Patients with Huntington Disease will be referred from the department of neurology in ChangGung Memorial Hospital, LinKou. Established diagnosis will be made by a neurological examination and genetic assessment of CAG expansion in the Htt gene. The severity and progression of the disease will be assessed by the Unified Huntington's Disease Rating Scale (UHDRS) (18). The cognitive performance will be evaluated by Mini-Mental State Examination (MMSE). The inclusion criteria are the following: