0550 In-sleep Mandibular Behaviour Changes In Patients Undergoing Oral Appliance Therapy Titration

Abstract

Introduction: The mandibular movements (MM) derived indices are reliable markers of respiratory effort (RE) during sleep disordered breathing. We aim at measuring the effectiveness of mandibular advancement device (MAD) therapy by examining MM hourly indices (MM-RDI), in comparison to the apnea-hypopnea (AHI), the oxygen desaturating hypopnea (HDI) and the oxygen desaturation (ODI) hourly indices. Method(s): OSA patients were initially diagnosed by conventional PSG, then treated with a custom MAD (Herbst appliance) for averagely 58 weeks before assessed again by Type-3 PSG during titration when snoring was reported disappearing. Both polygraphs were equipped with a magnetometer to capture vertical MM (Brizzy, Nomics-BE). The scoring was manually performed following AASM 2012 rules. MM-based events were scored blindly with the others indices. Total sleep time (TST) was provided by MM analysis. MAD effect on the outcomes was evaluated using Bayesian multilevel models. Result(s): a group of 43 OSA consecutive patients (median age =48.2 yrs) showed at baseline, HDI, AHI, ODI and MMRDI median values of 5.3, 9.5, 7.6 and 6.7 respectively. Median MM-RDI duration was 38% of TST. After being adjusted for TST and random individual variances, the models indicated significant improvements in all outcomes: The median reduction rates were -54%, -53%, -68.4% and -82% for HDI, AHI, ODI and MM-RDI, respectively. MM-RD duration was also reduced by 34% compared to baseline. Bayesian inference showed that the plausibility of MAD effects was largest for MM-RDI (Bayes-factor >100 at -50% threshold). Those effects were independent of MAD elastics wearing and appliance use duration. Conclusion(s): Our findings suggest that stabilization of the vertical respiratory mandibular movements as measured by MM-RDI and sleep respiratory effort duration accompanied the decrease in HDI, AHI and ODI when achieving snoring disappearance in OSA patients treated with MAD.