The Relation of Mental Status to Performance on Lexical-Semantic Tasks in Parkinson's Disease

Individuals with Parkinson's disease (PD) can experience changes in mental status and intellectual functioning. Those with dementia are said to exhibit a pattern of intellectual change similar to that experienced by individuals with Alzheimer's disease (AD), including deterioration of lexical-semantic knowledge. A popular theory about the dissolution of lexical-semantic knowledge in individuals with AD is that loss of attribute knowledge (knowledge of specific attributes of an object) precedes loss of categorical knowledge (knowledge of the category to which the object belongs). One hundred and one individuals with idiopathic PD, who varied in Mini-Mental State Examination (Folstein, Folstein, & McHugh, 1975) performance, were given three tests of attribute knowledge and three tests of category knowledge. Results indicate that performance on lexical-semantic tests was adversely affected in PD patients whose mental status scores were 26 or lower. However, no evidence was obtained that attribute knowledge w...