Trachea-noise biofeedback in asthma: A comparison of the effect of trachea-noise biofeedback,a bronchodilator,and no treatment on the rate of recovery from exercise- and eucapnic hyperventilation-induced asthma

We review some of the evidence that supports the existence of psychosomatic triggers to bronchospasm in asthmatics, and hypothesize that it may also be possible to consciously reverse bronchospasm using trachea-noise biofeedback. We precipitated significant levels of bronchospasm in 16 asthmatics using exercise or eucapnic-hyperventilation challenges on five occasions, and administered four different treatments and a no-treatment control. The treatments were trachea-noise biofeedback (TNBF), wrong-information TNBF, an inhaled adrenergic bronchodilator, and a placebo inhaler, all given double blind. Half of the subjects had 3 training days in the use of the TNBF device before study. Our results show that TNBF, in the trained subjects only, is associated with a detectable, but not statistically significant, increase in the rate of recovery from bronchospasm over that found with no treatment. We conclude that, although asthmatics seem to have a strong ability to consciously induce bronchospasm, conscious reversal of a full asthma attack using TNBF is limited. Despite contrary conclusions by other investigators, we believe that this study demonstrated little TNBF-assisted recovery from bronchospasm. We suggest that this is because its effect may be inhibited by humoral mechanisms that sustain the attack, but we believe further work is required to support this.The authors wish to thank Dr. Graham Williams for his assistance. This work was sponsored by South East Thames Regional Health Authority, England.     

An alternative perspective on biofeedback efficacy studies: a reply to Steiner and Dince

Clinical applications of biofeedback have proliferated and considerable lore surrounding the application of these techniques has evolved. Many assertions about the effectiveness of biofeedback training are based on findings of the least well-controlled studies, while many of the better controlled studies have failed to show that biofeedback directly mediates target symptoms or is superior to other treatments. Steiner and Dince (1981) suggest that the failure of these controlled studies is primarily attributable to methodological deficiencies. We believe that the question of whether or not there is a specific effect of biofeedback training is still frequently confused with the question of whether or not the treatment package as a whole has therapeutic value. Biofeedback is often therapeutic; however, evidence is often lacking that its effectiveness is due to biofeedback-trained changes in a target physiological process.     

Effect of mechanomyography as a biofeedback method to enhance muscle relaxation and performance

The purpose of the study was to examine the potential for using the mechanomyographic (MMG) signal as a biofeedback method to enhance muscular relaxation and to improve performance during forearm flexion repetitions to fatigue. Twelve adult (mean +/- SD; age: 22.0 +/- 1.1 years) moderately trained subjects (weight: 82.3 +/- 29.2 kg; height: 165.7 +/- 49.0 cm) were instructed to relax the biceps brachii muscle using MMG biofeedback (BIO) provided by viewing a computer screen graphically displaying the MMG signal and then without using MMG biofeedback (NOBIO). Electromyographic (EMG) and MMG signals were detected midway over the biceps brachii during the relaxation protocol. In subsequent visits to the laboratory, subjects performed as many repetitions as possible at 85% of 1 repetition maximum with BIO and NOBIO using the seated preacher curl exercise. Two-way (biofeedback x gender) mixed factorial analyses of variance revealed significantly (p < 0.05) lower MMG (mean +/- SEM; BIO = 0.6 +/- 0.1 mV; NOBIO = 1.1 +/- 0.2 mV) and EMG amplitudes (BIO = 6.6 +/- 0.6 microV; NOBIO = 9.4 +/- 1.4 microV) for BIO when subjects were instructed to relax the biceps brachii muscle. There was no significant difference in the number of forearm flexion repetitions performed for BIO (mean +/- SD; 7.9 +/- 0.4 reps) vs. NOBIO (8.1 +/- 0.6 reps). The results of the present study revealed that using MMG as a biofeedback technique can enhance the development of muscle relaxation, but is not useful in delaying fatigue during forearm flexion repetitions. Our results may have been influenced by a relatively short training phase designed to teach subjects to use the MMG signal as a biofeedback method. Future studies are needed to determine whether MMG biofeedback can be used for other purposes. If MMG is found to be useful as a biofeedback method, it has some distinct practical advantages over EMG that the strength and conditioning athlete and professional may find appealing.     

