Carbonated beverage-based sensory stimulation affects swallowing movements and contributes to safe swallowing. Although the effects of carbonated beverages on swallowing movements have been reported using swallowing sounds, small amounts of swallowing have not been investigated. In this study, we extracted the acoustic characteristics from swallowing sounds acquired when 15 healthy adults swallowed 3mL, 5mL, and 10mL of water or carbonated water five times each. Consequently, we confirmed that the acoustic features of the swallowing sound in time domain, i.e., peak intensity and energy, marginally significantly reduced when swallowing carbonated water compared to water, regardless of the quantity. Even with a mouthful volume of 3mL of carbonated water, this trend was confirmed. Therefore, the potential evaluation of swallowing and rehabilitation through the swallowing of small amounts of carbonated water, which has a lower risk of aspiration for dysphagia, was considered.
