Effect of body position on deglutition.

This study examined the effects of changes in body position on different swallowing parameters derived from manofluorographic examinations. Quantitative data were obtained in a group of 12 young healthy volunteers. They were all tested in the upright position; six of them were also evaluated in the supine position, and the other six in the upside down position. In the different positions all volunteers were able to swallow a liquid bolus without aspiration or stasis. However, the dynamics of the swallow became different. Lying down resulted in a pharyngeal transit time comparable with the upright position. The tongue driving force was higher and the hypopharyngeal suction power weakened. In the upside down position, the pharyngeal transit time became longer and the tongue driving force was even more powerful. There was no apparent difference in the traditional manometric parameters; the amplitude, duration, and propagation velocity of the pharyngeal contraction on swallowing did not change obviously in the different body positions.