Tower of California Performance Early in Parkinson's Disease

Cognitive impairment associated with Parkinson's disease (PD) is widely described in the literature. Executive dysfunction has been reported even when the patients are not experiencing dementia. A significant (24% - 50+%) number of PD patients display cognitive impairment from the onset of the disease and progressively worsen. However, executive dysfunction in newly diagnosed patients often escapes clinical detection. This paper describes a study designed to test both early and late PD patients (0-5 years disease duration and 5-10 years disease duration, respectively) vs. controls on a novel tower task, the Tower of California (TOC, Delis, Kaplan,&Kramer, 2001). Use of the TOC with PD patients has not been published. The TOC is designed to be more difficult and may be more sensitive to subtle executive impairment, specifically in the areas of planning and spatial working memory. It is predicted that the early PD group will perform worse than the control group but better than the late PD group in the number of successful towers (ST) built. The early PD group is also expected to have a longer time to first move on ST built even when corrected for bradykinesia, but not as long as the late PD group, which is anticipated to be the slowest. Implications of the possible outcomes of this study are then discussed.