Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth

Abstract

Aim: To determine associations between 2-year language outcomes and near-term equivalent age diffusion MRI (dMRI) white matter tract metrics in a cohort of preterm children. Method: 32 children, gestational age 28.9 (2.4) weeks, underwent dMRI at mean post-menstrual-age 36.4 (1.4) weeks and language assessment with the Bayley Scales of Infant Development-III at 18-24 months. Mean fractional anisotropy (FA) was calculated for 6 white matter tracts. Hierarchical linear regression assessed associations between tract FA, moderating variables, and language. Results: Language outcomes correlated positively with FA of the left inferior longitudinal fasciculus (ILF-L) (r = 0.44, p < 0.05), and negatively with FA of the posterior corpus callosum (r = -0.41, p < 0.05). Language-brain associations in the ILF-L were independent of the number of neonatal medical complications. Number of neonatal medical complications moderated the relationship between language and posterior corpus callosum FA. Interpretation: The findings suggest that microstructural properties of white matter tracts in the newborn period are associated with language outcomes in the toddler years. The direction of associations varied by fiber group and may relate to the stage of brain maturation and/or the nature and timing of medical complications related to preterm birth.

Microstructural Measures of the Inferior Longitudinal Fasciculus Predict Later Cognitive and Language Development in Infants Born With Extremely Low Birth Weight

“…In a similar study with a smaller cohort, Dubner et al associated fractional anisotropy of the left inferior longitudinal fasciculus at term-equivalent age with language outcomes at 2 years of age but did not determine an association between the fractional anisotropy of the uncinate fasciculus and language outcomes. 43 A handful of previous studies in very preterm infants using similar approaches did not find significant associations between the fractional anisotropy of the inferior longitudinal fasciculus and neurodevelopmental outcomes. 8,26 These studies may have been limited by their smaller sample sizes in relation to the Barnett study.…”

White matter myelination during early infancy is explained by spatial gradients and myelin content at birth

“…Finally, our study has important societal implications. First, as R1 values are quantitative and have units that can be numerically compared across scanners, populations, and individuals 26 , our measurements in typically-developing infants provide a key foundation for large-scale studies of infant brain development in typical 53,54 and clinical populations such as preterm infants 55 , infants with cerebral palsy 56 , or fetal alcohol spectrum disorders 57 . Second, our methodology is translatable to clinical settings as it is performed during natural sleep.…”