Development of Tract-Specific White Matter Pathways During Early Reading Development in At-Risk Children and Typical Controls

Abstract

Developmental dyslexia is a neurodevelopmental disorder with a strong genetic basis. Previous studies observed white matter alterations in the left posterior brain regions in adults and school-age children with dyslexia. However, no study yet has examined the development of tract-specific white matter pathways from the pre-reading to the fluent reading stage in children at familial risk for dyslexia (FHD+) versus controls (FHD-). This study examined white matter integrity at pre-reading, beginning, and fluent reading stages cross-sectionally ( n = 78) and longitudinally (n = 45) using an automated fiber-tract quantification method. Our findings depict white matter alterations and atypical lateralization of the arcuate fasciculus at the pre-reading stage in FHD+ versus FHD- children. Moreover, we demonstrate faster white matter development in subsequent good versus poor readers and a positive association between white matter maturation and reading development using a longitudinal design. Additionally, the combination of white matter maturation, familial risk, and psychometric measures best predicted later reading abilities. Furthermore, within FHD+ children, subsequent good readers exhibited faster white matter development in the right superior longitudinal fasciculus compared with subsequent poor readers, suggesting a compensatory mechanism. Overall, our findings highlight the importance of white matter pathway maturation in the development of typical and atypical reading skills.

Neural Noise Hypothesis of Developmental Dyslexia

“…For example, one study [37] provides evidence that poor access to phonological representations, arguably reflected in reduced functional connectivity with temporoparietal regions, is impaired, while phonological representations remain intact, although this study did not examine the detailed properties of phoneme encoding (as has been done in other studies [87]). RD risk mutations in DCDC2 have also been linked to structural connectivity within the reading network [25] and children at-risk for RD have persistently reduced temporoparietal white matter integrity [99]. While these studies do highlight the importance of connectivity in RD, and the need for systems-levels approaches to studying RD, these results are not necessarily incompatible with the neural noise hypothesis.…”

Individual differences in children’s global motion sensitivity correlate with TBSS-based measures of the superior longitudinal fasciculus

“…Other associations have been found between fractional anisotropy of the superior longitudinal fasciculus, and working memory (Vestergaard et al, 2011; Rizio & Diaz, 2016), executive function and sustained attention in children (Klaborg et al, 2013; Urger et al, 2015), and children’s reading development (Travis et al, 2016; Wang et al, 2016). …”

Neural Noise Hypothesis of Developmental Dyslexia

“…For example, one study [37] provides evidence that poor access to phonological representations, arguably reflected in reduced functional connectivity with temporoparietal regions, is impaired, while phonological representations remain intact, although this study did not examine the detailed properties of phoneme encoding (as has been done in other studies [87]). RD risk mutations in DCDC2 have also been linked to structural connectivity within the reading network [25] and children at risk for RD have persistently reduced temporoparietal white matter integrity [99]. While these studies highlight the importance of connectivity in RD and the need for systems-levels approaches to studying RD, these results are not necessarily incompatible with the neural noise hypothesis.…”