Examination of Submandibular Muscle Activity During Swallowing of Different Materials by Multichannel Surface Electromyography in Healthy Males

Introduction Surface electromyography (sEMG), a widely used noninvasive technique for assessing muscle activity, measures muscle activity during swallowing. However, changes in the activity of each swallowing-related muscle, depending on the materials swallowed, remain unclear. Therefore, we investigated changes in muscle activity in the submandibular region using a seven-channel sEMG when swallowing different materials. Materials and methods This study included 38 healthy males (mean age = 38 years, standard deviation (SD) = 15.6 years). A seven-channel sEMG assessed and recorded submandibular muscle activity while participants swallowed saliva, 5 mL of water, and a capsule. The rising time (milliseconds (ms)), duration (ms), peak amplitude (millivolts (mV)), and integration (mV × ms) during swallowing were calculated from the sEMG recordings. Statistical analyses were performed using JMP Pro 16 (SAS Institute, Cary, NC). A one-way analysis of variance analyzed muscle activity for the different materials swallowed, and a t-test compared the muscle activities of each electrode. Bonferroni correction was applied, and p-values < 0.017 were considered statistically significant. Results No significant differences were observed in the rising time and duration of muscle activity between the different materials swallowed in any channel. However, significant differences in peak amplitude were found between the swallowed materials in certain channels: center-middle channel: saliva versus water, p = 0.0004; capsule versus water, p = 0.008; right-rear channel: saliva versus water, p = 0.0002; and left-rear channel: saliva versus water, p = 0.0005. Additionally, a significant difference in integration between the swallowed materials was observed in the center-middle channel (saliva versus water, p = 0.0035). Conclusion Our findings suggest that muscle activity in the submandibular center to the posterior region changes when different materials are swallowed.