Chorea may also occur with a familial disease, Huntington's cho­rea. This disease begins in the middle years, usually with a chorei­form movement of a single extremity, and then progresses to involve all limbs. Unfortunately, it also invariably involves progressive mental deterioration. If mentation is good when the patient gets to the point of disability from the movement disorder, the chorea may respond well to a thalamotomy (Fig. 431-5). In­deed, this was the first movement disorder treated stereotacti­cally.72 It is, however, a progressive disease, and both movement and mental impairment eventually will progress.