Has science found the anatomic substrate for dyslexia? If so, will this knowledge lead to simple diagnostic tests and new treatment methods for this disorder?
These and similarly dramatic questions have been raised since an article entitled, "Study Ties Dyslexia to Brain Flaw Affecting Vision and Other Senses," appeared on the front page of The New York Times (September 15, 1991:1). The Times interviewed several investigators, including Drs Margaret Livingstone and Albert Galaburda, who discussed their study due to appear later in the Proceedings of the National Academy of Sciences of the United States of America (PNAS). The PNAS article, coauthored by Drs Glenn Rosen and Frank Drislane, used two approaches aimed at testing the magnocellular system (large ganglion cells) in dyslexic patients. First, they examined necropsy specimens from five dyslexic and five normal brains and reported a 27% reduction in the areas of magnocellular neurons in the lateral geniculate