High-density electromyography as a method for estimating laryngeal muscle activity: a preliminary study

Current methods for monitoring laryngeal muscle function include techniques such as intramuscular electromyography, external laryngeal palpation, and laryngeal endoscopy. Although these methods have provided much information about muscle activation and function during voice production, they are invasive, uncomfortable, and subjective. The objective of this work is to explore the use of the high-density electromyography (HDsEMG) as a non-invasive alternative that can potentially provide objective information on the activity of the laryngeal muscles during speech. with a focus on the cricothyroid muscle (CT). From this set of signals, it is possible to decompose the electromyography signal, providing indirect information on the spatial recruitment and firing rates of motor units (MU) within the muscle. It is hypothesized that the use of MU firing rate and recruitment will allow for a better estimation of muscle activation compared to traditional methods. A high-density wireless HDsEMG equipment (Sessantaquattro, OT Bioelettronica) is used with a 64-channel electrode grid, which are centered on the CT muscle. Preliminary results of a case study illustrated that it was possible to obtain the rates and firing trains of 4 motor units. Future work will explore how HDsEMG applied to the larynx has the potential to improve diagnostic and therapeutic follow-up of pathologies of laryngeal function.