Frontal electromyographic feedback. Stress attenuation and generalization

The role of awareness in the control of frontalis muscle activity

An experiment was conducted to evaluate whether awareness of change in frontalis muscle activity was necessary and sufficient for voluntary control over the muscle. Forty subjects were required to relax, tense and complete both a test of awareness and an isometric magnitude production task, using the frontalis muscle. Following the completion of these pre-training assessment procedures, one group of subjects underwent either: Training in muscular awareness; biofeedback training in muscular control; both awareness and muscular control training; or a non-training control procedure. Following training, all subjects were again evaluated using the pre-training assessment procedures. The results indicated that an increase in awareness was not sufficient to produce an increase in muscular control, nor was it necessary for an increase in the ability to tense the frontalis muscle. These results suggest that Brener's model of voluntary control needs to be re-examined.

Single- and successive-site EMG training in responding to anticipated pain

In a comparison among relaxation procedures, 32 college students were assigned to four group of equal size. Electromyographic response training was given with biofeedback (EMG training) on the forehead (frontal area) alone, on the frontal area, neck (sternomastoid), and forearm areas in succession, or on these three sites in conjunction with recorded relaxation instructions used at home. Relative to a control group, which received no training, the three biofeedback-trained groups maintained lower EMG levels on the frontal and sternomastoid sites, and the group provided with the relaxation instructions plus EMG training showed lower skin conductance levels. These patterns were generally maintained during the presentation of a stimulus (stressor) that ostensibly signaled an impending electric shock. Other measures, including peripheral temperatures and self-reported anxiety, also showed effects consistent with the stressor presentations but did not differentiate the groups. The results are discussed in terms of common clinical relaxation procedures, an alternative procedure for training several sites simultaneously, and implications for models of EMG training and arousal.