Changes in the performance of parkinsonian patients and normal aged on the Benton Visual Retention Test.

Performance on the Benton Visual Retention Test was compared between those with Parkinson's disease (PD) and age-equivalent controls. The major difference between groups was that those with PD showed an increase in figural reproduction errors between test periods spaced six months apart, while controls showed little increase in errors over this time and made fewer errors at each time of testing. Age and IQ accounted for major proportions of variance in performance for both groups (about 50%), far more than that attributable to group membership. Within the PD group, however, age and disease onset were confounded (r = .92), indicating that age as a variable is quite when disease onset is considered. The results support the notion that PD is associated with change in visual-spatial memory, beyond that predicted by age per se.