Acoustic myography, electromyography and bite force in the masseter muscle

Acoustic myography (AMG) offers some advantages over electromyography (EMG) in certain circumstances, but the use of AMG on the jaw-closing muscles ha s not been fully tested. The purpose of this study was to examine the relat ionship between AMG, EMG and force in the masseter muscles of nine healthy male subjects. The AMG was recorded using a piezoelectric crystal microphon e and the EMG was recorded simultaneously with surface electrodes. Force wa s recorded between the anterior teeth with a strain-gauge transducer. Analy sis showed that Pearson's correlation coefficient was 0.913 for force/AMG a nd 0.973 for force/EMG in all subjects, indicating a linear relationship be tween force, AMG and EMG at the four different force levels tested (25-75% of maximum). It is apparent that AMG may be used as an accurate monitor of masseter muscle force production, although some care is required in the tec hnique.