Hemispheric processing characteristics for lexical decisions in adults with reading disorders

The present study measured unilateral tachistoscopic vocal reaction times a nd er;or responses of reading-disordered and normally reading adults to sin gle words and nonwords in a series of lexical decision tasks at two linguis tic levels (concrete and abstract words). Analysis of variance on reaction rimes indicated that main effects of stimulus type, visual field, and the i nteraction of these variables were not significant for the reading-disorder ed group, but visual field and an interaction of visual field and stimulus type were for the normally reading adults. Error rate showed a significant interaction of stimulus x visual field for the reading-disordered group but not for the normal reading group. Pori hoc tests showed significant differ ences in error rates between visual fields for concrete lexicon but not for abstract or nonsense lexicon for the reading-disordered group. These findi ngs suggest a deficit in interhemispheric lexical transfer occurs for readi ng-disordered samples and suggest use of a callosal relay model wherein the left hemisphere is allocated responsibility for performing central operati ons underlying lexical decisions by adults with reading disorders.