Applications of biofeedback to the treatment of asthma: a critical review

Both muscular and respiratory biofeedback procedures have been employed in attempts to reduce symptoms of bronchial asthma. Research relating to these approaches is reviewed in the present article. Biofeedback training both for facial muscle relaxation and for respiratory resistance decrease improves short-term pulmonary function in asthmatic individuals. These forms of training represent promising avenues for the management of asthma. However, unqualified endorsement of these procedures is premature, at the present time, since their influence on asthma-related variables other than pulmonary function has not been determined and since their long-term effects have not been investigated.     

Self-control procedures in biofeedback: A review of temperature biofeedback in the treatment of migraine

It is argued that in order to optimize the achievement of self-control and to evaluate the clinical effects of biofeedback three skills should be included in training and assessment, namely: (1) the ability of voluntary control with external feedback, (2) the ability of voluntary controlwithout external feedback, and (3) the ability toapply the self-control skill in critical situations in everyday life. A review of the literature concerning temperature-biofeedback in the treatment of migraine headaches shows that the research from this point of view is in a rather poor state of affairs and that no definite conclusion can in fact be drawn about the degree of self-control which has been achieved and hence of the ultimate clinical value of biofeedback.This study was supported by grant no. 80/66 from the Bank of Sweden Tercentenary Foundation.     

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.     

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.     

Applications of mitochondrial DNA analysis in conservation: a critical review

Patterns of variation in mitochondrial DNA (mtDNA) increasingly are being investigated in threatened or managed species, but not always with clearly defined goals for conservation. In this review I identify uses of mtDNA analysis which fall into two different areas: (i) 'gene conservation' - the identification and management of genetic diversity, and (ii) 'molecular ecology' - the use of mtDNA variation to guide and assist demographic studies of populations. These two classes of application have different conceptual bases, conservation goals and time-frames. Gene conservation makes extensive use of phylogenetic information and is, in general, most relevant to long-term planning. Appropriate uses here include identification of Evolutionarily Significant Units and assessment of conservation priority of taxa or areas from an evolutionary perspective. Less appropriate are inferences about fitness from within-population diversity and about species boundaries. Molecular ecology makes more use of allele frequencies and provides information useful for short-term management of populations. Powerful applications are to identify Management Units and to define and use naturally occurring genetic tags. Estimating demographic parameters, e.g migration rate and population size, from patterns of mtDNA diversity is fraught with difficulty, particularly where populations are fluctuating, and is unlikely to produce quantitative estimates sufficiently accurate to be useful for practical management of contemporary populations. However, through comparative studies, mtDNA analysis can provide qualitative signals of population changes, allowing efficient targeting of resource-intensive ecological studies. Thus, there are some relatively straightforward uses of mtDNA, preferably in conjunction with assays of nuclear variation, that can make a significant contribution to the long-term planning and short-term execution of species recovery plans.     

Specific versus placebo effects in biofeedback training: A critical lay perspective

Recent interchanges on the question of how to evaluate biofeedback have been cast in terms of a researcher versus clinician dichotomy. This tends to make the arguments ad hominem and focuses attention on minutiae that are of limited general interest. Accordingly, one purpose of the present paper is to state the specific-effects approach to biofeedback evaluation from a critical lay, rather than a research, perspective. The logic of the specific-effects approach to treatment evaluation is first illustrated by a hypothetical example (the Minefield Parable), and it is then suggested that the approach is appropriate for the evaluation of any treatment, be it physical, psychological, or some complex combination. The other purpose of the paper is to further clarify the specific-effects position by responding to some difficulties that have been raised by critics of the position. Some of these difficulties are based on misrepresentations of the position, while others are genuine. However, even for the genuine difficulties, practical solutions are available. The paper concludes that the question of whether a particular class of treatments works is one that is properly raised by the intelligent consumer, and that, for the answer to that question, only the facts, based on adequately controlled clinical studies, will do.The preparation of this paper was supported by a grant from the National Science and Engineering Research Council of Canada. I am indebted to Hal Scher and Donna Shulhan for comments on an earlier draft.     

Systematic reviews and meta-analyses on treatment of asthma: critical evaluation

ObjectiveTo evaluate the clinical, methodological, and reporting aspects of systematic reviews and meta-analyses on the treatment of asthma and to compare those published by the Cochrane Collaboration with those published in paper based journals.DesignAnalysis of studies identified from Medline, CINAHL, HealthSTAR, EMBASE, Cochrane Library, personal collections, and reference lists.StudiesArticles describing a systematic review or a meta-analysis of the treatment of asthma that were published as a full report, in any language or format, in a peer reviewed journal or the Cochrane Library.Results50 systematic reviews and meta-analyses were included. More than half were published in the past two years. Twelve reviews were published in the Cochrane Library and 38 were published in 22 peer reviewed journals. Forced expiratory volume in one second was the most frequently used outcome, but few reviews evaluated the effect of treatment on costs or patient preferences. Forty reviews were judged to have serious or extensive flaws. All six reviews associated with industry were in this group. Seven of the 10 most rigorous reviews were published in the Cochrane Library.ConclusionsMost reviews published in peer reviewed journals or funded by industry have serious methodological flaws that limit their value to guide decisions. Cochrane reviews are more rigorous and better reported than those published in peer reviewed journals.     

