Dyslexia subtypes in languages differing in orthographic transparency:English, French and Spanish / Subtipos de dislexia en lenguas que difieren en la transparencia ortográfica: inglés, francés y espa ol
The existence of dissociated profiles in developmental dyslexia (the phonological profile with a selective deficit of the phonological reading route, and the surface profile with a selective deficit of the lexical reading route) versus mixed profiles (with both deficits) remains a major theoretical and clinical issue, along with the prevalence of these profiles and the variation in that prevalence across languages with different degrees of orthographic transparency. These issues are examined in a review of studies conducted in English, French and Spanish in which subtyping was established using either the classical method or the regression method. The most reliable results were those obtained with the classical method: (1) the most prevalent profile is the mixed profile; (2) the prevalence of dissociated profiles differs across languages and measures, phonological profiles being more frequent in the accuracy-based English studies than in the accuracy-based French and Spanish studies, and less frequent in the accuracy-based than in the latency-based French and Spanish studies. These last findings probably reflect a measurement issue, as it is easy to use the phonological reading route in transparent orthographies: in these cases, reading speed must be used to detect phonological deficits. These results are not consistent with the idea that clear-cut subtypes can be detected in developmental dyslexia.