Incidence, course, and predictors of apathy in Huntington's disease: a two-year prospective study.

This study examined the incidence and course of apathy in subjects with Huntington's disease (HD). Our results showed that at follow-up 14% of the subjects free of apathy at baseline had developed apathy. In these subjects, a lower baseline Mini-Mental State Exam score predicted incidence of apathy. Of the 34 subjects with apathy at baseline, 14 subjects were no longer apathetic at follow-up. Twenty subjects had persistent apathy, with a low baseline Symbol Digits Modalities Test as the only predictor. These results showed that apathy in HD is most closely linked to global and executive cognitive performance.