2 DIFFERENT READERS IN THE SAME BRAIN AFTER A POSTERIOR CALLOSAL LESION

Two different types of reading, one in each hemifield, were exhibited by a patient with a lesion of the posterior half of the corpus callosu m. The patient read normally when words and non-words were presented t o his right visual field. However, with left visual field presentation s, the patient could not read non-words and vocalized real words very slowly, especially abstract words, inflected verbs and function words. He often replaced concrete words by semantic associates. Such an abno rmal reading pattern is similar to that known as deep dyslexia. This u nilateral deficit reveals the competence of the right hemisphere to in itiate some semantic processing and its inability to manage phonologic al coding. The hypothesis that deep dyslexia is due to right hemispher e reading is reinforced by the present case.