At the age of 4, Woonsocket, R.I., preschooler Ryan Godin was labeled with attention deficit hyperactivity disorder. He displayed many of the classic symptoms--aggressive and disruptive in his preschool class, moody and irritable at home--his mother, Deanna Godin, said. But she was hesitant to put her son on Ritalin, a prescription drug used to help children with ADHD, as a licensed clinical social worker suggested.

When his symptoms continued through kindergarten, Godin took him to a second counselor, who asked if Ryan snored. He did, the mother replied, and the social worker suspected that Ryan, like thousands of other children, suffered from obstructive sleep apnea and suggested that he be taken to a medical expert.

Obstructive sleep apnea affects about 12 million adults and children in the United States. Normally, the brain puts breathing mechanisms on autopilot when a person sleeps, according to pediatric pulmonary specialist Gerald Loughlin, director of the Eudowood division of pediatric respiratory sciences at Johns Hopkins Children's Center in Baltimore. The soft muscles in the airway stiffen automatically when the sleeper breathes in. For unknown reasons, Loughlin said, when a person with obstructive sleep apnea has to breathe harder than usual to get air, the muscles and other soft tissues collapse and block the airway.

In adults, an obstruction can be caused by obesity, alcohol use or an oversized neck. In children under 10, the condition usually is caused by enlarged tonsils and adenoids, which makes breathing more difficult. The condition can cause a child to temporarily stop breathing while asleep. Enlarged tonsils by themselves do not always mean that apnea exists.

During an apnea episode, oxygen levels in the bloodstream may drop. The chest and abdomen work feverishly to get air flowing. After about 30 seconds, the brain is aroused in response to the drop in oxygen and messages the airway muscles to stiffen, the body changes position, an audible gasp occurs and normal breathing resumes.

While children with apnea may be in bed an adequate number of hours per night, the quality of sleep is poor, said pediatrician Judith Owens, director of the pediatric sleep disorders clinic at Hasbro Children's Hospital in Providence, R.I. "These children may appear hyperactive. After all, what does a tired 4-year-old look like?" Owens asked. "Think of a preschooler that has missed his nap."

There is little data on the effects of sleep apnea in children, according to Susan Redline, chief of the division of clinical epidemiology at Rainbow Babies and Children's Hospital in Cleveland. Redline and colleagues are studying the prevalance, causes and consequences of apnea in children under a grant from the National Heart, Lung and Blood Institute.

In the short term, apnea may stunt growth, affect attention span, school performance and aggressiveness, Redline said. In the long term, there can be marked increases in blood pressure as the brain loses oxygen over and over, night after night, with some children sustaining hypertension during daylight hours. Prolonged apnea and its obstructed breathing pattern and low oxygen levels also make it increasingly difficult for the heart to pump blood into the lungs. This puts the heart under stress and after an extended period could cause it to fail.

Redline's concern is that apnea left untreated for a number of years may alter upper airway development, since the blockage can lead to changes in the positions of airway structures. This may predispose the child to persistence of apnea later in life. In addition, learning and behavioral problems may not be easily reversible later, even if the apnea improves.

A study published last year in the journal Pediatrics looked at 297 first-grade children in New Orleans public schools who were ranked in the lowest 10 percent of their class. Fifty-four were diagnosed with apnea. Half of the 54 were treated and the others were not. For the first group, there was a significant increase in school performance in second grade. The untreated children showed no improvement.

Another study in the same journal suggested a relationship between behavioral problems and obstructive sleep apnea. In that research, Owens and her colleagues studied 152 children in Providence between the ages of 2 and 12 who had been diagnosed with that condition. The parents completed extensive sleep and behavioral questionnaires, while the children were interviewed by a pediatrician and a psychologist and given a physical exam.

The research found that apnea contributes significantly to sleep deprivation and to behavioral manifestations of daytime sleepiness. Children are more prone between the ages of 3 and 8, when tonsils and adenoids are most enlarged. From birth to age 5, tonsils and adenoids are growing. As children grow beyond age 8, their tonsils and adenoids shrink and the airway becomes larger.

Yet not every youngster who snores is affected. While 25 percent of children in this country snore, only about 3 percent, or about 2 million children, have sleep apnea, Redline said.

Awareness of apnea has increased among pediatricians in recent years, Loughlin said. However, it can be overlooked. Diagnosing and determining severity requires that the child spend the night in a sleep lab for a poly-somnography (sleep study) exam. While the child is sleeping, technicians monitor blood oxygen levels, heart rate, temperature, brain waves and the number of times breathing is obstructed. The study can cost as much as $1,500, and insurance coverage varies.

Treatment for obstructive sleep apnea is removal of the tonsils and adenoids. Although considered to be minor surgery, it can have significant complications such as hemorrhaging and adverse reactions to anesthesia, Loughlin said. Therefore, snoring without a diagnosis of obstructive sleep apnea is not an indication for surgery, said Carole Marcus, a pediatric pulmonary specialist who is medical director of the pediatric sleep laboratory at Johns Hopkins.

An ear, nose and throat specialist may recommend surgery to cure snoring alone, but the condition, often caused by allergies and colds, can many times be treated by other means, including the use of steroids and humidification to add moisture to the air in the home, Loughlin said. Both methods help to clear out secretions and reduce swelling in the nose.

A sleep study is also necessary before surgery to pinpoint the severity of the apnea. The child may require oxygen to overcome anesthesia after surgery, Loughlin said, and should be kept in the hospital overnight for observation.

Parents of children cured of sleep apnea say the changes are dramatic. Ryan had his tonsils and adenoids removed, and within weeks he was a different kid, Godin said. "He's able to control himself without flying off the handle. He's made friends, where he was an outcast before because of his temper."

Resources

For more information, contact:

* The American Sleep Apnea Association, 1424 K St. NW, Suite 302, Washington, DC 20005. Telephone: 202-293-3650.

* The American Academy of Sleep Medicine, 6301 Bandel Road, Suite 101, Rochester, MN 55901. Telephone: 507-287-6006.

* The National Heart, Lung and Blood Institute Information Center, P.O. Box 30105, Bethesda, MD 20824-0150. Telephone: 301-592-8573.