Increased reliance on a right hemispheric mechanism during idiom processing in adults with dyslexia.

Previous studies on adults with dyslexia (DYS) have indicated difficulties in the comprehension of figurative language. Using the divided visual field paradigm, the present study investigated the hemispheric processing of idioms among 22 adults with DYS and 21 regular reader (RR) adults. Participants performed a lexical decision task for a target word related to either a literal or a figurative interpretation of an idiom. The results show that whereas the RR group demonstrated a bilateral pattern of hemispheric processing of idiomatic meanings, the DYS group showed a right hemisphere (RH) advantage. Furthermore, both groups demonstrated the typical RH advantage in processing the literal meanings of idioms. Our findings indicate increased recruitment of the RH in dyslexia, probably due to differences in cerebral language areas or weaker LH semantic processing.