title: A visual processing but no phonological disorder in a child with mixed dyslexia.
abstract: The case study of Martial, a French 9-year-old boy, who exhibits severe mixed dyslexia and surface dysgraphia is reported. Despite very poor pseudo-word reading, Martial has preserved phonological processing skills as his good oral language, good phoneme awareness and good verbal short-term memory show. He exhibited a strong length effect when reading briefly presented words but no sign of mini-neglect. His letter-string processing abilities were assessed through tasks of whole and partial report. In whole report, Martial could only name a few letters from briefly displayed 5-consonant strings. He showed an initial-position advantage and a sharper than expected left-to-right gradient of performance. He performed better when asked to report a single cued letter within the string but then showed an atypical right-side advantage. The same rightward attentional bias was observed in whole report when top-down control was prevented. Otherwise, Martial showed preserved single letter identification skills and good processing of 5-letter strings when letters were sequentially displayed one at a time. His poor letter-string processing thus reflects a parallel visual processing disorder that is compatible with either a visual attention (VA) span or a visual short-term memory disorder. Martial was further engaged in a complex reaching movement task involving VA and simultaneous processing. He performed motor sequences not as a whole but as a succession of independent motor units, suggesting that his attention was not allocated in parallel to the two to-be-reached targets prior to movement execution. Against a more basic motor disorder however, he showed good performance in a task of cyclical pointing movements. The overall findings suggest that Martial suffers from a visual simultaneous processing disorder that disturbs letter identification in strings. Instead of being restricted to letter-string processing, this VA disorder might extend to non-verbal task.
authors.affiliation: Laboratoire de Psychologie et Neuro-Cognition (UMR 5105 CNRS), Université Pierre Mendès France, Grenoble, France. Sylviane.Valdois@upmf-grenoble.fr
authors.forename: Sylviane
authors.initials: S
authors.lastname: Valdois
authors.forename: Christel
authors.initials: C
authors.lastname: Bidet-Ildei
authors.forename: Delphine
authors.initials: D
authors.lastname: Lassus-Sangosse
authors.forename: Caroline
authors.initials: C
authors.lastname: Reilhac
authors.forename: Marie-Ange
authors.initials: MA
authors.lastname: N'guyen-Morel
authors.forename: Eric
authors.initials: E
authors.lastname: Guinet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Orliaguet
mesh_terms: D000381:Agraphia / Q000150:complications* / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D004410:Dyslexia / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D010700:Phonetics; D011597:Psychomotor Performance; D012016:Reference Values; D012691:Serial Learning; D014796:Visual Perception