Clinical and electromyographic effects of biofeedback training in mandibular dysfunction

Twenty patients with mandibular dysfunction, 10 acute and 10 chronic, were trained with electromyographic biofeedback from either m. masseter or m. frontalis area. The electromyographic activity in both muscle areas were recorded during six training sessions. The mean electromyographic activity decreased significantly within the sessions for both muscle areas, progressively more often for the m. masseter area. The activity did not decrease significantly between sessions for any muscle area. The clinical and subjective symptoms of mandibular dysfunction improved significantly after the training. No differences, electromyographically or clinically, among acute, chronic, m. masseter area, or m. frontalis area feedback patients could be observed. No correlation between decrease in electromyographic activity and symptoms could be established. Since a simplistic neuromuscular learning model for biofeedback training gains little support from these results, alternative views are discussed.This research was supported by grants to Sven G. Carlsson and Elliot N. Gale from the Swedish Council for Research in the Humanities and Social Sciences.     

Clinical and electromyographic effects of biofeedback training in mandibular dysfunction

Twenty patients with mandibular dysfunction, 10 acute and 10 chronic, were trained with electromyographic biofeedback from either m. masseter or m. frontalis area. The electromyographic activity in both muscle areas were recorded during six training sessions. The mean electromyographic activity decreased significantly within the sessions for both muscle areas, progressively more often for the m. masseter area. The activity did not decrease significantly between sessions for any muscle area. The clinical and subjective symptoms of mandibular dysfunction improved significantly after the training. No differences, electromyographically or clinically, among acute, chronic, m. masseter area, or m. frontalis area feedback patients could be observed. No correlation between decrease in electromyographic activity and symptoms could be established. Since a simplistic neuromuscular learning model for biofeedback training gains little support from these results, alternative views are discussed.     

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.     

Effects of an EMG biofeedback relaxation program on the control of diabetes

It was hypothesized that EMG biofeedback relaxation training, applied to a diabetic patient, would result in a decreased level of insulin with fewer episodes of ketoacidosis. A 20-year-old female, diabetic since age nine, kept daily records of insulin doses and rated herself on an emotionality and a diabetic scale. A full-semester baseline was taken. This was followed by a semester-long training program during which the patient practiced relaxing her frontalis muscle with a portable EMG feedback unit which produced a geiger-counter-like click feedback. A cassette-tape series was used along with the portable EMG. The patient was encouraged to practice twice each day and to attempt to maintain a relaxed state even when not in the practice situation. The daily use of the portable unit was terminated at the end of the semester. In addition, the patient ceased practicing twice daily with the cassette tape. Daily insulin averaged 85 units for the six-week baseline and 59 for the final six weeks of the training period. Moreover, at the end of the training period the average dose had reached 43 units. During the training period the patient rated herself as decreasing in emotionality and in diabetic fluctuations.Supported by the National Institute of Mental Health Grant MH-15596.     

Treatment of posttraumatic stress disorder with relaxation and biofeedback training

This study investigated the use of biofeedback and relaxation training on six patients with posttraumatic stress disorder (PTSD) referred routinely for biofeedback treatment in a VA medical center. Subjects received between 8 and 14 sessions of training overall, as well as concurrent individual and group therapy. Measures used to assess treatment outcome include pre- and posttreatment MMPI, State-Trait Anxiety Inventory, Beck Depression Inventory, and Multidimensional Health Locus of Control scores, as well as electromyographic and subjective measures of tension within each session. Additionally, an overall posttreatment clinical rating of change and 1- to 2-year follow-up data were obtained for each subject. Slight to marked improvements were demonstrated for each subject, as evidenced by improvements on the State Anxiety Inventory Scale and the Beck Depression Inventory, a decrease in overall MMPI scores, and lowered EMG and subjective tension ratings for all participants. Possible alternative explanations for improvement (situational demand characteristics, regression toward the mean, lack of independent subject evaluation) are described, along with other study limitations. This preliminary investigation suggests that the use of relaxation training and biofeedback may be a particularly useful component within a comprehensive treatment program for this disorder.     

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.     

