Associations Between Screen-Based Media Use and Brain White Matter Integrity in Preschool-Aged Children

Abstract

Importance: The American Academy of Pediatrics (AAP) recommends limits on screen-based media use, citing its cognitive-behavioral risks. Screen use by young children is prevalent and increasing, although its implications for brain development are unknown.

Objective: To explore the associations between screen-based media use and integrity of brain white matter tracts supporting language and literacy skills in preschool-aged children.

Design, setting, and participants: This cross-sectional study of healthy children aged 3 to 5 years (n = 47) was conducted from August 2017 to November 2018. Participants were recruited at a US children's hospital and community primary care clinics.

Exposures: Children completed cognitive testing followed by diffusion tensor imaging (DTI), and their parent completed a ScreenQ survey.

Main outcomes and measures: ScreenQ is a 15-item measure of screen-based media use reflecting the domains in the AAP recommendations: access to screens, frequency of use, content viewed, and coviewing. Higher scores reflect greater use. ScreenQ scores were applied as the independent variable in 3 multiple linear regression models, with scores in 3 standardized assessments as the dependent variable, controlling for child age and household income: Comprehensive Test of Phonological Processing, Second Edition (CTOPP-2; Rapid Object Naming subtest); Expressive Vocabulary Test, Second Edition (EVT-2; expressive language); and Get Ready to Read! (GRTR; emergent literacy skills). The DTI measures included fractional anisotropy (FA) and radial diffusivity (RD), which estimated microstructural organization and myelination of white matter tracts. ScreenQ was applied as a factor associated with FA and RD in whole-brain regression analyses, which were then narrowed to 3 left-sided tracts supporting language and emergent literacy abilities.

Results: Of the 69 children recruited, 47 (among whom 27 [57%] were girls, and the mean [SD] age was 54.3 [7.5] months) completed DTI. Mean (SD; range) ScreenQ score was 8.6 (4.8; 1-19) points. Mean (SD; range) CTOPP-2 score was 9.4 (3.3; 2-15) points, EVT-2 score was 113.1 (16.6; 88-144) points, and GRTR score was 19.0 (5.9; 5-25) points. ScreenQ scores were negatively correlated with EVT-2 (F2,43 = 5.14; R2 = 0.19; P < .01), CTOPP-2 (F2,35 = 6.64; R2 = 0.28; P < .01), and GRTR (F2,44 = 17.08; R2 = 0.44; P < .01) scores, controlling for child age. Higher ScreenQ scores were correlated with lower FA and higher RD in tracts involved with language, executive function, and emergent literacy abilities (P < .05, familywise error-corrected), controlling for child age and household income.

Conclusions and relevance: This study found an association between increased screen-based media use, compared with the AAP guidelines, and lower microstructural integrity of brain white matter tracts supporting language and emergent literacy skills in prekindergarten children. The findings suggest further study is needed, particularly during the rapid early stages of brain development.

Figure 1.. Scatterplots of ScreenQ Survey Total Scores vs Cognitive Assessment Scores

Solid blue line represents least squares fit; dashed blue lines, 95% CI bounds of slope; dashed orange lines, 95% prediction interval for new observations. CTOPP-2 indicates Comprehensive Test of Phonological Processing, Second Edition, Rapid Object Naming subtest; EVT, Expressive Vocabulary Test, Second Edition; GRTR, Get Ready to Read! assessment.

Figure 2.. Diffusion Tensor Imaging (DTI) Parameter Maps for Whole-Brain Analysis

White matter voxels exhibit a statistically significant correlation between screen-based media use (ScreenQ scores) and lower fractional anisotropy (FA; A) as well as higher radial diffusivity (RD; B) in whole-brain analysis, controlling for child age and household income level (P < .05, familywise error–corrected). Color indicates the slope or magnitude of correlation (ie, change in the DTI parameter for every point increase in ScreenQ score).

Figure 3.. Tract-Based Spatial Statistical Analysis in the Left Hemisphere

The tract-based spatial statistical analysis involves these 3 language- and literacy-associated tracts in the left hemisphere: arcuate fasciculus (white), inferior longitudinal fasciculus (tan), uncinate fasciculus (brown). A, Blue represents statistically significantly lower fractional anisotropy (FA) with higher ScreenQ scores. B, Red represents statistically significantly higher radial diffusivity (RD) with higher ScreenQ scores. Both analyses controlled for child age and household income level (P < .05, familywise error–corrected).