Effects of upper-airway stimulation on sleep architecture in patients with obstructive sleep apnea

Purpose: Selective upper-airway stimulation (UAS) is a novel therapy for patients with obstructive sleep apnea (OSA). The aim of this study was to compare changes in sleep architecture during the diagnostic polysomnography and the post-implantation polysomnography in UAS in patients with OSA. Methods: Twenty-six patients who received a UAS device (Inspire Medical Systems) were included. Treatment outcome was evaluated 2 and 3 months after surgery. Data collection included demographics, body mass index (BMI), apnea hypopnea index (AHI), oxygen saturation and desaturation index (ODI), Epworth sleepiness score (ESS), arousal parameter, and sleep patterns. Results: The mean age was 60.2 years, 25 patients were male, 1 patient was female. Mean BMI was 29.0 kg/m². The mean pre-implantation AHI of 33.9/h could be reduced to 9.1/h at 2 months post-implantation (p < 0.001). The amount of time spent in N1-sleep could be reduced from 23.2% at baseline to 16.0% at month 3 post-implantation. The amount of time spent in N2- and N3-sleep did not change during the observation period. A significant increase of the amount of REM sleep at month 2 (15.7%) compared to baseline (9.5%; p = 0.010) could be observed. A reduction of the number of arousals and the arousal index could be observed. Conclusion: In conclusion, significant changes in sleep architecture of patients with OSA and sufficient treatment with UAS could be observed. A reduction of the amount of time spent in N1-sleep could be caused by treatment with UAS and the rebound of REM sleep, observed for the first time in a study on UAS, is also a potential marker of the efficacy of UAS on sleep architecture. Trial registration: NCT02293746.