Effectiveness of emWave Biofeedback in Improving Heart Rate Variability Reactivity to and Recovery from Stress

The current study examined the efficacy of heart rate variability (HRV) biofeedback using emWave, a publicly available biofeedback device, to determine whether training affected physiological tone and stress responses. Twenty-seven individuals aged 18–30 years were randomized to a treatment or no-treatment control group. Treatment participants underwent 4–8 sessions of emWave intervention, and all participants attended pre-treatment and post-treatment assessment sessions during which acute stressors were administered. Physiological data were collected at rest, during stress, and following stress. emWave treatment did not confer changes in tonic measures of HRV or in HRV recovery following stress. However, treatment participants exhibited higher parasympathetic responses (i.e., pNN50) during stress presentations at the post-treatment session than their control counterparts. No treatment effects were evident on self-reported measures of stress, psychological symptoms, or affect. Overall, results from the current study suggest that the emWave may confer some limited treatment effects by increasing HRV during exposure to stress. Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in clinical settings, including the determination of what physiological changes are clinically meaningful during HRV biofeedback training.     

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.     

Effectiveness of multiple muscle-site EMG biofeedback and relaxation training in reducing the aversiveness of cancer chemotherapy

A 44-year-old female cancer patient was given progressive muscle relaxation training and multiple muscle-site EMG biofeedback to reduce the conditioned negative responses she had apparently developed to her chemotherapy treatments. Following three baseline chemotherapy sessions, the patient was given relaxation training and biofeedback during four consecutive chemotherapy treatments and was asked to practice her relaxation skills daily in the hospital or at home. After the patient felt able to relax on her own, relaxation training and biofeedback were terminated and three follow-up sessions were held. Results indicated that during the chemotherapy sessions in which the patient received relaxation training and biofeedback, she showed reductions in physiological arousal (EMG, pulse rate, systolic blood pressure, and diastolic blood pressure) and reported feeling less anxious and nauseated. Moreover, these changes were maintained during the follow-up sessions. These results suggest that relaxation training plus multiple muscle-site biofeedback may be an effective adjunctive procedure for reducing some of the adverse side effects of cancer chemotherapy.     

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.     

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.     

Effects of Relaxation Training on Glucose Tolerance and Diabetic Control in Type II Diabetes

The present study examined the effects of progressive relaxation training and EMG biofeedback on acute glucose disposal in diabetic subjects, as measured by glucose tolerance and three other measures of diabetic metabolic control. Twenty subjects with non-insulin-using Type II diabetes took part in progressive relaxation training and EMG biofeedback in a pre-post treatment versus wait-list experimental design. Treatment effects were assessed on glucose tolerance along with three measures of diabetic control: fasting blood glucose, two-hour postprandial blood glucose, and fructosamine. Stress reduction and relaxation was assessed with two physiological measures and two subjective questionnaires. The training program produced significant reductions in stress, as measured by State Anxiety, and significant changes in physiological measures of muscle activity and skin conductance compared to the control condition. However, no changes were found in glucose tolerance (while practicing relaxation) nor in any of the three measures of general diabetic metabolic control. The major implication of this study is that relaxation training does not appear to directly improve diabetic control in mildly stressed non-insulin-using Type II diabetic patients.     

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.     

The Effects of Respiratory Sinus Arrhythmia Biofeedback on Heart Rate Variability and Posttraumatic Stress Disorder Symptoms: A Pilot Study

Recent studies have found a significant association between PTSD and low heart rate variability (HRV), a biomarker of autonomic dysregulation. Research indicates that respiratory sinus arrhythmia (RSA) biofeedback increases HRV while reducing related pathological symptoms. This controlled pilot study compared RSA biofeedback to progressive muscle relaxation (PMR) as adjunctive interventions for 38 persons with PTSD symptoms in a residential treatment facility for a substance use disorder. Both groups were assessed at pre-intervention and 4-week post-intervention. Group × time interactions revealed significantly greater reductions in depressive symptoms and increases in HRV indices for the RSA group. Both groups significantly reduced PTSD and insomnia symptoms and a statistical trend was observed for reduced substance craving for the RSA group. Increases in HRV were significantly associated with PTSD symptom reduction. Overall, these results provide preliminary support for the efficacy of RSA biofeedback in improving physiological and psychological health for individuals with PTSD.     

