Biofeedback Pain Interventions
What is Biofeedback?
Several definitions of biofeedback have been proposed. Some emphasize the processes or procedures; others stress the goal or objectives, while others attempt to combine both elements. In the popular textbook, Biofeedback: A Practitioner’s Guide,1 Olson proposed a comprehensive definition that includes both the process and the purpose of biofeedback as follows:
“(1) A group of therapeutic procedures that (2) utilize electronic or electromechanical instruments (3) to accurately measure, process, and “feed back” to persons (4) information with reinforcing properties (5) about their neuromuscular and autonomic activity, both normal and abnormal, (6) in the form of analogue or binary, auditory and/or visual feedback signals. (7) Best achieved with a competent biofeedback professional, (8) the objectives are to help persons develop greatest awareness and voluntary control over their physiological processes that are otherwise outside awareness and/or under less voluntary control, (9) by first controlling the external signal, (10) and then with internal psycho-physiological cues.”
A Rich History with Multiple Roots
The field of biofeedback has a rich history with multiple roots. Biofeedback in the United States dates back to the 1950’s with the convergence of many disciplines, factors, and antecedent events, including:
- Instrumental conditioning of auto- nomic nervous system (ANS) responses
- Behavior therapy and behavioral A second subtype, EEG biofeedback medicine
- Stress research and stress-manage- ment strategies
- Biomedical engineering
- Electromyography (EMG), diagnostic EMG, and single motor unit control
- Consciousness, altered states of con- sciousness, and electroencephalo- graphic (EEG) feedback
- Cultural factors
- Professional development.2
Interest in biofeedback can be traced back to a time when researchers where searching for a means to decrease pathological autonomic responses, or alternately, increasing voluntary control, in conditions impacted by psycho-emotional processes.3,4 At about the same time, interest in developing ways that individuals could learn to recognize and control muscle tension lead to the development of early biofeedback devices for urinary incontinence and muscular re-education.5 This interest has waxed and waned over the years but research and clinical outcomes often produced results that exceeded expectations and that still continued to baffle researches. In relation to electroencephalograph (EEG) feedback, the detection of alpha rhythms in 1930’s stimulated a great deal of interest but there was no technology or equipment to support the necessary research.
There is huge quantity of scientific literature supporting clinical practices that incorporate voluntary self-regulation of physiology such as heart rate, blood pressure, finger temperature, galvanic skin response, and surface electromyography (for EMG, alone, about 3000 books, articles, etc. were published by 1985).6 This interest for research and clinical applications has continued to grow. However, biofeedback has been relegated to a secondary role by pharmacological breakthroughs in the last two decades.
Recent revival of interest in EEG biofeedback has been fueled in part by: (1) the emergence of new technology and algorithms for recording and analysis of EEG signals, (2) increased caution and skepticism regarding pharmacological interventions, and (3) growing interest in safe, nontoxic, noninvasive, and self-regulatory ways of dealing with symptoms to achieve a sense of well being. The focus of biofeedback has been on resolution, not symptom suppression.
An Overview of Biofeedback Therapies
As practiced today, there are two major subtypes of biofeedback therapy. What was traditionally referred to as biofeedback, which included the use of such modalities as surface EMG, skin temperature, heart rate, blood pressure, and galvanic skin response, is now known as peripheral or somatic biofeedback. According to a standard textbook on biofeedback by Schwartz et al.,34 a traditional focus of peripheral biofeedback has been on cultivating lowered arousal to treat a variety of disorders needing lower tension and arousal. Included in this category are headache, temporomandibular joint disorders (TMJ or TMD), Raynaud’s disease, various back pain and other musculoskeletal pain, anxiety disorders, and essential hypertension. More recent research and clinical experience by others have questioned this notion and presented other explanations for the efficacy of biofeedback. For instance, thermal biofeedback for Raynauds has been shown not to work through a lowered sympathetic arousal. Others have argued that poor posture and inability by chronic pain patients to calibrate muscle tension are more likely culprits. Therefore, the real benefit of biofeedback is to teach patients to become more physiologically aware of abnormal muscle tension and to adjust accordingly. Thus, patients can be abnormally aroused and yet remain relatively pain free. Within the last two decades or so, the applications of peripheral biofeedback have been extended to include neuromuscular re-education and gait training, biofeedback-assisted musculoskeletal therapy and neuromuscular re-education (for instance with stroke victims), and urinary and fecal incontinence. Finally, there is increasingly solid evidence that people can reduce severe pain associated with non-cardiac chest pain and, very probably, irritable bowel syndrome by learning to increase heart rate variability. The technique is currently called resonant frequency training (RFT) and was previously called respiratory sinus arrhythmia biofeedback (RSA).7,8