MI detected bolus movement

Changes in intraluminal impedance during swallowing and reflux. A drop in impedance identifies bolus entry in a segment followed by a recovery once the bolus exits the impedance-measuring segment. Changes in impedance progressing from proximal to distally indicate antegrade bolus movement as seen during swallowing while changes in impedance progressing distally to proximally indicate retrograde bolus movement as seen during reflux.