training in the 1930’s in the United States. This was a series of muscle activities to teach people awareness of tension and relaxation. The effect was to reduce muscle tension and certain causes and effects of stress and other symptoms.
In the 1960’s and 1970’s there began to be an awareness in the Western world of the Eastern yogic traditions and the ability of some yogis and other masters to alter their physiology volitionally. Most dramatically, a yogi could survive in a sealed box by voluntarily reducing his metabolic rate to the point where he would not exhaust the supply of oxygen over a period of hours—a hazard that would have killed any other man. After a designated period of time, he would raise his metabolic rate again and ask to be released from the enclosure. The altered states that were being achieved by meditative means attracted the attention of a few key researchers.
The gurus taught that in this state of relaxation and control they could change a number of variables that were thought to be autonomously regulated: blood pressure, heart rate, finger or hand temperature. These functions are managed by the autonomic nervous system, so named precisely because it was thought that such functions could not be altered voluntarily.
There are many other methods used to promote relaxation and manage pain and stress. A few of these include Silva Mind Control, Norman Shealy’s Biogenics, Interactive Guided Imagery (SM) (developed by Bresler and Rossman) and hypnosis. A number of these techniques have been combined with biofeedback instrumentation to enhance learning physiological self-regulation (or mind-body control).
History of Thermal or Temperature Biofeedback
Temperature biofeedback is the easiest to conceptualize and also to instrument. Straightforwardly, it is the body’s tendency to "conserve" resources when stressed, so circulation is withdrawn from both the periphery and the gut, and delivered instead to the large muscles, the heart, and the brain, which would be needed for fight/flight. When we are threatened by a disgruntled rhinoceros, digestion can wait, and we don’t need warm hands and feet. This stress response mechanism is meant to be used sparingly, only when needed. When stress is chronic, e.g. when the disagreeable supervisor is always oin your back, it takes a toll on the body. Temperature biofeedback can then teach the body how to return to a better resting state and "unlearn" its acquired bad habits.
Typical thermal biofeedback devices present a resistance to current flow that varies strongly with temperature. This resistance is measured and can be converted into degrees of temperature, and displayed in terms of a graph or an image for feedback to the person, and for display to the therapist. The person simply has to know when he is getting better or changing for the worse, and learning takes place. The measurements are non-invasive, requiring only the taping of a sensor on the skin (typically on the fingertip), and the probes involved do not deliver any current to the body.
History of Galvanic Skin Response Biofeedback
Galvanic Skin Response biofeedback has its basis in early medical research. In the latter half of the nineteenth century, investigators became aware that skin resistance varied all over the body. Although this was originally dismissed as artifact, eventually it was established that galvanic skin response varied systematically with the state of physiological arousal and even with mental processing. These changes were identified with sweat gland activity. Later the famous psychologist Carl Jung established GSR as an objective way to track physiological arousal, and laid the basis for the further development of the field.
In the general case, the stress response is accompanied by increased sweat gland activity. Hence, cold and clammy hands. Biofeedback training may be undertaken to train the body toward relaxation, as well as back to a more normal response pattern (warm and dry hands). Galvanic Skin Response (GSR) biofeedback is also known by other terms, including Electrodermal Response (EDR) or Skin Conductance Response (SCR) or Skin Conductance Level (SCL). GSR is measured by passing a miniscule current between two sensors mounted on the skin. The dominant current path will be via the layer of moisture on the skin, allowing its resistance (or, equivalently, conductance) to be measured and displayed. Two measures are of interest: 1) the steady-state skin conductance, and 2) the response to a sudden challenge, such as a handclap. Both are useful indicators.
The combination of temperature and GSR is a favorite way among biofeedback therapists to measure the effects of stress management. Initially, it is a matter of finding out where a person "carries his stress," and then addressing that variable. Additionally, these measures are often used to give clues to states of arousal and distress in psychotherapy. In cases of migraine headaches or Raynaud’s disease or other peripheral vascular diseases the patient is encouraged to learn temperature training (often using Autogenic Training as well).
History of Electromyographic Biofeedback
Electromyographic (EMG) Biofeedback has its origin in the work of Galvani, who discovered electrical responses in nerve and muscle action in the early 1800’s. EMG biofeedback utilizes the electrical activity generated by muscles as an indicator of muscle tension, and rewards a decrease in muscle tension toward more normal values. The EMG signal is picked up by electrodes placed on the muscle group of interest, and is expressed in microvolts.
