Longitudinal associations of screen time with brain development and expressive language skills in early childhood

Screen-based media may reduce reciprocal social interactions that support expressive language development, but little is known about how early language abilities, later screen use, and brain structure are related during toddlerhood. We examined 70 toddlers with structural magnetic resonance imaging and standardized developmental assessments at age 2, along with parent-reported screen time at ages 2 and 3. Greater weekday and weekend screen time at age 2 were associated with poorer concurrent expressive language skills. Right pars triangularis volume did not explain additional variance in these cross-sectional associations. Longitudinally, right pars triangularis volume moderated the association between expressive language skills at age 2 and screen time at age 3. Among toddlers with relatively smaller right pars triangularis volumes, poorer expressive language skills were associated with greater subsequent weekday and weekend screen time. These findings support guidance to limit screen use during toddlerhood, a sensitive window for language and brain development.