Parasympathetic rebound following EMG biofeedback training: A case study

The self-regulation literature contains very few reports of negative side-effects stemming from biofeedback training. Nevertheless, the case reported here is unique in that immediately following each of several early EMG feedback sessions, an otherwise headache-free patient reported an acute attack of headache and nausea. These attacks, the conditions under which they appeared, and the conditions leading to their remission will be described. Discussion will focus on the possible physiological mechanisms involved.     

Parasympathetic rebound following EMG biofeedback training: a case study

The self-regulation literature contains very few reports of negative side-effects stemming from biofeedback training. Nevertheless, the case reported here is unique in that immediately following each of several early EMG feedback sessions, an otherwise headache-free patient reported an acute attack of headache and nausea. These attacks, the conditions under which they appeared, and the conditions leading to their remission will be described. Discussion will focus on the possible physiological mechanisms involved.     

Blepharospasm: A case study comparison of trihexyphenidyl (Artane) versus EMG biofeedback

Blepharospasm is a chronic condition characterized by involuntary spasmodic closure of the eyelid(s). The present investigation empirically evaluated the relative efficacies of a current pharmacological and a psychological approach in the treatment of blepharospasm. An A-B-A-C-A single-case design was used to compare trihexyphenidyl [Artane] with EMG biofeedback. EMG activity in the frontalis muscle and number of eyeblinks were the dependent variables. The results indicated that Artane had no effect on either dependent measure and that biofeedback had a dramatic treatment effect on both dependent variables. Treatment gains were maintained at a 42-week follow-up. These results are discussed in light of the methodological considerations, the efficacy of psychological intervention, and the need for future research.     

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.     

Blepharospasm: a case study comparison of trihexyphenidyl (Artane) versus EMG biofeedback

Blepharospasm is a chronic condition characterized by involuntary spasmodic closure of the eyelid(s). The present investigation empirically evaluated the relative efficacies of a current pharmacological and a psychological approach in the treatment of blepharospasm. An A-B-A-C-A single-case design was used to compare trihexyphenidyl [Artane] with EMG biofeedback. EMG activity in the frontalis muscle and number of eyeblinks were the dependent variables. The results indicated that Artane had no effect on either dependent measure and that biofeedback had a dramatic treatment effect on both dependent variables. Treatment gains were maintained at a 42-week follow-up. These results are discussed in light of the methodological considerations, the efficacy of psychological intervention, and the need for future research.     

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.     

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.     

Yawning: A possible confounding variable in EMG biofeedback studies

An elderly hemiplegic patient participating in an EMG biofeedback training program was observed to produce a synergistic flexion movement of the plegic (determined by functional evaluations) upper limb while yawning. In the course of the training sessions the electrical activity of the anterior deltoid (the target muscle) was recorded during yawning. These peak EMG values were greatly facilitated in comparison with the session mean peak values obtained during an attempted maximum voluntary isometric contraction (shoulder flexion) of the same limb (e.g., Trial 1: 85.00 vs. 4.33 µV). The possibility of yawning as a confounding variable in EMG biofeedback studies is presented and discussed.This research was supported in part by Health and Welfare Canada (NHRDP).     

Treatment of phantom limb pain with combined EMG and thermal biofeedback: a case report

Phantom pain is a frequent consequence of the amputation of an extremity and causes considerable discomfort and disruption of daily activities. This study describes a patient with extreme phantom limb pain following amputation of the right upper limb. The treatment consisted of 6 sessions of EMG biofeedback followed by 6 sessions of temperature biofeedback. The patient did not use a prosthesis and had not received previous treatment for chronic pain. Results demonstrated complete elimination of phantom limb pain after treatment, which was maintained at a 3- and 12-month follow-up. Pain relief covaried with increase in skin temperature at stump and perceptual telescoping (retraction of phantom limb into stump).     

