VARIETIES OF DEVELOPMENTAL DYSLEXIA

This paper reviews and evaluates the evidence for the existence of dis tinct varieties of developmental dyslexia, analogous to those found in the acquired dyslexic population. Models of the normal adult reading process and of the development of reading in children are used to prov ide a framework for considering the issues. Data from a large-sample s tudy of the reading patterns of developmental dyslexics are then repor ted. The lexical and sublexical reading skills of 56 developmental dys lexics were assessed through close comparison with the skills of 56 no rmally developing readers. The results indicate that there are at leas t two varieties of developmental dyslexia, the first of which is chara cterised by a specific difficulty using the lexical procedure, and the second by a difficulty using the sublexical procedure. These subtypes are apparently not rare, but are relatively prevalent in the developm ental dyslexic population. The results of a second experiment, which s uggest that neither of these reading patterns can be accounted for in terms of a general language disorder, are then reported.