Snoring and Brain Function
A new study led by researchers at Cincinnati Children’s opens the door to understanding the complex relationship between sleep, breathing and brain regional cerebral oxygenation in a whole new way.
About two-thirds of children with sleep-disordered breathing (SDB) — snoring or obstructive sleep apnea (OSA) — have some degree of cognitive deficit, but the severity of the cognitive deficit has been notoriously difficult to correlate to the severity of the SDB. This suggests that other issues may be at play, or that the right factors were simply not being measured.
In the study, principal investigator Raouf Amin, MD, and colleagues measured a new parameter to determine whether it could explain the variability in cognitive dysfunction: the degree to which the brain's blood remains oxygenated during sleep. Using a technology called near infrared spectroscopy, they measured the "regional cerebral oxygen concentration" (SrO2) in children 7 to 13 years old with SDB to varying degrees. They also measured blood pressure (BP) during sleep.
As expected, the researchers found that children with snoring had lower regional cerebral oxygen concentration than healthy children. They also found, though, that children with sleep apnea have higher regional cerebral oxygen concentration than children with just snoring.
"During normal sleep, when breathing appears to be stable, there seems to be higher oxygen in the brain among children with sleep apnea compared even to normal children," said Dr. Amin, director of the Division of Pulmonary Medicine at Cincinnati Children's. "Children with sleep apnea have higher BP compared to children with snoring. This may explain why paradoxically we find higher oxygen levels in children with OSA."
The study opens up new avenues of inquiry for investigating the link between SDB and cognitive deficits in children. Understanding the source of that association will be key in future efforts to treat or prevent it.
"By taking into account the role of blood pressure in regulating the amount of oxygen concentration in the brain, we might have a better understanding of the relationship between sleep-disordered breathing and cognitive deficit," concludes Dr. Amin.
