Premium
Cold thermal oral stimulation produces immediate excitability in human pharyngeal motor cortex
Author(s) -
Magara J.,
Watanabe M.,
Tsujimura T.,
Hamdy S.,
Inoue M.
Publication year - 2018
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/nmo.13384
Subject(s) - swallowing , tongue , pharyngeal muscles , transcranial magnetic stimulation , stimulation , analysis of variance , motor cortex , electromyography , anesthesia , medicine , sensory stimulation therapy , repeated measures design , post hoc analysis , sensory system , pharynx , audiology , psychology , physical medicine and rehabilitation , neuroscience , anatomy , surgery , pathology , statistics , mathematics
Abstract Background Current strategies of swallowing therapy include facilitation of swallowing initiation by sensory modulation. Although thermal tactile oral stimulation is a common method to treat dysphagic patients to improve swallowing movement, little is known about the possible mechanisms. This study is aimed to investigate whether thermal oral (tongue) stimulation can modulate the cortico‐pharyngeal neural motor pathway in humans. Methods Eighteen healthy volunteers participated and were intubated with an intraluminal catheter for recording pharyngeal electromyography. Each participant underwent baseline transcranial magnetic stimulation (TMS) cortico‐pharyngeal motor evoked potential (MEP) measurements bilaterally. MEPs were then measured during thermal stimulation over the dorsal tongue, applied using the Peltier device at three different temperatures; 45°C, 37°C, and 15°C, in a pre‐ordered manner. Each of the three temperatures was given twice with a 5‐min resting time between each trial. Averaged MEP amplitude changes were analyzed using ANOVA and post‐hoc t ‐tests. Key Results Two‐way repeated measures ANOVA with factors of Temperature × Trial in amplitude of MEP demonstrated a significant effect of Temperature both in the stronger ( F 2,34 = 5.775, P = .007) and weaker ( F 2,34 = 4.771, P = .017) pharyngeal hemispheres. Subsequent post‐hoc tests showed the significant increase in pharyngeal MEPs at 15° compared to 37° in both hemispheres ( P < .05). Conclusions & Inferences Cold oral stimulation was able to induce significant changes in pharyngeal cortical excitability, demonstrating evidence for a sensorimotor interaction between oral and pharyngeal cortical areas.