Relative efficacy of ritalin and biofeedback treatments in the management of hyperactivity

This study examined the efficacy of biofeedback and Ritalin treatments on hyperactivity as reflected by muscular electrical activity and as observed by teachers and parents. Eighteen male subjects between the ages of 10 and 13 were assigned to three groups, matched by age, IQ, and race. One group received 10 biofeedback sessions, another received Ritalin, and the third group controlled for nonspecific treatment effects. EMG readings, the Conners Teacher Rating Scale, the Werry-Weiss-Peters Scale, and the Zukow Parent Rating Scale were used to measure treatment efficacy. Results indicated that biofeedback-assisted relaxation significantly reduced muscle tension levels, whereas neither Ritalin nor personal attention produced significant change. On teacher ratings of hyperactivity, significant improvement was made by all three groups. Parent ratings on the Zukow scale indicated significant improvement by subjects in all groups. On the Werry-Weiss-Peters scale, the biofeedback and control groups made significant improvements in hyperactivity.     

Relative efficacy of Ritalin and biofeedback treatments in the management of hyperactivity

This study examined the efficacy of biofeedback and Ritalin treatments on hyperactivity as reflected by muscular electrical activity and as observed by teachers and parents. Eighteen male subjects between the ages of 10 and 13 were assigned to three groups, matched by age, IQ, and race. One group received 10 biofeedback sessions, another received Ritalin, and the third group controlled for nonspecific treatment effects. EMG readings, the Conners Teacher Rating Scale, the Werry-Weiss-Peters Scale, and the Zukow Parent Rating Scale were used to measure treatment efficacy. Results indicated that biofeedback-assisted relaxation significantly reduced muscle tension levels, whereas neither Ritalin nor personal attention produced significant change. On teacher ratings of hyperactivity, significant improvement was made by all three groups. Parent ratings on the Zukow scale indicated significant improvement by subjects in all groups. On the Werry-Weiss-Peters scale, the biofeedback and control groups made significant improvements in hyperactivity.     

EMG biofeedback and discriminative muscle control

The awareness model of biofeedback suggests that training teaches new skills or enhances performance at old skills, while the cognitive or feed-forward models suggest that biofeedback brings attention to the response of interest but does not actually increase task skill. In a test of the predictions made by these models, subjects were tested on one or more cross-modal matching tasks, provided brief training, and retested on the task(s). Thirty subjects participated in integer-matching tasks in which they were instructed to produce various levels of frontalis activity corresponding to the levels of a ratio scale. Forty-five subjects participated in a tone-matching task in which they tried to match their frontalis tension to the pitch of a tone. The results indicated that the groups receiving biofeedback training improved at the more difficult integer task and at the tone task. Subjects performed better on the integer tasks than at the tone task. Our findings suggest that an awareness model accounts for changes occurring during biofeedback training. However, an awareness model may be applicable only for tasks of moderate difficulty; for relatively easy tasks, a feed-forward model may be more appropriate. The clinical utility of cross-modal matching tasks is also described.This paper is based on a thesis conducted by the second author under the direction of the first author. Portions of this paper were presented at the annual meeting of the Association for Applied Psychophysiology and Biofeedback, March 1989, San Diego.     

EMG biofeedback and discriminative muscle control

The awareness model of biofeedback suggests that training teaches new skills or enhances performance at old skills, while the cognitive or feed-forward models suggest that biofeedback brings attention to the response of interest but does not actually increase task skill. In a test of the predictions made by these models, subjects were tested on one or more cross-modal matching tasks, provided brief training, and retested on the task(s). Thirty subjects participated in integer-matching tasks in which they were instructed to produce various levels of frontalis activity corresponding to the levels of a ratio scale. Forty-five subjects participated in a tone-matching task in which they tried to match their frontalis tension to the pitch of a tone. The results indicated that the groups receiving biofeedback training improved at the more difficult integer task and at the tone task. Subjects performed better on the integer tasks than at the tone task. Our findings suggest that an awareness model accounts for changes occurring during biofeedback training. However, an awareness model may be applicable only for tasks of moderate difficulty; for relatively easy tasks, a feed-forward model may be more appropriate. The clinical utility of cross-modal matching tasks is also described.     

