White matter properties underlying reading abilities differ in 8-year-old children born full term and preterm

Diffusion magnetic resonance imaging (dMRI) studies find differences in associations between reading and white matter fractional anisotropy (FA) in children born full term (FT) versus preterm (PT). Use of complementary neuroimaging modalities may reveal neurobiological factors driving these associations. We used two MRI methods to interpret associations of reading abilities and white matter properties in FT and PT children. Participants (N=79: 36 FT and 43 PT) were administered the Gray’s Oral Reading Test at age 8 years. We segmented two dorsal and two ventral white matter tracts associated with reading abilities and quantified (1) FA from dMRI and (2) R1 from quantitative relaxometry, as a proxy for myelin content. We examined correlations between reading scores and neuroimaging metrics, assessing trajectories along the tracts. Mean reading scores fell in the typical range in both groups. Reading positively correlated with FA in segments of the left arcuate and the left and right superior longitudinal fasciculi in FT children, but not in PT children. Reading positively correlated with R1 in segments of the left superior longitudinal, right uncinate, and left inferior longitudinal fasciculi in PT children, but not in FT children. The significantly different patterns of associations between reading abilities and white matter properties across FT and PT groups suggest variations in the neurobiology of typical reading abilities.