Association of sleep spindle activity and sleepiness in children with sleep-disordered breathing

Study Objectives: The association of snoring and sleep-disordered breathing (SDB) with daytime sleepiness is well documented; however, the exact mechanisms, and especially the role of sleep microstructure that may account for this association remain incompletely understood. In a cohort of children with SDB, we aimed to compare sleep spindle activity between children with daytime sleepiness versus those without daytime sleepiness. Methods: Children with SDB who reported daytime sleepiness were recruited and compared with age- and sex-matched SDB controls. Polysomnographic recordings were analyzed evaluating sleep spindle activity. A statistical comparison was carried out in both groups to assess the association between sleepiness and sleep spindle activity. Results: Thirty-three children with SDB (mean age: 7.5 ± 1.7 years) were included, 10 with and 23 without daytime sleepiness. Spindle activity was lower in children with daytime sleepiness compared with those without; in stage N2, median (interquartile range) sleep spindle indexes were 77.5 (37.3) and 116.9 (71.2) (P = .015), respectively. Conclusions: Spindles were significantly reduced in children with SDB and daytime sleepiness. The exact mechanisms of this association remain unknown and future research is needed in order to establish the exact role of sleep spindle activity on daytime symptoms in children with SDB.