Motor imagery in Huntington's disease.

We investigated the role of the basal ganglia (BG) in motor imagery in patients with Huntington's disease (HD). A visually guided pointing task assessed whether patients could predict actual movement time (MT) through motor imagery. Executed and imagined movements were performed when vision was constrained centrally, or was free to move. Participants completed a series of imagined and actual movements, with and without central fixation, between two target circles. Patients with HD and controls' imagined MTs were significantly faster than their executed MTs. In compliance with Fitt's law, both actual and imagined MTs increased as a function of increasing task difficulty. We conclude that motor imagery is relatively preserved in HD.