Authors: Nadège Doignon-Camus, Alix Seigneuric, Emeline Perrier, Aurélie Sisti & Daniel Zagar.
Publication: Annals of Dyslexia (Springer). 2013 | DOI: 10.1007/s11881-012-0075-3
To evaluate the orthographic and phonological processing skills of developmental dyslexics, we (a) examined their abilities to exploit properties of orthographic redundancy and (b) tested whether their phonological deficit extends to spelling-to-sound connections for large-grain size units such as syllables. To assess the processing skills in dyslexics, we utilized the illusory conjunction paradigm to investigate the nature of reading units in French dyslexic and control children matched in reading age. In control children, reading units were defined by both orthographic redundancy and phonological syllable information. In dyslexics, however, reading units were defined only by orthographic redundancy. Therefore, despite their impairment in reading acquisition, developmental dyslexics have the ability to encode and exploit letter frequency co-occurrences. In contrast, their access to phonological syllables from letters was impaired, suggesting that their phonological deficit extends to large grain-size phonological units.
Doignon-Camus, N., Seigneuric, A., Perrier, E. et al. Evidence for a preserved sensitivity to orthographic redundancy and an impaired access to phonological syllables in French developmental dyslexics. Ann. of Dyslexia 63, 117–132 (2013). https://doi.org/10.1007/s11881-012-0075-3
In congruent conditions, in which syllable and orthographic boundaries coincided, dyslexics were able to parse pseudowords into syllable units. In contrast to control children at the same reading level, dyslexics produced significantly more violation than preservation errors in the conflicting condition, in which syllable and orthographic boundaries did not coincide. This result clearly showed a pure orthographic effect on letter string parsing, in that dyslexic children only used statistical properties of orthographic redundancy to mark visual reading units.
Here, we show that children can acquire knowledge about orthographic statistical regularities while their spelling-to-sound correspondences are impaired. Phonological decoding skills appear therefore not absolutely necessary to attune the attention to the children to orthographic information of letter strings.
The present data suggest that developmental dyslexics are not sensitive to phonological structures of written syllable units. These findings extend previous results, by showing that the phonological deficit in developmental dyslexia not only affects letter-to-grapheme connections but the correspondences between letter clusters and phonological large-grain size units such as syllables.
The two primary findings of our investigation of the phonological and orthographic processing abilities of French developmental dyslexics were that dyslexics had impaired access to phonological syllable units from letters while having a preserved sensitivity to distributional properties of written language. These results suggest that future reading remediation is possible in dyslexic individuals. Learning to read requires the isolation of visual units in written language and phonological units in speech, and their association. We found that dyslexics have the ability to encode statistical orthographic properties, allowing the isolation of visual units.