BOSTON – Neuronal abnormalities in the brains of children with obstructive sleep apnea are reversible with treatment, a prospective study has shown.
The findings are the first to show that the altered brain metabolites of the frontal cortex – the neuronal network responsible for attention and executive function – normalize with treatment of pediatric obstructive sleep apnea, Dr. Ann C. Halbower reported at the annual meeting of the Associated Professional Sleep Societies.
Previous studies have demonstrated an association between obstructive sleep apnea (OSA) and deficits in attention, cognition, and executive function, "but ours is the first to look at the effect of [OSA] treatment on the neuronal brain injury and to show a relationship between treatment and improvements in attention and verbal memory in these patients," said Dr. Halbower of the Children’s Hospital Colorado Sleep Center and the University of Colorado at Denver.
The study included 28 children aged 8-11 years; 17 had moderate or severe OSA and 11 were healthy controls matched by age, sex, race, and socioeconomic status. At study baseline, all participants underwent neuropsychological testing, and 22 of the children (15 with OSA and 7 healthy controls) also underwent magnetic resonance spectroscopy imaging. Six months post treatment, 11 of the OSA patients underwent repeat brain imaging and neuropsychological testing, Dr. Halbower said. Treatment for OSA consisted of adenotonsillectomy followed by monitored continuous positive airway pressure (CPAP) for children whose apnea-hypopnea index (AHI) score was higher than 3, or nasal treatments for those with an AHI score of 2-3, she explained.
Among the OSA patients, the mean AHI score at baseline was 13.6, compared with 0.3 for the healthy controls – a discrepancy mirrored by differences observed in both the brain imaging and the function tests. Specifically, Dr. Halbower reported, "the N-acetyl aspartate to choline (NAA/Cho) ratios in the left hippocampus and left frontal cortex were significantly decreased in [OSA] patients, compared with healthy controls, and the [OSA] patients had significant decreases in the executive function of working memory, attention, and verbal memory."
After treatment, "the neuronal metabolites of the right and left frontal cortex normalized, and the hippocampal metabolites improved with a medium effect size," Dr. Halbower said. The follow-up neuropsychological testing showed significant improvements in verbal memory and attention, "which correlated with the normalization of the [NAA/Cho] ratios in the frontal lobes," she said. A further analysis of the data linked improvement on the AHI with a more complete reversal of the hippocampal abnormalities in children with mild OSA, she said, noting, however, that this finding "is very preliminary."
Based on the study results, "we speculate that early diagnosis and treatment of obstructive sleep apnea in children could have profound effects on the trajectory of their development," Dr. Halbower said. In particular, she suggested, earlier treatment may lead to a "more brisk improvement" in the hippocampus, which is the "relay station" for executive function, learning, and memory.
Dr. Halbower said she had no relevant financial disclosures.