Infant White Matter Microstructure Predicts Preschool Pre-Reading Skills in Children With and Without a Familial Risk of Developmental Dyslexia

Infant White Matter Microstructure Predicts Preschool Pre-Reading Skills in Children With and Without a Familial Risk of Developmental Dyslexia

First Author/Chair:Michael Figuccio -- Boston Children’s Hospital & Harvard Medical School
Additional authors/chairs: 
Yingying Wang; Nadine Gaab
Keywords: Developmental neuroscience, Familial Risk, causality, Infant, Diffusion Tractography
Abstract / Summary: 

Children and adults with developmental dyslexia (DD) display atypical white matter microstructure compared to controls in tracts implicated in reading. Specifically, patients with DD display reduced fractional anisotropy (FA) in the left arcuate fasciculus (LAF) and increased FA in the posterior corpus callosum (PCC). Whether these neural differences emerge prior to reading instruction and predict subsequent reading skills remains in question. The current study investigates whether white matter microstructure in infants predicts preschool pre-reading skills. Twenty-six infants with (mean age=9.8 months) and twenty-five without (mean age=10.1 months) a familial risk of DD underwent diffusion-weighted imaging. The LAF and PCC were segmented into 100 equidistant units with automated fiber-tract quantification. A subset of infants with and without a familial risk of DD underwent cognitive-linguistic testing at age four. Infants without at risk of DD displayed greater FA in the LAF and PCC than controls. Additionally, FA values in the LAF positively correlated with picture vocabulary at age four. Furthermore, FA values in the PCC positively correlated with print knowledge at age four. Further analyses of radial diffusivity, a measure of water diffusion perpendicular to the tract, suggest that picture vocabulary and print knowledge may be associated with greater myelination in LAF and PCC, respectively. These results suggest that early white matter microstructure is associated with the development of later reading skills. Future longitudinal studies are needed to tract reading development from infancy through school age when DD can be diagnosed.