The study of maximum electromyogram of masseter muscle before and during modified electroconvulsive therapy in psychiatric patients

Background: Electroconvulsive therapy (ECT) is generally used to treat various severe and treatment resistant psychiatric disorders. Nowadays modified ECT is used, injury to teeth and other oral structure remain a risk in ECT despite the use of muscle relaxants due to the electrodes are placed on the temporal, quite close to the masseter muscle. The use of a bite guard is essential to prevent dental and soft tissue injuries; however, limited evidence exists regarding electromyogram (EMG) of the masseter muscle before and during modified ECT. Objectives: To compare the maximum EMG of the masseter muscle under three conditions: 1) maximal clenching without a bite guard, 2) maximal clenching with a bite guard, and 3) during modified ECT with anesthesia, muscle relaxants and a bite guard and to evaluate post procedural oral complications. Materials and Methods: This cross-sectional study included 40 psychiatric inpatients who undergoing modified ECT at Suanprung Psychiatric Hospital. Surface EMG signals of the masseter muscle were recorded using the Thymatron® System IV (Somatics LLC, USA) under the three conditions: before anesthesia without a bite guard (NB), before anesthesia with a bite guard (B), and during ECT with anesthesia, muscle relaxants and a bite guard (ECT). Differences among conditions were analyzed using repeated measures ANOVA, and independent samples t-tests were used to compare EMG values between groups (