Change mechanisms in EMG biofeedback training: cognitive changes underlying improvements in tension headache

Presentation and Evaluation of a Manual for Heart Rate Variability Biofeedback in Somatic Symptom Disorder

<b><i>Background:</i></b> There is initial evidence for the efficacy of heart rate variability biofeedback (HRV-BF) in depression, anxiety disorders, and functional somatic syndromes. In somatic symptom disorder (SSD), evidence is lacking. The aim of this study was to describe a newly developed HRV-BF brief intervention and to analyze HRV changes, and to examine the applicability and acceptance in SSD. <b><i>Methods:</i></b> We analyzed the data of the subsample of a pilot randomized controlled trial (22 subjects with SSD) who received HRV-BF over 4 sessions. We assessed HRV (SDNN: standard deviation of the NN interval, RMSSD: root mean square of successive differences between NN interval, LF: low frequency) and the subjective evaluation and acceptance of the intervention. <b><i>Results:</i></b> HRV analyses within therapy sessions showed that individuals learned to increase their HRV significantly during biofeedback sessions and were able to maintain it during self-regulation periods without feedback (SDNN, RMSSD, LF: 5.7 ≤ <i>F</i>_<i>t</i> ≤ 11.1). Moreover, HRV improved across sessions (SDNN). The majority of participants rated the intervention very positively (e.g., satisfaction, improvement in mood and physical well-being). <b><i>Conclusions:</i></b> HRV-BF can be learned within 4 sessions and shows positive effects in patients with SSD. Adding HRV-BF to existing treatments, e.g., psychotherapy, seems promising.

Effects of Transcranial Alternating Current Stimulation and Neurofeedback on Alpha (EEG) Dynamics: A Review

Transcranial alternating current stimulation (tACS) and neurofeedback (NFB) are two different types of non-invasive neuromodulation techniques, which can modulate brain activity and improve brain functioning. In this review, we compared the current state of knowledge related to the mechanisms of tACS and NFB and their effects on electroencephalogram (EEG) activity (online period/stimulation period) and on aftereffects (offline period/post/stimulation period), including the duration of their persistence and potential behavioral benefits. Since alpha bandwidth has been broadly studied in NFB and in tACS research, the studies of NFB and tACS in modulating alpha bandwidth were selected for comparing the online and offline effects of these two neuromodulation techniques. The factors responsible for variability in the responsiveness of the modulated EEG activity by tACS and NFB were analyzed and compared too. Based on the current literature related to tACS and NFB, it can be concluded that tACS and NFB differ a lot in the mechanisms responsible for their effects on an online EEG activity but they possibly share the common universal mechanisms responsible for the induction of aftereffects in the targeted stimulated EEG band, namely Hebbian and homeostatic plasticity. Many studies of both neuromodulation techniques report the aftereffects connected to the behavioral benefits. The duration of persistence of aftereffects for NFB and tACS is comparable. In relation to the factors influencing responsiveness to tACS and NFB, significantly more types of factors were analyzed in the NFB studies compared to the tACS studies. Several common factors for both tACS and NFB have been already investigated. Based on these outcomes, we propose several new research directions regarding tACS and NFB.

The Influence of Physiological and Psychological Learning Mechanisms in Neurofeedback vs. Mental Imagery Against Binge Eating

In biofeedback research, the debate on physiological versus psychological learning has a long tradition and is still relevant today, regarding new developments of biofeedback for behavior modification. Analyzing the role of these learning mechanisms may help improving the protocols and answer the question, whether feedback of physiological functions is necessary to modify a target behavior. We explored the presence and impact of physiological (EEG changes) versus psychological learning (changes in somatic self-efficacy) in a recently developed EEG neurofeedback protocol for binge eating. The protocol targets a reduction of food-cue induced cortical arousal through regulation of EEG high beta activity. In an experimental study accompanying a randomized controlled trial, pre and post treatment EEG measurements were analyzed in a neurofeedback group (n = 18) and an active mental imagery control group without physiological feedback (n = 18). Physiological learning in terms of EEG high beta reduction only occurred in the neurofeedback group. Post treatment, participants with successfully reduced binge eating episodes (≥ 50% reduction) showed lower EEG high beta activity than unsuccessful participants (p = .02) after neurofeedback, but not after mental imagery. Further, lower EEG high beta activity at post-treatment predicted fewer binge eating episodes in neurofeedback only. In mental imagery, somatic self-efficacy predicted treatment success instead of EEG activity. Altogether, the results indicate that physiological changes serve as a specific treatment mechanism in neurofeedback against binge eating. Reducing cortical arousal may improve eating behaviors and corresponding neurofeedback techniques should therefore be considered in future treatments.

Behavioral treatments of chronic tension-type headache in adults: are they beneficial?

