Swallowing assessment in obstructive sleep apnea: insights from surface electromyography

PURPOSE: To investigate the electromyographic activity (sEMG) of the suprahyoid/submental (SH) muscles during swallowing in adults with different OSA severities, controlled for body mass index (BMI), and to establish predictive factors for changes in muscle activity. METHODS: This cross-sectional observational study included 37 adults diagnosed with OSA (AHI > 5). The patients were divided into two groups according to the apnea-hypopnea index (AHI): Group I (AHI = 5 ≤ 30) and Group II (AHI > 30). sEMG activity was recorded during the voluntary swallowing of 10 mL and 15 mL of thin liquid (water). The sEMG peak, integral, and maximum velocity (Vmax) were calculated. Groups were compared by general multivariate analysis of covariance, with BMI as a covariate. A general multivariate linear regression model (GRM) was applied to analyze the contribution of predictors to the EMG parameters. The significance level was set at p < 0.05. RESULTS: There was a predominance of males (n = 24, 64.9%) and obese individuals (BMI > 30, n = 25, 67.6%) in the sample. Compared with Group I, Group II presented significantly lower peak, Vmax and integral values (P ≤ 0.006). The GRM revealed that the peak and integral were explained by the AHI and BMI, whereas the tongue volume and behavior during swallowing together explained the Vmax. CONCLUSION: Activation of the suprahyoid (SH) muscles was reduced in patients with severe OSA. In addition to disease severity, BMI and the myofunctional condition of the tongue also contribute to impaired activation. Taken together, these findings indicate that muscle weakness and deficits in motor control compromise the activation of SH muscles during swallowing.