Abstract
It is said that EMG biofeedback training of the frontal muscle (BFT) has the ability to create an antagonistic effect against stress. To better understand this relationship, the effects of psychological stress on physiological responses were studied using experimentally induced stress.
Subjects, consisting of 16 adults with no craniomandibular disorders or autonomic nervous system abnormalities were studied and asked to go through two sessions, namely one with no biofeedback training (Pre-BFT) and another after having gone through biofeedback training (Post-BFT). The training consisted of a 2 min rest period, followed by 2 min of arithmetic memorization (i. e. stress period). In the Post-BFT session, the subjects were asked to relax their frontal muscle during the stress period. During the entire session, the pneumogram, electrocardiogram, plethysmogram, and the electromyogram of the facial - neck muscles (frontal, temporal, masseter, sternocleidomastoid) were recorded.
Results showed an elevated autonomic response and stimulation of the sympathetic nervous system in the Pre-BFT. Muscle activities also showed an increase in EMG activity for all 4 muscles.
Post-BFT showed similar autonomic response to that of Pre-BFT and since the activities of the frontal, temporal, and masseter muscles during the stress period were similar to that of the rest period, it was thought that BFT was able to lighten some of the stress load. However, the muscle activity controlled by BFT does not affect the autonomic responses.
