Comorbidity of Phonological Deficits in Chinese Developmental Dyscalculia and Dyslexia: A Test of Double Dissociation Model and Common Etiology Model

Abstract

The present study aimed to explore whether phonological deficits in comorbidity of developmental dyscalculia and dyslexia of Chinese children fit into a double dissociation model or a common etiology model. Out of 1675 primary school students in grade 3 and 4 from northwestern China, we identified 61 children with dyscalculia only, 63 children with dyslexia only, 56 children with comorbid dyscalculia and dyslexia, and 59 children as age-matched controls. Phonological awareness (PA), rapid automatized naming (RAN), visuospatial skills, pattern recognition, and morphological awareness (MA), were assessed for all children from the four groups. Results showed that compared to the controls, the common cognitive deficits of children from the three disability groups were in PA and RAN. The RAN deficits in the comorbid group were less than the addition of that in the dyscalculia group and dyslexia group. However, the PA deficits in the comorbid group were almost the addition of that in the dyscalculia group and dyslexia group. Multinomial logistic regression analysis revealed that the comorbid group could only be distinguished from the dyscalculia/dyslexia group by PA. These results suggest that comorbidity of Chinese developmental dyscalculia and dyslexia fit into common etiology model in RAN deficit and double dissociation model in PA deficit.