New Hope for Correctional Officers: An Innovative Program for Reducing Stress and Health Risks

This study investigated the impact of a new stress management program on physiological and psychological stress and health risk factors among 75 correctional officers. The experimental group received training in emotion self-regulation techniques intended to reduce stress and health risk factors. Practice of the techniques was enhanced by heart rate variability feedback, which helped participants learn and sustain use of the self-management tools. Measures of physiological stress included cortisol, DHEA, cholesterol, triglycerides, fasting glucose levels, 10-min resting electrocardiogram, heart rate variability, and blood pressure. Three psychological questionnaires assessed emotional stress and work-related variables. There were significant improvements in the experimental group in cholesterol, glucose, heart rate, blood pressure and positive outlook and significant reductions in overall psychological distress. There were significant increases in productivity, motivation, goal clarity, and perceived support. The mean difference between pre- and post-intervention projected health care costs was calculated to be $1,179 per employee per year.     

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.     

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.     

Learned Cardiac Control with Heart Rate Biofeedback Transfers to Emotional Reactions

Emotions involve subjective feelings, action tendencies and physiological reactions. Earlier findings suggest that biofeedback might provide a way to regulate the physiological components of emotions. The present study investigates if learned heart rate regulation with biofeedback transfers to emotional situations without biofeedback. First, participants learned to decrease heart rate using biofeedback. Then, inter-individual differences in the acquired skill predicted how well they could decrease heart rate reactivity when later exposed to negative arousing pictures without biofeedback. These findings suggest that (i) short lasting biofeedback training improves heart rate regulation and (ii) the learned ability transfers to emotion challenging situations without biofeedback. Thus, heart rate biofeedback training may enable regulation of bodily aspects of emotion also when feedback is not available.     

Respiratory Sinus Arrhythmia Feedback in a Stressed Population Exposed to a Brief Stressor Demonstrated by Quantitative EEG and sLORETA

Previous investigations of electroencephalograms during relaxation have identified increases in slow wave band power, correlations between increased levels of alpha activity with lower levels of anxiety, and autonomic changes characterized by otherwise documented decreased sympathetic activity. This study was carried out to determine the overall changes in quantitative electroencephalographic activity and the current source as a result of an acute session of respiratory sinus arrhythmia (RSA) biofeedback in a population of subjects experiencing stress. This study’s findings provide physiological evidence of RSA feedback effect and suggest that RSA training may decrease arousal by promoting an increase of alpha band frequencies and decrease in beta frequencies overall and in areas critical to the regulation of stress. It was of interest that novices could achieve these objective alterations in EEG activity after minimal training and intervention periods considering that the previous literature on EEG and meditative states involve experienced meditators or participants who had been given extensive training. Additionally, these effects were present immediately following the training suggesting that the intervention may have effects beyond the actual practice.     

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 heterogenous 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.     

A preliminary investigation on time perception and autonomic self-regulation

This study sought to examine how perception of time duration was affected by two autonomic self-regulation treatment procedures: a biofeedback/self-regulation treatment program and a relaxation response treatment program. Time experience was assessed in two ways: time interval estimation during an actual treatment session (N=5, in each of the two groups) and subjective reporting (all 10 subjects in each group were evaluated). During an actual relaxation/self-regulation session, patients overestimated time duration and, retrospectively, patients in the group that learned to reduce blood pressure experienced time as slowing, whereas participants in the other treatment program experienced time as passing “normally” during the treatment sessions. All subjects reported that they usually experienced time as passing “normally” or corresponding to clock time. These results raise the question as to whether the experience of temporal slowing may be an important component of the psychological experience of the patients that allows autonomic learning to occur. Further research in this area is recommended and briefly discussed.     

Biofeedback treatment of dysmenorrhea

Nine dysmenorrheic women were run in EMG and thermal biofeedback procedures with concurrent autogenic relaxation practice. Significant reductions in subjective estimates of symptomology associated with dysmenorrhea were noted in all subjects. EMG levels correlated positively with the reductions in symptoms. Thermal levels did not correlate with EMG. In fact no consistent patterns in thermal measures were noted. However, thermal biofeedback cannot be ruled out as an effective treatment for dysmenorrhea since reductions in symptoms occurred during thermal biofeedback training. Another significant aspect of the present study is the effectiveness of long treatment procedures. A six month period was employed and significant reductions in symptoms were noted following two months of biofeedback treatment. Finally, the importance of beginning biofeedback treatment prior to onset of menstrual symptoms is indicated.     

