Predicting math achievement through neuropsychological interpretation of WISC-III variance components

Although prevalence estimates suggest that mathematics learning disorders (MLD) are as common as reading disorders, there has been comparatively little research conducted that examines the psychological processes involved in math competency for typical children, and the characteristics, etiology, and treatment of children with MLD. Previous research in disabled populations has implicated dysfunctional right hemisphere cognitive processes as a cause of MLD and suggested that impaired visual-spatial skills lead to specific MLD error patterns. In this study of 587 nonidentified children with variable intellectual test profiles, the cognitive predictors necessary for math competency were interpreted from a neuropsychological orientation. Results revealed that complex interactions between WISC-III Verbal and Performance subtests were predictive of math word problems and computation skills, suggesting that semantic/mathematics knowledge, working memory, executive function, novel problem solving, and visual-perceptual-motor processes are necessary for mathematics performance. Contrary to the right hemisphere hypothesis of math competency, results suggest that left hemisphere crystallized abilities and frontal executive functions are most predictive of mathematics achievement for children with variable test profiles. Consistent with theoretical and empirical advances regarding lateralization of function, the numerous predictor commonalities found support a reconceptualization of the left-verbal/right-nonverbal dichotomy of the cognitive processes underlying mathematics competency.