Sleep Apnea in Children Linked To Brain Damage

Utilizing magnetic resonance spectroscopic (MRS) imaging, investigators identified changes to the hippocampus and the right frontal cortex.

After that, using intelligence quotient (IQ) tests and other standardized performance tests that measure verbal performance, memory, and executive function, researchers were able to link the changes in the two brain structures to deficits in neuropsychologic performance.

The hippocampus, a structure situated in the temporal lobe, is essential for learning and memory storage, whereas the right frontal cortex controls higher-level thinking, such as retrieving old memories and using them in new situations. While researchers have known for years that fragmented sleep, interrupted breathing, and oxygen deprivation--all symptoms of sleep apnea--damage children's learning ability and school performance, this is the first time they have linked changes in the brain's chemistry to the syndrome in children, Dr. Halbower believes.

Children with OSA had lower mean IQ test scores (85) than children without OSA (101). Using MRS imaging, which plots peak levels of brain chemicals in the form of graphs, researchers compared the ratios between each two of three chemicals--N-acetyl aspartate (NAA), creatine, and choline--in children with apnea and in those without. The hippocampus and the right frontal cortex of children with sleep apnea showed altered ratios of these neurochemicals that are not specific to any one disorder but indicate injury to brain cells.

In both children and adults, untreated sleep apnea has been tied to cardiovascular problems and learning and memory deficits. However, the cognitive effects of untreated apnea might be much more damaging in children than in adults, researchers stressed, because they occur during crucial developmental periods. The frontal cortex matures throughout the teenage years and continues well into the 30s, and researchers are concerned that childhood injury to this region might lead to long-term cognitive deficits.

Obstructive sleep apnea affects 2% of children in the United States, but it is not clear how many of these suffer from severe apnea. Dr. Halbower estimated that up to 17% of sleep apnea patients seen at the Children Center's sleep clinic have the severe form.

In children, the leading cause of sleep apnea is enlarged tonsils and adenoids, and the first line of treatment is surgical removal. Another treatment is wearing a special mask at night to ensure smooth airflow and uninterrupted breathing during sleep.



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