COLECA: Associations and Dissociations of Dyslexia and Dyscalculia:

Wider research context / theoretical framework: Reading, spelling, and arithmetic are crucial domains of school achievement, and neurodevelopmental learning disorders in written language processing (dyslexia) and arithmetic (dyscalculia) have massive negative impacts on academic and professional perspectives and psychosocial wellbeing. There is high cooccurrence of dyslexia and dyscalculia, but the neurocognitive mechanisms underlying this comorbidity are not well understood. Theoretical models must explain the high rates of comorbidity as well why the two disorders can dissociate.

Hypotheses / research questions / objectives: We aim to specify a multi-deficit model that can explain associations and dissociations of dyslexia and dyscalculia, by investigating the complex interplay of neurocognitive predictors that are domain-specific (dyslexia: phonological processing; dyscalculia: numerical processing) with domain-general predictors of school achievement (language, working memory, executive functions, processing speed).

Approach / methods: Based on a large and representative sample of primary school children (N ≈ 3200) we investigate direct and indirect effects of domain-specific and -general predictors on variance in reading, spelling, and arithmetic, and especially on their co-variance. We will also compare thoroughly selected subgroups of children with isolated disorders in literacy or arithmetic, comorbid disorder and typical development to investigate differences in cognitive profiles and the long-term (18 months) stability of subgroup selection.