Dyslexia speed problems in a transparent orthography

Annals of Dyslexia, Jun 2008 by Serrano, Francisca, Defior, Sylvia

Abstract

This study was intended to help clarify the nature of dyslexia in Spanish. A sample of 30 children, 8 to 16 years old, participated in this study. Dyslexic children were compared to two control groups, a chronological age-matched control group and a reading level-matched control group. Measures included nonword and pseudohomophone reading (phonological procedure), homophone choice (orthographic procedure), and phonological awareness tasks (syllabic, intrasyllabic, and phonemic level). For each task, accuracy (error percentage) and performance time were measured. Results showed a deficit in the dyslexic group on all the tasks, which was more evident when time was considered. With the results consistent with studies in other transparent orthographies such as Italian and German, speed problems seem to be more evident and relevant than accuracy problems in Spanish dyslexic children.

Keywords Accuracy and speed problems * Dyslexia * Phonological deficit * Transparent orthographies

Dyslexia speed problems in a transparent orthography

Dyslexia is a persistent problem that involves a serious difficulty in identifying written words. This problem affects people of otherwise normal intellectual capacity. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR, First et al., 2002), this learning disorder involves substantially lower reading performance than expected according to the child's chronological age, intelligence, and school grade. The International Dyslexia Association's definition1 clarifies that dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities, typically resulting from a deficit in the phonological component of language.

To explain what is causing dyslexia has been an important aim in literacy research. There have been different explanations to the deficit involved in dyslexia. Some have focused on its biological causes (Grigorenko, 2001, for a review) whereas others defend a cognitive and psycho-linguistic approach (Lundberg & Hoien, 2001, for a review).

Most of the studies examining reading acquisition, reading difficulties, and dyslexia have involved English-speaking subjects. However, cross-linguistic studies (Defior, Martos, & Gary, 2002; Goswami, Gombert, & Barrera, 1998; Landed, Wimmer, & Frith, 1997; �ney & Durgunoglu, 1997; Seymour, Aro, & Erskine, 2003; Ziegler & Goswami, 2005; Ziegler, Perry, Ma-Wyatt, Ladner, & K�rne, 2003) have highlighted differences among the orthographic systems. These studies suggest that the results of the studies carried out with English speakers are not totally applicable to other languages.

It is well known that alphabetic writing systems are situated along a continuum of opacity-transparency, depending on their code consistency (Frost, Katz, & Bentin, 1987). Thus, transparent orthographies are those in which grapheme-phoneme correspondences are mainly one to one, whereas opaque ones are those where several graphemes may correspond to the same phoneme and, conversely, where several phonemes may be represented by the same grapheme. There is consensus that the European orthographies closest to the opaque extreme are English, French, Danish, and Portuguese. Spanish is closest to the transparent extreme as well as Finnish, Greek, Italian, and German (Seymour et al., 2003).

According to cross-linguistic studies, reading acquisition takes place differently depending on the orthographic system and the linguistic environment where the reader's development takes place (Defior, 2004; Miiller & Brady, 2001). For example, it was found that phonological decoding skills are mastered earlier in a more consistent orthography like German (Frith, Wimmer, & Landed, 1998). It was also found that children learning in more opaque orthographies present higher error rates and less fluency in reading than children learning in transparent orthographies after 1 year of teaching (see Seymour et al., 2003 for a review).

Furthermore, it has been suggested that reading development in dyslexic subjects reflects differences in the orthographic complexity of the writing system (Ziegler & Goswami, 2005). Thus, in languages with a more transparent orthography like Spanish, dyslexia seems to involve less severe deficits than those found in opaque writing systems (Jim�nez & Hemandez-Valle, 2000). Additionally, the indicators of dyslexia may vary depending on the written system under consideration. For example, dyslexia in less consistent orthographies becomes apparent on the basis of problems in reading accuracy, although of course speed problems are also characteristic (Ziegler et al., 2003). In more transparent orthographies, reading accuracy seems to be a less important factor, whereas reading speed appears more determining. Research undertaken in German (Wimmer, 1993; Wimmer & Mayringer, 2001), Finnish (Holopainen, Ahonen, & Lyytinen, 2001; Miiller & Brady, 2001), Italian (Brizzolara et al., 2006; Tressoldi, Stella, & Faggella, 2001), and Spanish (Jim�nez Gonz�lez & Hern�ndez-Valle, 2000) supports these ideas.