Change Mechanisms in EMG Biofeedback Training: Cognitive Changes Underlying Improvements in Tension Headache

Authors

  • Jeanetta C. Rains PhD


Abstract

Forty-three college students suffering from recurrent tension headache were randomly assigned to 1 of 4 electromyographic (EMG) biofeedback training conditions. Although all subjects were led to believe they were learning to decrease frontal EMG activity, actual feedback was contingent on decreased EMG activity for half of the subjects and increased EMG activity for the other half. Within these 2 groups, subjects also viewed bogus video displays designed to convince them they were achieving large (high success) or small (moderate success) reductions in EMG activity. Regardless of actual changes in EMG activity, subjects receiving high-success feedback showed substantially greater improvement in headache activity (53%) than subjects receiving moderate success feedback (26%). Performance feedback was also related to changes in locus of control and self-efficacy. Changes in these 2 cognitive variables during biofeedback training were also correlated with reductions in headache activity following treatment, whereas changes in EMG activity exhibited during training were uncorrelated with outcome. These results suggest that the effectiveness of EMG biofeedback training with tension headache may be mediated by cognitive changes induced by performance feedback and not primarily by reductions in EMG activity.

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Dr. Rains is Clinical Director of the Center for Sleep Evaluation at Elliot Hospital in Manchester, NH. She is a Fellow of both the American Headache Society and the American Academy of Sleep Medicine and Diplomate of the American Board of Sleep Medicine. She serves as an Associate Editor for Headache.

My favorite headache article remains the 1984 article by Holroyd, Penzien, and colleagues. This influential study was the first to demonstrate that the effectiveness of biofeedback may be mediated by cognitive changes induced through biofeedback training rather than primarily by learned physiological control. In the 1970s and early 1980s, the rationale for biofeedback training as an intervention for recurrent headache was derived from the widely accepted notion that migraine was a vascular phenomenon and tension-type headache was a musculoskeletal phenomenon. Accordingly, thermal and electromyographic (EMG) biofeedback targeted the supposed physiological responses involved in migraine and tension-type headache, respectively.

The 1984 study manipulated both the contingency of the feedback in EMG biofeedback training and patients' perceptions of their success with biofeedback, using a 2 (EMG increase vs EMG decrease) × 2 (high vs moderate success) experimental design. Results demonstrated headache improvement with biofeedback regardless of whether patients had been trained to decrease or to increase EMG activity. Furthermore, superior headache improvement was achieved by the group who received the “high success” condition, regardless of biofeedback training. Headache improvements instead correlated with cognitive changes in self-efficacy and locus of control.

The exemplary study challenged the popular beliefs of the day about mechanisms of biofeedback, and moreover raised questions for the prevailing notions concerning basic pathophysiology of so-called muscle contraction headache. Although previous studies had questioned the mechanisms of biofeedback with altered-contingency control conditions, this study surpassed earlier research to test a coherent competing cognitive explanation for headache change. As a result of this line of research, it is now widely recognized that biofeedback's impact on headache involves therapeutic mechanisms that are more complex than simple training of a physiologic response, and stimulated the combined cognitive–behavioral therapy for headache.

In 1984, as an undergraduate psychology major in Kansas with a fascination for science, health psychology, and (of course) anything counterculture, I had 2 general reactions to the study. First, the caliber of science was nothing less than excellent – the embodiment of my research methods and statistics courses. As an undergraduate, I seemed to have some gift for punching holes in the methods of published studies, but here I could find no holes. Second, I just wanted to meet these guys – scientists who were not confined by prevailing theories of muscle contraction headache pathophysiology and biofeedback mechanisms, and who dared to engage headache sufferers in training that might by conventional thinking be expected to worsen their headaches.

The study is a powerful demonstration of the impact of one well-designed and well-reported study to advance science. Authors succeeded in subjecting complex physiological and psychological processes to methodologically rigorous research. Beyond the science, the study demonstrated to me the power of the psychological experience to alter physical symptoms. The opportunities to improve headache and broaden health through cognitive and behavioral processes appeared to me to be infinite.

In 1989, I had the opportunity to meet and, ultimately, the great privilege to work with Dr. Penzien and soon after also with Dr. Holroyd. Those early meetings have blossomed into a collaboration that extends over almost 20 years in headache research. I commend them for the excellent article which inspired my interest in behavioral science and headache. I believe the study remains one of the finest examples of experimental research conducted in headache to date.

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