Exploring Pharyngeal Swallow Biomechanical Events in Obstructive Sleep Apnea and Assessing Expiratory Muscle Strength Training Effects on These Events: A Pilot Investigation.

Purpose: This study quantified pharyngeal swallow biomechanical events in persons with obstructive sleep apnea (OSA) and compared values to healthy controls. We also assessed the impact of expiratory muscle strength training (EMST) on these biomechanical events. Method: This prospective single-arm, pre--post intervention design enrolled 10 participants (five men) with moderate-to-severe OSA (Mage = 65.2 years). Participants completed 4 weeks of EMST utilizing the EMST150 device (Aspire Products) via one in-person weekly visit and 4 days of telehealth. Pharyngeal biomechanical measures from the Analysis of Swallowing Physiology: Events, Kinematics and Timing methods derived from baseline and post-EMST videofluoroscopic swallowing studies were reported. Published normative data were used for comparison. Results: At baseline, 60% of the swallows across several biomechanical events were quantified as atypical, but no significant effect of the swallow task was observed (p values > .05). Following EMST, a significant intervention effect was observed only for upper esophageal sphincter opening duration (UESO; p = .012, d = 0.357) and maximum upper esophageal sphincter distention (UESMax; p = .025, d = 0.151). Four individuals were classified as treatment responders, demonstrating specific improvements in four pharyngeal biomechanical measures. Significant swallow task effects were observed for UESO and UESMax. Conclusions: Study findings revealed atypical biomechanical events of the pharyngeal swallow in individuals with moderate-to-severe OSA treated with continuous positive airway pressure. Results provide preliminary evidence suggesting that EMST intervention improves upper esophageal sphincter function, with individual variability observed in the treatment response.