Deep dyslexic phenomena in a letter-by-letter reader.

Numerous accounts of pure alexia have suggested that prelexical impairment precludes rapid access to orthographic information in patients with the disorder. We report a patient with features of both pure and partially recovered deep dyslexia in whom we demonstrate prelexical deficits in maintaining a reliable abstract representation of the right side of letter arrays, as well as in modulating a "spotlight" of visual attention. These deficits, we suggest, encourage the patients's use of a letter-by-letter reading strategy; despite them, however, he demonstrates rapid, accurate reading of some, but not all classes of words. Furthermore, the patient's reading is influenced by both prelexical and lexical-semantic factors such that speed and accuracy are optimal for high imagiability nouns of few letters. Finally, the patient accurately names orally spelled words of all classes. Taken together, these data are consistent with the hypothesis that rapid reading may be enabled by lexical-semantic support from a right hemisphere-mediated processing system which recognizes words as whole, thereby mitigating the effect of the prelexical deficits.