REM sleep and sleep apnea are associated with language function in Down syndrome children: An analysis of a community sample

Background: The prevalence rate of obstructive sleep apnea (OSA) in the community Down syndrome (DS) children is not clear. Moreover, the impact of OSA and sleep structure on the cognitive function is inconclusive. The present study aimed to investigate 1) the prevalence rate of OSA in the community DS children and 2) the impact of OSA and sleep structure on cognitive performance. Methods: Thirty DS children aged 6–18 years were recruited and evaluated with the performance of the language domain and sensorimotor domain, combining neuropsychological tests and parent-rated behavior. The outcomes were the age-adjusted scores, of which the lower the score was, the better was the patient's ability. The association of score with OSA and sleep structures was determined by linear regression. To diminish the age-related difference, all analyses were conducted separately for all subjects and 6–12-year-old subjects. Results: The median age was 11.3 years and median Full-Scale Intelligence Quotient (FSIQ) was 44. The prevalence of OSA (apnea–hypopnea index ≥ 1/h) was 80% and 62.5% in all subjects and 6–12-year-old subjects, respectively. For 6–12-year-old subjects, after adjustment for age and FSIQ, both %REM and OSA were associated with lower score of the subtest of language domain, WPPSI-R Vocabulary, while %REM was also associated with lower score of VABS-II Communication – Expressive. In contrary, % slow wave sleep was not associated with any subtest. Conclusion: This study identified that OSA may be highly prevalent in community DS children. Among 6–12-year-old DS children, OSA and % REM were associated with their language function. Keywords: Down syndrome, Neuropsychological tests, Polysomnography, Sleep apnea, Slow wave sleep