Frequency characteristics of signals and instrumentation: implication for EMG biofeedback studies

Signals can be analyzed in either the time or frequency domain. In the time domain, the analysis consists of manipulating and measuring one or more characteristics of the signal that may vary with time. One can, for instance, rectify a signal, filter it, calculate its mean value, display the histogram of its amplitude, and so forth. Frequency analysis is less well understood because it requires a lengthy mathematical treatment most easily done by computer. However, it gives exclusive information on a signal. For instance, when the frequency content of a signal is known, it is easy to specify which characteristics an amplifier must have in order to amplify the signal without distortion, or to set the cutoff frequencies of filters to eliminate noise. Also, in many circumstances, frequency spectra are more easily interpreted than the original raw data. Such is the case with the EMG where the random aspect of the signal makes some form of processing (i.e., rectification, filtering, etc.) necessary, but not always as meaningful as we would like. Thus we present here the principal characteristics of frequency analysis, and discuss its usefulness in analyzing EMG signals and its application to biofeedback, clinical practice, and research.     

Frequency characteristics of signals and instrumentation: Implication for EMG biofeedback studies

Signals can be analyzed in either the time or frequency domain. In the time domain, the analysis consists of manipulating and measuring one or more characteristics of the signal that may vary with time. One can, for instance, rectify a signal, filter it, calculate its mean value, display the histogram of its amplitude, and so forth. Frequency analysis is less well understood because it requires a lengthy mathematical treatment most easily done by computer. However, it gives exclusive information on a signal. For instance, when the frequency content of a signal is known, it is easy to specify which characteristics an amplifier must have in order to amplify the signal without distortion, or to set the cutoff frequencies of filters to eliminate noise. Also, in many circumstances, frequency spectra are more easily interpreted than the original raw data. Such is the case with the EMG where the random aspect of the signal makes some form of processing (i.e., rectification, filtering, etc.) necessary, but not always as meaningful as we would like. Thus we present here the principal characteristics of frequency analysis, and discuss its usefulness in analyzing EMG signals and its application to biofeedback, clinical practice, and research.The authors acknowledge the technical assistance of F. Kemp, M. Goyette, and C. Goulet. T. Milner kindly reviewed the final version of the text. The preparation of this paper was supported through funds from Health and Welfare Canada (NHRDP) and the Centre de recherche, Institut de réadaptation de Montréal.     

Yawning: a possible confounding variable in EMG biofeedback studies

An elderly hemiplegic patient participating in an EMG biofeedback training program was observed to produce a synergistic flexion movement of the plegic (determined by functional evaluations) upper limb while yawning. In the course of the training sessions the electrical activity of the anterior deltoid (the target muscle) was recorded during yawning. These peak EMG values were greatly facilitated in comparison with the session mean peak values obtained during an attempted maximum voluntary isometric contraction (shoulder flexion) of the same limb (e.g., Trial 1: 85.00 vs. 4.33 microV). The possibility of yawning as a confounding variable in EMG biofeedback studies is presented and discussed.     

Skin temperature biofeedback for Raynaud's disease: A double-blind study

The lack of control procedures inherent in most of the experiments conducted to assess the effectiveness of skin temperature biofeedback in the treatment of Raynaud's disease renders the results inconclusive. In this study, control groups and a double-blind approach are adopted. Thirty-six patients, carefully screened for a diagnosis of primary Raynaud's disease, were assigned to a skin temperature increase group (N=12), to an EMG relaxation control group (N=12), or to a notreatment control group (N=12). All patients kept records of their symptoms for the duration of the study. Each subject in the two training groups received 20 sessions, the last 2 conducted under cold stress. Data analysis according to original group assignment, as well as following regrouping of subjects according to several learning criteria, showed that while all patients reported a marked decrease in the number of vasospastic attacks, no significant differences were found among the three groups on the clinical measures used to assess symptomatic relief. The general improvement reported must therefore be attributed to nonspecific factors.This study was supported in part by Rehabilitation Services Administration Grant No. 16-P-56810/5–17 to the University of Minnesota Medical Rehabilitation Research and Training Center. We are grateful to Gail Gaebe, Carla Grossman, Steve Janousek, Linda Rubbelke, and Scott Williamson, who served as blind assistants, and to Steve Sheffield for his technical support.     

