Effects of alternative control procedures for electromyographic biofeedback relaxation training

Twenty-four college students participated in a single session of electromyographic (EMG) biofeedback in a comparison of three experimental control procedures commonly employed in biofeedback relaxation training research. One group received contingent EMG biofeedback from the forehead area, and each subject in this group served as his or her own control. Subjects in a second group received noncontingent EMG feedback from a tape recorder but were instructed to use the feedback signal to relax their forehead muscles (single blind). Subjects in a third group received the same auditory feedback as those in the second group but were not told the purpose or source of the feedback stimulus (yoked control). The contingent feedback group showed significantly less EMG activity when compared to the other two groups. However, this group did not exhibit significant EMG level decrements from the beginning to end of the session. This seemingly contradictory finding may have been due to statistically capitalizing on the artifactually high EMG level of the experimental and control groups, although the single-blind and yoked-control groups showed nonsignificant increases across the session. The single-blind group's data had a variance several times larger than the other two groups' variance. Findings are discussed with respect to a probing hypothesis as opposed to the previously offered frustration hypothesis. Of the three control procedures, the data suggest the yoked control as the procedure of choice for EMG biofeedback relaxation research.The authors would like to thank David Kazar and Claudia Coleman for their technical assistance with this article.     

Effects of relaxation and/or biofeedback training upon hip flexion in gymnasts

In Study I 10 male gymnasts were matched for hip flexibility and then randomly placed in either a control or a biofeedback group. After warm-up exercises, the control group practiced self-relaxation while the biofeedback group received EMG feedback from the hip extensors. Both groups significantly improved hip flexion from trial 1 to trial 9. The biofeedback group significantly improved more quickly across trials, as measured by slope analysis, than the control group. In Study II 15 female gymnasts were matched for flexibility then randomly placed in control, relaxation, or biofeedback plus relaxation groups. Each gymnast completed STAI (A-state), warm-up exercises, and a 10-minute treatment and was then tested for hip flexion. The control group received no treatment, the second group received modified progressive relaxation, while the last group received relaxation and EMG hip extensor feedback. All groups significantly improved from trial 1 to trial 8 with no one group superior to the others. There were no significant differences among groups for rate of improvement across trials. There were no significant correlations among state anxiety, age, and flexibility measures.This work was funded in part by a Canada Council Leave Fellowship and Research Grant. Appreciation is extended to Ole Pedersen, Frank Circelli, and Dave Steeper for the data collection in the first study. The authors also extend their thanks to the gymnasts and coaches from York University, Toronto, and the Aztec Gymnastics Club, San Diego.     

The production and generalization of large-magnitude heart rate deceleration by contingently faded biofeedback

Eight subjects were taught to decrease their heart rates via biofeedback training. Four of these received contingently faded, beat-by-beat analogue feedback and contingent reinforcement each time their performance met a specified and adjusting criterion. The other four received continuous, beat-by-beat analogue feedback, but not the contingent reinforcement. Subjects in the two groups were yoked to ensure equal densities of reinforcement. Subjects in the first group were asked to decrease heart rates 15% from baseline and were then trained using only 75%, 50% and 25% of beat-by-beat feedback. It was hypothesized that the immediate reinforcement of appropriate behavior and the contingent fading(following mastery) of feedback would aid in the generalization of the response. Following completion of all criterion steps or 10 training sessions, whichever came first, all subjects were tested with no feedback and no contingent reinforcement. The group receiving contingently faded feedback training showed a significantly greater heart rate decrease in the training sessions and also the test session. These results were interpreted as indicating that biofeedback can be conceptualized as an operant conditioning paradigm, and that the use of operant techniques may help subjects produce clinically significant changes.This research was supported in part by a grant to Robert J. Gatchel from the National Heart, Lung, and Blood Institute (Grant No. NIH HL 21426-01).     

Feedback delays and relaxation expectancies in EMG biofeedback

The use of noncontingent feedback controls in studies of the efficacy and process of electromyographic (EMG) biofeedback may yield results confounded by differential expectancies for relaxation. Furthermore, the role of expectancies in producing psychological and physical relaxation as well as reducing muscle activity is unclear. This study investigated the effects of feedback delays and induced relaxation expectancies on EMG activity and experienced relaxation. One hundred four non-clinical subjects participated in one auditory frontal EMG biofeedback training session. Subjects were assigned to one of four computerized feedback delay conditions (0.0037, 0.7493, 2.2481, 6.7444 s) and to one of two relaxation expectancy conditions (positive or negative). During 20 minutes of biofeedback training, all groups decreased frontal activity. Feedback delays interacted with training epochs in affecting EMG; the longest delay group reduced frontal activity more slowly than the shortest delay group during training. Positive relaxation expectancies produced greater experienced relaxation than did negative relaxation expectancies. Instrumental and expectancy factors in EMG biofeedback appear to operate independently of each other by reducing physiological activity and producing psychological relaxation respectively.     

