Effects of Expiratory Muscle Strength Training on Oropharyngeal Swallow Physiology in Persons with Obstructive Sleep Apnea (OSA): A Preliminary Study.

Despite the high estimated prevalence of dysphagia in OSA, there is a paucity of evidence supporting behavioral interventions for treatment. The purpose of this study was to assess the impact of expiratory muscle strength training (EMST) on validated, standardized metrics of swallow and airway clearance capacity functions in moderate-to-severe OSA. 10 participants with OSA (mean age = 65.2 years) completed four weeks of EMST training employing a prospective single-arm, double-baseline interventional design. The Modified Barium Swallow Impairment Profile (MBSImP) Component and Composite (Oral Total [OT] and Pharyngeal Total [PT]) scores measured swallow physiology. Airway clearance capacity measures included maximum expiratory pressure (MEP) and peak cough flow (PCF). A historical normative database was used for OSA patient comparison of swallowing metrics. A total of 234 swallows were analyzed. At baseline, impairments in lingual control, oral residue and esophageal clearance were observed. However, no significant differences in the MBSImP Composite (OT/PT) scores were observed between the OSA and healthy referent group. After EMST intervention, there were no significant differences in pre- to post-intervention Composite (OT/PT) scores. However, large effect size was observed for MEP (p < 0.001, d = 3.0), and non-significant, but moderate effect size was observed in PCF (p = 0.19, d = 0.44). Study findings further quantify swallowing in moderate-to-severe OSA and provide preliminary evidence supporting the impact of EMST on airway clearance capacity.