Background & Objectives: While patients with right brain damage (RBD) have preserved syntactic and semantic language competence, they have difficulty with pragmatic language competence, and thus, trouble understanding non-literal texts. The present study investigates the comprehension of indirect speech acts in patients with RBD. Methods: Sixteenpatients with RBD (without aphasia) and sixteen normal subjects participated in the present study. The indirect speech acts were divided into five types: interrogative-assertive acts, interrogative-ordering acts, interrogative-offering acts, declarative-ordering acts, and declarative-offering acts. Results: First, the performance of the RBD group was significantly lower than the control group in the comprehension of indirect speech acts. Second, the ratio of literal errors in the RBD group was higher than the ratio of non-related errors. There was no difference between the groups regarding the proportion of literal to nonrelated errors. Third, there was no difference between the groups in the ratio of error with regards to sentence type. Both the RBD and control group showed more errors in interrogative, indirect speech acts than in declarative, indirect speech acts. Discussion & Conclusion: The right brain is known to be responsible for generating multiple, loosely connected, and subordinate meanings. When the right brain is damaged, indirect speech acts are interpreted as direct speech acts. The results from the present study show damage to the right hemisphere causes a pragmatic communication disorder and confirm the limited ability that RBD patients have with non- literal texts.
