain-stem ischemia, a large, bilateral pontomesencephalic hemorrhage developed in the ischemic region. He survived a period of being "locked in" to attain a limited functional recovery. When he first became alert, brain-stem auditory evoked potentials and short-latency somatosensory evoked potentials (SEPs) demonstrated bilateral brain-stem damage; computed tomography revealed a bilateral tegmental hematoma. Results of repeated studies changed little as clinical improvement occurred. Recovery from brain-stem hemorrhage is rare, and return of consciousness with bilateral tegmental involvement is even more rare. The short-latency SEPs are useful in defining the extent of brain-stem damage, but they evaluate structures distinct from those regulating consciousness and cannot predict a return to alertness.