Long-Term Impact of Digital Media on Brain Development in Children

Abstract

ImportanceDigital media takes an increasingly large part of children’s time, but the effect on brain development is unclear.ObjectiveTo investigate the effects of digital media (watching television and videos, using social media, or playing video games respectively) on the development of the cortex, striatum, and cerebellum over two years.Design, setting, and participantsA prospective, multicenter, longitudinal study of children from the Adolescent Brain and Cognitive Development Study, recruited between 2016-2018. Children underwent magnetic resonance imaging scan at two different time points and completed the Youth Screen Time Survey at first timepoint, answering questions about digital media use. The analysis controlled for differences in socioeconomic status (SES) and polygenic scores for educational attainment.ExposureDigital media use.Main outcome measuresThe primary outcome measure was the changes in the global cortical surface area.Results6492 children (age in months, mean [SD] = 118.6 [7.2], i.e., 9.9 years were included at the baseline. Of these, 4502 children (age in months = 142.6 [7.6], i.e., 11.9 years were included at the two years follow-up. The average time spent by children on screen time was 2.2h/day for watching television and videos, 0.4h/day for using social media, and 0.9h/day for playing video games.Over the two-year observation period, the average cortical surface area increased by approximately 2%, reflecting normal cortical development. The amount of time spent playing video games was weakly but positively correlated to change in global cortical surface area (standardised beta, β = 0.03; 95% CI [0.001 – 0.06]; P=.06). No global or regional effect on brain development was observed for a time watching television and videos or using social media. However, the regional analysis showed that playing video games was associated with a larger increase in the volume of the cerebellum (β = 0.01 [0.001 – 0.02]; P=.02).Conclusions and RelevanceThis study does not suggest that digital media use in children harms brain development in mid-childhood and within a window of two years, but a longer follow-up is necessary.Key pointsQuestionDoes the use of digital media affect brain development in children aged 9-10 years of age?FindingsIn this two-year longitudinal study of 4502 children, we found no effect of playing video games, watching television, or using social media on the development of cortical surface area. playing video games was associated with a larger increase in the volume of cerebellum.MeaningThis study does not indicate that the use of digital media harms brain development.