Validation of a novel wearable electromyography patch for monitoring submental muscle activity during swallowing: A randomized crossover trial

Purpose: Surface electromyography (sEMG) is often used for biofeedback during swallowing rehabilitation. However, commercially available sEMG electrodes are not optimized for the head and neck area, have rigid form, and are mostly available in large medical centers. We developed an ultrathin, soft, and flexible sEMG patch, specifically designed to conform to the submental anatomy and which will be ultimately incorporated into a telehealth system. To validate this firstgeneration sEMG patch, we compared its safety, efficiency, and signal quality in monitoring submental muscle activity with that of widely used conventional sEMG electrodes. Method: A randomized crossover design was used to compare the experimental sEMG patch with conventional (snap-on) sEMG electrodes. Participants completed the same experimental protocol with both electrodes in counterbalanced order. Swallow trials included five trials of 5-and 10-ml water. Comparisons were made on (a) signalrelated factors: signal-to-noise ratio (SNR), baseline amplitude, normalized mean amplitude, and sEMG burst duration and (b) safety/preclinical factors: safety/adverse effects, efficiency of electrode placement, and satisfaction/ comfort. Noninferiority and equivalence tests were used to examine signal-related factors. Paired t tests and descriptive statistics were used to examine safety/preclinical factors.Results: Forty healthy adults participated (24 women, M_age = 67.5 years). Signal-related factors: SNR of the experimental patch was not inferior to the SNR of the conventional electrodes (p < .0056). Similarly, baseline amplitude obtained with the experimental patch was not inferior to that obtained with conventional electrodes (p < .0001). Finally, normalized amplitude values were equivalent across swallows (5 ml: p < .025; 10 ml: p < .0012), and sEMG burst duration was also equivalent (5 ml: p < .0001; 10 ml: p < .0001). Safety/preclinical factors: The experimental patch resulted in fewer mild adverse effects. Participant satisfaction was higher with the experimental patch (p = .0476, d =0.226). Conclusions: Our new wearable sEMG patch is equivalent with widely used conventional sEMG electrodes in terms of technical performance. In addition, our patch is safe, and healthy older adults are satisfied with it. With lessons learned from the current COVID-19 pandemic, efforts to develop optimal swallowing telerehabilitation devices are more urgent than ever. Upon further validation, this new technology has the potential to improve rehabilitation and telerehabilitation efforts for patients with dysphagia. Supplemental Material: https://doi.org/10.23641/asha. 12915509.