Sleep disorders are not the sole domain of adults. Children get them, too.

No magic number of hours guarantees a child is getting enough sleep. The best clue is to "look and see how a child responds to the amount of sleep he's getting," says Dr. Dominic Gault, medical director of pediatric sleep medicine at Primary Children's Medical Center.

When they don't get enough sleep, youngsters' behavior may mimic attention deficit hyperactivity disorder. They don't function well at school. Sometimes it shows up as impulsivity or behavior problems. Or plain orneriness and tantrums.

If sleep deprivation happens long-term, heart, lungs and blood pressure may suffer, sleep experts warn, although children who are otherwise healthy are unlikely to suffer those effects.

Children are subject to many of the same sleep problems as adults, he says. And they can face behavioral disorders not seen in adults, such as limit-setting sleep disorder and sleep-onset association disorders. Those are the most common, experienced by otherwise healthy children, and they're "relatively easy to fix."

Remember the debate about whether babies should cry themselves to sleep? You're there. That baby has not yet developed the ability to soothe itself to sleep.

If the behaviors are not changed — something most parents accomplish without intervention — they can extend into early school years and it may require professional help.

In the limit-setting area, parents are not creating an environment that fosters sleep.

Both children and adults have to learn the skill of falling asleep, just as they learn to walk and talk.

People cite night terrors and other "confusional arousings" like sleepwalking as sleep disorders. They're not. Children stay asleep during those events. The parent's job is not to wake the child up, but to make sure that the environment is safe and let her be. Interfering prolongs it.

Children who have sleep apnea may be overweight, have enlarged tonsils, cranial structure problems or neuro- muscular conditions that weaken muscles. If the cause is structural, surgery is needed. Children tolerate the CPAP (Continuous Positive Airway Pressure) mask well, Gault says. Still, it's hard to explain to a 4-year-old that wearing the unfamiliar mask will make him feel better.

Some youngsters become insomniacs, triggered by various events and stressors. The start of the school year is a big one. "Like adults, kids can learn to be bad sleepers and behavioral insomnias result," Gault says.

Medication can play an important role in treatment, he says, but getting to the root cause is more likely going to cure it.