Neural Foundations of Action-related Language: Studies in Parkinson’s Disease

Abstract

Parkinson’s disease (PD), which is one of the most common neurodegenerative disorders, is a disorder that affects quality of life due to non-motor symptoms in addition to motor symptoms. The non-motor symptoms of this disease vary greatly and affect patients starting from early stages. These symptoms also include language deficits. Besides motor language disorders such as hypophonia and dysarthria, which are common in PD, deficits in morphosyntax, semantics, and understanding metaphors have been reported. Various studies have also shown deficits in action language in PD, in which the ability of action is affected. Although language deficits are thought to be caused by cognitive deficits in this disease, there are studies showing language deficits being independent of cognitive deficits. These language deficits in PD, caused by basal ganglia dysfunctions, may provide valuable information in determining brain areas related to language. In this review, we aimed to assess action language deficits in PD and to evaluate the location of action language in the brain in light of this disorder.