Akinetic mutism with recovery after repeated carbon monoxide poisoning

SUMMARY A 27-year-old man developed signs of personality change after exposure to carbon monoxide. One month later a second exposure was followed by an akinetic mute state with unusual motor seizures, probably associated with tentorial herniation and brain-stem compression. Elimination of carbon monoxide was unduly prolonged after the second exposure. The patient showed clinical evidence of dementia, but there has been a gradual improvement in cognitive and social functioning over two years.