Does your child blink a lot? It may not be a vision problem.

If your child has what looks like nothing more than a nervous habit, you may want to take it more seriously. A new study shows that chronic tics are more common than once thought and they may be a red flag for a bigger problem.

Frankie Baliva loves playing video games.

His brother, Santino, would much rather play street hockey.

But the two have one thing in common, Tourette's syndrome, a disorder noted for its tics.

Both boys were diagnosed around age 6.

"In the beginning I would go into a store and they would be swearing at me and I'd have 50 people looking at me like 'why am I not doing anything,'" recalled their father, Chris Baliva.

Dr. Donna Palumbo explained that "the swearing tic is called coprolalia, so it really is a true tic."

The swearing tic is rare, but according to new research by Palumbo at the University of Rochester, NY, tics in general are grossly underdiagnosed.

"In our epidemiologic study we found rates of almost 19 percent of kids in a school-age population who had tics in a regular classroom setting," Palumbo said.

That's important for parents and teachers to know. Fifty percent of the time, kids with chronic tics also have attention deficit disorder (ADHD) or obsessive-compulsive disorder (OCD).

"All three of those things can significantly impact school functioning," Palumbo said.

Life hasn't been easy for the Balivas. The boys take medications to suppress their tics and treat the associating ADHD and OCD.

"I have found with my kids that it just wasn't medication, it was behavioral therapy also to cope," Baliva said. "Because there is no magic pill. With the doctors and the medications that they've had, I think that they're going to do ok."

Eye blinking and throat clearing are two of the more common tics. Others include nose twitching, head jerks, sniffing, humming, and shoulder shrugs. The swearing tic that involves the shouting of obscenities accounts for 5 percent of Tourette tics.

For more information on tics and Tourette's, check out Tourette Syndrome, American Academy of Child and Adolescent Psychiatry, National Institute of Neurological Disorders and Stroke and Tourette Syndrome Association.