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.     

Self-directed EMG training for the control of pain and spasticity in paraplegia: A case study

A 25-year-old paraplegic woman was able to gain control of her debilitating leg and bladder spasms and abdominal pain using self-directed EMG biofeedback. The case is significant in that she previously had only cursory exposure to biofeedback as an undergraduate student and received only minimal support and direction from an instructor. She proceeded through daily home practice using a borrowed EMG unit and audiotapes from Lester Fehmi'sOpen Focus series. Records were kept of the frequency and intensity of her pain and spasms, as well as the frequency and procedures of her home practice. She also maintained a record of specific psychosocial events in her life, which, over time, showed a strong, consistent pattern of influence on the recurrence and severity of her symptoms. The woman's physician declared her medical progress remarkable and encouraged her biofeedback work. At 2-year follow-up, she remains virtually symptom- and medication-free. Her successful biofeedback training program provides support for the value of client-directed biofeedback in selected cases.     

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 preliminary analysis of EMG variance as an index of change in EMG biofeedback treatment of tension-type headache

The effectiveness of EMG biofeedback training for tension headache has been well established. Previous studies evaluating changes in an average EMG activity score from pre- to posttreatment have not consistently found a relationship between a reduction in average EMG activity and headache improvement at posttreatment. The current study is a preliminary analysis of the utility of EMG variance as another possible mechanism of change. Frontalis EMG average activity and variances from 6 chronic tension-type headache sufferers who demonstrated significant improvement in headache activity at posttreatment (at least 70%) and 6 chronic tension-type headache sufferers who did not demonstrate improvement (less than 30%) were examined across 6 sessions of biofeedback treatment. The improved group demonstrated larger time-specific EMG variance in relation to mean EMG amplitudes during all treatment sessions. A dramatic decline in time-specific variance was observed during the later treatment sessions for improved participants; this pattern was not observed in the group who demonstrated little or no improvement. Results from the current study suggest that the inclusion of both average EMG activity and EMG variance may provide a more comprehensive measure to evaluate possible physiological changes responsible for improvement in headache activity following EMG biofeedback training.     

A device for functional residual capacity controlled biofeedback of respiratory resistance

A computer-aided procedure is presented providing subjects with analogous visual feedback of respiratory resistance, which is continuously measured using the forced oscillation method. Simultaneous pneumotachographical control of the breathing volume curve makes it possible to prevent reinforcement for decreases of respiratory resistance which are due to increases of functional residual capacity (FRC). Lung hyperinflation is an unsuitable way to reduce respiratory resistance; if it occurs, feedback is interrupted until the subject decreases his FRC to its initial level. Analysis of the data of 15 adult asthmatic subjects which underwent a 12-sessions feedback training showed that no substantial changes of FRC appeared within feedback trials. Advantages of this new biofeedback technique compared to other procedures are discussed with regard to volume control and feedback signal.     

Effectiveness of EMG biofeedback training for controlling arousal in subsequent stressful situations

Thirty-five subjects participated in (1) a pretreatment session during which arousal was measured while subjects anticipated and then viewed a stressful film; (2) four 20-min treatment sessions during which subjects received either contingent EMG biofeedback (biofeedback treatment), instructions to attend to a variable pitch tone (attention-placebo control), instructions to relax as much as possible (instructions-only control), or instructions to sit quietly (no-treatment control); and (3) a posttreatment session that was identical to the pretreatment session. Results indicate that when compared to the subjects in the control conditions, subjects who received EMG biofeedback were not effective in reducing frontalis EMG levels during treatment or while viewing the stressful film, but they were effective in reducing frontalis EMG levels while anticipating the stressful film. There was no evidence that EMG biofeedback influenced either skin conductance or self-reports of arousal.This research was supported in part by Bio-Medical and General Research Fund grants from the University of Kansas to David S. Holmes. Appreciation is due to B. Kent Houston, Edward F. Morrow, and Charles A. Hallenbeck for their contributions to the project.