Sleep spindle activity in children with obstructive sleep apnea as a marker of neurocognitive performance. A pilot study

Study objectives: To assess spindle activity as possible markers for neurocognitive consequences in children with mild obstructive sleep apnea. Methods: Children aged 6–11 years diagnosed with mild OSA (i.e., an apnea hypopnea index <5.0) were recruited and compared with age and gender-matched healthy controls. Polysomnographic recordings were analyzed for sleep microstructure and spindle activity. All children completed also an intelligence test battery (i.e., the Wechsler intelligence test for children, 4th version). Results: Nineteen children with OSA (13 boys, mean age 7.1 ± 1.4 y), and 14 controls (7 boys, mean age 8.1 ± 1.9 y) were included. Mean IQ was 110 ± 12 for the complete sample, in children with OSA 111 ± 13, and in controls 108 ± 12 (p = 0.602). Controls showed a higher spindle index in N2 stage than children with OSA: 143.0 ± 42.5 vs 89.5 ± 56.9, respectively (p = 0.003). Spindle index in NREM was strongly and significantly correlated with Verbal Comprehension Index (VCI), Working Memory Index (WMI), Processing Speed Index (PSI), and total IQ in children with OSA. Conclusions: Children with mild OSA demonstrate a different pattern of sleep spindle activity that seems to be linked with neurocognitive performance, especially concerning memory. Sleep spindle activity seems to be involved with mechanisms related with neurocognitive consequences in children with OSA.