To assess the efficacy of behavioral treatments in patients with tension headache. Medline, Cinahl, EMBASE, and the Cochrane library were searched from inception to October 2007 and reference lists were checked. We selected randomized trials evaluating behavioral treatments (e.g., relaxation, electromyographic [EMG] biofeedback, and cognitive behavioral training) in patients with tension-type headache (TTH). We assessed the risk of bias using the Delphi list and extracted data from the original reports. A qualitative analysis was carried out. We found 44 trials (2618 patients), which were included in this review, of which only 5 studies (11.4%) were considered to have low risk of bias. Most trials lacked adequate power to show statistical significant differences, but frequently, recovery/improvement rates did not reach clinical relevance. In 8 studies, relaxation treatment was compared with waiting list conditions, and in 11 studies, biofeedback was compared with waiting list conditions, both showing inconsistent results. On the basis of the available literature, we found no indications that relaxation, EMG biofeedback, or cognitive behavioral treatment is better than no treatment, waiting list, or placebo controls.

Effect of biofeedback-assisted autogenic training on headache activity and mood states in Korean female migraine patients

Biofeedback with or without combined autogenic training is known to be effective for the treatment of migraine. This study aimed to examine the effect of biofeedback treatment on headache activity, anxiety, and depression in Korean female patients with migraine headache. Patients were randomized into the treatment group (n=17) and monitoring group (n=15). Mood states including anxiety and depression, and psychophysiological variables such as mean skin temperature of the patients were compared with those of the normal controls (n=21). We found greater treatment response rate (defined as > or =50% reduction in headache index) in patients with biofeedback-assisted autogenic training than in monitoring group. The scores on the anxiety and depression scales in the patients receiving biofeedback-assisted autogenic training decreased after the biofeedback treatment. Moreover, the decrease in their anxiety levels was significantly related to the treatment outcome. This result suggests that the biofeedback-assisted autogenic training is effective for the treatment of migraine and its therapeutic effect is closely related to the improvement of the anxiety level.

Behavioral research and the double-blind placebo-controlled methodology: challenges in applying the biomedical standard to behavioral headache research

The randomized, double-blind, placebo-controlled experimental design has prevailed as the "gold standard" in biomedical research, intended to control potential bias in patient/group assignment, investigator allegiance, patient expectations, and nonspecific therapeutic effects. Properly executed, such designs ensure a study's internal validity and allow differential group outcomes to be attributed to the active treatment. These controlled trials generally yield more conservative outcomes than open trials and case reports and establish efficacy in pharmaceutical research. In meta-analytic reviews, studies are often assigned quality scores based in part on the degree to which they meet this scientific standard. Applying the biomedical research design standards for blinding and placebo control to clinical trials evaluating behavioral and other nonpharmacologic headache treatment nearly always is either infeasible or simply not possible. Only rarely is blinding meaningfully achievable in administration of behavioral or psychological therapies. Various "psychological placebo" control conditions have been forwarded in behavioral studies (eg, sham treatments, pseudomeditation), but these controls are incapable of emulating an inert control condition comparable to that of the pill placebo in pharmacologic research, and they are best reserved for studies examining the mechanisms whereby an intervention produces improvement. This article reviews the conceptual and procedural challenges in applying the standard pharmaceutical clinical trials research design to behavioral headache research as well as implications for meta-analyses across studies of various treatment modalities.

Methodological issues in clinical trials of drug and behavior therapies

Trials that compare drug and behavior therapies or evaluate combination therapy raise special methodological issues. This article reviews these methodological issues and, where possible, offers guidelines for addressing them. Sources of bias in the selection and recruitment of participants and in the measurement of treatment outcomes are discussed. In addition, methodological problems presented by the differing structures of behavior and drug therapy, by confounding variables, such as allegiance effects, differential expectations and preferences for drug or behavior therapy, and differential adherence with drug or behavior therapy also are reviewed. Issues in the selection of appropriate control groups are also discussed.

Guidelines for Trials of Behavioral Treatments for Recurrent Headache, First Edition: American Headache Society Behavioral Clinical Trials Workgroup

Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache.