Effects of discrete visual feedback on the electrodermal control of a stressful situation

Two groups of human volunteers received three sessions of discriminated avoidance and punishment with the skin resistance response (SRR) as the operant. During each session one group (feedback) received three 6–8-min periods of Sidman avoidance of a 1.5-mA shock (R-S=40 sec, S-S=35 sec) mixed with three periods of punishment with a 20-sec time-out after each period. The avoidance and punishment periods were signaled by red and green lights, and a circle appeared superimposed on the discriminative stimuli for the duration of a criterion response. A second group (no feedback) received the same conditions as the feedback group except that no circle appeared. Instructions to the subject were not informative regarding experimental events. Subjects made significantly more SRR's during avoidance, a contingency in which responding prevented shock, than during punishment, a contingency in which responding produced shock. A reliable four-way interaction suggested that the feedback stimulus curtailed a tendency for avoidance response rate to diminish within and between experimental sessions. The data are considered as evidence for electrodermal (autonomic) control of two different stressful situations, and the potential value of the paradigm for establishing tonic autonomic arousal and suppression is considered.This research was supported by the Charles L. Mix Memorial Fund. The data were collected in part by M. D. McCrary.     

Biofeedback training in frontalis muscle relaxation and enhancement of belief in personal control

The hypothesis that biofeedback training in frontalis muscle relaxation increases beliefs in internal (personal) locus of control was tested. Subjects were divided into two groups (internals and externals) based on Mirels' (1970) factor analyzedpersonal control subscale of Rotter's (1966) I-E Scale. Internal and external subjects were assigned randomly to one of three conditions: biofeedback (BF), false feedback (FF), or no feedback (NF). All subjects were measured on frontalis electromyographic (EMG) activity. Training consisted of three sessions spaced 1 week apart. Each session was comprised of a 5-minute baseline (nonfeedback) trial followed by a 20-minute experimental session. After each experimental session, subjects completed a questionnaire which assessed the extent to which they attributed their EMG performance to personal and environmental sources. After three sessions, subjects were posttested on the I-E Scale. Results indicated that subjects receiving BF reduced their EMG activity more than did subjects in either the FF or NF conditions, and this effect was maintained across all three sessions. Subjects who received BF shifted toward internal personal locus of control from pre- to posttesting, whereas no such change was found for either FF or NF subjects. Also, the relationship between BF training and change in personal locus of control was mediated by subjects attributing their EMG reduction more to personal effort than to properties of the task. Results are discussed in terms of the importance of contingent feedback as a determinant of cognitions of control.     

Expectancies of reinforcement control in biofeedback and cognitive performance

This study investigated the effects of expectancies concerning the controllability of outcomes in a biofeedback task. Forty-eight college undergraduates were subjects. Frontal (forehead) electromyographic (EMG) responses were measured during baseline (no treatment), pretreatment, and test sessions. During pretreatment, subjects were assigned to one of three groups. Using a fictitious blood vessel control task, the success group received false feedback and instructions that conveyed that outcomes had been successfully controlled. The failure group received feedback and instructions that conveyed that outcomes had not been controlled. A control group was given no specific task. During the subsequent test stage, all subjects were asked to reduce frontal muscle tension levels through relaxation while assisted with true EMG feedback. Relative to the success and control groups, EMG levels of the failure group reflected more rapid acquisition of frontal muscle relaxation. However, performance on a cognitive task was not affected by the pretreatment. It was concluded that expectancies generated during the false feedback pretreatment were related to later biofeedback performance. The results were discussed in terms of concepts of locus of control and theories of learned helplessness and reactance.A version of this paper was presented at the annual meeting of the Biofeedback Society of America, San Diego, 1979.     

