Impaired comprehension of non-literal language in Tourette syndrome.

Objective: To investigate theory of mind and the understanding of nonliteral language in patients with Tourette syndrome (TS). Background: In TS, striatal dysfunction could affect the functioning of the frontal cortex. Changes in frontal functioning could lead to impairments in theory of mind: the understanding of mental states, such as beliefs, emotions, and intentions. Poor understanding of a speaker's mental state may also impair interpretation of their nonliteral remarks. Method: In this study, patients with TS and healthy controls completed tasks to assess their understanding of sarcasm, metaphor, indirect requests, and theory of mind. These tasks were the Pragmatic Story Comprehension Task, the Hinting task, and a faux pas task. Inhibitory ability was also assessed through the use of the Hayling task and a black and white Stroop test. Results: Patients with TS exhibited significant impairment on the faux pas task and Pragmatic Story Comprehension Task despite limited evidence of inhibitory impairment. Conclusion: TS may be associated with changes in theory of mind.