A multiple-response evaluation of EMG biofeedback performance during training and stress-induction conditions.

The present study evaluated multiple system physiological responding which accompanied EMG biofeedback performance under two conditions—during EMG biofeedback training sessions, and during the utilization of that training in the presence of a stressor. Twelve subjects were randomly assigned to one of two groups: 1) an EMG biofeedback group, or 2) a false-EMG biofeedback group. During the training sessions, significant frontalis EMG decreases were produced by the biofeedback group. This performance was associated with a concomitant decrease in heart rate and respiration rate, but an increase in skin conductance level. The biofeedback group was also able to maintain a low level of EMG activity during a stress-induction procedure. However, this low level of activity did not generalize to other physiological responses. Heart rate and skin conductance levels both increased, which coincided with the subjects' self-report of anxiety during this phase of the study. These data clearly demonstrate that single-system arousal reduction produced by EMG biofeedback training, rather than producing cross-system arousal reduction, produces specificity of a single response change under a stress-inducing situation.