Respiration-Triggered Olfactory Stimulation Reduces Obstructive Sleep Apnea Symptoms Severity – A Prospective Pilot Study

Abstract

ABSTRACTStudy ObjectivesObstructive sleep apnea (OSA) is a prevalent sleep-disordered breathing condition characterized by repetitive cessations in breathing during sleep. Current standard of care for OSA management is continuous positive air pressure (CPAP) devices, which often suffer from low tolerance due to limited adherence. Capitalizing on the unique neurocircuitry of the olfactory system and its retained function during sleep, we set out to test the feasibility of transient, respiration-based olfactory stimulation as a treatment for OSA symptoms.MethodsThirty-two OSA patients (AHI ≥ 15 events/hour) were recruited and underwent two polysomnography sessions, ‘Odor’ and ‘Control’, counterbalanced for order. In ‘Odor’ night, patients were presented with transient olfactory stimulation delivered via a computer-controlled olfactometer. The olfactometer, equipped with a wireless monitoring unit, analyzed respiratory patterns and presented stimulation upon detection of respiratory events. No odor was presented ‘Control’ nights.ResultsOlfactory stimulation reduced AHI (Apnea-Hypopnea Index) (n = 17, 49.2±10.2 years, range: 30–66; p = 0.02, BF10= 115.85), reflecting an average decrease of 31.3% in the number of events. Post hoc planned comparisons revealed a reduction in HI (Hypopnea Index) (p = 0.02, BF10= 2.39), but not AI (Apnea Index) (p = 0.26, BF10= 1.56). This effect was not linked to baseline symptoms severity (ρ = −0.042, p = 0.87) and did not vary across odorants (F(4,64) = 0.56, p = 0.67). Finally, olfactory stimulation did not affect sleep structure (all p > 0.44, all BF01 > 2.9).ConclusionsOlfactory stimulation during sleep was effective in reducing OSA symptoms severity and may provide a novel treatment modality, therefore prompting continued research on this front.