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Too Much Screen Time Changes Structure of Toddlers' Brains
Too many hours looking at smartphones and tablets 'slows down toddlers' language and reading development because it changes the structure of their brains.
Too much screen time changes structure of toddlers' brains. Photo: Alejandro Escamilla/Unsplash
Scientists took brain scans of children aged between three and five, and compared the results with screen use. Those who spent the most time on tablets, phones and the TV had less white matter in their brain. The tracts affected included those which support language skills, such as speech, thinking and reading.
The same children also scored lower on literacy tests. But critics of the research implied the findings were misleading, and urged parents not to worry about whether their child's brain is 'damaged'.
Lead author Dr John Hutton and colleagues asked their parents to report how much the children used screens. This was using the ScreenQ test, a 15-item questionnaire that took into account easy access, frequency of use and content viewed.
A low score reflects good adherence to screen recommendations by the American Association of Pediatrics (AAP). The AAP advises children aged between three and five spend no more than one hour a day looking at screens.
At the same time, the children also had MRI scans taken and took part in three standard tests that measured language, including their vocabulary, reading and speed of information retrieval skills.
Youngsters with a high ScreenQ score had lower brain white matter quality, which affects the formation of myelin.
Myelin is a fatty substance that covers the nerve fibers of white matter in the brain. It allows nerve impulses to quickly move in 'tracts', which send messages between the different parts of the brain. If myelin wastes away - normally due to disease - messages can't pass through as quickly.
The tracts implicated in the children's brains also involved executive function, which is involved in self-control. Dr Hutton and colleagues did not specify how many hours of screen-time a day was linked to the changes.
Cognitive test results appeared to support the findings - those with high screen use also performed lower on the cognitive tests. They had 'significantly' lower expressive language, defined as how a person expresses their thoughts and feelings.
They had a lower ability to rapidly name objects, known as processing speed, and weaker emergent literacy skills, which is a child's knowledge of reading and writing before they learn how to read and write words.
Dr Hutton said six in ten of the children studied had their own smartphone or tablet, and four in ten had a television or portable device in their bedroom.
He said: '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.
'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.
"These findings highlight the need to understand effects of screen time on the brain, particularly during stages of dynamic brain development in early childhood."
Last year another US study found children who spent the most time on screens had around a five per cent lower cognitive function than other eight to 11-year-olds. (Tasnim News Agency)
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