Examination of Submandibular Muscle Activity During Swallowing Using Multi-Channel Surface Electromyography

Abstract

　Introduction:　Surface electromyography (sEMG), a widely used noninvasive technique for assessing muscle activity, can be used to measure muscle activity during swallowing. However, the changes in the muscle activity of each swallowing-related muscle depend on the material swallowed and remain unclear. Therefore, we investigated the changes in muscle activity in the submandibular region using a seven-channel sEMG when swallowing different materials.

　Materials and Methods:　This study included 66 healthy volunteers (53 males; mean age, 37.3±13.9 years). A seven-channel sEMG was used to assess and record the submandibular muscle activity of each participant when swallowing saliva, 5 mL of water, and a capsule. The duration of muscle activity (ms), maximum amplitude (mV), and integrated muscle activity (mV・ms) during swallowing were calculated from the sEMG recordings. Statistical analysis was performed using JMP pro16. One-way analysis of variance was used to analyze the muscle activity for the different materials swallowed, and a t-test was performed to compare with muscle activities from each electrode. Bonferroni correction was performed and p-values ＜0.017 were considered statistically significant.

　Result:　No significant difference was observed in the duration of muscle activity among the different materials swallowed in any channel. Some channels indicated a significant difference in the maximum amplitude between the swallowed materials as follows: center-middle channel: saliva vs. water, and capsule vs. water. Moreover, some channels indicated a significant difference in the muscle activity between the swallowed materials as follows: right-front channel: capsule vs. saliva, and capsule vs. water, center-middle channel: capsule vs. water, center-rear channel: capsule vs. water.

　Conclusion:　The results of this study suggest that the muscle activity required was greater for solids than for water, and for saliva than for water, in the central part of the submandibular region during swallowing.