Volitional augmentation of upper esophageal sphincter opening during swallowing.

Studies were done on eight normal subjects with synchronized videofluoroscopy and manometry to facilitate a biomechanical analysis of the extent and mechanism of voluntary augmentation of upper esophageal sphincter (UES) opening during swallowing. Movements of the hyoid and larynx, dimensions of sphincter opening, and intraluminal pressure events were determined at 1/30-s intervals during swallows of 1 and 10 ml of liquid barium. Swallows of each volume were obtained both before and after subjects were taught a maneuver designed to augment UES opening, the Mendelsohn maneuver (voluntary prolongation of laryngeal excursion at the midpoint of the swallow). At either volume, use of the maneuver increased the duration of the anterior-superior excursion of the larynx and hyoid and consequently delayed sphincter closure by maintaining traction on the anterior sphincter wall. The onset of the pharyngeal contraction (the event normally culminating in sphincter closure) was not affected by the maneuver. We conclude that swallow-related hyoid motion, laryngeal motion, and UES opening are subject to volitional augmentation, supporting the notion that biofeedback techniques can be used to modify impaired swallowing.