Title: The Reading Brain – White matter development in children at risk for dyslexia
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 depicted white matter alterations and atypical lateralization of the arcuate fasciculus at the prereading stage in FHD+ versus FHD- children. Moreover, we demonstrated 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 to 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.
