Monitoring and modeling of pharyngeal behavior during swallowing using bioelectrical impedance technique

To perform a non-invasive swallowing test for patients suspected of having dysphagia, a system capable of monitoring pharyngeal behavior simply and easily during swallowing was considered. The system incorporating a bioelectrical impedance technique was assembled to input an alternating current into the neck of the subjects and to output the corresponding voltage response. We measured the voltages during swallowing using this system and observed the voltage changes for swallowing to evaluate the system validity. The relationship between the characteristic voltage changes and the movements of tissues or organs, specifically those of the hyoid bone, were investigated on the basis of the measurements at various positions in the neck region. The actions of the related muscles in the pharyngeal phase of swallowing were explained by a muscle group model described with an electrical circuit. Additionally, the voltage measured in swallowing was assessed as resistive and reactive components. This approach demonstrated a potential of this system to detect cellular-level changes.