[Application of EMG biofeedback to patients with mandibular dysfunction. Part 2. Validity of frontal EMG biofeedback].

The purpose of this study was to investigate the mean integral EMG level of the masseter muscle, which was obtained from the EMG biofeedback of the frontal muscle of those patients whom once had a case of mandibular dysfunction, and to use this as an effective means of treatment. Furthermore, the correlation between the psychological characteristics of mandibular dysfunction patients and EMG biofeedback of the frontal muscle were examined. Results showed; 1. EMG biofeedback of the frontal muscle of a normal group to decrease in mean integral EMG level of the masseter muscle, indicating that it was controllable and a learned effect. 2. Patients whom once had a case of mandibular dysfunction also showed similar results, but its inhibitory effect was not to the extent of the normal group. 3. When patients were further divided into those having psychological problems and those who have not'a decrease in the mean integral EMG level of the masseter muscle after Biofeedback Training and a low and stable EMG level even before BFT that did not vary between and during the session were observed. The findings above, thus suggest a clinical value for EMG biofeedback of the frontal muscle of mandibular dysfunction patients.