Disrupted neural responses to phonological and orthographic processing in dyslexic children: an fMRI study

Developmental dyslexia, characterized by difficulty in reading, has been as sociated with phonological and orthographic processing deficits. fMRI was p erformed on dyslexic and normal-reading children (8-12 years old) during ph onological and orthographic taslts of rhyming and matching visually present ed letter pairs. During letter rhyming, both normal and dyslexic reading ch ildren had activity in left frontal brain regions, whereas only normal-read ing children had activity in left temporo-parietal cortex. During letter ma tching, normal reading children showed activity throughout extrastriate cor tex, especially in occipito-parietal regions,whereas dyslexic children had little activity in extrastriate cortex during this task. These results indi cate dyslexia may be characterized in childhood by disruptions in the neura l bases of both phonological and orthographic processes important for readi ng. NeuroReport 12:299-307 (C) 2001 Lippincott Williams & Wilkins.