On clinical efficacy: Why biofeedback does—and does not—Work

Questions of clinical efficacy are becoming more prominent in this era of diminishing funds for research and clinical care, and new treatment procedures, in particular, are being rigorously scrutinized. This presents a challenge for the relatively recent field of biofeedback and applied psychophysiology. This field has a strong scientific orientation and a rapidly expanding research base, which includes many well-controlled clinical outcome studies. The point is raised, and illustrated with data from current clinical outcome studies, that it is time for a shift in emphasis away from simply piling study upon study and toward more thoughtful interpretation of experimental and clinical findings and the development of a clearer conceptual framework for biofeedback therapy and research.Preparation of this paper was supported in part by NIDRR grant No. H133G90085, Department of Education, DHEW.     

Specific effects and biofeedback versus biofeedback-assisted self-regulation training

In any field, clear and logical conceptualizations are the basis of accurate models----correct research design----correct results----correct conclusions----advancement in the field. Faulty conceptualizations----faulty models----faulty research design----faulty results----faulty conclusions----confusion. In analyzing the conceptualizations of "biofeedback" as expressed by John Furedy (1987) in, "Specific versus Placebo Effects in Biofeedback Training: A Critical Lay Perspective," we focus on two issues: Does biofeedback have a treatment effect? Is biofeedback necessary for the training effect? In discussing issue (1) we describe the multiple meanings of "biofeedback" and raise the fundamental question: Is biofeedback a treatment? We argue that faulty conceptualizations of clinical biofeedback (1) assume that the treatment in clinical biofeedback is "biofeedback" with specific effects, (2) assume that the scientific basis of biofeedback is dependent upon demonstrations of these specific effects through double-blind design that distinguish "specific" from "placebo effects," and (3) trivialize clinical research by attempting to determine the usefulness of biofeedback information--usefulness that is already understood logically by professionals and consumers and demonstrated by clinical studies in the laboratory and in the clinic. We further argue that accurate conceptualizations of clinical biofeedback (1) identify self-regulation skills as the treatment with specific effects of physiological change and symptom reduction, and (2) describe the use of information from biofeedback instruments as scientific verification of self-regulation skills. Finally, the scientific basis of clinical biofeedback is based on (1) evidence from experimental and clinical control studies that have demonstrated the effectiveness of self-regulation skills for symptom alleviation, and (2) the use of biofeedback instruments to verify the acquisition of self-regulatory skills, thus fulfilling the scientific dictum of verifiability.     

Specific effects and biofeedback versus biofeedback-assisted self-regulation training

In any field, clear and logical conceptualizations are the basis of accurate models → correct research design → correct results → correct conclusions → advancement in the field. Faulty conceptualizations → faulty models → faulty research design → faulty results → faulty conclusions → confusion. In analyzing the conceptualizations of “biofeedback” as expressed by John Furedy (1987) in, “Specific versus Placebo Effects in Biofeedback Training: A Critical Lay Perspective,” we focus on two issues: Does biofeedback have a treatment effect? Is biofeedback necessary for the training effect? In discussing issue (1) we describe the multiple meanings of “biofeedback” and raise the fundamental question: Is biofeedback a treatment? We argue that faulty conceptualizations of clinical biofeedback (1) assume that the treatment in clinical biofeedback is “biofeedback” with specific effects, (2) assume that the scientific basis of biofeedback is dependent upon demonstrations of these specific effects through double-blind designs that distinguish “specific” from “placebo effects,” and (3) trivialize clinical research by attempting to determine the usefulness of biofeedback information — usefulness that is already understood logically by professionals and consumers and demonstrated by clinical studies in the laboratory and in the clinic. We further argue that accurate conceptualizations of clinical biofeedback (1) identify self-regulation skills as the treatment with specific effects of physiological change and symptom reduction, and (2) describe the use of information from biofeedback instruments as scientific verification of self-regulation skills. Finally, the scientific basis of clinical biofeedback is based on (1) evidence from experimental and clinical control studies that have demonstrated the effectiveness of self-regulation skills for symptom alleviation, and (2) the use of biofeedback instruments to verify the acquisition of self-regulatory skills, thus fulfilling the scientific dictum of verifiability.     

Pelvic Floor Muscle Biofeedback in the Treatment of Urinary Incontinence: A Literature Review

Biofeedback is efficacious in the training of the pelvic floor musculature in order to enhance continence. This article reviews the anatomy and physiology of micturition as the underlying rationale for pelvic floor muscle biofeedback in the treatment of urinary incontinence. It critically reviews 28 studies published in peer reviewed journals from 1975 to 2005 that were prospective, randomized studies with parametric statistical analyses, operationally defined patient selection criteria, treatment protocols and outcome measures. The overall mean treatment improvement for patients undergoing biofeedback for urinary incontinence was 72.61%. In 21 of 35 (60%) paired comparisons, biofeedback demonstrated superior symptomatic outcome to control or alternate treatment groups. Larger studies and a standardization of technology and methodology are required for more conclusive determinations.     

