Alpha-pattern coma: 24 cases with 9 survivors.

Alpha-pattern coma denotes the association of a comatose state with an electroencephalogram consisting predominately of alpha-frequency activity. Over the past three years we have studied 24 such cases: 14 following cardiopulmonary arrest, 6 following respiratory arrest, and 3 following brainstem infarction. Of the 9 patients who survived, only 1 had a significant neurological deficit. It was found that: (1) alpha-pattern coma can result from a variety of neurological insults; (2) a significant proportion of patients survive, often with little or no deficit; (3) clinical evidence of intact brainstem function implies a favorable outcome; (4) the electroencephalogram was similar in survivors and nonsurvivors and did not differentiate diffuse cerebral dysfunction from focal brainstem disease; and (5) neuropathological studies demonstrated diffuse cortical as well as brainstem changes.