Frequency of electromyographic indices alterations in temporomandibular disorders and their correlation with pain intensity

Abstract

BACKGROUND AND OBJECTIVES: Understanding the importance of surface electromyography as a complementary method to understand the myofunctional status of the stomatognathic system, this study aimed at analyzing the frequency of altered and normal electromyographic indices in a sample of subjects with temporomandibular disorders, in addition to their relation with pain complaint. METHODS: Participated in the study 44 individuals with temporomandibular disorder signs and symptoms (11 males and 33 females), with mean age of 39 years, who were submitted to surface electromyography. Pain intensity was measured by the visual analog scale. Total Asymmetry Index (AStotal), Masseter Asymmetry Index (ASMM), Temporal Asymmetry Index (ASTA), Activation Index (ACtotal) and Torque Index (TOtotal) were calculated. Correlation between pain intensity and electromyographic indices was checked by Pearson correlation test and sample characterization with regard to investigated indices was done by descriptive analysis. RESULTS: Means of all indices were within previously established normality patterns. The frequency of altered electromyographic indices in our sample was high (ASMM=68%; ASTA=64%; TOtotal=64%; AStotal=55%). With regard to ACtotal, there has been predominance of masseter activity as compared to temporal activity, both for normal and altered values. Among individuals with altered indices, the left side had superior activity. No correlation was found between pain intensity and the level of electromyographic indices alterations (p>0.05). CONCLUSION: The frequency of electromyographic indices alterations in individuals with temporomandibular disorders is high, pointing to the possible presence of myofunctional disorders of the stomatognathic system. These indices have no direct relation with pain complaint but show muscular activity imbalance, which may not be useful to diagnose pain, but may help the correct referral to relevant muscle therapies. .(AU)