Many kids with tics can suppress them, and learning how they do it could lead to ways to help prevent major tic disorders such as Tourette syndrome, researchers say.
At least 20% of elementary school-age children develop tics, such as excessive blinking, throat clearing or sniffing, but they don't become a long-term problem.
More common in boys
It was believed that most tics go away on their own and only in rare cases become chronic or develop into Tourette syndrome, a neurological disorder marked by involuntary repetitive movements and vocalizations.
But this new study found that in many children, tics don't go away completely. Instead, they learn to suppress them when others are watching.
The study included 45 children, ages five to 10, who had recently started experiencing some sort of tic. Thirty were boys, in whom tics are more common. All were examined within a few months after their tics first appeared, and again 12 months after the tics began.
"Our expectation, initially, was that maybe one in 10 kids would still have tics at their follow-up exams," said first author Soyoung Kim, postdoctoral research associate at Washington University School of Medicine in St. Louis. "Most had improved a year later, but to our surprise, in every case the children still had tics – many of them just controlled them better."
To verify the presence of tics, each child was left alone in a room monitored with a video camera. Most could suppress their tics during exams, but all exhibited tics when left alone.
Higher autism scores
"I find tics fascinating because they illustrate the interplay between what is volitional and what is involuntary," principal investigator Dr Kevin Black said in a university news release. "People don't tic on purpose, and most can suppress it for a short period of time, but at some point, it's going to come out."
Black is a professor of psychiatry at Washington University.
"Uncovering just how they are able to control these tics may help other children do the same and perhaps avoid chronic tic disorders such as Tourette syndrome," he said.
A history of anxiety disorders, pronounced tics during the initial exam, and having three or more vocal tics – such as throat clearing or making other noises – indicated a likelihood of tics at the one-year follow-up. Kids with higher scores on an autism screening test were also likely to have continued tics, researchers found. None of the study participants had autism.
About 3% of people have chronic tic disorders, Black said.
The findings were published online in the Journal of Child Neurology.
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