2.3.2. HD-sEMG
The muscle activity of the SHMG was measured using HD-sEMG. The electrodes were 64 channels in 13 rows and 5 columns of a 1 mm diameter sheet (GR04MM1305, OT Bioelettronica Co. Ltd., Torino, Italy). The electrode sheet was affixed to the anterior cervical midline between the mandible and hyoid bone (The electrode sheet was affixed to the anterior cervical midline between the mandible and hyoid bone. Signals from each electrode were captured and the EMG signals were analyzed using analysis software (MATLAB 2019a, MathWorks, Inc., MA, USA).