Visual-Spatial and Set-Shifting Functions in Patients with Parkinson\u27s Disease

Patients with Parkinson\u27s disease (PD) (N=20) were compared to age and education-matched normal control subjects (N=20) on 18 paper-and-pencil neuropsychological measures. These tests were chosen to measure two specific functions. The first set of tests was chosen to measure spatial orientation, and these tests were divided into those that measure personal orientation, extrapersonal orientation, mental rotation, and right/left orientation. The second set of tests was chosen to measure the ability to shift mental set. Hotelling\u27s multivariate T2 tests revealed a significant difference between the PD patients and the normal control subjects on the tests chosen to measure set-shifting ability but no difference between the groups on those tests chosen to measure spatial orientation. These results are related to other studies that have demonstrated deficits in PD patients similar to those observed in patients with damage to the frontal lobes, supporting the hypothesis that a disruption of dopaminergic fibers to the prefrontal cortex may partly account for the cognitive deficits observed in patients with PD