Speed of processing and reading disability: a cross-linguistic investigation of dyslexia and borderline intellectual functioning.
English and Italian children with dyslexia were compared with children with reading difficulties associated with low-IQ on tests of simple and choice RT, and in number and symbol scanning tasks. On all four speed-of-processing tasks, children with low-IQ responded more slowly than children with dyslexia and age-controls. In the choice RT task, the performance of children with low-IQ was also less accurate than that of children of normal IQ, consistent with theories linking processing speed limitations with low-IQ. These findings support the hypothesis that dyslexia is a specific cognitive deficit that can arise in the context of normal IQ and normal speed of processing. The same cognitive phenotype was observed in readers of a deep (English) and a shallow (Italian) orthography.
Bonifacci
Paola
P
Dipartimento di Psicologia, Università degli Studi di Bologna, Viale Berti Pichat n.5, 40127 Bologna, Italy. paola.bonifacci@unibo.it
Snowling
Margaret J
MJ
D000293:Adolescent; D002648:Child; D003431:Cross-Cultural Comparison; D004410:Dyslexia / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis*; D008297:Male; D010641:Phenotype; D011930:Reaction Time; D021641:Recognition, Psychology; D012720:Severity of Illness Index