Variable memory profiles in Parkinson's disease.

Thirty-nine patients with Parkinson's disease (PD) were categorized into one of three subgroups using discriminant function analysis and three key indices from the California Verbal Learning Test (CVLT). Patients were classified as having one of three memory profiles: (a) a normal memory profile; (b) a memory profile often observed in patients with Huntington's disease (HD); or (c) a memory profile often observed in patients with Alzheimer's disease (AD). Twenty of the patients with PD were classified as having a normal profile, 10 as having an HD profile, and 9 as having an AD profile. The three subgroups did not differ on measures of global cognitive functioning, letter fluency, confrontation naming, or visuo-construction, suggesting that the patients with PD with an AD memory profile were not experiencing AD, per se. These results demonstrate that the memory deficits associated with PD can be similar to those found in patients with either HD or AD, and argues against the notion that the behavioral manifestations of PD are homogeneous.