Verb Generation in Parkinson's Disease Patients

Previous research has shown that people with Parkinson's disease (PD) have deficits in verb processing. However, the interpretation about the deficits is still in controversy. Motor theory suggests that the deficits in PD patients reflect the role of basal ganglia and frontal regions in the semantic representation of verbs. Grammatical view suggests that the deficits in PD patients indicate that basal ganglia and frontal regions play roles in the grammatical processing of verbs. Executive control view claims that PD patients show deficits in verb processing because basal ganglia and frontal regions are involved in executive control functions that are not specific to language processing. This paper reviews current findings about verb generation in PD patients, and discusses the evidence that supports different views and the possible confounding factors that may influence the interpretations.