Research in this field began in 1969. By 1974, EMG biofeedback was used for muscle spasm in such conditions as spastic torticollis. In 1977, Wolf and Basmajian set up a measurement scale for grading stroke patients as they made progress in neuromuscular re-education. Basmajian showed that humans could learn to exercise control over the firing of single motor units. (In a charming but undignified detail that did not make it into the published literature, the control was so complete that a subject could get his wired-up motor unit beating out the rhythm of Yankee Doodle Dandy.) By repeatedly exercising the muscle with EMG feedback, function could be gradually restored in many instances where it has been completely lost. In recent years the practical application of this technique of retraining individual muscle groups for spinal cord injury and other cases of paralysis has been pioneered by Bernard Brucker. Unfortunately, this spectacular breakthrough in the treatment of various kinds of paralysis and paresis is not yet widely known, and remains available only to the fortunate few. Jeff Cram, Stu Donaldson and others have refined the more standard EMG feedback techniques in recent years to include very specific muscle exercises and movement. The potential benefit of these techniques unfortunately also remains under-exploited.
Currently, EMG biofeedback is standardly used for muscle tension and muscle spasms, in pain management where muscle tension is involved, and in certain physical therapy applications such as neuromuscular re-education. This work is relevant to stroke victims, accident victims, and to those suffering from spasticity. EMG biofeedback is also a standard component of any program of general relaxation training.
History of Muscle Strength Training
A close relative of the EMG technique is muscle strength training. Whereas in EMG training we monitor electrical activity in neurons that control individual muscle groups, in muscle strength training we measure the output of muscle activity directly. This has its most prominent application to incontinence. The use of biofeedback as a treatment for urinary incontinence started with Kegel in 1948. First, Kegel used a structured exercise program for lax pelvic floor muscles. After exercising, the improved pelvic floor muscle tone enhanced the support to the pelvic structures (bladder neck and urethra) and therefore reduced incontinence. Subsequently, Kegel introduced the pressure perineometer to give direct feedback on the effectiveness of the muscle-strengthening exercise. The unit is placed in the vagina and the pressure of the muscle contraction is displayed on a pressure gauge or a computer screen. This work may have been the very first use of biofeedback instrumentation of any kind. The exercises have been taught to women post-pregnancy for many years to strengthen perineal structures stretched in childbirth. It turns out to be important that these exercises—when used for incontinence training—be taught with the periometer. Otherwise, other muscles can enter into the exercises and failure of the treatment, or even adverse consequences, can ensue. Since the time of Kegel there have been many studies and many methods used. The periometer still appears to be the instrument of choice for urinary incontinence. There can be more than 80% success with long-term follow-up showing retention of benefit.
Muscle strength training is also the method of choice for fecal (stool) incontinence. In 1973, Kohlenberg successfully used a water balloon attached to a tube and a clear cylinder to encourage the strengthening of the external anal sphincter muscle, which began the current treatment for fecal incontinence. In 1974, Engel used a three-balloon device to reinforce three of the responses that encourage continence. Another version of the periometer is also used with success for stool incontinence. Since then, the techniques have improved and the success rate for biofeedback training for those who are good candidates is at least 70% for continence or 75% for decrease in frequency of incontinent episodes
History of Breath Training
Many symptoms that are experienced as caused by stress may in fact be due to breathing incorrectly. These symptoms include panic, functional chest pain, asthma, irritable bowel syndrome, migraine headaches and hypertension and many others. The influence of breathing on regulation of state is just coming to be understood. One of the things that distinguishes us as human beings is the exquisite control of breath that makes speech possible. For us, therefore, control of the breath is not quite as "automatic" as other autonomic functions. There is more of a voluntary component, and that may enlarge the opportunities for things to go wrong on the one hand, and the possibilities of re-regulation by explicit training on the other.
In 1975, Hirai suggested that the regularity of the lung action which moves the diaphragm caused the abdominal contents to stimulate the vagus nerve. This stimulates the parasympathetic nervous system, bringing about relaxation. More recently, the important role of blood carbon dioxide level in autonomic nervous system regulation was recognized (Naifeh, Kamiya, and Sweet). The stress response has the characteristic of driving one toward hyperventilation. Chronic hyperventilation, accompanied by excessively low carbon dioxide levels, can then create its own set of problems.
