Influence of postural changes on the dynamics of swallowing

Abstract

In order to evaluate how postural changes affect swallowing of liquids, we analyzed simultaneously recorded data of intraoral and pharyngeal pressures during a single, continuous swallowing of water. The subjects were 7 males who had no detectable abnormalities in eating and swallowing function. Intraoral pressure was measured using a microchip pressure transducer in the oral cavity, and pharyngeal pressure was measured by transnasal insertion of a pressure measuring microchip. The head position at which the subject could most easily swallow water through a straw in a single action was defined as the upright position. The positions where the subject was bent forward and backward 30 degrees were defined as the forward and backward inclinations, respectively. We defined a single swallow as sucking and swallowing water through a straw one time. Continuous swallow was defined as repeating the above single swallowing action ten times without rest. We found that postural changes affected how smoothly the water passed from the oral cavity to the pharynx. When we analyzed the early and late stages of swallowing, which were divided at the time of elevation of the larynx, we found that posture affected swallowing in the early stage. However, postural changes did not affect swallowing in the pharyngeal stage, nor did it affect the rhythm or volume of swallowing.