Are WISC IQ scores in children with mathematical learning disabilities underestimated?: The influence of a specialized intervention on test performance

Background: Intelligence measures play a pivotal role in the diagnosis of mathematical learning disabilities (MLD). Probably as a result of math-related material in IQ tests, children with MLD often display reduced IQ scores. However, it remains unclear whether the effects of math remediation extend to IQ scores. Aims: The present study investigated the impact of a special remediation program compared to a control group receiving private tutoring (PT) on the WISC IQ scores of children with MLD. Methods: We included N = 45 MLD children (7-12 years) in a study with a pre- and post-test control group design. Children received remediation for two years on average. Results: The analyses revealed significantly greater improvements in the experimental group on the Full-Scale IQ, and the Verbal Comprehension, Perceptual Reasoning, and Working Memory indices, but not Processing Speed, compared to the PT group. Children in the experimental group showed an average WISC IQ gain of more than ten points. Conclusion: Results indicate that the WISC IQ scores of MLD children might be underestimated and that an effective math intervention can improve WISC IQ test performance. Taking limitations into account, we discuss the use of IQ measures more generally for defining MLD in research and practice. (übernommen).