Biofeedback of Heart Rate Variability and Related Physiology: A Critical Review

Low heart rate variability (HRV) characterizes several medical and psychological diseases. HRV biofeedback is a newly developed approach that may have some use for treating the array of disorders in which HRV is relatively low. This review critically appraises evidence for the effectiveness of HRV and related biofeedback across 14 studies in improving (1) HRV and baroreflex outcomes and (2) clinical outcomes. Results revealed that HRV biofeedback consistently effectuates acute improvements during biofeedback practice, whereas the presence of short-term and long-term carry-over effects is less clear. Some evidence suggests HRV biofeedback may result in long-term carry-over effects on baroreflex gain, which is an area most promising for future investigations. On the other hand, concerning clinical outcomes, there is ample evidence attesting to efficacy of HRV biofeedback. However, because clinical and physiological outcomes do not improve concurrently in all cases, the mechanism by which HRV biofeedback results in salutary effects in unclear. Considerations for the field in addressing shortcomings of the reviewed studies and advancing understanding of the way in which HRV biofeedback may improve physiological and clinical outcomes are offered in light of the reviewed evidence.     

Controlled group designs in biofeedback research: Ask, “what does the control group control for?”

The extant literature on the specific role of biofeedback in promoting skeletal muscular relaxation is reviewed and found deficient with respect to the use of properly controlled group outcome research. The review emphasizes the failure of commonly used control procedures to adequately control a number of potentially confounding variables. Strengths and weaknesses of three types of controlled group design (attention placebo, pseudofeedback, and altered contingency) are discussed with respect to their relative usefulness in controlling certain nonspecific or placebo effects in biofeedback research. Many published biofeedback studies failed to measure the credibility of control procedures or the subject's ability to discriminate different feedback contingencies. The studies reviewed suggest that the various control procedures used are not inert and are not equivalent with respect to their effects on control group behavior. The suggestion is made that the controlled group outcome design be accepted as the minimum requirement for testing the specific effects of biofeedback, and possible methods for improving control procedures are discussed.     

Common Factors in Biofeedback Administered by Psychotherapists

Common factors are nonspecific therapeutic elements common across different varieties of psychotherapy. In a recent study, 68 expert psychotherapy researchers with a variety of allegiances collectively rated biofeedback as being negatively associated with many common factors (Tschacher et al. in Clin Psychol Psychother 21(1):82–96, 2014), including the therapeutic alliance. However, it seems implausible that biofeedback could benefit so many people while being incompatible with the therapeutic alliance and other common factors. The present study investigated the experiences of biofeedback clients who participated in a brief heart rate variability biofeedback protocol in order to explore the potential roles of common factors in biofeedback. The results of this study offer preliminary evidence that many common factors—including therapeutic alliance, self-efficacy expectation, mastery experiences, provision of explanatory scheme, mindfulness, and even cognitive restructuring—may play a role in biofeedback outcomes. Future research on this topic should include mediation and moderation models investigating the role of specific common factors on outcome and process studies to help determine what clinician behaviors are most helpful. Deeper investigation of common factors in biofeedback may benefit future biofeedback research and practice and address the concerns of colleagues outside of the biofeedback community who believe that biofeedback is at odds with common factors.

     

The role of absorption capacity in thermal biofeedback treatment of vascular headache

The clinical utility of Tellegen's Absorption Scale was examined using a sample of 32 chronic vascular headache patients drawn from a larger treatment study investigating the efficacy of thermal biofeedback with vascular headache. A regression analysis found that acquisition of the hand-warming response was directly related to increase in capacity for absorption. Conversely, a trend was found for absorption capacity to be inversely related to reductions in headache frequency and intensity. Reasons for these differences in process and outcome variables are discussed.This research was supported in part by a grant No. NS23440 from NINDS.     

Scientific and clinical biofeedback in the USSR

This paper describes the history of biofeedback research and application in the USSR. The approach of USSR scientists to the study of basic mechanisms of biofeedback and the status of clinical applications of biofeedback in the Soviet Union are described. Trends in the publication of biofeedback-related papers in Russian are presented, and the present "state of the art" described. Promising prospects for biofeedback research and application are discussed.     

