Wernicke's and global aphasia without alexia.

It has been proposed that the comprehension of written language requires transcoding from the visual (grapheme) to the auditory (phoneme). It has also been proposed that visual word images can be comprehended without grapheme-phoneme transcoding. We describe three aphasic patients with left hemisphere impairment who had poor speech comprehension but could comprehend written language. One of these patients had a subsequent right hemisphere lesion and lost his ability to read. We propose that the right hemisphere in some individuals may be capable of extracting semantic information from iconic images (ideogram) without phonological processing.