Motor learning and Parkinson disease: Refinement of movement velocity and endpoint excursion in a limits of stability balance task.

Objective: To investigate the effects of practice on performance and retention of a balance task in persons with Parkinson disease (PD).

Methods: Ten persons with PD and 10 age and gender-matched healthy control subjects were tested on an anticipatory, static base of support, limits of stability (LOS) balance task on a force plate. The motor learning paradigm utilized for all subjects included an acquisition phase and retention tests at 24 h and 1 week after acquisition.