||Effect of body posture on involuntary swallow in healthy volunteers
学位の種類: 博士（歯学）. 報告番号: 甲第4154号. 学位記番号: 新大院博（歯）甲第352号. 学位授与年月日: 平成28年3月23日
Physiology & Behavior, 2016, 155, 250-259
Clinically, reclining posture has been reported to reduce risk of aspiration. However, during involuntary swallow in reclining posture, changes in orofacial and pharyngeal movement before and during pharyngeal swallow should be considered. Further, the mechanisms underlying the effect of body posture on involuntary swallowremain unclear. The aimof the present studywas to determine the effect of body posture on activity patterns of the suprahyoid muscles and on patterns of bolus transport during a natural involuntary swallow. Thirteen healthy male adults participated in a water infusion test and a chewing test. In the water infusion test, thickened water was delivered into the pharynx at a very slowrate until the first involuntary swallowwas evoked. In the chewing test, subjectswere asked to eat 10 g of gruel rice. In both tests, the recordingwas performed at four body postures between upright and supine positions. Results showed that reclining changed the location of the bolus head at the start of swallow and prolonged onset latency of the swallowing initiation. Muscle burst duration and whiteout time measured by videoendoscopy significantly increased with body reclining and prolongation of the falling time. In the chewing test, reclining changed the location of the bolus head at the start of swallow, and the frequency of bolus residue after the first swallowincreased. Duration and area of EMGburst and whiteout time significantly increased with body reclining. These data suggest that body reclining may result in prolongation of pharyngeal swallow during involuntary swallow.