Alpha-pattern coma in primary brainstem hemorrhage; clinical, electrophysiologic, and cerebral blood flow studies.

A patient with a brainstem hemorrhage and alpha-pattern coma is reported. Brainstem auditory and somatosensory evoked responses were severely abnormal, suggesting bilateral lesions of the pons, which was confirmed by magnetic resonance imaging. Regional cerebral blood flow, studied using IMP-SPECT, showed no remarkable regional radioactive accumulation or deficit in either the cerebral cortex or the subcortical regions. Based on these findings, we speculate that the alpha-pattern coma may be observed when the functions of brain structures rostral to the pontomesencephalic junction are preserved.