Children with OSA had lower mean IQ test scores (85) than children without OSA (101). Children with OSA also performed worse on standardized tests measuring executive functions, such as verbal working memory (8 versus 15) and word fluency (9.7 versus 12).
Using magnetic resonance spectroscopic 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 disease but indicate injury to brain cells. Next, researchers plan to study whether the ratios will return to normal once the sleep apnea is treated.
In both children and adults, untreated sleep apnea has been linked to cardiovascular problems and learning and memory deficits. However, the cognitive effects of untreated apnea might be far more damaging in children than in adults, researchers point out, because they occur during critical developmental periods. The frontal cortex matures throughout the teen years and continues well into the 30s, and researchers fear that childhood injury to this area might lead to long-term cognitive deficits.
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
'"/>
Contact: Katerina Pesheva
epheshev1@jhmi.edu
410-516-4996
Johns Hopkins Medical Institutions
21-Aug-2006