Dyslexia and dyscalculia: two learning disorders with different cognitive profiles.
This study tests the hypothesis that dyslexia and dyscalculia are associated with two largely independent cognitive deficits, namely a phonological deficit in the case of dyslexia and a deficit in the number module in the case of dyscalculia. In four groups of 8- to 10-year-olds (42 control, 21 dyslexic, 20 dyscalculic, and 26 dyslexic/dyscalculic), phonological awareness, phonological and visual-spatial short-term and working memory, naming speed, and basic number processing skills were assessed. A phonological deficit was found for both dyslexic groups, irrespective of additional arithmetic deficits, but not for the dyscalculia-only group. In contrast, deficits in processing of symbolic and nonsymbolic magnitudes were observed in both groups of dyscalculic children, irrespective of additional reading difficulties, but not in the dyslexia-only group. Cognitive deficits in the comorbid dyslexia/dyscalculia group were additive; that is, they resulted from the combination of two learning disorders. These findings suggest that dyslexia and dyscalculia have separable cognitive profiles, namely a phonological deficit in the case of dyslexia and a deficient number module in the case of dyscalculia.
Landerl
Karin
K
Department of Psychology, University of Tuebingen, Tuebingen, Germany. karin.landerl@uni-tuebingen.de
Fussenegger
Barbara
B
Moll
Kristina
K
Willburger
Edith
E
D001364:Awareness; D002648:Child; D003072:Cognition Disorders / Q000523:psychology*; D015897:Comorbidity; D004410:Dyslexia / Q000523:psychology*; D005260:Female; D006801:Humans; D007807:Language Tests; D007859:Learning Disabilities / Q000523:psychology*; D008297:Male; D008433:Mathematics; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D011930:Reaction Time; D012660:Semantics; D013028:Space Perception; D013067:Speech Perception; D014706:Verbal Learning