Effect of age and bolus characteristics on the acoustic parameters of ear and neck swallowing sounds

Although the vibrations and acoustics related to swallowing have been observed by placing microphones on the surface of the neck in many cases, previously suggested trends in acoustic parameters related to swallowing sound signals have not yet been integrated into a consistent view. To draw more consistent conclusions on the behavior of the acoustic parameters based on the acoustic waveforms caused by swallowing, in the present study, we aimed to develop and validate a method to observe the swallowing sounds inside the ear canal. By placing an air conduction microphone in the ear canal in addition to a contact microphone on the neck surface, the acoustic characteristics of various parameters obtained from these two locations were comparatively discussed. The differences in the characteristics of these contrasting sensing methods were then investigated through a discussion of the effects of participant age and the physical characteristics of a swallowed bolus on various acoustic parameters.