PREDICTABILITY OF JAW MUSCLE PAINS FROM SURFACE ELECTROMYOGRAMS

In seven (88%) of eight healthy subjects, weak to moderate pains were elicited in the masseter muscles through the isometric contractions of maximum voluntary teeth clenching. Integrated surface electromyograms of the right and left masseter muscles were used to quantify the abso lute and relative contractile activities of the two muscles. The risk (relative probability) of inducing pain onset in the single masseter m uscle generating the larger amount of isometric activity was 2.5 times the risk of eliciting pain onset in the single masseter muscle genera ting the lesser amount of isometric activity. However, as an aid in th e diagnosis of pain onset, the method of masseteric surface electromyo graphy had a false diagnostic ratio of 0.67.