Biofeedback efficacy studies

Biofeedback, a field still in its infancy, has developed treatments that have been used with clinical success in the treatment of a number of disorders. Many have expressed their public concern that biofeedback has not lived up to its early promise and that it has not developed treatments that are, in fact, efficacious. A number of factors, which are inherent in biofeedback research, confound the results of clinical efficacy studies of biofeedback treatments. Researchers interested in the efficacy of biofeedback must address several issues: (1) Rejecting the null hypothesis is not equal to proving the null hypothesis (without the use of power analysis); (2) control for nonspecific effects is not equal to a double-blind experimental design; (3) ignorance of a mechanism of action is not equal to a lack of clinical efficacy; (4) the administration of training is not equal to the subject's learning to criterion; (5) untrained therapists are not equal to trained therapists; (6) statistical significance is not equal to clinical significance; and (7) the laboratory setting is not equal to the clinical setting.     

Self-regulation of respiratory sinus arrhythmia

Respiratory sinus arrhythmia (RSA) — the peak-to-peak variations in heart rate caused by respiration — can be used as a noninvasive measure of parasympathetic cardiac control. In the present study four strategies to increase RSA amplitude are investigated: (1) biofeedback of RSA amplitude, (2) biofeedback of RSA amplitude plus respiratory instructions, (3) respiratory biofeedback, and (4) respiratory instructions only. All four procedures produce a significant increase of RSA amplitude from the first physiological control trial compared to baseline. This increase is faster for the groups that received respiratory biofeedback and respiratory instructions only than for the two groups that received biofeedback of RSA amplitude, the increases being equivalent for the four groups in the third session. All subjects of the group that received biofeedback of RSA amplitude only reported respiratory strategies in order to achieve the increase in RSA. Possible clinical implications of these results for parasympathetic cardiac control and cardiovascular disorders are discussed.This research was supported by a grant to the first author from the University of Granada (Spain).     

EMG biofeedback treatment of torticollis: a controlled outcome study.

Successful treatment of torticollis with electromyographic (EMG) biofeedback has been reported in a number of single case and single group studies. The present investigation represents the first controlled outcome study. Twelve torticollis patients were randomly assigned to EMG biofeedback or relaxation training and graded neck exercises (RGP). The procedure involved three sessions of baseline assessment, 15 sessions of EMG BF or RGP, 6 sessions of EMG BF or RGP plus home-management, 6 sessions of home-management alone, and follow-up 3 months after the end of treatment. A variety of outcome measures were used including physiological (EMG from the two sternocleidomastoid muscles, skin conductance level), behavioral (angle of head deviation, range of movement of the head), and self-report (depression, functional disability, body concept), therapist and "significant other" reports and independent observer assessment of videos. In both groups, neck muscle activity was reduced from pre- to posttreatment. This reduction was greater in the EMG biofeedback group. There was evidence of feedback-specific neck muscle relaxation in the EMG biofeedback group. Therefore, the outcome was not due to nonspecific factors and could be attributed to feedback-specific effects. Changes in skin conductance level showed that neck muscle relaxation was not simply mediated by a general reduction of "arousal." Significant improvements of extent of head deviation, and range of movement of the head, as well as reductions of depression were present, which were not different in the two groups. At the end of treatment, no patient was asymptomatic. Any therapeutic benefit was generally maintained at follow-up. The results and the procedural simplicity of RGP make the issue of cost-efficacy of EMG biofeedback a pertinent one. Further controlled outcome studies of EMG biofeedback treatment of torticollis with larger samples are required.     

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.     

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.     

The Influence of Respiration on Biofeedback Techniques

This research is based on previous studies which identified a specific respiratory pattern and inhalation-exhalation ratio, with which we were able to obtain significantly greater reductions in psychophysiological activation than with other respiratory patterns. The present study aimed to check the effectiveness of this respiratory pattern in learning based on biofeedback from the electrical conductance of the skin. The results obtained demonstrated that biofeedback combined with this respiratory pattern produced a significant reduction in psychophysiological activation and improved learning through biofeedback techniques.     

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.     

Scientific and clinical biofeedback in the USSR

This paper describes the history of biofeedback research and application in the USSR. The approach of USSR scientists to the study of basic mechanisms of biofeedback and the status of clinical applications of biofeedback in the Soviet Union are described. Trends in the publication of biofeedback-related papers in Russian are presented, and the present state of the art described. Promising prospects for biofeedback research and application are discussed.     

Single-case designs and clinical biofeedback experimentation

Rigorous evaluation of the effects of biofeedback with clinical populations is necessary, but practical problems often preclude utilization of between-groups experimental designs involving large numbers of clients with clinically relevant problems. Single-case experimental designs provide a viable alternative for answering most research questions. In addition, single-case designs possess several distinct advantages for biofeedback research, including a focus on clinical significance, the use of variability as data not error, unique procedures for establishing generality of findings, and an ability to deal with ethical concerns in clinical research. Basic procedures in the use of single-case experimental designs are described and illustrations in clinical biofeedback research are provided.