Division of Dysphagia Rehabilitation, Niigata University, Niigata, Japan.
Gastrointestinal Sciences, Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, Salford, UK.
Neurogastroenterol Motil. 2021 Jan;33(1):e13938. doi: 10.1111/nmo.13938. Epub 2020 Jul 12.
Thermal tactile oropharyngeal stimulation has been clinically used to facilitate swallowing initiation in dysphagic patients. We previously demonstrated that thermal stimulation applied to the oral cavity provokes an immediate excitability in pharyngeal motor cortex. The aim of the current study was to investigate whether thermal stimulation can produce longer lasting effects on the corticopharyngeal neural pathway.
Healthy volunteers (n = 8/12) underwent baseline pharyngeal motor evoked potential (PMEP) measurements evoked by transcranial magnetic stimulation. In the first experiment, subjects received thermal stimulation alternating 30 seconds of 15 and 36°C applied to the tongue surface for either 10 minutes, 5 minutes, or sham. In the second experiment, one of three intermittent thermal stimulus patterns was delivered: cold (alternating 30 seconds of 15 and 36°C), warm (continuous 36°C), or hot (alternating 30 seconds of 45 and 36°C) for 10 minutes. In both experiments, PMEP were remeasured every 15 minutes up to 60 minutes following thermal stimulation.
Repeated measures ANOVA for each stimulus time in the first experiment showed a significant increased change in PMEP amplitude at 30 minutes following only 10-minute stimulation compared with sham (P < .05). In the second experiment, we found that cold stimulation was more effective than the other stimulation (P < .05) at increasing PMEP amplitudes.
Ten-minute cold stimulation on the tongue can induce a delayed (30 minutes) increase in pharyngeal cortical excitability, providing a clinically useful therapeutic window for its application in dysphagic patients.
热触觉口腔刺激已在临床上用于促进吞咽困难患者的吞咽启动。我们之前的研究表明，口腔热刺激会引起咽运动皮层的即刻兴奋性。本研究的目的是探讨热刺激是否能对皮质咽神经通路产生更长时间的影响。
健康志愿者（n=8/12）接受经颅磁刺激诱发的咽运动诱发电位（PMEP）的基线测量。在第一个实验中，受试者接受热刺激，舌表面交替 30 秒 15 和 36°C，持续 10 分钟、5 分钟或假刺激。在第二个实验中，给予三种间歇性热刺激模式之一：冷（交替 30 秒 15 和 36°C）、温（连续 36°C）或热（交替 30 秒 45 和 36°C）刺激 10 分钟。在两个实验中，热刺激后每 15 分钟测量一次 PMEP，最长 60 分钟。
第一个实验中每个刺激时间的重复测量方差分析显示，与假刺激相比，仅 10 分钟刺激后 30 分钟时 PMEP 振幅的变化显著增加（P<.05）。在第二个实验中，我们发现冷刺激比其他刺激更能有效增加 PMEP 振幅（P<.05）。
舌部 10 分钟冷刺激可引起咽皮质兴奋性的延迟（30 分钟）增加，为其在吞咽困难患者中的应用提供了一个有临床意义的治疗窗口。
