Background: Children with obstructive sleep disordered breathing (OSDB) have both impaired cognitive performance and frequent movements during sleep. It is not known whether movements during sleep are related to cognitive function.
Methods: We studied 56 children with adenotonsillar hypertrophy suspected of having OSDB with actigraphy for six consecutive days and nights, followed by cognitive and performance tests. Attended polysomnography was performed on the seventh night.
Results: Slower reaction time correlated with both higher sum of all movements during Time in Bed (r(2)=0.19, p=0.001) and higher number of minutes with >5 movements/night (r(2)=0.23, p=0.0003). Low Vocabulary, Similarities and General Memory Index scores correlated with more consolidation of movements (consecutive minutes with >5 movements) (r(2)=0.16, p=0.002, r(2)=0.16, p=0.0026, respectively). Correlation with Vocabulary and Similarities scores improved when Time in Bed was added as an independently significant covariate (r(2)=0.25, p=0.0006, r(2)=0.27, p=0.00028, respectively). Actigraphy correlated with Vocabulary and Similarities scores as well as polysomnography. Other cognitive or behavioral scores were not correlated with actigraphy or polysomnography. Children with more consolidation of movements had higher values for log10(OAHI+1) (r(2)=0.38, p=0.000001).
Conclusions: (1) Frequency of movement during sleep correlated with impaired vigilance while consolidation of movements correlated with impaired verbal and memory skills. (2) OAHI was associated with more consolidation of movements.