A dissociation between developmental surface and phonological dyslexia in two undergraduate students.

This study compares the nature of the reading deficit that was observed in two dyslexic undergraduate students who were severely impaired at reading and spelling compared with normal undergraduates. They both achieved the same (below average) score on the National Adult Reading Test and on the Schonell spelling test. One of them, however, was good at reading and spelling nonwords, had good phonological awareness skills, was better at reading regular than irregular words, and made phonologically accurate reading and spelling errors (i.e. was a surface dyslexic). The other had poor phonological awareness, produced relatively few phonologically accurate spelling errors, and was poor at reading and spelling nonwords (i.e. was a phonological dyslexic). It is particularly noteworthy that such a clear dissociation between surface and phonological forms of developmental dyslexia occurred in two subjects who were closely matched in terms of their overall reading and spelling ability, and also in terms of their memory span and vocabulary. It is argued that this study strengthens the evidence for the existence of qualitatively different types of developmental dyslexia. The findings are also consistent with the view that phonological awareness skills are more closely related to the operation of the phonological rather than the visual reading route.