Sleep Apnea in Children May Lead to Impaired Learning

-- Children with untreated sleep apnea perform significantly worse on IQ tests and may have some brain impairment that could hinder their ability to learn new tasks, according to new research from Johns Hopkins University.

The new study was published in the journal Public Library of Science Medicine.

"This is paving new ground, scary new ground," says Dr. Ronald D. Chervin, the director of the University of Michigan Sleep Disorders Center, who was not associated with the study.

"The fact that children with sleep apnea would score worse on neurocognitive testing than normal children is not new. The new part is actually showing evidence of neurochemical changes in the brain," adds Dr. Chervin.

Brain Changes Found with Sleep Apnea

Dr. Ann Halbower, medical director of the pediatric sleep disorders program at the Hopkins' Children's Center in Baltimore, and colleagues looked at 31 children between the ages of 6 and 16. Nineteen of the children studied had untreated severe sleep apnea, a condition associated with repeated nighttime awakenings and daytime grogginess.

Using a special type of magnetic resonance imaging (MRI), the researchers found that those children with sleep apnea had significant changes in two brain regions associated with higher mental function: the hippocampus and the right frontal cortex.

These brain regions are responsible for behavior and for encoding and retrieving memories.

They also determined that the children had altered ratios of three brain chemicals - N-acetyl aspartate, creatine, and choline - which are indicative of brain damage.

The kids with sleep apnea had lower mean IQ test scores than the healthy children (85 compared to 101) and performed significantly worse on standardized tests that measure executive functions such as verbal working memory and verbal fluency.

"Executive function is the ability to take an old memory and put it to use in a new situation," Dr. Halbower explains. "It's what makes smart people smart. The clinical implications are that doctors need to understand that sleep apnea is more of a problem than we thought it was. It's not just a disease of old people."

Because untreated sleep apnea appears to impair brain chemistry, its effects could be permanent, Dr. Halbower adds.

"We can only assume that it could turn an otherwise smart kid into a mediocre kid, which could mark him for life," she says.

Signs and Symptoms of Sleep Apnea

Because untreated sleep apnea may have even more severe effects in children than in adults, the sooner it is detected, the better, Dr. Halbower says.

So parents should be aware that one of the most important symptoms of sleep apnea is frequent pauses in breathing that result in arousal from sleep and stirrings in bed.

Other symptoms include snoring, labored or loud breathing, coughing, choking, gasping, excessive nighttime sweating, and, sometimes, bedwetting by children older than 6.

"If you're looking at an infant or young child, they may sleep in odd positions," Dr. Chervin says. "They may sleep with their rear end up in the air and their head tilted back, which is probably an effort to open their airway."

Periodic apnea is common in premature infants, but it generally resolves as the infant's brain and lungs develop and mature.

Daytime signs of sleep apnea include sleepiness, an inability to concentrate, and poor performance in school. "But it should be remembered that younger children with sleep apnea aren't just sleepy," Dr. Halbower points out. "They also show signs of hyperactivity and irritability."

Caution Suggested

While the prevalence of snoring in children is about 16 percent to 20 percent, the prevalence of true obstructive sleep apnea in children is only 2 percent to 3 percent, Dr. Halbower says.

But, like the adult version, children's sleep apnea is usually unrecognized, and it is often difficult for doctors to diagnose because its effects may not be evident during a typical examination.

However, Dr. Chervin cautions that the Hopkins study, because of the small number of children studied, should not be considered the last word on any possible link between sleep apnea and brain damage.

"I would describe it as preliminary news, because it opens up a whole area that needs further investigation," he says. "It'll be fascinating to see if the neurochemical changes that were present before treatment are still present after treatment."

Dr. Halbower's next study will try to determine whether sleep-apnea treatment can restore normal brain chemistry and cognitive function.

Always consult your child's physician for more information.

For more information on health and wellness, please visit health information modules on this Web site.

About Sleep Apnea in Children

Obstructive sleep apnea occurs when a child stops breathing during periods of sleep. The cessation of breathing usually occurs because of a blockage (obstruction) in the airway.

Tonsils and adenoids may grow to be large relative to the size of a child's airway (passages through the nose and mouth to the windpipe and lungs).

Inflamed and infected glands may grow to be larger than normal, thus causing more blockage. The enlarged tonsils and adenoids block the airway during sleep, for a period of time.

The tonsils and adenoids are made of lymph tissue and are located at the back and to the sides of the throat.

During episodes of blockage, the child may look as if he/she is trying to breath (the chest is moving up and down), but no air is being exchanged within the lungs.

Often these episodes conclude with a period of awakening and compensation for lack of breathing. Periods of blockage occur regularly throughout the night and result in a poor, interrupted sleep pattern.

Sometimes, the inability to circulate air and oxygen in and out of the lungs results in lowered blood oxygen levels. If this pattern continues, the lungs and heart may suffer permanent damage.

There are many muscles in the head and neck that help to keep the airway open. When a person (child or adult) falls asleep, muscle tone tends to decrease, thus allowing tissues to fold closer together. If the airway is partially closed (by enlarged glands) while awake, falling asleep may result in a completely closed passage.

Obesity may also cause obstructive sleep apnea. While a common cause in adults, obesity is a far less common reason for obstructive sleep apnea in children.

A rare cause of obstructive sleep apnea in children is a tumor or growth in the airway. Certain syndromes or birth defects, such as Down syndrome and Pierre-Robin syndrome, can also cause obstructive sleep apnea.

The treatment for obstructive sleep apnea is based on the cause.

Since enlarged tonsils and adenoids are the most common cause of airway blockage in children, the treatment is surgery and removal of the tonsils (tonsillectomy) and/or adenoids (adenoidectomy).

Your child's otolaryngologist will discuss the treatment options, risks, and benefits with you. This surgery requires general anesthesia. Depending on the health of the child, surgery may be performed on an outpatient basis.

If the cause of the disorder is obesity, less invasive treatments may be appropriate, including weight loss and wearing a special mask while sleeping to keep the airway open. This mask delivers continuous positive airway pressure (CPAP). The device itself may be clumsy, and it may be difficult to convince a child to wear such a mask. Surgery may be necessary.

Always consult your child's physician for more information.