Voluntary heart rate deceleration: A critical evaluation

This experiment was designed as a test of the view that the human heart rate (HR) deceleration response can be brought under voluntary control, when some form of exteroceptive feedback is available. Sixteen female volunteers were randomly assigned to two groups. The first group received instructions to decrease their HR plus a continuous negative (failure) binary feedback, while the second group received only the instructions. Each subject was given four sessions of HR deceleration training. Two identical tests were presented, one before and the other after the series of training sessions. These tests were divided into two parts. In the first part, subjects attempted to decrease their HR while undergoing an ischemic arm pain stress. In the second part, subjects performed a 40-trial HR discrimination task. The results indicate that all subjects decrease HR during both rest and voluntary control periods within each training session, but there are no significant group differences, no improvement in HR deceleration control over the four training sessions, and no difference in performance between rest and voluntary control periods. Similarly HR, blood pressure (BP), and the HR×BP product levels during the ischemic stress condition and the HR discrimination performance do not show group differences. It is suggested that the HR deceleration response may not meet the criteria generally applied to the definition of a voluntary response.     

Comparisons of high, medium, and low feedback sensitivity for the control of heart-rate acceleration

Thirty-four student volunteers were randomly assigned to one of three feedback sensitivity conditions: high sensitivity, medium sensitivity, or low sensitivity. Each subject received four sessions of biofeedback training with instructions to accelerate heart rate. In each condition, analogue feedback was provided during heart-rate acceleration trials. In addition to heart rate, frontal EMG and digital skin temperature were also recorded. Results replicated and extended the findings of a previous study in that medium and low sensitivity feedback was found to be superior to high sensitivity feedback during the final training session. These results confirm previous findings that a high sensitivity feedback produces very poor control of heart-rate acceleration. These data were discussed in terms of motor skills theory and in terms of possible effects of feedback sensitivity upon the motivation of subjects.     

Respiratory Sinus Arrhythmia Versus Neck/Trapezius EMG and Incentive Inspirometry Biofeedback for Asthma: A Pilot Study

This pilot study compared biofeedback to increase respiratory sinus arrhythmia (RSA) with EMG and incentive inspirometry biofeedback in asthmatic adults. A three-group design (Waiting List Control n = 5, RSA biofeedback n = 6, and EMG biofeedback n = 6) was used. Six sessions of training were given in each of the biofeedback groups. In each of three testing sessions, five min. of respiratory resistance and EKG were obtained before and after a 20-min biofeedback session. Additional five-min epochs of data were collected at the beginning and end of the biofeedback period (or, in the control group, self-relaxation). Decreases in respiratory impedance occurred only in the RSA biofeedback group. Traub-Hering-Mayer (THM) waves (.03-.12 Hz) in heart period increased significantly in amplitude during RSA biofeedback. Subjects did not report significantly more relaxation during EMG or RSA biofeedback than during the control condition. However, decreases in pulmonary impedance, across groups, were associated with increases in relaxation. The results are consistent with Vaschillo's theory that RSA biofeedback exercises homeostatic autonomic reflex mechanisms through increasing the amplitude of cardiac oscillations. However, deep breathing during RSA biofeedback is a possible alternate explanation.     

Biofeedback modification of frontal EMG in normal subjects

We carried out a controlled study on the voluntary control of the frontalis muscle by biofeedback procedures employing 20 normal subjects. Subjects were randomly divided into two groups of 10: (1) the biofeedback group and (2) the control group. Each of the two groups received five training sessions of about 40 minutes' duration each on different days. The results obtained are as follows: (1) In the biofeedback group, mean EMG levels decreased progressively and markedly from 2.16µVp-p min in the first session to 1.54µVp-p min in the last session. On the contrary, the control group did not show constant decreases in EMG levels over sessions. (2) The changes in the heart rate did not correlate with the changes in EMG activity. (3) The changes in the respiratory rate correlated with the changes in EMG activity.     

The effects of the distribution of training on learning feedback-assisted cardiac acceleration

In order to test a hypothesis derived from a motor skills learning model of cardiac acceleration control, groups of subjects were given biofeedback training for four sessions to learn cardiac acceleration under four different training schedules: (1) all sessions in one day, (2) daily sessions, (3) sessions every other day, and (4) weekly sessions. Ability to accelerate heart rate both with and without feedback was determined at each session. Also ability to accelerate heart rate without feedback was determined 1 week after the last training session as a measure of retention. Although there was highly significant (p less than.0001) evidence of heart rate control both with and without feedback, there were no differences in degree of control attributable to distribution of training sessions. There was, however, a trend (p less than .10) for subjects trained under the most distributed training schedule (weekly) to show more retention than subjects trained under a less distributed schedule (daily).     

