A Response: Change Mechanisms in EMG Biofeedback Training Revisited


  • Donald B. Penzien PhD,

  • Kenneth A. Holroyd PhD

Long ago, a wiser person than we suggested: “You know that your work is important when others begin to criticize you.” By this criterion, we received the first message that we were onto something at the scientific meeting of the Biofeedback Society of America (now the Association for Applied Psychophysiology Biofeedback; Denver, March 1983).1 The barrage of angry criticism that followed the presentation of these results had us anticipating overly ripe fruit hurled toward the podium. We had not foreseen that clinicians in the audience whose livelihood depended upon applications of biofeedback (BF) would be so threatened by these findings, which, after all, again confirmed the effectiveness of electromyographic (EMG) BF.

The prevailing and face valid explanation of EMG BF's therapeutic mechanism (ie, EMG BF improves muscle contraction headache through enhanced self-regulation of scalp and neck musculature) was discounted by our research. To be sure, this was not the first study to reveal a “disconnect” between EMG activity and improvements in tension-type headache following EMG BF training; approximately a dozen articles had reported this finding before our 1984 article was in print.2 But our work was perhaps especially compelling owing to its experimental rather than correlational design paired with its demonstration of an alternate therapeutic mechanism. Studies including this one examining the efficacy and mechanisms of EMG BF helped to challenge our long-held notions of the pathophysiology of muscle contraction headache, ultimately inducing the International Headache Society's Classification Committee to rename this disorder (p. 29).3

Ironically, it was in listening to patients who were receiving either EMG BF or cognitive therapy that the idea for this study was born.4 The efficacy of EMG BF had been established in controlled trials,5 but we had already shown experimentally that changes in EMG activity could be varied during EMG BF without affecting subsequent improvements in headaches.6 But, if EMG BF did not work by controlling EMG activity, then how did it work? Coping interviews confirmed the obvious: most patients entering treatment feel discouraged and helplessness and have largely given up on their efforts to manage their headaches. However, as patients successfully learned to control EMG activity, the content of the coping interviews changed: patients began to make the same types of life changes as patients undergoing cognitive therapy. Ken still recalls a 27-year-old woman with a long history of headaches and moderate depression. As she gained confidence in her ability to regulate EMG activity, she not only brightened noticeably, but somehow found the strength to terminate a highly stressful and conflicted relationship. Might this be the missing therapeutic mechanism we were looking for?7

The major challenge in testing this hypothesis was to develop an experimental EMG BF therapy that allowed self-efficacy (or confidence that one can take actions to manage headaches) and EMG learning to be manipulated independently. Using the “high technology” of the time (an Apple II-based Cyborg Biolab 21) and a bit of technical creativity, we were able to devise a highly credible and effective method for manipulating not only the direction of BF training (EMG decrease vs increase) but also self-efficacy expectations – the latter relying on bogus computer-generated feedback displays. So it was our reliance on emerging personal computer technology that allowed us to meet the challenge in the laboratory and shed some new light on the mechanisms of headache improvement.

It is gratifying to see that although now 25 years old, this work continues to be cited and to influence research on BF and beyond. It is now clearer that helplessness/self-efficacy influences central pain modulation as well as coping and that changes in physiology and self-efficacy can both be important. And it is especially flattering that this article served as a catalyst in forging our long-time collaborative relationship with Dr. Rains!