||Immediate Effect of Laryngeal Surface Electrical Stimulation on Swallowing Performance
学位の種類: 博士（歯学）. 報告番号: 甲第4155号. 学位記番号: 新大院博（歯）甲第353号. 学位授与年月日: 平成28年3月23日
Surface electrical stimulation of the laryngeal region is used to improve swallowing in dysphagic patients. However, little is known about how this affects tongue movements or other subsequent functions. We investigated the effect of electrical stimulation on tongue pressure and hyoid movement as well as supra- and infrahyoid muscle activities in 18 healthy young subjects. Electrical stimulation (0.2 ms duration, 80 Hz, 80% of each participant’s maximal tolerance) of the laryngeal region corresponding to the infrahyoid muscles was applied. Each subject swallowed 5 mL of barium sulfate liquid 12 times at 10-s intervals before (baseline), during, and after electrical stimulation. Tongue pressure was assessed using a sensor sheet, and the surface electromyography of the supra- and infrahyoid muscles and videofluorography were simultaneously recorded. Tongue pressure during stimulation was significantly less than baseline or after stimulation, with that after stimulation being significantly more than baseline. The uprahyoid electromyographic activity after stimulation was more than baseline while infrahyoid muscle activity did not change. During stimulation, the position of the hyoid at rest was descended, the highest position of hyoid was significantly inferior, and the vertical movement was greater than baseline or after stimulation. After stimulation, the hyoid at rest and at the maximum elevation were positioned more superiorly than baseline. The deviation of the highest positions of the hyoid between baseline and after stimulation corresponded to the differences in tongue pressures at those times. Surface electrical stimulation applied to the laryngeal region during swallowing may facilitate hyoid movement and tongue pressure generation.