Ego-syntonic alien hand syndrome after right posterior cerebral artery stroke.

The alien hand syndrome classically consists of involuntary movements accompanied by a feeling of foreignness and personification of the affected limb. Autocriticism, in which patients criticize and express astonished frustration with the behavior of the autonomous limb, is a commonly noted feature. Most cases of alien hand are associated with lesions of the supplementary motor areas of the frontal lobes, the corpus callosum, or both. The authors report on a 79-year-old man who sustained a right posterior cerebral artery distribution infarction and developed alien hand syndrome in the absence of callosal involvement. Also unique is that the patient perceived the alien hand as acceptable and positive, not hostile and repugnant. This case suggests not only that the neuroanatomic regions responsible for alien hand syndrome may require re-examination, but also that its definition may need expansion.