title: Impaired letter-string processing in developmental dyslexia: what visual-to-phonology code mapping disorder?
abstract: Poor parallel letter-string processing in developmental dyslexia was taken as evidence of poor visual attention (VA) span, that is, a limitation of visual attentional resources that affects multi-character processing. However, the use of letter stimuli in oral report tasks was challenged on its capacity to highlight a VA span disorder. In particular, report of poor letter/digit-string processing but preserved symbol-string processing was viewed as evidence of poor visual-to-phonology code mapping, in line with the phonological theory of developmental dyslexia. We assessed here the visual-to-phonological-code mapping disorder hypothesis. In Experiment 1, letter-string, digit-string and colour-string processing was assessed to disentangle a phonological versus visual familiarity account of the letter/digit versus symbol dissociation. Against a visual-to-phonological-code mapping disorder but in support of a familiarity account, results showed poor letter/digit-string processing but preserved colour-string processing in dyslexic children. In Experiment 2, two tasks of letter-string report were used, one of which was performed simultaneously to a high-taxing phonological task. Results show that dyslexic children are similarly impaired in letter-string report whether a concurrent phonological task is simultaneously performed or not. Taken together, these results provide strong evidence against a phonological account of poor letter-string processing in developmental dyslexia.
authors.affiliation: Laboratoire de Psychologie et NeuroCognition (UMR CNRS 5105), Grenoble, France. Sylviane.Valdois@upmf-grenoble.fr
authors.forename: Sylviane
authors.initials: S
authors.lastname: Valdois
authors.forename: Delphine
authors.initials: D
authors.lastname: Lassus-Sangosse
authors.forename: Muriel
authors.initials: M
authors.lastname: Lobier
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000209:etiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003118:Color Perception; D004410:Dyslexia / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual; D010700:Phonetics; D011932:Reading; D013223:Statistics as Topic; D014796:Visual Perception / Q000502:physiology*