0641 Impact of Hypoglossal Nerve Stimulation on N3 Sleep Percentage: A Pre- And Post-Implantation Analysis

Abstract Introduction Hypoglossal nerve stimulation (HNS) is an established therapy for moderate to severe obstructive sleep apnea (OSA) in patients who are intolerant to continuous positive airway pressure (CPAP). While HNS effectively maintains upper airway patency, its longitudinal effect on sleep architecture—specifically the percentage of time spent in slow-wave sleep (stage N3)—remains less understood. In this study, we investigated whether HNS implantation alters the proportion of N3 sleep by comparing pre-implantation and post-implantation polysomnographic data within the same cohort. Methods We analyzed data from 8 patients who underwent HNS implantation. Stage N3 sleep percentages were recorded for each patient at two time points: prior to implantation (Baseline) and following implantation (Treatment). Statistical analysis was performed using a paired two-sample t-test to compare the mean percentage of N3 sleep between the pre- and post-implant conditions. The level of significance was set at p < 0.05. Results The mean percentage of N3 sleep prior to implantation was 5.80% (Variance = 54.03), compared to 4.58% (Variance = 30.66) following implantation. Although there was a slight numerical decrease in N3 sleep percentage post-implant, this difference was not statistically significant (p = 0.47, two-tail). Conclusion In this cohort, hypoglossal nerve stimulation did not significantly alter the percentage of time spent in stage N3 sleep compared to pre-implantation baselines. These findings suggest that while HNS treats obstructive events, it may preserve the patient's existing sleep architecture regarding slow-wave sleep. Further research with a larger sample size is warranted to confirm these observations and explore long-term effects on sleep stages. This is an ongoing project. Support (if any)