0540 Comparing Periodic Limb Movements of Sleep Before and After Hypoglossal Nerve Stimulation Therapy

Abstract Introduction Patients with obstructive sleep apnea (OSA) exhibit high prevalence of periodic limb movements of sleep (PLMS). While many studies have explored the impact of positive air pressure (PAP) therapy on PLMS, there was no study of the impact of hypoglossal nerve stimulation (HNS) therapy on PLMS. We reported high prevalence of PLMS in patients receiving HNS therapy (separate abstract). We hypothesized the following: 1) OSA patients with PLMS become candidates for HNS therapy at a higher rate given PAP failure associated with PLMS; 2) HNS therapy itself increases PLMS. This study aims to test the above hypotheses by assessing pre- and post-HNS sleep study data and comparing PLMS in temporal fashion. Methods Among subjects receiving HNS therapy from December 2020 to August 2023, 38 subjects with periodic limb movement index (PLMI) data before and after HNS therapy were selected for the subgroup analysis. PLMS diagnosis was based on PLMI ≥ 15. We compared PLMI and PLMS diagnosis between before and after HNS therapy using Wilcoxon's signed rank test and McNemar test. Results In our study of 38 subjects, the average of PLMI before and after HNS therapy were median 7.1/hr (interquartile range, 0, 34.6) and 17.2/hr (interquartile range, 3.1, 37.5) respectively, resulting in no statistical significance (P=0.064 by Wilcoxon's signed rank test). Prevalence of PLMS before and after HNS therapy were 36.8% and 60.5% respectively showing significant increase with HNS therapy (P=0.039 by McNemar test). Conclusion Our study results indicate comparable baseline prevalence of PLMS as shown in other studies among OSA and significant increase in PLMS while using HNS therapy in this paired pre- and post-HNS analysis, suggesting HNS therapy being a possible cause of PLMS in OSA patients. Further work is warranted to re-confirm the above finding and potentially investigate long-term effect of HNS therapy on PLMS, and PLMS on the outcome of HNS therapy. Support (if any)