Cognitive impairments associated with early Parkinson's disease.

We administered a battery of cognitive tests to 41 recently diagnosed Parkinson patients and 41 controls to assess the early neuropsychological changes associated with Parkinson's disease (PD). Parkinson subjects did as well as controls on tasks assessing attention and select language and visuospatial measures. However, PD subjects did significantly worse on embedded figures, facial recognition, proverbs, and verbal and figural memory measures, and made more perseverative responses on a set shifting task. A discriminant function of measures of proverbs, embedded figures, and memory accounted for 22% of the variance between groups. These data suggest that the cognitive changes in early PD are more pervasive than originally described and may reflect the onset of a more widespread pathologic process.