EMG stability as a biofeedback control.

Factors that may confound comparisons between electromyographic (EMG) biofeedback training and its control conditions include feedback quality and experience of success. We investigated the usefulness of a control procedure designed to overcome these potential sources of confounding. The procedure consisted of training muscle tension stability. We used it as a control for frontal EMG relaxation training in children with asthma. To equate the groups for feedback quality and experience of success, we gave each child in the control condition audio feedback decreasing in pitch when muscle tension was at or near baseline levels, and feedback increasing in pitch when muscle tension was either substantially above or below baseline levels. Children in both groups were instructed to decrease the pitch of the tone. In comparison to children in the relaxation condition, the children in the control condition exhibited stable levels of muscle tension throughout eight training sessions. We concluded that feedback for stable muscle tension may be a useful control procedure for EMG biofeedback training whenever experimental and control procedures differ in either feedback quality of degree to which they permit subjects to experience success.     

EMG stability as a biofeedback control

Factors that may confound comparisons between electromyographic (EMG) biofeedback training and its control conditions include feedback quality and experience of success. We investigated the usefulness of a control procedure designed to overcome these potential sources of confounding. The procedure consisted of training muscle tension stability. We used it as a control for frontal EMG relaxation training in children with asthma. To equate the groups for feedback quality and experience of success, we gave each child in the control condition audio feedback decreasing in pitch when muscle tension was at or near baseline levels, and feedback increasing in pitch when muscle tension was either substantially above or below baseline levels. Children in both groups were instructed to decrease the pitch of the tone. In comparison to children in the relaxation condition, the children in the control condition exhibited stable levels of muscle tension throughout eight training sessions. We concluded that feedback for stable muscle tension may be a useful control procedure for EMG biofeedback training whenever experimental and control procedures differ in either feedback quality of degree to which they permit subjects to experience success.This research was supported by NIH-Grant HL 27402. We are grateful to Paul Schnitter who constructed the EMG stability feedback device.     

Electromyographic biofeedback training for tension headache in the elderly: a prospective study.

This study evaluated the effects of a 12-session frontal electromyographic biofeedback training regimen on the headache activity of eight tension headache sufferers aged 62 and older. The biofeedback sessions were slightly modified for a geriatric population, essentially to increase comprehension and retention of rationale and instructions. Post-treatment assessment at three months revealed significant decreases in overall headache activity (50% or greater) in 50% of the subjects, and moderate improvement (35%-45%) in three of the remaining four subjects. Significant clinical and/or statistical pre-post differences were also found for the number of headache-free days, peak headache activity, and medication index. This is the first prospective study of biofeedback training for tension headache in an elderly population and, unlike previous retrospective studies, suggests that such therapy may be an effective intervention in the treatment of tension headaches in the elderly.     

Multimodal biofeedback in the treatment of migraine

The purpose of this study was twofold: (a) to compare the effects of three behavioral strategies for the relief of migraine, and (b) to examine different combinations of the treatments to assess the effectiveness of multimodal biofeedback with this problem. Twenty-four volunteer migraine sufferers not on medication, and with at least weekly occurrence of headaches, participated in the study. Results indicated that (a) subjects who learned temporal cooling, frontalis relaxation, and progressive muscular relaxation exhibited the best success with headache relief; (b) control subjects, who did not show the same psychophysiological changes as experimental subjects, reported no headache relief; and (c) subjects in the group with only relaxation exercises performed similarly to control subjects and reported no headache relief.     

Muscular and intraocular pressure responses among ocular-hypertensive subjects: is there a rationale for biofeedback?

