TORONTO -- From bedrooms to cars, portable electronic devices have become an inescapable part of life for most families. But for young children, there may be measurable changes in the brain associated with excess screen time.

Preschoolers who spend more time in front of a screen have lower structural integrity of white matter in areas of the brain – or brain wiring that relates to language, literacy, imagination, and executive function such as self-regulation, according to a new study published in JAMA Pediatrics.

Researchers found that 16 to 56 per cent of those areas of the brain were negatively affected by higher screen use.

“What we saw was the fiber tracts, or the wires connecting different parts of the brain that are involved with language and literacy, had lower measures of insulation and organization,” said Dr. John Hutton, a pediatrician at the Cincinnati Children’s Hospital Medical Center and lead author of the study.

The study involved a group of 47 healthy children aged three to five, and their parents. There were 27 girls and 20 boys. A Diffusion Tensor Imaging (DTI) MRI scan was administered along with cognitive tests that measured things like language literacy and speed processing.

An assessment of screen use was also given, based on guidelines provided by the American Academy of Pediatrics (AAP). The “ScreenQ” assessment included the child’s access to screens (such as the location), their frequency of use, the content (such as educational or violent content), and whether the caregiver watched with their child and talked with them about what they were watching. The higher the score, the more time the children spent in front of a screen. 

Key findings from the study included a strong connection between higher ScreenQ scores and lower expressive language, emerging literacy skills, and ability to quickly name objects. Higher ScreenQ scores were also associated with lower measures of structural integrity of white matter, which also affects the formation of a myelin sheath around a nerve, which helps nerve impulses move more quickly.

The study found that wiring in the brains of children whose families practiced screen habits that aligned with AAP recommendations were more well-developed. In other words, the connections were stronger between different networks in those children’s brains.

“It used to be that the TV was in the living room and kids would watch it … but now with portable devices, the screens literally follow kids everywhere,” said Hutton, adding that technology has advanced so much faster than the research.

“All the bells and whistles (from devices) and stimulating things probably do too much for kids and make it so that they’re not as incentivized to use their imaginations, and to talk and really practice these skills that they’re just learning how to use at a young age.”

Hutton said good brain development really depends on practicing important real-world experiences, such as reading, playing outside, interacting with caregivers, and imaginative play.

“This is a very exciting study because it links digital media use behavior with observed and measured brain differences,” Dillon Browne, a psychology professor at the University of Waterloo, told CTV News in an email.

“This study adds to a growing body of science suggesting that there is probably something important to consider in regards to digital media use and early development across biological, psychological, and socioemotional domains. It would be foolish to dismiss the number of independent studies across different research groups and parts of the world that are coming to similar conclusions.”

While brains can be rewired at any age, they are much more responsive in younger children, making them far easier to stimulate. The concern is that children with under-stimulated brains in early childhood could develop less efficient connections that become harder to reinforce or fix as they get older.

Hutton said this type of study does not prove causality, since it does not show whether screen exposure causes these measures of the brain to be lower. The study merely shows an association and merits further studies.

“Mostly it’s a call for caution. I think that we need to really call ‘time-out’ to a certain degree and look more closely at the idea that children when they’re little really aren’t small grown-ups,” said Hutton.

“We’ve jumped into a lot of these technologies very quickly and children are given screens at younger ages and we really need to probably be a little more careful.”

Dr. Janice Heard, a member of the public education advisory committee of the Canadian Paediatric Society, told CTV News that the study reinforces what pediatricians have worried about for years.

“We’ve been concerned that children who use a lot of media perhaps are not developing language, imagination and play in a way that we’d like them to,” she said. “This study gives us a little insight into what’s exactly happening in the brain.”

Heard added that some parents who come to her practice are also concerned about what these devices are doing to their children.

“I see parents worrying about this all the time,” she said. “I also see some parents who, it’s not even on their radar, and in fact that where I really like to get on my soap box and talk about the fact that media use for the smaller children is not necessary and probably is not good for them.”

Some key recommendations by various pediatric associations include:

  • Keep children off screens for as long as possible when they are younger. The Canadian Paediatric Society (CPS) recommends waiting until 2 years old.
  • Limit regular screen time for children 2 to 5 years of age to less than 1 hour per day.
  • Avoid screen time for at least an hour before bedtime.
  • No screens in the bedroom and at meal times, or set daily “screen-free” times and locations.
  • Watch or be engaged with your child when possible during screen time and choose high-quality programming.

“Keeping kids off the screen or away from screens as much as possible -- I think no parent really will regret that,” said Hutton, who has also done extensive research on the benefits of early reading exposure.

“Giving a child the opportunity to play with blocks and play with their pets and interact with their siblings and families is something that will always be valuable and will also be good for their brains.”

Heard added if a child does want to play with a device, they should do so in the company of an adult.

“(We) very strongly recommend that that time be spent co-viewing with a caregiver who can interact with the child while they’re on a device to explain what they’re seeing and answer questions,” she said.

“It’s very much like reading a story to a child. We want that same interaction.”

With files from Writer Ben Cousins