Iconic reading in a case of alexia without agraphia caused by a brain tumor: a tachistoscopic study

The lack of nonverbal reading comprehension in the clinical disconnection syndrome, alexia without agraphia, has been contradictory to the relative reading comprehension of the right hemisphere in split brains. We report a 39-year-old patient with verbal alexia without agraphia caused by brain tumor. On rapid tachistoscopic presentation of object names, he denied seeing anything but showed nonverbal reading comprehension by pointing to the corresponding objects. He lost this ability when he recovered ability to name individual letters of the object names. Our results suggest that even partial verbal reading such as the naming of single letters makes demonstration of iconic reading impossible and that total functional disconnection from verbalization, as initially noted in this case or in split brain studies, is necessary to show nonverbal reading comprehension.