Umezaki Toshiro, Sugiyama Yoichiro, Fuse Shinya, Mukudai Shigeyuki, Hirano Shigeru
Department of Speech and Hearing Sciences, International University of Health and Welfare, and the Voice and Swallowing Center, Fukuoka Sanno Hospital, Fukuoka, 814-0001, Japan.
Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, Kyoto, 602-8566, Japan.
Exp Brain Res. 2018 Oct;236(10):2661-2676. doi: 10.1007/s00221-018-5325-0. Epub 2018 Jul 4.
Sensory-motor control of the pharyngeal swallow requires sensory afferent inputs from the pharynx and larynx evoked by introducing bolus into the pharynx. Patients with reduced sensitivity of the pharynx and larynx are likely to have a swallowing impairment, such as pre-swallow aspiration due to delayed swallow triggering. Interferential current stimulation applied to the neck is thought to improve the swallowing function of dysphagic patients, although the mechanism underlying the facilitatory effect of such stimulation remains unknown. In the present study, we examined the changes in the elicitability of swallowing due to the stimulation and the responses of the swallowing-related neurons in the nucleus tractus solitarius and in the area adjacent to the stimulation in decerebrate and paralyzed guinea pigs. The swallowing delay time was shortened by the stimulation, whereas the facilitatory effect of eliciting swallowing was attenuated by kainic acid injection into the nucleus tractus solitarius. Approximately half of the swallowing-related neurons responded to the stimulation. These data suggest that the interferential current stimulation applied to the neck could enhance the sensory afferent pathway of the pharynx and larynx, subserving excitatory inputs to the neurons of the swallowing pattern generator, thereby facilitating the swallowing reflex.
咽吞咽的感觉运动控制需要通过向咽部引入食团来诱发来自咽部和喉部的感觉传入输入。咽部和喉部敏感性降低的患者可能存在吞咽障碍，例如由于吞咽触发延迟导致的吞咽前误吸。尽管这种刺激的促进作用的潜在机制尚不清楚，但颈部施加的干扰电流刺激被认为可以改善吞咽困难患者的吞咽功能。在本研究中，我们在去大脑和瘫痪的豚鼠中，研究了由于刺激导致的吞咽诱发能力的变化以及孤束核和刺激邻近区域中与吞咽相关神经元的反应。刺激缩短了吞咽延迟时间，而向孤束核注射 kainic 酸减弱了诱发吞咽的促进作用。大约一半的与吞咽相关的神经元对刺激有反应。这些数据表明，颈部施加的干扰电流刺激可以增强咽部和喉部的感觉传入通路，为吞咽模式发生器的神经元提供兴奋性输入，从而促进吞咽反射。