Biodesensitization: Biofeedback-controlled systematic desensitization of the stress response to infant crying

Infant crying can be a source of parental stress both psychologically and physiologically and also may be an antecedent to physical child abuse or neglect. Biodesensitization is a new therapeutic technique that allows people to control the source of stress and develop self-control over their physiological responses to the stress-eliciting stimuli. Randomly assigned between three groups, 15 female participants were either given EEG biofeedback pretraining without stress, pretraining while listening to infant crying, or no stress management pretraining while listening to crying. After the pretraining manipulation all participants had biodesensitization training while listening to infant crying. Compared to control participants who were habituated to crying, stress management training significantly reduced the EEG cortical arousal as well as perceived arousal, and anxiety associated with listening to infant crying. The shift in participants' EEG power spectrum produced by infant crying was significantly correlated with perceived arousal and this relationship was strengthened after biofeedback training. In conjunction with other research, the experimental results suggest that stress management training may help ameliorate an aversive response to infant crying and possibly prevent child abuse as a response to physiological hyperreactivity.The author is grateful to Stan Sadava, Shoshana Tyson, and Joanna Manning for their helpful comments on this paper.     

The effect of stressful life events on EMG biofeedback and relaxation training in the treatment of anxiety

The present study evaluated the effect of frontal EMG biofeedback and relaxation training on a group of 20 anxious patients experiencing stressful life events. The patients were divided into two groups, high and low in stress, based on their life change score on the Recent Life Changes Questionnaire. Patients were evaluated at pre, post, and 6-week follow-up. Treatment consisted of 10 sessions of biofeedback-assisted relaxation. Results indicated that the high stress group showed pre to post changes on anxiety, depression, symptoms, and EMG, while low stress showed no change. Post to follow-up comparisons showed maintenance of improvement for the high stress group and no change for low stress. From pre to follow-up assessment, the high stress group showed significant changes. Both groups reported internal attributions following biofeedback and relaxation training. The high stress group attributed their improvement to the belief they were in control of their minds and bodies, while the low stress group most frequently reported the effort put into the task. The results indicate support for a cognitive explanation for some of biofeedback's effects.     

Systematic Review of Biofeedback Interventions for Addressing Anxiety and Depression in Children and Adolescents with Long-Term Physical Conditions

Children and adolescents with long-term physical conditions are at increased risk of psychological problems, particularly anxiety and depression, and they have limited access to evidence-based treatment for these issues. Biofeedback interventions may be useful for treating symptoms of both psychological and physical conditions. A systematic review of studies of biofeedback interventions that addressed anxiety or depression in this population was undertaken via MEDLINE, EMBASE, PsycINFO, CINAHL and the Cochrane Central Register of Controlled Trials databases. Primary outcomes included changes in anxiety and depression symptoms and ‘caseness’. Secondary outcomes included changes in symptoms of the associated physical condition and acceptability of the biofeedback intervention. Of 1876 identified citations, 9 studies (4 RCTs, 5 non-RCTs; of which all measured changes in anxiety and 3 of which measured changes in depression) were included in the final analysis and involved participants aged 8–25 years with a range of long-term physical conditions. Due to the heterogeneity of study design and reporting, risk of bias was judged as unclear for all studies and meta-analysis of findings was not undertaken. Within the identified sample, multiple modalities of biofeedback including heart rate variability (HRV), biofeedback assisted relaxation therapy and electroencephalography were found to be effective in reducing symptoms of anxiety. HRV was also found to be effective in reducing symptoms of depression in two studies. A range of modalities was effective in improving symptoms of long-term physical conditions. Two studies that assessed acceptability provided generally positive feedback. There is currently limited evidence to support the use of biofeedback interventions for addressing anxiety and depression in children and adolescents with long-term physical conditions. Although promising, further research using more stringent methodology and reporting is required before biofeedback interventions can be recommended for clinical use instead or in addition to existing evidence-based modalities of treatment.