Visuospatial impairment in Parkinson's disease. Role of perceptual and motor factors.

We investigated the role of perceptual and motor factors in visuospatial impairment in 30 patients with Parkinson's disease (PD) and 30 matched controls. All subjects were administered visuospatial tests, which included "visuoperceptual" tasks, requiring minimal motor responses, and "visuomotor" tasks. The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment. Patients in stage 3 of the disease tended to show the greatest impairment. Those in stage 1 (unilateral symptoms), however, tended to show more impairment than those in stage 2.