Is There Just One Dyslexic Reader? Evidence for the Existence of Distinct Dyslexic Sub-Groups

Abstract

It is generally agreed that there are individual differences in the severity of the reading deficit in dyslexia. The purpose of this review is to discuss whether recent research strengthens claims that there are also qualitative differences in the type of reading impairment that individual dyslexic children experience. Recent research suggests that surface dyslexia exists in larger numbers than has previously been assumed and that different subtypes of surface dyslexia exist in English as well as in Hebrew. Bilinguals with surface dyslexia in English also show the hallmarks of surface dyslexia when reading a more transparent orthography. The developmental reading impairments that have been observed in children with phonological dyslexia and in children with letter position dyslexia can also be found in several different orthographies and are quite distinct from those seen in surface dyslexia. Surface dyslexia, phonological dyslexia, and letter position dyslexia represent qualitatively different types of developmental reading impairments and can all be seen in both opaque and more transparent alphabetic orthographies.