Close-up of a toddler and mother using a touch screen tablet.
New guidelines on screen time for young children
00:42 - Source: CNN Business
CNN  — 

Screen time use by infants, toddlers and preschoolers has exploded over the last decade, concerning experts about the impact of television, tablets and smartphones on these critical years of rapid brain development.

Now a new study scanned the brains of children 3 to 5 years old and found those who used screens more than the recommended one hour a day without parental involvement had lower levels of development in the brain’s white matter – an area key to the development of language, literacy and cognitive skills.

Higher screen use was associated with less well-developed white matter tracts (shown in blue in the image)  throughout the brain.

“This is the first study to document associations between higher screen use and lower measures of brain structure and skills in preschool-aged kids,” said lead author Dr. John Hutton, a pediatrician and clinical researcher at Cincinnati Children’s Hospital. The study was published Monday in the journal JAMA Pediatrics.

“This is important because the brain is developing the most rapidly in the first five years,” Hutton said. “That’s when brains are very plastic and soaking up everything, forming these strong connections that last for life.”

Screens ‘follow kids everywhere’

Studies have shown excessive TV viewing is linked to the inability of children to pay attention and think clearly, while increasing poor eating habits and behavioral problems. Associations have also been shown between excessive screen time and language delay, poor sleep, impaired executive function, and a decrease in parent-child engagement.

“It’s known that kids that use more screen time tend to grow up in families that use more screen time,” Hutton said. “Kids who report five hours of screen time could have parents who use 10 hours of screen time. Put that together and there’s almost no time for them to interact with each other.”