The nightly trip to dreamland is a frustrating one for millions of American children suffering from insomnia, night awakenings and even sleep apnea, experts say.

"Across every study, 20 to 25 percent of children have some kind of sleep problem," said Jodi Mindell, associate director of the Sleep Center at Children's Hospital of Philadelphia. "That spans everything from kids who are waking during the night, to resisting bedtime, to sleepwalking, disordered breathing — the gamut," she said.

One 2004 National Sleep Foundation poll found that, among children under 11, 60 percent experienced some kind of sleep trouble at least a few nights a week, Mindell said. "And 74 percent of parents said they wanted to change something about their child's sleep," she added.

So, parents awakened in the night by a sleepless child have lots of company nationwide. One big culprit: sleep apnea, which occurs when blockages in the airway trigger snoring and frequent nighttime awakenings.

"About 2 to 3 percent of children will have sleep apnea," said Mindell, co-author of Take Charge of Your Child's Sleep. "About 10 to 12 percent of kids snore on a regular basis, but not all children who snore have sleep apnea. In children, the primary cause of obstructive sleep apnea is enlarged tonsils or adenoids."

OBESITY, APNEA LINKED

In most cases, tonsillectomy or adenoidectomy offers a quick fix for pediatric sleep apnea, Mindell said. But there's another contributing factor that's rising in prevalence — obesity. "In obese kids, what you're getting is the tonsils and adenoids being big, and then the weight on the neck closing the airways," she explained.

The daytime drowsiness that comes with sleep apnea can greatly affect a child's mood, daytime alertness and academics. One 2006 study in the journal Public Library of Science Medicine found that youngsters with sleep apnea scored lower on standard IQ tests compared with unaffected kids — an average of 85 points vs. 100, respectively.

Left untreated, sleep apnea might even permanently damage cognitive function, the researchers said. "We can only assume that it could turn an otherwise smart kid into a mediocre kid," said lead investigator Dr. Ann Halbower, of the John Hopkins University Children Center.

EASING INTO SLEEP

But there are other sleep woes affecting children, including insomnia, night terrors, and frequent awakenings and sleepwalking.

Many can be fixed with simple behavioral changes at home, Mindell said. Those steps include:

— Setting firm schedules. "Get them to bed the same time every night and wake them up the same time every morning," Mindell said. "This sets a child's internal clock and makes it so they'll get sleepy easier and fall asleep easier."

— Create a bedtime routine. Implementing a "wind-down" time before bed, perhaps 20 to 30 minutes each night, helps kids of all ages settle down and ready their minds and bodies for sleep, Mindell said.

— Ban electronics from the bedroom. According to polls, 97 percent of U.S. kids have some kind of electronic distraction — TV, cell phone, computer, Gameboy — in their rooms. "That has a major impact on sleep," Mindell said. "We want to get kid's bedrooms unplugged."

— Limit caffeine. This doesn't mean only coffee — it's iced tea, plus dark- and light-colored sodas. "For some kids it takes much longer to metabolize caffeine," Mindell said. "So, that ice tea at 3 o'clock in the afternoon can still be keeping them up at 10 p.m."

— Make sleep-time a solo affair. Kids who get used to a parent being with them as they drift off will need that parent every time they seek slumber. "So, if you're lying down with your 5-year-old at bedtime, be prepared to be lying down with him at 1 a.m.," Mindell warned. Allowing a child to fall asleep on his or her own eliminates that problem.

TEENAGE NIGHT OWLS

School boards have an important role to play, too, Mindell said.

"Many high schools are starting now at 7:15 in the morning, and that's completely against what is happening with teenagers' internal clocks," she explained. "Their clocks actually shift later (than adults) — that's just a simple biological function."

So, later school start times can make a big difference. According to Mindell, school districts that have made such a change "have seen huge, positive responses in their kids' grades."