Oral physiological analysis of dysphagia-relation of feeding posture and the masticatory movement-

本研究旨在阐明咀嚼头部姿势对咀嚼性能的影响，以及咀嚼难度对吞咽困难发生的影响。10名健康青年受试者被招募为受试者，通过二腹肌和咬肌的肌肉活动和颌骨运动次数来评估咀嚼运动，用胶冻程序分析咀嚼性能，通过下颌运动图分析下颌运动。结果如下：自由咀嚼过程中下颌运动次数的分析表明，随着身体姿势向仰卧位置的改变，咀嚼运动减少，咀嚼持续时间也减少。这一趋势在用水喂养食物的情况下观察到的更为明显。口香糖咀嚼性能随体位向仰卧位的变化而降低。另外，对自由活动大鼠的咀嚼运动进行了系统的多巴胺激动剂的分析，结果表明，咀嚼感觉对舌头运动的重要性。总之，咀嚼过程中身体的变化导致了下巴和舌头运动的困难，这也是由于食物在口腔中的位置所引起的。这些咀嚼困难可能是老年人吞咽困难的主要原因之一。

This research was performed to clarify the influence of the masticatory head posture on the performance of mastication and to show the influence of the difficulty of mastication on occurrence of dysphagia.10 healthy young adult was recruited as the subjects and the masticatory movement was assessed by the muscle activity of both digastric and masseter muscles and the number of jaw movement, masticatory performance analyzed by gummy jelly procedure, and jaw movement analysis by mandibular kinesiograph(gnathohexagraph).The results were summarized as follow.The analysis of the number of jaw movements during freely mastication revealed the decreases of this movements according to the change of body posture toward supine position and the duration of mastication also decreased. This trend is more significantly observed in the condition of the feeding the foods with water. The performances of mastication using gummy jelly were decreased according to the changes of body posture toward the supine position. Analysis of jaw movements revealed the shortened time of each masticatory cycles in the supine position and the speed of crashing the foods also delayed in the supine position.Another analysis of the masticatory movement using systemic administration of Dopamine agonists in freely moving rats well showed the importance of palatal sensation for tongue movements.In conclusion, the changes of body during mastication causes the difficulty of jaw and tongue movements and the changes of them also produced by the location of the foods in oral cavity. These difficulty of mastication may be one of most considerable causes of dysphagia in elderly.