Fine body movement during autogenic training

A sensitive electronic device (static sensograph) was used to record fine body movement in two similar groups of normal high school girls at intervals over a few months. One group received weekly instructions in the technique of autogenic training (AT) and was urged to practice it daily, whereas the other (control group) received no such instructions. In the AT group mean body movement (eyes closed, sitting position) decreased with every session. At 3 and 4.5 months after training was begun (sessions 3 and 4, respectively) mean body movement of this group was significantly lower than in the first session, before training was begun. In the fourth (but not earlier) sessions the AT group also showed a significant decrease in mean body movement during AT compared with the periods immediately preceding and following it. In contrast, the control group showed no significant differences in means between any sessions or periods within a session. The results suggest that fine body movement as measured by a static sensograph is a useful parameter for studying AT and probably other relaxation procedures.Visiting professor from the Australian National University, supported by the Japan Society for the Promotion of Science.     

The use and utility of EMG biofeedback with chronic schizophrenic patients

This study examined the efficacy of muscle relaxation training via electromyographic (EMG) biofeedback from the frontalis and forearm extensor muscles of schizophrenic inpatients. Thirty chronically hospitalized patients were randomly assigned to one of three conditions: EMG biofeedback from the forearm extensor and frontalis muscles, progressive relaxation, and a control group. Treatment consisted of one session of orientation and baseline, and six sessions of training. The results indicated that the schizophrenic patients receiving EMG training had significantly lower EMG recordings than the progressive relaxation group, which, in turn, was significantly lower than the control group. Analyses of covariance on the Tension-Anxiety scale from the Profile of Mood States revealed no significant effects, while finger-tapping rates were significantly improved only for the arm receiving feedback training in the EMG group. On the Nurses Observation Scale for Inpatient Evaluation the biofeedback group significantly improved on the Social Competence and Social Interest factors.     

Biofeedback modification of frontal EMG in normal subjects

We carried out a controlled study on the voluntary control of the frontalis muscle by biofeedback procedures employing 20 normal subjects. Subjects were randomly divided into two groups of 10: (1) the biofeedback group and (2) the control group. Each of the two groups received five training sessions of about 40 minutes' duration each on different days. The results obtained are as follows: (1) In the biofeedback group, mean EMG levels decreased progressively and markedly from 2. 16 muVp-p min the first session to 1.54 muVp-p min in the last session. On the contrary, the control group did not show constant decreases in EMG levels over sessions. (2) The changes in the heart rate did not correlate with the changes in EMG activity. (3) The changes in the respiratory rate correlated with the changes in EMG activity.     

Change Mechanisms Associated with Combined Relaxation/EMG Biofeedback Training for Chronic Tension Headache

Therapeutic mechanisms hypothesized to underlie improvements in tension headache activity achieved with combined relaxation and eleclromyographic (EMG) biofeedback therapy were examined. These therapeutic mechanisms included (1) changes in EMG activity in frontal and trapezii muscles, (2) changes in central pain modulation as indexed by the duration of the second exteroceptive silent period (ES2), and (3) changes in headache locus of control and self-efficacy. Forty-four young adults with chronic tension-type headaches were assigned either to six sessions of relaxation and EMG biofeedback training (N = 30) or to an assessment only control group (N = 14) that required three assessment sessions. Measures of self-efficacy and locus of control were collected at pre- and posttreatment, and ES2 was evaluated at the beginning and end of the first, third, and lost session. EMG was monitored before, during, and following training trials. Relaxation/EMG biofeedback training effectively reduced headache activity: 51.7% of subjects who received relaxation/biofeedback therapy recorded at least a 50% reduction in headache activity following treatment, while controls failed to improve on any measure. Improvements in headache activity in treated subjects were correlated with increases in self-efficacy induced by biofeedback training but not with changes in EMG activity or in ES2 durations. These results provide additional support for the hypothesis that cognitive changes underlie the effectiveness of relaxation and biofeedback therapies, at least in young adult tension-type headache sufferers.     

Feedback delays and relaxation expectancies in EMG biofeedback

The use of noncontingent feedback controls in studies of the efficacy and process of electromyographic (EMG) biofeedback may yield results confounded by differential expectancies for relaxation. Furthermore, the role of expectancies in producing psychological and physical relaxation as well as reducing muscle activity is unclear. This study investigated the effects of feedback delays and induced relaxation expectancies on EMG activity and experienced relaxation. One hundred four non-clinical subjects participated in one auditory frontal EMG biofeedback training session. Subjects were assigned to one of four computerized feedback delay conditions (0.0037, 0.7493, 2.2481, 6.7444 s) and to one of two relaxation expectancy conditions (positive or negative). During 20 minutes of biofeedback training, all groups decreased frontal activity. Feedback delays interacted with training epochs in affecting EMG; the longest delay group reduced frontal activity more slowly than the shortest delay group during training. Positive relaxation expectancies produced greater experienced relaxation than did negative relaxation expectancies. Instrumental and expectancy factors in EMG biofeedback appear to operate independently of each other by reducing physiological activity and producing psychological relaxation respectively.This study was completed by the first author under the direction of the second author in partial fulfillment of the requirements for the Master of Arts degree. We gratefully acknowledge the computerization advice and assistance provided by Larry Wheeler, and the assistance in data collection provided by Dawn Dexter and Michael Winstanley.     

