Mathematical abilities in dyslexic children: a diffusion tensor imaging study

Abstract

Dyslexia is characterized by a deficit in language processing which mainly affects word decoding and spelling skills. In addition, children with dyslexia also show problems in mathematics. However, for the latter, the underlying structural correlates have not been investigated. Sixteen children with dyslexia (mean age 9.8 years [0.39]) and 24 typically developing children (mean age 9.9 years [0.29]) group matched for age, gender, IQ, and handedness underwent 3 T MR diffusion tensor imaging as well as cognitive testing. Tract-Based Spatial Statistics were performed to correlate behavioral data with diffusion data. Children with dyslexia performed worse than controls in standardized verbal number tasks, such as arithmetic efficiency tests (addition, subtraction, multiplication, division). In contrast, the two groups did not differ in the nonverbal number line task. Arithmetic efficiency, representing the total score of the four arithmetic tasks, multiplication, and division, correlated with diffusion measures in widespread areas of the white matter, including bilateral superior and inferior longitudinal fasciculi in children with dyslexia compared to controls. Children with dyslexia demonstrated lower performance in verbal number tasks but performed similarly to controls in a nonverbal number task. Further, an association between verbal arithmetic efficiency and diffusion measures was demonstrated in widespread areas of the white matter suggesting compensatory mechanisms in children with dyslexia compared to controls. Taken together, poor fact retrieval in children with dyslexia is likely a consequence of deficits in the language system, which not only affects literacy skills but also impacts on arithmetic skills.

Understanding comorbidity of learning disorders: task‐dependent estimates of prevalence

“…estimating calculation results) and comparing magnitudes are separable from those supporting exact arithmetic (Dehaene, Piazza, Pinel, & Cohen, ). Especially relevant for this study are findings showing that the representation of exact arithmetic recruits language‐related networks (Dehaene et al., ; Evans, Flowers, Napoliello, Olulade, & Eden, ; Koerte et al., ) that are also involved in reading. Based on these findings, the association between literacy and exact arithmetic found in this study is to be expected and is in line with recent fMRI findings showing similar neural activation patterns in children with RD, MD and comorbid problems during arithmetic tasks (Peters, Bulthé, Daniels, de Beeck, & De Smedt, ).…”

No Evidence for Systematic White Matter Correlates of Dyslexia: An Activation Likelihood Estimation Meta-Analysis

“…More problematic perhaps, Keller and Just (2009) were unable to replicate these findings in an intervention study, instead reporting lower FA in an anterior region, the left anterior centrum semiovale. Similarly, Koerte et al (2016) found no significant differences in FA when controlling for false positives adequately. Studies have also found a variety of significant differences in other brain regions, including the superior and inferior frontal regions, precuneus, insula and occipital region in the left hemisphere, superior corona radiata, splenium of the corpus callosum and throughout the right hemisphere (Carter et al, 2009;Deutsch et al, 2005;Frye et al, 2008;Niogi & McCandliss, 2006;Rimrodt et al, 2010;Steinbrink et al, 2008).…”

No Evidence for Systematic White Matter Correlates of Dyslexia and Dyscalculia

“…Individuals with dyslexia are known to experience particular mathematical difficulties with verbal arithmetic, likely related to impaired phonological retrieval processes (Boets & De Smedt, 2010). In this study, arithmetic efficiency showed a greater correlation with FA in children with dyslexia vs. controls in a large number of white matter tracts, including the bilateral ILF and SLF (Koerte et al, 2016).…”

“…Although departing from some of the published literature, our results are in line with some of the prior research examining white matter tracts in dyslexic and typical readers. For example, a study by Koerte et al (2016) reported no difference between dyslexics and typical readers using various diffusion measures, after correcting for multiple comparisons. In addition, a meta-analysis by Vandermosten and colleagues (2012) yielded two clusters with a significant difference in FA between poor and typical readers.…”

“…Despite the high rate of comorbidity between dyslexia and dyscalculia, there is no published research that has investigated whether the white matter integrity differences found in one of the two disorders vary as a function of the other disorder also being present. A recent study used DTI to examine mathematical difficulties in dyslexic children (Koerte et al, 2016). Individuals with dyslexia are known to experience particular mathematical difficulties with verbal arithmetic, likely related to impaired phonological retrieval processes (Boets & De Smedt, 2010).…”