Effects of electromyographic biofeedback on quadriceps strength: a systematic review

Quadriceps strength is a vital component to lower extremity function and is often the focus in resistance training interventions and injury rehabilitation. Electromyographic biofeedback (EMGBF) is frequently used to supplement strength gains; however, the true effect remains unknown. Therefore, the objective of this investigation was to determine the magnitude of the treatment effect for EMGBF on quadriceps strength compared with that of placebo and traditional exercise interventions in both healthy and pathological populations. Web of Science and ProQuest databases were searched, and bibliographies of relevant articles were crossreferenced. Six articles measuring isometric quadriceps strength in response to EMGBF training were included and methodologically assessed using the Physiotherapy Evidence Database (PEDro). Standardized effect sizes with 95% confidence intervals (CIs) were calculated from preintervention and postintervention measures for EMGBF, placebo, and exercise-only interventions. Separate comparisons were made between studies assessing different intervention length (<4 and ≥4 weeks) and patient populations (pathological and healthy). Articles included received an average PEDro score of 6.5 ± 0.84. Homogeneous EMGBF effect sizes were found in all 6 studies (d = 0.01-5.56), with 4 studies reporting CI that crossed 0. A heterogeneous collection of effect sizes was found for exercise alone (d = -0.12 to 1.18) and placebo (d = -0.2 to 1.38), with 4 and 1 studies having a CI that crossed 0, respectively. The greatest EMGBF effects were found in pathological populations (d = 0.01-5.56), with the strongest effect found in the subjects with knee osteoarthritis (d = 5.56, CI = 4.26-6.68). As a group, effects were the strongest for EMGBF compared with that of placebo and exercise-only interventions, yet definitive evidence that EMGBF is beneficial for increasing quadriceps strength could not be concluded because of the 4 studies demonstrating a wide CI.     

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.     

Locus of control and frontal electromyographic response training

Forty-eight normal subjects from a college population, representing extreme internal and external orientations on a locus of control scale, were provided an auditory signal in a laboratory relaxation setting. For one group (feedback) the pitch of the signal varied as a function of frontal electromyographic (EMG) levels, while for another group (control) the pitch was constant. The feedback subjects acquired lower EMG potentials than did the control subjects, and the internal subjects in the feedback condition acquired lower levels than did the external subjects. In the control condition, no consistent differences in EMG levels between internal and external subjects were obtained. These results were stable across two replications, three ethnically distinct groups, and both sexes. Additional measures designed to reflect the effects of the frontal EMG training as a generalized relaxation technique for this population, including finger temperatures and a variety of postexperiment questionnaire ratings of relaxation, yielded negative results. Tests of other predictions from the locus of control construct are also discussed.This research was supported by NIMH Special Postdoctoral Fellowship No. MH58202-01.     

Biofeedback-induced relaxation training as an alternative for the elementary school learning-disabled child

This study examined the effects of biofeedback-induced relaxation training on attention to task, impulsivity, and locus of control among 32 learning-disabled children between the ages of 8 and 11 years. Attention to task and impulsivity were measured by the Matching Familiar Figures Test and locus of control was measured by the Nowicki-Strickland Scale. Participants were randomly assigned to experimental (N=16) and control (N=16) groups. The study spanned a total of 8 weeks, with the experimental treatment consisting of three sessions spaced approximately 2 weeks apart. The treatment included EMG biofeedback training used with relaxation tapes. Univariate F values and discriminant analysis procedures revealed that the attention to task and impulsivity measures proved to be valid discriminators, respectively beyond the .01 and .05 levels of significance. Experimental group subjects had significantly fewer number of errors on the attention to task measure and significantly lower impulsivity scores. It was concluded that the biofeedback-induced relaxation training affords promise in assisting learning-disabled children in reaching their education potentials. It was recommended that future research examine the long-term efficacy and the transfer to school-related tasks of this intervention.     

Biofeedback-induced relaxation training as an alternative for the elementary school learning-disabled child

This study examined the effects of biofeedback-induced relaxation training on attention to task, impulsivity, and locus of control among 32 learning-disabled children between the ages of 8 and 11 years. Attention to task and impulsivity were measured by the Matching Familiar Figures Test and locus of control was measured by the Nowicki-Strickland Scale. Participants were randomly assigned to experimental (N = 16) and control (N = 16) groups. The study spanned a total of 8 weeks, with the experimental treatment consisting of three sessions spaced approximately 2 weeks apart. The treatment included EMG biofeedback training used with relaxation tapes. Univariate F values and discriminant analysis procedures revealed that the attention to task and impulsivity measures proved to be valid discriminators, respectively beyond the .01 and .05 levels of significance. Experimental group subjects had significantly fewer number of errors on the attention to task measure and significantly lower impulsivity scores. It was concluded that the biofeedback-induced relaxation training affords promise in assisting learning-disabled children in reaching their education potentials. It was recommended that future research examine the long-term efficacy and the transfer to school-related tasks of this intervention.     

