Efficacy of oropharyngeal exercises as an adjuvant therapy for obstructive sleep apnea: A randomized controlled trial

Purpose: Some patients with mild -to -moderate obstructive sleep apnea (OSA) undergoing mandibular advancement device (MAD) therapy may exhibit residual sleep-breathing abnormalities. These cases require adjunctive treatment to further reduce the remaining airway inadequacy, which may affect the health and quality of life. This clinical trial was conducted since the oropharyngeal exercise, which aims to enhance the muscular function of the upper airway, combined with MAD, is unknown. We assessed the possible improvements in respiratory event parameters and lip and tongue physiological properties in patients with OSA who received oropharyngeal exercises for 2 months as an adjunct to MAD therapy. Methods: Twenty-three participants with OSA who had been using MAD but still had residual apnea-hypopnea were randomly allocated to either the oropharyngeal exercise (OE group; N=12) or the sham exercise group (N=11). Lip and tongue strength, endurance, daytime sleepiness, respiratory event index (REI), and the lowest oxygen saturation (SpO2 nadir) were determined. Results: Within and between the treatment groups, no significant improvement in the REI or SpO2 nadir was found. In both groups, there was a significant reduction in the Epworth Sleepiness Scale at 2 months (OE, P = 0.02; control, P = 0.02). In the OE group, lip endurance (P = 0.03), anterior tongue strength (P = 0.02), and endurance (P = 0.02) increased after 2-month of exercise, but only anterior tongue endurance increased significantly compared with the sham control (P = 0.01). Conclusions: This study found that adjunctive OE to MAD showed no additive effect in treating patients with moderate OSA who had a mild residual apnea-hypopnea index following MAD treatment. However, the exercises successfully enhanced lip and anterior tongue endurance, as well as anterior tongue strength.