Biofeedback-assisted sexual arousal in females a comparison of visual and auditory modalities

This study was undertaken to investigate the effects of instructional set and biofeedback modality upon the ability of 23 females to achieve control over sexual arousal. Two levels of instructional set (increase, decrease) were completely crossed with three feedback modalities (audio, visual, no feedback). Changes in vaginal blood volume (VBV) and vaginal pulse amplitude (VPA) were monitored by a vaginal plethysmograph and reduced on line by a microcomputer. During feedback trials, all subjects received audio- or visual feedback of the VBV response. Subjects participated in two sessions, each consisting of six 3-minute trials, one in each instruction/feedback combination. Order of trials was counterbalanced. Subjective levels of arousal, VBV, and VPA were significantly higher under increase instructions. Also, a significant feedback effect was noted in the subjective measure and the VBV measure, favoring visual feedback for overall control of sexual arousal. However, the feedback effect accounted for a small portion of the variance, and it was concluded that performance was not appreciably superior with or without feedback. Thus practical considerations may determine the feedback modality to be used for vaginal vasocongestion in future research. Higher positive correlations of subjective ratings with vaginal blood volume occurred during feedback trials, which suggests that biofeedback may be helpful in discrimination training to facilitate awareness of the feelings associated with different arousal levels and correct labeling of increased vasocongestion as sexual. Further research is necessary to see if sexually dysfunctional women can benefit from a biofeedback component in a comprehensive therapy program and to determine the effect of many training sessions on discrimination and self-control of arousal.     

Biofeedback-assisted sexual arousal in females: a comparison of visual and auditory modalities

This study was undertaken to investigate the effects of instructional set and biofeedback modality upon the ability of 23 females to achieve control over sexual arousal. Two levels of instructional set (increase, decrease) were completely crossed with three feedback modalities (audio, visual, no feedback). Changes in vaginal blood volume (VBV) and vaginal pulse amplitude (VPA) were monitored by a vaginal plethysmograph and reduced on line by a microcomputer. During feedback trials, all subjects received audio- or visual feedback of the VBV response. Subjects participated in two sessions, each consisting of six 3-minute trials, one in each instruction/feedback combination. Order of trials was counterbalanced. Subjective levels of arousal, VBV, and VPA were significantly higher under increase instructions. Also, a significant feedback effect was noted in the subjective measure and the VBV measure, favoring visual feedback for overall control of sexual arousal. However, the feedback effect accounted for a small portion of the variance, and it was concluded that performance was not appreciably superior with or without feedback. Thus practical considerations may determine the feedback modality to be used for vaginal vasocongestion in future research. Higher positive correlations of subjective ratings with vaginal blood volume occurred during feedback trials, which suggests that biofeedback may be helpful in discrimination training to facilitate awareness of the feelings associated with different arousal levels and correct labeling of increased vasocongestion as sexual. Further research is necessary to see if sexually dysfunctional women can benefit from a biofeedback component in a comprehensive therapy program and to determine the effect of many training sessions on discrimination and self-control of arousal.     

Flexibility development in sprinters using EMG biofeedback and relaxation training

This study compared the effectiveness of electromyographic (EMG) biofeedback and relaxation treatment in producing flexibility increases at the hip joint. Retention of flexibility gains and changes in sprinting performance were also examined. Fifteen male and 15 female athletes, predominantly sprinters, were matched according to age, sex, and flexibility and were randomly assigned to one of three groups. The control group received only the testing, the biofeedback group received visual and auditory EMG training, and the relaxation group received modified PMR and imagery exercises. Subjects in the two experimental groups were given eight twice-weekly 10-minute sessions and then were retested for flexibility. Retention of flexibility was reassessed 2 and 4 weeks later. Sprint performance improved for all groups. EMG biofeedback and relaxation treatment methods were no more effective than stretching exercises used by the control group for improving flexibility during the treatment period, but they did produce evidence of superior flexibility gains in the retention period. This may be important as flexibility has been reported to be related to the incidence of injuries.