Differentiation of Bolus Texture During Deglutition via High-Density Surface Electromyography: A Pilot Study

Objective: Swallowing is a complex neuromuscular task. There is limited spatiotemporal data on normative surface electromyographic signal during swallow, particularly across standard textures. We hypothesize the pattern of electromyographic signal of the anterior neck varies cranio-caudally, that laterality can be evaluated, and categorization of bolus texture can be differentiated by high-density surface electromyography (HDsEMG) through signal analysis.Methods: An HDsEMG grid of 20 electrodes captured electromyographic activity in eight healthy adult subjects across 240 total swallows. Participants swallowed five standard textures: saliva, thin liquid, puree, mixed consistency, and dry solid. Data were bandpass filtered, underwent functional alignment of signal, and then placed into binary classifier receiver operating characteristic (ROC) curves. Muscular activity was visualized by creating two-dimensional EMG heat maps.Results: Signal analysis results demonstrated a positive correlation between signal amplitude and bolus texture. Greater differences of amplitude in the cranial most region of the array when compared to the caudal most region were noted in all subjects. Lateral comparison of the array revealed symmetric power levels across all subjects and textures. ROC curves demonstrated the ability to correctly classify textures within subjects in 6 of 10 texture comparisons.Conclusion: This pilot study suggests that utilizing HDsEMG during deglutition can noninvasively differentiate swallows of varying texture noninvasively. This may prove useful in future diagnostic and behavioral swallow applications.

Automated summary

This study utilized high-density surface electromyography (HDsEMG) to analyze the electromyographic signal during swallowing in healthy adults, and found a positive correlation between signal amplitude and bolus texture. The study also observed differences in electromyographic signal between the cranial and caudal regions of the neck, but symmetric power levels in the lateral comparison. ROC curve analysis demonstrated the ability of HDsEMG to accurately classify different textures of food to a certain extent. This research provides valuable insights for noninvasive differentiation of swallowing with varying textures, which can be applied in future diagnostic and therapeutic applications.