The acquisition of new orthographic representations among dyslexic children

Purpose – In developmental dyslexia, spelling deficits have been much less explored than reading deficits, although the former tend to be more persistent than the latter. The aim of this study was to explore the ability to acquire new orthographic representations through different learning conditions in dyslexic children.
Method – Fifteen dyslexic French-speaking children (mean chronological age: 11; 4 years; mean reading age: 7; 6 years), 15 chronological age (CA) and 15 reading age (RA) matched controls participated in the study. Their ability to acquire new orthographic representations was assessed through different learning conditions: isolated pseudowords decoding, text reading with embedded target pseudowords and writing of pseudowords after presentation in their visual form associated or not to a semantic representation. In each condition, ten target pseudowords were presented six times. Orthographic learning was measured by a dictation of the targets immediately after the learning session and one week later.
Results – Orthographic learning of dyslexics was significantly impaired and decreased more over time relative to CA group but not to RA group. Otherwise, dyslexics, as other groups, performed better when learning conditions consisted in writing pseudowords than in decoding them. Furthermore the condition associating a semantic representation to the pseudowords did not enhance the performances in any group.
Conclusion – These results confirm that decoding abilities are essential to develop orthographic representations and suggest that writing is a powerful learning mechanism in dyslexic as in normal readers. By contrast, a semantic representation seems not to support the development of orthographic representations.