Hemispheric Processing of Idioms and Irony in Adults With and Without Pervasive Developmental Disorder.

Previous studies on individuals with pervasive developmental disorders (PDD) have pointed to difficulties in comprehension of figurative language. Using the divided visual field paradigm, the present study examined hemispheric processing of idioms and irony in 23 adults with PDD and in 24 typically developing (TD) adults. The results show that adults with PDD were relatively unimpaired in understanding figurative language. While the TD group demonstrated a right hemisphere advantage in processing the non-salient meanings of idioms as well as the ironic endings of paragraphs, the PDD group processed these stimuli bilaterally. Our findings suggest that brain lateralization is atypical in adults with PDD. Successful performance along with bilateral brain activation suggests that the PDD group uses a compensation mechanism.