Various techniques for teaching breathing skills have been developed, utilizing both biofeedback measures and/or behavioral techniques. Eric Peper has pioneered in this field, developing programs for patients as well as training professionals. Since we can be aware of our own breathing without instrumentation, much of this can be rehearsed on an individual basis.
However, these techniques can be aided as well by instrumentation that ranges from the simplest augmentation device that allows one to hear one’s own breath all the way to capnometers that measure carbon dioxide content in the exhaled breath. In the middle lie other instruments such as inspirometers that measure air inhalation/exhalation volume, or pneumographs (strain gauges) that measure expansion of the chest or abdominal area with breathing. Such instruments can encourage a shift from thoracic breathing to the more healthful diaphragmatic or abdominal breathing. Yet other instruments guide a trainee in maintaining a suitably low breathing rate during the training session by giving him or her a signal to track. Most recently, measurements have extended to what is called Respiratory Sinus Arrhythmia (RSA), a subtle pattern of variation in heart rate that tracks the breathing process.
History of General Relaxation Training
The verbal techniques of promoting relaxation and control remain a very important part of the biofeedback discipline, whether or not instrumentation is employed to aid the process. Relaxation with guided imagery, that is, suggestion of a beautiful place, a healing story, or a reframing of an old problem have become very popular. Many practitioners have become experts in this area. Emmett Miller, for example, has developed numerous videotapes for support in addressing various problems such as smoking, chronic headaches, or immune system insufficiency. In the 1970’s, Carl Simonton showed that imagery could augment the treatment of cancer patients. David Bresler and Martin Rossman developed "Interactive Guided Imagery" (SM), in which a guide encourages the client to develop his own imagery and dialogue with his/her own inner wisdom (called "Inner Advisor" or "Inner Healer") and thus encourages self-management for one’s own health. An important way in which our body can communicate to us is through visual imagery. Conversely, by invoking imagery, we can direct the response of the body. Religious and spiritual imagery can be very significant here as well, since much stress that is experienced may in fact emerge out of a fundamental spiritual yearning.
Another tool, Conditioned Relaxation, was developed by David Bresler ("Free Yourself From Pain") in the 1970’s to encourage busy people to realize that with very little effort they could accomplish stress management. It is based on Pavlov’s theory of Classical Conditioning in which he trained dogs to salivate to a bell by pairing the bell with meat powder, and after some time he found that the dogs would salivate upon hearing the bell alone. The relaxation exercise is preceded by (paired with) a signal, in this case, a breath (hence his term "signal breath"). The exercise proceeds with certain key phrases built into it (called anchors). The body learns to relax. After some dedicated practice the body is able to relax just with the signal or the breath.
Les Fehmi developed the "Open Focus"® self-guided program of learning attentional skills. The techniques have been refined over many years of clinical research. The work emanates out of the realization that our state of arousal and activation are closely coupled to our state of attention. If we "pay attention to how we pay attention" we can also re-normalize arousal. The larger objective, then, remains the "control of state," but in this case the task can be accomplished without instrumentation on a personal training basis.
Training ourselves to enlarge our attentional focus calms the body. A repeated exercise of this opening up of our attentional focus can be a useful corrective for the tendency in the industrialized world to become narrowly focused, fragmented in mental processing, and distractible as a result of the daily challenges we face. It is found that we perform best when we work out of the most relaxed state consistent with the challenges we face. Relaxed in this sense does not mean belly-up at the beach, but rather a state of de-stressed control. And when a particular task can be rehearsed, it is best overlearned, so that it can be accomplished without conscious micro-management. Giving our bodies regularly the experience of learned "open focus" allows us to maximize resilience in the face of challenge.
Summary
The above has covered briefly some of the dominant themes that have emerged in the field of biofeedback. The over-arching message of all of these developments is that the body-mind is profoundly responsive to interventions that simply support the way the body is supposed to work in the first place. Biofeedback is a gentle but persistent nudge to get the "system" back toward a better, more functional place. Self-regulation is the way the system works. Training in self-regulation simply takes advantage of that. In our enthusiasm for the latest findings of allopathic medicine, we lose sight of the fact that ultimately nearly all healing is self-healing. We now turn to the emerging field of EEG biofeedback, which is extending the reach of self-regulation techniques to yet other conditions.