Several animal and human investigations have indicated that intraocular pressure (IOP) levels may be associated with extreme drug-induced changes in the extraocular muscles. Further, recent data suggest that, among individuals with normal IOP level, moderate increases in facial muscle (EMG) activity around the eye while the eye is open are associated with increases in IOP. To investigate further the relationship between facial EMG activity and IOP levels and to examine a group of individuals with elevated IOP levels, subjects were recruited from outpatients at an optometry clinic. Three groups of subjects were selected: a group of ocular hypertensive subjects who showed elevated pressures at the optometry clinic and upon the day of testing, a group of labile ocular hypertensive subjects who evinced elevated pressures during their visit to the optometry clinic but lower pressures on the day of testing, and a group of normal IOP subjects who showed normal pressures both during their optometry clinic visit and on the day of testing. To investigate anxiety differences, subjects were administered the State-Trait Anxiety Inventory, but subsequent analysis revealed no group differences. To evaluate the role of stress upon muscle (EMG) functioning around the eye, subjects were subjected to imagery and standardized mental arithmetic stressors; analyses of these results also revealed no significant group differences. Finally, subjects were given EMG biofeedback for muscle activity around the eye while IOP was assessed during five alternating periods in which they made decreases and increases in EMG activity. Results revealed significant group, period, and group by period interaction effects. The pattern of results is interpreted as implicating EMG activity in IOP fluctuations; the implications of these data for potential biofeedback and stress management treatments are discussed.     

Plasma catecholamine levels during temperature biofeedback training in normal subjects

Thirty-nine normal volunteers of both sexes were randomly assigned to receive 8 sessions of temperature biofeedback or autogenic training to increase finger temperature. Temperature biofeedback subjects produced significant elevations in finger temperature during training, whereas those who received autogenic training did not. Temperature feedback subjects had significantly higher heart rates and diastolic blood pressures during training compared to autogenic subjects. There were no significant changes or group differences in plasma catecholamine levels. These data do not support the hypothesis that feedback-induced vasodilation is accompanied by decreased sympathetic activation in normal populations, when only temperature biofeedback is employed.Supported by research grant No. HL-30604 from NHLBI. Dr. Angela McGuady served as Action Editor for this paper.     

Heat and water flux in the intrathoracic airways and exercise-induced asthma

To explore the relationship between the flux of heat and water within the respiratory tract during exercise and recovery to the development of exercise-induced asthma (EIA), we recorded airstream temperature at multiple points throughout the tracheobronchial tree in 10 normal and 10 asthmatic subjects before, during, and after cycle ergometry. In both groups, the intra-airway temperature fell progressively as ventilation increased, and there were no significant differences between the thermal profiles of the two populations at rest or during exercise. Calculation of water losses and the osmolality of the airway surface fluid failed to demonstrate significant airway drying in either group. With cessation of the work load, the airstream temperature increased abruptly, rising two times more rapidly in the asthmatics than the normals. Since the major source of heat in these experiments is the bronchial circulation, our findings suggest a reaction sequence consisting of vasoconstriction and airway cooling during exercise followed by a rapid resupply of heat when exercise ceases. The latter may cause the hyperplastic capillary bed in the airways of asthmatics to develop an exaggerated rebound hyperemia which may lead to airway edema and EIA.     

Temperature biofeedback and relaxation training in the treatment of migraine headaches

In a previous controlled group outcome study, a comparison of temperature biofeedback with progressive relaxation indicated that relaxation training was more effective in reducing migraine headache activity at the end of treatment. However, follow-up data obtained at 1, 2, and 3 months after the completion of treatment showed no difference between the two groups on any dependent measure. In the current study, 18 of 26 subjects who completed treatment in the original investigation collected headache data and completed a headache questionnaire I year subsequent to the conclusion of treatment in order to evaluate the long-term effectiveness of the two treatments. The results indicated that gains achieved in the reduction of headaches during both treatments were maintained at a 1-year follow-up. With the exception of medication consumption (for which relaxation training led to better long-term results) the 1-year follow-up data reveal no differential efficacy for temperature biofeedback or progressive relaxation in treating migraine headaches.     

Effectiveness of multiple-site EMG biofeedback in the reduction of arousal

During the training phase, 36 subjects received (a) EMG biofeedback from multiple muscle sites, (b) EMG biofeedback from the frontal site, or (c) no biofeedback. Results indicated that neither biofeedback procedure reduced self-reports of anxiety, but that multiple-site biofeedback was effective in reducing several indices of autonomic arousal (pulse rate, finger pulse volume, and skin temperature) while frontal biofeedback was not. During the generalization/stress phase, all subjects were threatened with and received electric shocks and were told to apply the relaxation techniques they learned during the training phase even though no additional biofeedback would be provided. Results indicated that multiple-site biofeedback was effective in reducing self-reports of anxiety and autonomic arousal but that frontal biofeedback was not. These results confirm previous data indicating that frontal biofeedback is not an effective procedure for controlling stress, but suggest that EMG biofeedback can be effective in reducing self-reported anxiety and autonomic arousal if a multiple muscle-site feedback procedure is employed.     

