Effects of methylphenidate on cognitive function and gait in patients with Parkinson's disease: a pilot study.

Twenty-one patients with Parkinson's disease were studied before and 2 h after the administration of a single dose of 20 mg of methylphenidate. In response to methylphenidate, attention significantly improved, whereas memory and visual-spatial performance were unchanged. Gait speed, stride time variability, and Timed Up and Go times (demonstrated measures of fall risk) significantly improved. These findings suggest a new potential pharmacologic means of enhancing mobility and decreasing fall risk in Parkinson's disease.