The Relation of Home Literacy Environment to Brain Specialization and Sensitivity for Phonological and Semantic Processing of Spoken Words.

purposeNeural specialization is a developmental phenomenon across multiple domains of language processing. The home literacy environment (HLE) is observed to relate to brain activation during language and reading tasks; however, whether HLE relates to phonological and semantic functional specialization and sensitivity remains unknown.

methodUsing an open-source data set, this study examined thirty-three 5- to 6-year-olds and seventy-six 7- to 8-year-olds. Data from functional magnetic resonance imaging sound and meaning judgment tasks were used to examine phonological and semantic functional specialization (contrasting tasks) and sensitivity (comparing conditions within a task). Then, voxel-wise regression analyses were used to test correlations between those brain indexes and HLE (i.e., family-to-child reading, child independent reading) measured using a parent survey.

resultsWe observed weak evidence of phonological specialization at 5 years old and weak evidence of semantic specialization at 7 years old associated with family-to-child reading. We also observed weak evidence of phonological sensitivity at 5 years old and strong evidence of semantic sensitivity at 7 years old associated with family-to-child reading. Across the cohorts, a progression from temporal to frontal brain regions was observed in those relations, in line with prior literature on language specialization and sensitivity across development.

conclusionsOverall, our results suggest that HLE is linked to functional specialization and sensitivity, with family-to-child reading showing a weak relation to sound structure processing at 5 years old but a stronger relation to meaning processing at 7 years old. This finding supports the interactive specialization theory, which emphasizes the role of environmental inputs in neural specialization. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.31606621.