Sleep spindle characteristics in overweight adolescents with obstructive sleep apnea syndrome

摘要

Sleep spindles may display a sleep protective function. Thus, their activity is also a stable marker of sleep disturbances. We investigated whether spindle activity could be altered in overweight (OW) adolescents with obstructive sleep apnea syndrome (OSAS), compared with OW controls and normal weight (NW) adolescents. We also evaluated spindle characteristics correlation with body mass index (BMI) and OSAS-related sleep parameters. Thirty OW adolescents and 15 NW adolescents (age 14-17 years; all males) underwent polysomnography. Sleep spindles were automatically detected during stage 2 non-rapid eye movement sleep. The spindle activity characteristics involved: number of spindles; mean spindle density; mean maximum spindle amplitude; mean spindle duration; and mean spindle frequency. All adolescents were divided into three groups (18 OW patients with OSAS, 12 OW controls and 15 NW controls). Number of spindles and spindle density were significantly higher, but maximum spindle amplitude and spindle frequency were significantly lower in OSAS patients, as compared in both OW controls and NW controls. In this group, significant correlations were also found between spindle characteristics and OSAS-related sleep parameters (apnea hypopnea index, min SaO(2) and total arousal index), but no significant correlations were found between spindles and BMI. The increased spindle number and spindle density in OW adolescents with OSAS might be the EEG responses to multiple brief occlusions or loads applied during inspiration in impaired sleep, an adaptive response to sleep fragmentation and hypoxia.