What is the research about?

Sleep disorders can have a negative effect on people’s ability to think and learn. They also influence their mood and temperament, and can impair their immune function. Past research has shown the children and adults with Down Syndrome (DS) have much higher than average rates of Obstructive Sleep Apnea Syndrome (OSAS), a condition in which people stop and start breathing multiple times per hour while asleep. However, little research has been done on the effects of OSAS on their thinking and learning abilities. This study addressed that issue.


What did the researchers do?

By advertising throughout their community in Tucson, Arizona, the researchers recruited 38 7-to 12-year-old children with DS, and their parents. Overnight testing measured body movement, blood oxygen levels, and brain wave activity. It also identified snoring and episodes where the person stops breathing intermittently (apnea). The children were given IQ tests and were rated on their ability to engage in everyday activities. They were also tested on behaviours and skills that can show how well certain regions of the brain are functioning. The researchers asked the parents to record their child’s restlessness and noisy breathing during sleep, as well as if the children had daytime sleepiness. After these tests were conducted, the researchers compared the findings of the group of children with DS who were found to have OSAS to those in the children with DS but without OSAS.


What did the researchers find?

The researchers reported on the 31 of 38 children recruited for the study that had useable sleep testing results. Of these 31 children, 19 had OSAS and 12 did not. Compared to the children without OSAS, the children with the condition had a slightly lower general IQ. However, their verbal IQ, which indicates the ability to use everyday language, was an average of 9 points lower than the non-OSAS group. This drop is enough to negatively affect their ability to communicate. The children with OSAS showed less ability to deal successfully with daily activities and to alter their thinking as needed. They also had less slow wave sleep, a stage which is important for processing new memories and remembering facts. Parental reports of restlessness or noisy breathing showed no relationship to the presence of OSAS or to its severity.


Take home message

Persons with Down Syndrome (DS) are known to have high rates of OSAS and other sleep disorders. This study showed that having OSAS and reduced slow wave sleep, negatively affected the children’s ability to learn, make decisions, judge situations, and use language. The exact ways in which sleep apnea and other sleep disorders affect thinking and learning ability are not yet fully understood. However, this study does suggest that early testing and treatment of these sleep disorders may prevent or lessen their negative effects.


Notes

The original Research Report was written by J. Breslin and associates and was published in Developmental Medicine & Child Neurology. 2014.