The relation of the home literacy environment to white matter pathways associated with language in children 5–8 years old

Prior work suggests relations between the home literacy environment (HLE) and white matter in children less than 7 years, but studies have not yet examined the relation of the HLE to white matter pathways in older children. The studies on young children have investigated two dorsal tracts (arcuate fasciculus [AF] and superior longitudinal fasciculus [SLF]) and one ventral tract (inferior longitudinal fasciculus [ILF]), but not the inferior fronto-occipital fasciculus (IFOF). Moreover, these studies have not used a method to examine specific relations with phonological or semantic mechanisms. The present study examined the relation of HLE to these four white matter pathways in a group of children 5–6 years old (N = 79, Mage = 5.9) and a group 7–8 years old (N = 107, Mage = 7.6). Participants completed diffusion weighted imaging scans and standardized assessments of phonology and semantics. Pre-registered node-wise regression analyses tested relations of HLE to fractional anisotropy (FA). Relations were examined across 100 nodes and in the 30 nodes most associated with phonological awareness in the left AF and left SLF or semantic knowledge in the left IFOF and left ILF. Results only suggest a relation of parent-to-child reading and FA in the left IFOF for the group of children 5–6 years old. We suggest this relation may be related to the importance of picture naming in early shared reading of books. Given the limited relations demonstrated in the current pre-registered study with relatively large samples, coupled with inconsistent findings in the literature, future research is needed to investigate robust relations of HLE to white matter.