A multiple-baseline evaluation of the treatment of subjective tinnitus with relaxation training and biofeedback

Six subjects with subjective tinnitus received training in relaxation techniques and EMG and thermal biofeedback in a multiple-baseline across-subjects design. Daily tinnitus disturbance and sleep disturbance diaries were kept throughout. Audiological and psychological evaluations were made at various treatment phases. At posttreatment assessment, subjects also completed global ratings of their perceived improvement in ability to cope with the tinnitus, stress caused by the tinnitus, and severity of the tinnitus, as well as their overall satisfaction with the treatment. Ratings on the global scales were generally very positive. By way of contrast, the daily diary results revealed little if any treatment effect. The implications of these disparate results are discussed.     

A multiple-baseline evaluation of the treatment of subjective tinnitus with relaxation training and biofeedback

Six subjects with subjective tinnitus received training in relaxation techniques and EMG and thermal biofeedback in a multiple-baseline across-subjects design. Daily tinnitus disturbance and sleep disturbance diaries were kept throughout. Audiological and psychological evaluations were made at various treatment phases. At posttreatment assessment, subjects also completed global ratings of their perceived improvement in ability to cope with the tinnitus, stress caused by the tinnitus, and severity of the tinnitus, as well as their overall satisfaction with the treatment. Ratings on the global scales were generally very positive. By way of contrast, the daily diary results revealed little if any treatment effect. The implications of these disparate results are discussed.     

Effects of group relaxation training and thermal biofeedback on blood pressure and related physiological and psychological variables in essential hypertension

One hundred and one patients, 70 experimental and 31 controls, with a diagnosis of essential hypertension, were examined for the effects of group relaxation training and thermal biofeedback on blood pressure and on other psychophysiologic measures: heart rate, forehead muscle tension, finger temperature, depression, anxiety, plasma aldosterone, plasma renin activity, and plasma and urinary cortisol. Eighty percent of the participants were medicated. Treatment yielded a short-term success rate, defined as a decrease in mean arterial pressure of 5 mm Hg, of 49% in the experimental group. Other significant short-term changes included a reduction of forehead muscle tension, state anxiety, plasma aldosterone, and increased finger temperature. Follow-up measurements were made approximately 10 months after treatment in 36 patients, 51% of the treatment completers. Twenty of the 36 were short-term treatment failures, while 16 were treatment succeeders. Thirty-seven percent of the short-term succeeders continued to meet blood pressure criterion at follow-up. In short-term succeeders, continued practice of relaxation may influence long-term maintenance of decreased blood pressure. It is suggested that group relaxation training can be beneficial for short-term and long-term adjunctive treatment of essential hypertension in selected individuals.I greatly appreciate the assistance of Minda Sogocio, Judy Stewart, and Kay Gerstenmaier from the Toledo Health Department, and Ilona Jurek, Carrie Wakai, and Robert Spain from the Medical College of Ohio at Toledo. This research was supported by a grant to A. McGrady through the Hypertension Control Program of the City of Toledo Health Department, from the Ohio Department of Health.     

Temperature biofeedback and relaxation training in the treatment of migraine headaches. One-year follow-up.

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 1 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.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.     

Interpersonal stress and style as predictors of biofeedback/relaxation training outcome: preliminary findings

Although the data base describing clinical outcome following biofeedback/relaxation training is accumulating, there have been relatively few attempts to predict short-term outcome, and even fewer for long-term outcome. Significant short-term outcome predictors have been identified, and they often allude to the level of psychological distress as a major factor affecting outcome. To investigate further the role of psychological variables in outcome prediction, this project presents preliminary findings that demonstrate the relationship involving interpersonal psychological stress, interpersonal style of behavior, and outcome. With a very heterogeneous group of patients (N = 39), measures of interpersonal style of behavior were used to discriminate correctly 80% of cases by outcome at the 3-month postadmission evaluation. With a more homogeneous group having somatic disorders alone (headache, Raynaud's, etc.), the accuracy of prediction at 3 months was 90%. No measures were capable of predicting long-term outcome with accuracies even moderately greater than chance. The results indicate that style of interpersonal behavior (e.g., managerial, dependent) and, to a lesser extent, interpersonal stress is predictive of short-term outcome following biofeedback/relaxation training. Individuals who tend to like responsibility and who are more executive and independent generally benefited more than doubtful, obedient, and depressed individuals. While the resulting prediction rates were only slightly more accurate than MMPI D and Pt subscales alone, the procedures provide additional information regarding the personality characteristics of successful and unsuccessful biofeedback clients, and may also provide the clinician with information regarding treatment choice if biofeedback is provided as an adjunct to psychotherapy.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.