Parameter analysis using swallowing sounds shows differences in bolus volume, bolus viscosity, sex, and age.

Acoustic analysis of pharyngeal sounds during swallowing may capture physiological functions, providing a noninvasive method for early screening of swallowing decline. In this study, we examined changes in swallowing function across variations in bolus volume, bolus viscosity, sex, and age using parameters such as swallowing duration, average voltage, and swallowing power derived from swallowing sounds. The results showed that average voltage and swallowing power were significantly higher in men, both in younger (aged 20-25 years) and older (aged 50-65 years) groups, regardless of bolus volume and viscosity. These parameters generally decreased as bolus viscosity increased, with significant differences observed in all participants except older men. Regarding swallowing duration, older men took significantly longer to swallow a high-viscosity bolus compared to younger men, whereas no age-related differences were observed in women. This finding suggests that men experience greater age-related deterioration in swallowing than women. Overall, this simple and noninvasive measurement method appears to be an effective and objective tool for evaluating swallowing function. It is capable of detecting alterations associated with sex and aging, as well as changes in swallowing status related to the physical properties of dysphagia diets.