Correlation between the clinical phonoaudiological assessment and electromyographic activity of the masseter muscle

The objective of this paper was to evaluate the specificity of masseter muscle palpation when compared to its electromyographic activity.

Twenty-one young female adults, aged between 17 and 25, participated in this research. The speech therapy evaluation data were obtained by two speech therapists through masseter muscle palpation during isometric contraction, and the electromyographic exam was achieved by using bipolar superficial electrodes, positioned on the masseter muscle. The volunteers were instructed to chew the Parafilm M® material bilaterally and simultaneously. The capture of the electromiographic signals occurred during masseter muscle isometric contractions. The electrical activity study of the masticatory muscle was analyzed through the Root Mean Square value during its isotonic contraction.

All data were then submitted to Kappa statistical analysis.

The results of this study have shown a low correlation between palpation and electromyography (25%), as well as between evaluators (40%).

According to the findings of the present study, it could be observed that the correlation between masseter muscle palpation and its electromyographic activity was very low, which allows to conclude that muscular palpation cannot effectively replace the eletromyographical exam, but complement it instead.