Young children who routinely snore appeared to have an elevated risk for learning deficits, including problems with attention, memory, and language, researchers reported here.

Verbal and nonverbal performance, assessed through Differential Abilities Scales (DAS) scoring, differed significantly across four groups (P=0.002), as did IQ (Global Conceptual Ability scores, P<0.001). Attention and executive functioning test scores also differed by sleep group, indicating differences in levels of engagement and problem solving, according to Leila Gozal, MD, of the University of Chicago, and colleagues.

Kids with moderate to severe obstructive sleep apnea, mostly caused by enlarged tonsils and adenoids, had the highest risk for these deficits in the study that examined learning outcomes among 1,359 public school children, ages 5 to 7 years, they said in a presentation at the American Thoracic Society annual meeting.

The study is one of the few to examine a community-representative sample of kids, Gozal explained.

“We recruited the children through flyers and advertisements because we wanted the sample to resemble the population,” she said.

While her group had hypothesized that severe snoring would be associated with the greatest cognitive deficits in the study sample, they said they were surprised to find deficits in children with less severe sleep disordered breathing, Gozal told MedPage Today.

“There seems to be a dose-response effect — the worse the sleep apnea is, the more children showed behavioral issues and issues with school performance,” she said. “But we also saw deficits in children who were only snoring, which suggests that young children don’t have to have severe obstructive sleep apnea to experience these issues.”

All children recruited for the study, including both snorers and non-snorers, underwent comprehensive sleep assessment which included sleep questionnaires and overnight polysomnography testing to measure apnea episodes (Apnea-Hypoxic Index [AHI] per hour TST).

Based on these findings, the children were categorized into four groups: non-snoring (AHI <1/hrTST), habitual snoring (AHI <1/hr/TST), habitual snoring and AHI >1 to <5/hrTST, and habitual snoring and AHI >5/hrTST.

The children also underwent cognitive testing, designed to measure intelligence, language development, attention, memory, and executive functioning.

“Children with higher AHI (>5/hrTST) were significantly more impaired than all three lower AHI groups, indicating a dose-response impact of sleep disordered breathing,” the researchers wrote. “In addition, both the severity of sleep fragmentation (i.e., respiratory arousal index), and hypoxemia (i.e., nadir SpO2) contributed to cognitive function variance.”

The researchers stated that the findings highlight the need for early intervention in young children with sleep disordered breathing and sleep apnea.

Gozal said the vast majority of young children with sleep disordered breathing and sleep apnea have enlarged tonsils and/or adenoids, which can be treated with medical management if the cause is allergies, or surgical removal.

“The message to parents is that they need to pay attention to their children’s sleep,” she said. “If they are seeing behavioral issues such as (new onset) bed-wetting or trouble in school, poor sleep quality may be a factor.”

Dean Schraufnagel, MD, at the University of Illinois College of Medicine at Chicago, said he was not surprised by the findings.

“We are learning so much about how the quality of our sleep affects just about every aspect of our health and our functioning, and it stands to reason that this would be the case for children as well as adults,” said Schraufnagel, who was not involved in the study.