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.This work was funded by grants from the Medical Research Council and the Dystonia Society.     

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

This paper reviews multicomponent behavioral medicine studies that contain cost-effectiveness andor 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.This work first appeared in a paper presented as the presidential address at the 18th annual meeting of the Biofeedback Society of America, Boston, March 15, 1987.     

Experimental foundations of EMG biofeedback with the upper extremity: A review of the literature

This article reviews the experimental foundations of EMG biofeedback with the upper extremity. Considered are investigations on recruitment and training of single and multiple motor units in both normal and nonnormal subjects, on transfer of training effects from trained to untrained muscles, and on the relationship of reduced muscle output to relaxation. Examined are procedures, results, and conclusions of these basic studies. Problems noted in the research are discussed and suggestions are made for further work in the area.     

A comparison of frontal EMG biofeedback and neck EMG biofeedback in the treatment of muscle-contraction headache

EMG biofeedback from the frontal area (FFB) was compared to EMG biofeedback from the neck (NFB) in the treatment of chronic muscle-contraction headache. Both treatment groups (N=10) evidenced significant decreases in reported headache activity, with the NFB group also significantly reducing medication consumption. An analysis of EMG changes suggested that subjects were able to produce large within-session changes in EMG activity during initial sessions, with the major effect of additional training being an increase in speed with which these changes occurred. In neither group, however, did changes in EMG activity correspond closely to changes in reported headache activity.     

The treatment of psychophysiologic insomnia with biofeedback: A replication study

To replicate a previous study, 16 psychophysiological insomniacs were randomly assigned to either Theta feedback or sensorimotor rhythm (SMR) feedback. Evaluations by home sleep logs and by 3 nights in the laboratory were done before biofeedback, immediately after biofeedback, and 9 months later. Results from this study replicate previous findings. Both Theta and SMR feedback seemed effective treatments of insomnia according to home sleep logs. According to evaluations at the sleep laboratory, tense and anxious insomniacs benefited only from Theta feedback but not from SMR feedback, while those who were relaxed at intake but still could not sleep benefited only from SMR but not from Theta feedback.This research was supported by Grant No. MH24268 from NIMH. The authors would like to thank Michael Sateia, Elaine Olmstead, Molly Oldfield, and Boyd Hayes for their assistance with this paper.     

A critical review of the statisticalist debate

Over the past decade philosophers of biology have discussed whether evolutionary theory is a causal theory or a phenomenological study of evolution based solely on the statistical features of a population. This article reviews this controversy from three aspects, respectively concerning the assumptions, applications, and explanations of evolutionary theory, with a view to arriving at a definite conclusion in each contention. In so doing I also argue that an implicit methodological assumption shared by both sides of the debate, namely the overconfidence in conceptual analysis as a tool to understand the scientific theory, is the real culprit that has both generated the problem and precluded its solution for such a long time.     

Thermal biofeedback in the treatment of intermittent claudication in diabetes: A case study

The objective of the present case study was to examine the therapeutic effects of thermal biofeedback-assisted autogenic training on a patient with non-insulin-dependent diabetes mellitus (NIDDM), vascular disease, and symptoms of intermittent claudication. The patient received thermal biofeedback from the hand for five sessions, then from the foot for 16 sessions, while hand and foot skin temperature were monitored simultaneously. In addition, the patient was instructed in autogenic training and practiced daily at home. Follow-up measurements were taken at 12 and 48 months. Within-session foot temperature rose specifically in response to foot temperature biofeedback and starting foot temperature rose between sessions. Posttreatment blood pressure was reduced to a normal level. Attacks of intermittent claudication were reduced to zero after 12 sessions and walking distance increased by about a mile per day over the course of treatment. It would appear that thermal biofeedback and autogenic training are potentially promising therapies for persons with diabetes and peripheral vascular disease.Preparation of this article was supported in part by NIDDK grant No. R0128288 and the Commonwealth of Virginia Diabetes Clinical Research Institute.     

