Differentiation of Alzheimer's, Huntington's, and Parkinson's Disease Patients on the Basis of Verbal Learning Characteristics

This study examined the degree to which patients with dementia could be differentiated on the basis of their verbal learning characteristics. Patients with Parkinson's disease (PD), Huntington's disease (HD), and probable Alzheimer's disease (AD) were administered the California Verbal Learning Test. PD and HD patients were divided into subgroups to control for the severity of overall memory impairment. Discriminant function analysis correctly categorized over 76% of cases. Intrusions, perseverations, and rate of forgetting were the most discriminating variables. Profile differences between HD and PD were sufficiently robust to separate these two groups with reasonable accuracy. These results do not support a simplistic cortical-subcortical dichotomy; rather, individual dementing syndromes have unique patterns of verbal learning performance that are distinct from one another.