The study, which was published in the journal JAMA Pediatrics on Monday, was conducted by the Cincinnati Children’s Hospital Medical Center. The participants consisted of 47 children (27 girls and 20 boys) between the ages of three and five. The participants underwent resonance brain imaging and cognitive testing, and their parents were asked to complete a survey regarding their children’s screen time, answering questions related to frequency, type of screen and content.
The researchers found that children who used screens frequently had "lower measures of microstructural organization and myelination of brain white matter tracts that support language and emergent literacy skills.” According to Better Brains for Babies, myelination is the process in which neurons are coated with myelin, an insulating layer or sheath that protects them. White matter refers to areas of the central nervous system consisting of myelinated axons (threadlike parts of nerve cells), which are also known as tracts. Children with higher screen time usage had lower myelination, lower brain white matter integrity and struggled more with expressive language, processing speed and other literacy skills than kids with lower screen time usage.
"This study raises questions as to whether at least some aspects of screen-based media use in early childhood may provide sub-optimal stimulation during this rapid, formative state of brain development," lead author of the study John Hutton is quoted as saying by Science Daily. "While we can't yet determine whether screen time causes these structural changes or implies long-term neurodevelopmental risks, these findings warrant further study to understand what they mean and how to set appropriate limits on technology use."
The American Academy of Pediatrics (AAP) recommends that children under the age of 18 months avoid screens altogether, other than for video-chatting.
“Parents of children 18 to 24 months of age who want to introduce digital media should choose high-quality programming, and watch it with their children to help them understand what they're seeing,” the AAP guidelines read. Meanwhile, children aged between two and five should “limit screen use to 1 hour per day of high quality programs.”
In fact, an AAP report published last year recommended that doctors prescribe a daily dose of playtime for kids, noting that average playtime among US kids has dropped by as much as 25% during the last 30 years, while screen time has increased significantly.
Hutton also pointed out that screen time among children is increasing not just at home, but also in other settings.
"Screen-based media use is prevalent and increasing in home, childcare and school settings at ever younger ages," Hutton said. "These findings highlight the need to understand effects of screen time on the brain, particularly during stages of dynamic brain development in early childhood, so that providers, policymakers and parents can set healthy limits."