A components analysis of biofeedback in the treatment of fecal incontinence

Fecal incontinence is a socially disabling symptom for which rectosphincteric biofeedback has been reported to be dramatically effective. The most commonly employed biofeedback procedure incorporates three separate and potentially effective components: (1) exercise of the external sphincter muscle, (2) training in discrimination of rectal sensations, and (3) training synchrony of the internal and external sphincter responses. This paper reports the results of single case experiments employed with eight incontinent patients to examine the contributions of each of these components. All eight patients improved, but only one required the biofeedback procedure as it was originally described. Three responded to sensory discrimination training, one to exercise training, and one to the training of synchronous sphincteric responses; three recovered independently of the effects of biofeedback. Despite the achievement of continence, the rectosphincteric reflexes following treatment continued to be abnormal in every case. These findings suggest that the character of the external sphincter response to rectal distension is an unreliable index of sphincter function and that exercise and sensory discrimination training procedures are effective for some cases of fecal incontinence.The work described in this paper was supported by Grant No. MA 6241 from the Medical Research Council of Canada.     

Blood volume pulse biofeedback in the treatment of migraine headache: A controlled evaluation

In order to evaluate the specific effects of blood volume pulse (BVP) biofeedback in the treatment of migraine headaches, 21 female migraine patients were randomly assigned to one of three experimental conditions: temporal artery constriction feedback, temporal artery dilation feedback, or waiting list. Biofeedback training consisted of 15 sessions over an 8-week period. All patients completed 5 weeks of daily self-monitoring of headache activity and medication before and after treatment. Results showed that constriction and dilation biofeedback were equally effective in controlling migraines and produced greater benefits than the waiting-list condition. No significant relationships were found between therapeutic gains and BVP self-regulation skills. However, further analyses revealed that changes in headache activity and medication were associated with changes in vasomotor variability. The current rationale for the use of BVP biofeedback in the treatment of migraine is questioned and a new one is proposed.     

Utilization of iron sulfides for wastewater treatment: a critical review

Acid mine drainage due to weathering of iron sulfide minerals is one of the biggest global environmental issues. However, due to the unique physicochemical properties of natural and synthesized iron sulfides (i.e. pyrite, pyrrhotite, and mackinawite), they can be effectively used for wastewater treatment. These properties, such as ≡SH functional groups as Lewis bases, reducibility of surface Fe and S species, dissolved Fe²⁺ as a catalyst, and dissolved S^2? as an electron donor, are extensively reviewed in this article. The target water pollutants include toxic metals (i.e. lead, mercury, cadmium, and hexavalent chromium) and metalloid (i.e. arsenic), radionuclides (i.e. uranium and selenium), organic contaminants (i.e. chlorinated organic pollutants, benzene and polycyclic aromatic hydrocarbons), and nutrients (i.e. nitrogen and phosphorus). The dominant interaction mechanisms between iron sulfides and these contaminants, and the removal efficiencies are elucidated. This article focuses on the role of iron sulfides as functional materials for wastewater treatment. A recent development of nanostructured pyrrhotite with a high specific surface area for wastewater treatment is also highlighted.     

Reciprocal altruism in birds: A critical review

Many proposed examples of reciprocal altruism are either misidentified or involve questionable assumptions concerning the costs and benefits accruing to the interactors. Waltz's (Am. Nat. 118: 588–592, 1981) definition of reciprocal altruism as an interaction in which “one individual aids another in anticipation that the recipient will return the favor benefiting the actor in the future” is not sufficiently restrictive: there must also be a direct fitness cost to the individual performing the original beneficent act that is less than the fitness benefit received when the act is reciprocated (again at a cost) by the second individual.Several recurring problems in identifying potential examples of reciprocal altruism are discussed, including the assumption that restraint is an act of altruism and the misclassification of “generational mutualisms,” in which individuals helping to raise young are “repaid” one generation later by the offspring they assisted in raising. No definite case of reciprocal altruism is currently known in birds, but examples in which this phenomenon may be involved include helping behavior in a few cooperative breeders and communal feeding in several taxa including gulls, jays, and juncos.     

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.     

Salivary biomarkers of oxidative stress: A critical review

Human saliva is an increasingly attractive medium for biomarker discovery due to its amenability to noninvasive and repeated sampling, ease of collection and processing, and suitability for single analyte or metabolomic measurements. Salivary biomarkers of oxidative stress reflect local and systemic pathologies and may inform on the diagnosis, prognosis, and therapeutic responsiveness of numerous human diseases. However, for many of the disorders investigated, data reporting on alterations in salivary redox homeostasis are often highly conflicted across studies. We surveyed the available biomedical literature on this topic and noted significant discrepancies in the study designs, target populations, and operating procedures which likely contribute to the discordant data sets reported. Based on these observations, guidelines are provided to minimize interlaboratory variability in redox biomarker discovery based on human saliva.