Continuous Biofeedback and Discrete Posttrial Verbal Feedback in Frontalis Muscle Relaxation Training

During training to relax the frontalis muscle, continuous biofeedback (BF) was compared to discrete verbal feedback (VF) delivered immediately after each trial. Both feedback modalities were based on frontalis electromyographic (EMG) activity. Training consisted of 3 consecutive daily session-each comprised of 3 baseline (nonfeedback) trials followed by 10 training trials of 128 see. The presence or absence of the two informationally positive feedback modalities were combined factorially to define four training conditions: BF + VF, NO BF + VF, BF + NO VF, and NO BF + NO VF. Results indicated that while VF alone facilitated muscle relaxation, BF was clearly prepotent ill effecting consistent decreases in EMG activity both across trials and days of training. Additionally, the facilitating effect of BF transferred to nonfeedback trials while VF did not affect performance on nonfeedback trials. Finally, accuracy of self-evaluations of performance on a trial by trial basis was markedly improved by BF, while VF improved accuracy only for trials having a very large absolute difference between levels of EMG activity. Ss receiving no feedback neither reduced muscle tension during training not were able to evaluate their performance accurately even when large absolute differences occurred between trials in frontalis EMG activity.