There are television shows created just for toddlers, so it's understandable if parents put their little one in front of a television screen for an episode or two of educational programs or cartoons.

Many toddlers spend as much as two hours a day watching their screens by the time they turn three-years-old.

A new study from Philadelphia's Drexel's College of Medicine may have parents reconsidering their child's TV time.

One child might become captivated by dumping and rummaging through toy bins, aimlessly chewing on objects; another might need additional sensory stimulation to pay attention.

Kids who are most frequently exposed to television or DVD viewing by their second birthday are more likely to develop what are called sensory processing behaviors, the researchers found.

What are sensory processing behaviors? These are inappropriate responses to sensory inputs. They can be behavioral and emotional and may interfere with the child's functioning. The most common are:

  • Sensory seeking: This means the child is highly interested in movement, lights, colors, sounds, smells and tastes. They might be captivated by dumping and rummaging through toy bins, aimlessly chewing on objects or clothing, rubbing against walls or furniture and bumping into people. They might also love to spin in circles and are constantly on the move.
  • Sensation avoiding: This means the child avoids or is overwhelmed by certain sensory input such as certain textures, sounds or smells and becomes agitated in certain environments.
  • Low registration: This means the child may have a tough time registering sensory information and needs additional sensory input to pay attention.

In order to understand the connection between toddler screen time and sensory issues, the Drexel researchers collected data on TV or DVD viewing from the National Children's Study on nearly 1,500 babies and toddlers. Half of the toddler participants were male, half were female.

At 12 months their parents or caregivers were asked “Does your child watch TV and/or DVDs?” (yes or no). Between 18 and 24 months, they were asked, “Over the past 30 days, on average, how many hours per day did your child watch TV and/or DVDs?” By the time the toddlers reached 33 months, their parent/caregivers completed a questionnaire called the Infant/Toddler Sensory Profile (ITSP).

At 12 months, any screen exposure compared to no screen viewing was associated with a 105 percent greater likelihood of exhibiting “high” sensory behaviors instead of “typical” sensory behaviors.

The ITSP questions are designed to give insights into how kids process what they see, hear, smell, taste and touch. For example, it looked at how upset or irritated a toddler is by lights and noise, or how they try to avoid or control their environment such as resisting teeth brushing, among other issues.

Depending on how the children reacted to sensory-related experiences, they were scored either “typical,” “high,” or “low.” Scores were considered “typical” if they were within one standard deviation from the average norm on the ITSP.

Here's what the researchers discovered:

  • At 12 months, any screen exposure compared to no screen viewing was associated with a 105 percent greater likelihood of exhibiting “high” sensory behaviors instead of “typical” sensory behaviors.
  • At 18 months, each additional hour of daily screen time was associated with 23 percent increased odds of exhibiting “high” sensory behaviors
  • At 24 months, each additional hour of daily screen time was associated with 20 percent increased odds of “high” sensation seeking, sensory sensitivity and sensation avoiding.

What do these findings mean for a child's development? “Repetitive behaviors, such as [those] seen in autism spectrum disorders, [are] highly correlated with atypical sensory processing,” Karen Heffler, an associate professor of Psychiatry in Drexel's College of Medicine, said in a press release.

“Future work may determine whether early life screen time could fuel the sensory brain hyperconnectivity seen in autism spectrum disorders, such as heightened brain responses to sensory stimulation,” she added.

Based on her study's findings, Heffler offers this advice to parents of toddlers: “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.”

If you feel your toddler is exhibiting behaviors suggesting sensory sensitivity, speak with your pediatrician and start to find ways to reduce his or her screen time.

The study is published in JAMA Pediatrics