Is a Good Night's Sleep Enough

Sleepiness linked to hyperactivity plus learning difficulties and misbehavior

(RxWiki News) If your child is acting up at school or struggling to focus or learn, it may not necessarily be a psychiatric condition or learning disability. They might just be really, really sleepy.

A recent study found that the approximately 15 percent of children who suffer from excessive daytime sleepiness are more likely to experience learning difficulties, to have attention or hyperactivity issues, or to misbehave.

"See a sleep specialist if your child is excessively sleepy during the day."

Susan Calhoun, PhD, an associate professor of psychiatry in the Sleep Research and Treatment Center at Penn State College of Medicine, and her colleagues conducted a study of 508 children, aged 6 to 12, from a group called The Penn State Child Cohort.

Each child underwent a 2.5-hour neurocognitive assessment and then went through a 9-hour sleep study to see if they had any sleeping issues. The tests measured the student's thinking speed, intelligence, attention skills, memory and visual-motor skills.

The researchers also questioned the parents about their children's behavior and learning and attention abilities. Then the children were divided into two groups according to whether their parents reported that their child had excessive daytime sleepiness or not.

A child was identified as having excessive daytime sleepiness if his or her parent answered yes to either "Does your child have a problem with sleepiness during the day?" or "Has a teacher or other supervisor commented that your child appears sleepy during the day?"

Approximately a third of the children were identified as being excessively sleepy during the day based on observations of both the parent and a teacher. The number identified as sleepy by parents only was 42 percent and, by teachers only, 26 percent.

They found that children whose parents reported had excessive daytime sleepiness were more likely to misbehave, have trouble learning or be hyperactive - even when controlling for the amount of sleep the children got.

The largest association was with learning problems: kids with excessive sleepiness were seven times more likely to have learning difficulties.

However, the reasons for the daytime sleepiness did not include the expected usual suspects of sleep apnea or simply not getting enough sleep - the aspects that William Kohler, MD, the director of the Florida Sleep Institute in Spring Hill, Florida, found most intriguing about the study.

Because the study authors defined obstructive sleep apnea as stopping breathing for at least five seconds - instead of the ten seconds more typically used in the definition - Dr. Kohler said he would have expected that the researchers would have found more sleep apnea. But that wasn't the case.

"The fact that in this particular study, they did not show any correlation between the excessive daytime sleepiness and the obstructive sleep apnea was interesting," Dr. Kohler said. "But it's a good article, one of the many showing the significance of abnormal functioning related with sleep or sleep aspects."

Although Dr. Kohler said it was valuable for providing more evidence of the way problems with sleepiness or sleep can contribute to poor cognitive function, poor functioning during the day, poor emotional functioning and similar issues, it did not discuss treatment or go into much detail on possible causes of excessive daytime sleepiness.

"Unfortunately, it didn't point out potential treatment mechanisms, which would get back to whatever the cause of the excessive daytime sleepiness was," Dr. Kohler said.

The researchers did note that the problems with feeling sleepy appeared rooted in obesity, depression, anxiety, asthma and an inability to fall asleep. But the article does not go into detail on these.

The researchers did find that the fast thinking abilities and a good memory lessened the impact that daytime sleepiness had on a child's learning or attention and hyperactivity problems.

According to Calhoun, the researchers were surprised that the children showing the difficulties in school or with paying attention were not showing symptoms of getting insufficient sleep. In fact, insufficient sleep in this study was not associated with the behavior and learning problems observed.

The article appeared in the May issue of the journal Sleep. The research was funded by the National Institutes of Health. The authors declared no financial conflicts of interest.

Review Date: 
May 1, 2012