Use of audio biofeedback to reduce tibial impact accelerations during running

Visual biofeedback of tibial peak positive acceleration (PPA) during running has been used successfully as a method of gait retraining to reduce PPAs. Audio biofeedback generated from PPA may present a novel, portable alternative. The purpose of this study was to investigate the feasibility of using PPA-generated audio biofeedback to reduce PPAs while running. Nine runners were fitted with a wireless accelerometer on their left tibia. PPAs were recorded and a custom LabVIEW program was used to emit a single beep once the PPA reached a preset threshold. The numerical difference between this threshold and peak PPA during running was scaled to the pitch of the beep, such that a foot strike with greater PPA would result in a beep with higher pitch. Subjects were then instructed to (1) run without any beeps, and/or (2) keep the pitch of the beep as low as possible. Subjects participated in a single testing session that included a five minute warm-up and two rounds of biofeedback, which consisted of five minutes of running with biofeedback followed by five minutes of running without biofeedback. Subjects were able to significantly reduce PPAs during exposure to audio biofeedback. In addition, two rounds of biofeedback were sufficient for subjects to retain a reduction in PPAs without biofeedback. PPA-generated audio biofeedback therefore appears to be a feasible method of gait retraining to reduce PPAs in runners.     

The comparative effectiveness of heart rate biofeedback,speech skills training,and a combination of both in treating public-speaking anxiety

Forty-two speech-anxious undergraduate students (21 female, 21 male) were administered either heart rate biofeedback training, speech skills training, or a combination of both to aid in the alleviation of speech anxiety. Physiological (heart rate, tonic skin conductance level, systolic blood pressure, and diastolic blood pressure), overt motor, and self-report measures of anxiety were assessed during a pretreatment speech and two posttreatment speeches. Results indicated that all treatments were effective in lowering overt motor and self-report components of anxiety. However, only the biofeedback and combined group subjects demonstrated significantly less heart rate increase while speaking before an audience during the posttreatment assessment. Two individual difference variables examined in this study — cognitive/autonomic focus of anxiety and subjective confidence in treatment — were not found to significantly influence treatment effectiveness. Finally, factor analyses of the physiological data suggested that heart rate changes play a large role in the physiological component of anxiety.     

Learned helplessness and the facilitation of biofeedback performance

The present article reports the results of two studies, which, taken together, support the hypothesis that learned helplessness resulting in effort cessation, while detrimental to performance on cognitive tasks, is actually facilitative to performance in a biofeedback relaxation task. Data are presented indicating that false failure feedback leads to the typically reported decrement in performance on a cognitive arithmetic task, while such feedback leads to enhanced performance in biofeedback relaxation. Self-report data suggest that this occurs because when subjects encounter failure, they revise their expectancies of future success downward and consequently plan to exert less effort. Reduction of effort is proposed as the common mechanism underlying the contrast in results between the arithmetic and biofeedback tasks. Results are discussed in terms of their implications for the way in which theories of self-efficacy and learned helplessness are commonly interpreted.     

Cost effectiveness of biofeedback and behavioral medicine treatments: a review of the literature

This paper reviews multicomponent behavioral medicine studies that contain cost-effectiveness and or cost-benefit data relevant to the field of biofeedback and relaxation training, primarily when assisted by biofeedback, with or without stress management, in the treatment of psychosomatic illness and pain. A model for evaluating biofeedback treatment is presented. Cost-effectiveness data concerning reduction in physician visits and/or medication use, decrease in medical care costs to patients, reduction in hospital stays and rehospitalization, reduction of mortality, and enhanced quality of life are reviewed. Evidence suggests that multicomponent behavioral medicine treatments are cost-effective on all dimensions reviewed. Cost/benefit ratios range between 1:2 and 1:5, with a median of 1:4. Evidence that could increase the cost effectiveness of biofeedback is reviewed.