White matter alterations in young children with prenatal alcohol exposure

Abstract

Prenatal alcohol exposure (PAE) can lead to cognitive, behavioural, and social-emotional challenges. Previous neuroimaging research has identified structural brain alterations in newborns, older children, adolescents, and adults with PAE; however, little is known about brain structure in young children. Extensive brain development occurs during early childhood; therefore, understanding the neurological profiles of young children with PAE is critical for early identification and effective intervention. We studied 54 children (5.21 ± 1.11 years; 27 males) with confirmed PAE (94% also had other prenatal exposures, 74% had adverse postnatal experiences) compared with 54 age- and sex-matched children without PAE. Children underwent diffusion tensor imaging between 2 and 7 years of age. Mean fractional anisotropy (FA) and mean diffusivity (MD) were obtained for 10 major white matter tracts. Univariate analyses of covariance were used to test group differences (PAE vs. control) controlling for age and sex. The PAE group had higher FA in the genu of the corpus callosum and lower MD in the bilateral uncinate fasciculus. The PAE group also had lower tract volume in the corpus callosum, the bilateral inferior fronto-occipital fasciculi, and the right superior longitudinal fasciculus. Our findings align with studies of newborns with PAE reporting lower diffusivity, but contrast those in older populations with PAE, which consistently report lower FA and higher MD. Further research is needed to understand trajectories of white matter development and how our results of higher FA/lower MD in young children connect with lower FA/higher MD observed at older ages.

Keywords: diffusion tensor imaging; fetal alcohol spectrum disorder; prenatal alcohol exposure; preschool children; white matter.