Parents may have new reason to be concerned if their child snores. A study by Johns Hopkins researchers has found that children with sleep apnea appear to suffer damage in two brain structures tied to learning ability. Writing in the Public Library of Science Medicine, the Hopkins investigators say they compared children with severe obstructive sleep apnea (OSA) to others without the disorder using a special type of MRI. The MRI scans revealed physical changes to both the hippocampus and the right frontal cortex of the brain. The hippocampus, a structure in the temporal lobe, is vital to learning and memory storage, while the right frontal cortex governs higher-level thinking, such as accessing old memories and using them in new situations.
Additionally, using IQ tests and other standardized performance tests that measure verbal performance, memory and executive function, the researchers were able to link the changes in the two brain structures to poor neuropsychological performance.
"This should be a wake-up call to both parents and doctors that undiagnosed or untreated sleep apnea might hurt children's brains," says lead researcher Ann Halbower. "This is truly concerning because we saw changes that suggest brain injury in areas of the brain that house critical cognitive functions, such as attention, learning and working memory."
Fragmented sleep, interrupted breathing and oxygen deprivation have been known to harm children's learning ability and school performance for some time, but this is the first time researchers have linked changes in the brain's chemistry to sleep apnea. "We cannot say with absolute certainty that sleep apnea caused the injury, but what we found is a very strong association between changes in the neurons of the hippocampus and the right frontal cortex and IQ and other cognitive functions in which children with OSA score poorly," Halbower said.
Obstructive sleep apnea affects 2 percent of children in the United States, but it is unclear how many of these suffer from severe apnea. Halbower estimates that up to 17 percent of sleep apnea patients seen at the Children Center's sleep clinic have the severe form. Sleep apnea occurs because of partial or complete obstruction of the airways during sleep due to anatomic and/or neuromotor factors. In children, the leading cause of sleep apnea is enlarged tonsils and adenoids, and the first line of treatment is surgical removal.
Source: Johns Hopkins Medical Institutions
