The contribution of the basal ganglia to expressive language performance

The basal ganglia is a structure known for its role in motor functioning. Disorders of the basal ganglia are typically accompanied by motor deficits and expressive language skills are generally thought to be preserved. Studies of expressive language in individuals with basal ganglia disorders have traditionally used standardized language measures of language form and their results have been mixed. As a result, it has been generally concluded that the basal ganglia has no role in expressive language. However, recent models of basal ganglia functioning suggest a specific role for the basal ganglia in language form and language use. Therefore, the belief that language integrity exists in individuals with basal ganglia disorders has been based primarily on results from studies using language measures of language form and not language use. The analysis of discourse has been hypothesized as a methodology to identify language form and use deficits that may exist following neurological injury or disease. This study tested the hypothesis that individuals with disease of the basal ganglia exhibit language form and use differences in narrative discourse compared to individuals who have no evidence of the disease. Results indicated differences in language use although no significant differences were observed in language form. These results suggest that the basal ganglia has an executive role in expressive language use and that individuals with basal ganglia disorders can exhibit deficits in language use while maintaining relatively unimpaired language form.