Many diffusion magnetic resonance imaging (dMRI) studies document associations between reading skills and fractional anisotropy (FA) within brain white matter, suggesting that efficient transfer of information across the brain contributes to individual differences in reading. Use of complementary imaging methods can determine if these associations relate to myelin content of white matter tracts. Compared to children born at term (FT), children born preterm (PT) are at risk for reading deficits. We used two MRI methods to calculate associations of reading 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. We segmented three dorsal (left arcuate and bilateral superior longitudinal fasciculus) and four ventral (bilateral inferior longitudinal fasciculus and bilateral uncinate) tracts and quantified (1) FA from dMRI and (2) R1 from quantitative T1 relaxometry. We examined correlations between reading scores and these metrics along the trajectories of the tracts. Reading positively correlated with FA in segments of left arcuate and bilateral superior longitudinal fasciculi in FT children; no FA associations were found 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; no R1 associations were found in FT children. Birth group significantly moderated the associations of reading and white matter metrics. Myelin content of white matter may contribute to individual differences in PT but not FT children.
Bibliographical noteFunding Information:
The authors received funding support from the National Institute of Child Health and Human Development (Grant # R01HD069162 and 2RO1- HD069150 [Feldman], 5K99HD084749 [Travis]), a Young Investigator Award to Dr. Travis, from the Society of Developmental and Behavioral Pediatrics (2014), a Tashia and John Morgridge endowed fellowship through the Stanford Maternal Child Health Research Institute Clinical Trainee Grant to Dr. Dubner, and a Postdoctoral Research Training in Child Psychiatry and Neurodevelopment fellowship to Dr. Brignoni-Pérez from the National Institute of Mental Health (A. Reiss, PI: T32 MH019908). Funders were not involved in study design, data collection, data analysis, manuscript preparation or publication decisions. We thank the children and their families for their gracious participation.
- Fractional anisotropy