LANGUAGE AND VERBAL REASONING IN PARKINSONS-DISEASE

Deficits in fluency, memory and comprehension of verbal material are c ommon findings associated with linguistic performance in Parkinson's d isease (PD), a neurodegenerative disorder primarily involving basal ga nglia structures. Until recently, little attention has been directed t o more complex language tasks such as verbal reasoning. This study exa mines verbal fluency and inferential and logical reasoning to determin e to what extent PD may compromise higher-level linguistic abilities. Measures from a battery of tests (verbal fluency, CVLT, similarities, a lexical test, logical reasoning, and invited inference) were obtaine d from nondemented PD patients (n = 38) and age- and education-matched controls (n = 19). MANOVA results showed a general impairment in lang uage tasks. Post hoc univariate analyses revealed no group differences in letter and category fluency and in inferential reasoning; specific deficits in similarities, logical reasoning, and on memory measures o f the CVLT were, however, observed. We conclude that PD is associated with impairment of inferential reasoning abilities that rely upon the application of algorithms, in contrast to more pragmatic or heuristic strategies.