Behavioral Headache Treatment: History, Review of the Empirical Literature, and Methodological Critique

Theoretical developments and burgeoning research on stress and illness in the mid-20th century yielded the foundations necessary to conceptualize headache as a psychophysiological disorder and eventually to develop and apply contemporary behavioral headache treatments. Over the past three decades, these behavioral headache treatments (relaxation training, biofeedback, cognitive-behavioral therapy, and stress-management training) have amassed a sizeable evidence base. Meta-analytic reviews of the literature consistently have shown behavioral interventions to yield 35% to 55% improvements in migraine and tension-type headache and that these outcomes are significantly superior to control conditions. The strength of the evidence has lead many professional practice organizations to recommend use of behavioral headache treatments alongside pharmacologic treatments for primary headache. The present overview was prepared as a companion article to and intended to provide a background for the Guidelines for Trials of Behavioral Treatments for Recurrent Headache also published within this journal supplement. This article begins with a synopsis of key historical developments leading to our current conceptualization of migraine and tension-type headache as psychophysiological disorders amenable to behavioral intervention. The evolution of the behavioral headache literature is discussed, exemplified by publication trends in the journal Headache. Leading empirically-based behavioral headache interventions are described, and meta-analytic reviews examining the migraine and tension-type headache literatures are summarized, compared, and contrasted. A critique of the methodological quality of the clinical trials literature is presented, highlighting the strengths and weaknesses in relation to recruitment and selection of patients, sample size and statistical power, the use of a credible control, and the reproducibility of the study interventions in clinical practice.

[Physiodiagnostic indicators in tension headache.]

Practitioners often rely on physiodiagnostic indicators to corroborate the hypothesis of a muscular origin of headache. Although these indicators have been widely applied, their reliability and validity have seldom been tested empirically in headache sufferers. In a controlled double blind study, two trained raters palpated muscle tension and latent and active myogeloses of the left and right trapezius and sternocleidomastoideus muscles and measured passive head rotation flexibility. There were 28 subjects in the study, 14 suffering from tension headache and 14 matched controls. In spite of the training, interrater reliability of ratings concerning degree of muscle tension and number of latent myogeloses proved to be too low to justify subsequent use of these indicators. In keeping with the hypothesis, the various parameters of active myogeloses very clearly differentiated between the experimental groups. The hypothesis turned out not to be true for the parameters of head rotation flexibility. In subjects suffering from tension headache, no correlations could be found between the number of myogeloses of the right trapezius muscle and parameters recorded in long-term EMGs of this muscle, and no correlations could be found between the total number of myogeloses and the chronicity of headache.

Tension headache: disregulation at some levels of stress

This study evaluated the role of stress disregulation in tension headache. Two headache groups, a low-life stress group (N = 12) and a high-life stress group (N = 12), that represented different probable etiologies within the disregulation model were compared to analogous control groups. Subjects were selected after screening 441 undergraduate students. Measures of frontalis EMG and self-report acute stress were obtained at multiple intervals during a series of four laboratory stress tasks. Data supported the disregulation model as determined by replication of the significantly different correlations between self-report acute stress and EMG for the headache versus control groups reported by Hovanitz and co-workers (1989), and by several new within-group and within-individual analyses. Curiously, disregulation was found for acute and life stress but not for the intermediate level of daily hassle stress. These data are presented as support for a reformulation of Schwartz' disregulation model.

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.

Client variables and the behavioral treatment of recurrent tension headache: a meta-analytic review

Meta-analysis revealed that in studies evaluating behavioral treatments for tension headaches, the treatment outcome has varied with the client samples (e.g., age, gender, referral source) that have been used but not with the treatment procedures (e.g., type of behavioral intervention, length of treatment, whether or not efforts were made to facilitate transfer of training) or the research designs (e.g., internal validity, explicitness of diagnostic criteria) that have been used. Mean client age proved the best predictor of treatment outcome, accounting for 30% of the outcome variance following behavior therapy. Significantly poorer outcomes have also been reported in recent studies than were reported in early studies. These findings suggest that outcomes obtained with behavioral interventions have been less dependent upon the treatment variables that have been the primary focus of research attention than upon characteristics of client samples and behavioral interventions may be less effective in reducing headache activity than has previously been assumed.

Biofeedback control of migraine headaches: a comparison of two approaches

In order to assess the relative effectiveness of finger warming and temporal blood volume pulse reduction biofeedback in the treatment of migraine, 22 female migraine patients were assigned to one of three experimental conditions: temporal artery constriction feedback, finger temperature feedback, or waiting list. Biofeedback training consisted of 12 sessions over a 6-week period. All patients completed 5 weeks of daily self-monitoring of headache activity (frequency, duration, and intensity) and medication before and after treatment. Treatment credibility was assessed at the end of Sessions 1, 6, and 12. Results showed that temporal constriction and finger temperature biofeedback were equally effective in controlling migraine headaches and produced greater benefits than the waiting list condition. Power analyses indicated that very large sample sizes would have been required to detect any significant differences between the two treatment groups. No significant relationships were found between levels of therapeutic gains and levels of thermal or blood volume pulse self-regulation skills. Likewise, treatment outcome was not found to be related to treatment credibility. Further analyses revealed that changes in headache activity and medication were associated with changes in vasomotor variability. Because blood volume pulse variability was not significantly affected by biofeedback training, questions about its role in the therapeutic mechanism are raised.