No evidence for a core deficit in developmental dyscalculia or mathematical learning disabilities. (8th March 2021)

• Record Type: Journal Article
• Authors: Mammarella, Irene C.; Toffalini, Enrico; Caviola, Sara; Colling, Lincoln; Szűcs, Denes
• Is Part Of: Journal of child psychology and psychiatry and allied disciplines. Volume 62:Number 6(2021)
• Page Start: 704
• Page End: 714
• Publication Date: 2021-03-08
• Subjects: Child psychology -- Periodicals; Child psychiatry -- Periodicals; 155.4
• DOI: 10.1111/jcpp.13397
• Languages: English
• ISSNs: 0021-9630

Abstract

Abstract : Background: Two hypotheses were tested regarding the characteristics of children with mathematical learning disabilities (MLD): (a) that children with MLD would have a 'core deficit' in basic number processing skills; and (b) that children with MLD would be at the end of a developmental continuum and have impairments in many cognitive skills. Methods: From a large sample ( N = 1, 303) of typically developing children, we selected a group definable as having MLD. The children were given measures of basic number processing and domain‐general constructs. Differences between the observed sample and a simulated population were estimated using Cohen's d and Bayes factors. Receiver operating characteristic curves were plotted, and the area under the curve was computed to ascertain the diagnostic power of measures. Results: Results suggest that the differences between the MLD and control group can be defined along with general characteristics of the population rather than assuming single or multiple 'core deficits'. None of the measures of interest exceeded the diagnostic power that could be derived via simulation from the dimensional characteristics of the general population. Conclusions: There is no evidence for core deficit(s) in MLD. We suggest that future research should focus on representative samples of typical populations and on carefully tested clinical samples confirming to the criteria of international diagnostic manuals. Clinical diagnoses require that MLD is persistent and resistant to intervention, so studies would deliver results less exposed to measurement fluctuations. Uniform diagnostic criteria would also allow for the easy cross‐study comparison of samples overcoming a serious limitation of the current literature.