Neurological Effects of Childhood Sleep Apnea

Children with severe Obstructive Sleep Apnea (OSA) have lower IQs, decreased problem solving skills, and changes in neuronal metabolites of the brain, similar to those seen in diseases in which there is damage to brain cells. The study, published in the international open-access medical journal PLoS Medicine, by Ann Halbower and colleagues from Johns Hopkins University School of Medicine looked at 19 children aged 6-16 y with OSA and compared them with 12 healthy controls. The children underwent sleep tests, a battery of neuropsychological assessments, including IQ tests, and tests of executive function, and a group of children were assessed by magnetic resonance spectroscopy, a special form of brain imaging.

Children with OSA had significantly lower scores than matched controls on full scale IQ tests and significantly lower performance on measures of executive function, including verbal working memory (sentence span) and word fluency. The special brain imaging (proton magnetic resonance spectroscopic imaging) showed decreases in the mean neuronal metabolite ratio of N-acetyl aspartate/choline in the left hippocampus and right frontal cortex, indicating possible neuronal injury in these areas.

Symptomatic childhood sleep-disordered breathing includes a range of conditions in which children have difficulties with breathing when they are asleep. The conditions range from simple snoring to the most severe condition, obstructive sleep apnea (OSA). In children, OSA may be associated with enlarged tonsils, long-term allergy, or obesity. About two in every hundred children have OSA. The symptoms of OSA are loud snoring at night, disrupted, restless sleep, undue tiredness, and difficulties in concentration. If untreated, researchers believe that it may lead to a number of long-term problems with health and learning. Children with disorders of sleep have previously been shown to have memory problems, lower general intelligence, and worse executive function (the ability to adapt to new situations), and may have behavioral problems similar to those of attention deficit hyperactivity disorder.

Previous work has shown that adults with sleep apnea have abnormalities of parts of their brain, specifically the frontal cortex, cerebellum, and hippocampus, but this is the first study to investigate similar changes in children. The authors speculate that untreated childhood OSA could permanently alter a developing child's cognitive potential, but that the changes in metabolites are not necessarily permanent—in other diseases where changes have been found they can be reversed with treatment.

If these results are confirmed in other children with OSA, and if these results are reversible with treatment, it will highlight the importance of treating children for OSA as soon as possible. In addition, the measurement of metabolites may be a way of measuring how well children are responding to treatment.