A case of subcortical dementia due to sarcoidosis of the hypothalamus and fornices.

A patient with sarcoidosis involving predominantly the hypothalamus and fornices was evaluated for dementia. He showed a relative sparing of fund of knowledge and orientation. Memory skills, particularly short-term memory, were severely impaired. Behavioral changes included apathy and a lack of spontaneity. Insight was relatively preserved. The pattern of his deficits showed some similarities to the pattern reported in patients with Huntington's disease and was different from that described in Alzheimer's disease. The dementia caused by subcortical pathology may differ in important respects from that caused by diffuse cortical dysfunction.