Edmund Jacobson first developed the progressive muscle relaxation technique. Although most of his research on the conditioning of muscle relaxation was conducted 50 years ago, it remains relevant
today. For example, most therapeutic applications of biofeedback include the use of a systematic relaxation technique. Although Jacobson's system has been modified over time, his ideas and research
methods have much to offer clinicians and researchers. Based on an interview reported by McGuigan, he may have been the first researcher to use medical instrumentation to provide feedback about
physiological responses (Jacobson and McGuigan, 1978). His procedure, employing a prototype of modern biofeedback instrumentation, involved an individual observing an oscilloscope to determine the
level of tension in his forearm extensor muscle. Later, Wolpe modified Jacobson's technique and popularized it as part of the systematic desensitization procedure.
In 1958, Kamiya began to study the changes in consciousness that accompanied variations in EEG alpha rhythm of human subjects. He developed a discrimination conditioning task in which a bell was rung
periodically and the subject was requested to indicate if he had been generating EEG alpha just prior to the auditory stimulus. Many subjects were able to learn this task and this led to further
research of alpha rhythm control. Kamiya and his associates later discovered that subjects could suppress alpha when given auditory feedback concerning its presence or absence.
One of the intriguing areas of investigation concerns the search for empirical validation of visceral or smooth-muscle operant conditioning. Neal Miller and his colleagues most notably, the late Leo
DiCara, have been involved in research on instrumental autonomic conditioning in animals for a number of years. In 1968, DiCara and Miller observed that curarized rats could learn to avoid a shock by
lowering their heart rate. Other investigators showed that visceral conditioning, through the use of feedback techniques, could be demonstrated in humans (Miller and Dworkin, 1974).
Although less well known, H D Kimmel (1960) spent years investigating instrumental conditioning off the autonomic nervous system (ANS) in man. Stimulated by results of earlier experiments in
conditioning of the galvanic skin response (GSR), Kimmel and his students found that subjects' GSR's could be conditioned using pleasant odors. Kimmel (1974) summarized the research up to 1967,
including 16 studies of GSR, five of heart rate and three of the vasomotor response. Results of all these studies supported the contention that the ANS could be modified through operant conditioning.
Subsequently biofeedback procedures were applied to clinical problems. In 1973, two innovative treatment procedures were developed which are widely used today, with certain technical refinements.
Elmer and Alyce Green (1977) developed a clinical protocol for thermal feedback training. They used peripheral skin temperature as a measure of vasodilatation and combined skin temperature feedback
with Schultz and Luthe's (1969) "Autogenic Training". Sargent, Green and Walters (1972) applied temperature biofeedback training to treat migraine. Patients were taught to increase the warmth in
their fingers (vasodilatation) while decreasing the temperature of their foreheads (vasoconstriction). They found that almost 75 percent of the subjects were able to decrease both the duration and
intensity of migraine attacks. Later studies have confirmed these results.
While the Green's were developing their treatment technique for migraine, Thomas Budzynski (1973) and his associates at the University of Colorado developed a feedback technique to treat muscle
contraction (tension) headaches. They used EMG training to teach patients to reduce the tension in their frontalis (forehead) muscles. Their results showed that average muscle tension levels dropped
from 10 to 3.5 (microvolts) and headaches intensity was reduced over the 16-week training period. Two control groups of headache patients were employed in the experimental design; one group received
"false" or pseudofeedback and the other group received no feedback at all. Neither of these groups improved as much as the EMG treatment group.
The clinical research which has been reviewed thus far has involved procedures where feedback is used to reduce muscle and blood vessel contraction ("physiological arousal"); however, a technique to
increase muscle contraction (a form of EMG biofeedback training) has existed for almost 25 years. John Basmajian's early research, first published in 1963, indicated that patients can increase the
functioning of single motor units through the use of EMG biofeedback. Even earlier, Marinacci and Horande (1960) demonstrated that EMG feedback could be applied to improve neuromuscular functioning
in several disorders. Basmajian and his colleagues have designed specially constructed biofeedback instruments for use in rehabilitation, e.g., a miniature EMG feedback device. They have applied such
instrumentation to various disorders including paralytic foot-drop. There is significant difference between the EMG units used in rehabilitation and those adapted for use with psychophysiological
disorders. The biofeedback units employed in rehabilitation are designed to transmit information about single motor units or the functioning of a specific muscle. Most of the EMG units used to
enhance relaxation, however, summate the bioelectrical information of a particular muscle group. The resulting feedback is somewhat less specific.
Prior to 1970, relatively few studies were conducted using biofeedback techniques. Since then, however, hundreds of investigations have been done and the accumulation of data has been impressive. For
this reason, BSA task forces were developed to survey the current literature and summarize the current status of biofeedback as a therapeutic technique in a number of areas including:
psychophysiological disorders (Fotopoulos and Sunderland, 1978), gastrointestinal disease (Whitehead, 1978), vasoconstrictive disorders (Taub and Stroebel, 1978), muscle tension headache (Budzynski,
1978) and others.
In 1989, it was proposed and proved that biofeedback technique need not involve just a conscious or verbal process, but could work just as effectively at the subconscious level. The SCIO was designed
to provide feedback to the individual’s subconscious.