Just an hour of screen time per day can lead to unusual sensory problems in toddlers, study warns

Giving a toddler an iPad for as little as an hour a day can impair their ability to make sense of the world around them, a new study suggests.

Researchers at Drexel University in Philadelphia found that any amount of screen time starting at a year old was linked with a two-fold increased risk of unusual sensory behaviors, such as an inability to respond to their name being called.

Each additional hour of screen time doubled the risks of later sensory behavior issues compared to children not exposed to digital media.

Children with a sensory processing disorder, which often goes hand-in-hand with ADHD and autism spectrum disorder (ASD), may be extremely sensitive to lights and loud noises, or they may seek out additional stimulation in other ways.

Their findings add abnormal sensory processing to the laundry list of potentially severe effects of spending too much time glued to screens, including language delays, poor cognitive functioning, and the development of autism.

Any amount of time watching TV and movies starting at a year old was linked with a two-fold increased chance of unusual sensory behaviors, such as an inability to respond to their name being called at 33 months

Despite the known harms of excess time spent in front of the TV, iPad, and other electronic devices, children are locked on screens more than ever. 

As of 2014, American children aged two and under averaged more than three hours a day of screen time, up from one hour 19 minutes a day in 1997.

The Drexel University doctors analyzed data on nearly 1,500 children taken between 2011 and 2014. Parents were asked about their children’s levels of exposure to TV and movies at the ages of 12 months, 18 months, and 24 months.

Around 11 percent of parents said their child did not watch TV or DVDs at 18 months of age. 

Around 48 percent of them said their children watched about half an hour of media per day, 18 percent said their children watched for two hours per day, and eight percent reported their children watched three to five hours per day.

At 12 months, any exposure to screens was linked to a 105 percent greater likelihood of exhibiting ‘high’ sensory behaviors related to failure to respond appropriately to stimuli in their environment at 33 months compared to children who did not get any screen time.

By 18 months, each additional hour of daily screen time increased the odds of showing ‘high’ sensory behaviors related to sensation avoidance and low registration of external stimuli such as their name being called by 23 percent.

At 24 months, each additional hour of screen time was associated with a 20 percent increased likelihood of ‘high’ odds of sensation seeking, sensory sensitivity, and sensation avoiding at 33 months.

Dr Karen Heffler, lead author and an associate professor of Psychiatry in Drexel’s College of Medicine, said: ‘Considering this link between high screen time and a growing list of developmental and behavioral problems, it may be beneficial for toddlers exhibiting these symptoms to undergo a period of screen time reduction, along with sensory processing practices delivered by occupational therapists.’

Sensation seeking can look like staring at bright lights, watching ceiling fans spin, twirling in place, chewing or constantly touching objects, and listening to loud noises.

Sensation avoiding, meanwhile, sees a child actively trying to escape overstimulation in the form of loud sounds and bright lights or unpleasant tastes or smells.   

The study did not find a direct cause-and-effect relationship between sensory disorders and excess screen time in early life.

Still, the findings suggest that the latter might intensify the connections between areas of the brain responsible for processing sense stimuli, such as smells and sounds, that are commonly seen in people with ASD.

The researchers said: ‘To the extent that high screen time may increase risk for ASD symptoms, the current findings raise the possibility that screen time may do so by impacting sensory development.’

Their study focused specifically on TV and DVD viewing and not the use of ubiquitous tablets and smartphones. But despite the slight technological differences between a TV screen and that of an iPad, the effects are likely the same, if not very similar.

It was published in the journal JAMA Pediatrics.