The possibility of using biofeedback for training the amplitude of independent components of event-related potentials

The possibility of voluntary training of the independent component of event-related potentials (ERPs) by the method of biological feedback (BFB) using a modified two-stimulus test of Go/NoGo paradigm was studied. Ten subjects had to increase the amplitude of the P3b component of ERPs induced by the Go stimulus during one training session. This component is generated in the parietal cortex and is associated with an operation of action engagement. The study consisted of three sessions that included determination of the average amplitude, training, and placebo. It was found that the amplitude of the P3b component did not significantly change during the training and placebo sessions as compared to the session of threshold measurement, whereas the amplitude of the SPD component, which was also observed in ERPs in response to the Go stimulus, significantly decreased in both sessions. According to the sLORETA data, the source of the SPD component is located in the parahippocampal area. The results obtained help to determine further pathways to study the possibility of the use of BFB for correction of components of cognitive evoked potentials.     

Finger pulse amplitude and frontalis EMG biofeedback effects of single- and two-system training

The relationship between finger pulse amplitude (PA) and frontalis EMG was studied first by looking at general physiological changes accompanying successful bidirectional PA control. Seven successful subjects were then asked to produce two patterns of PA and EMG (PAincEMGdec and PAdecEMGdec) while receiving both PA and frontalis EMG biofeedback. Results indicate subjects can easily produce the differentiation pattern of PAdecEMGdec but cannot produce the integration pattern of PAincEMGdec. These rather paradoxical results may indicate subjects were using an attentional rather than arousal strategy for controlling PA and have implications for the use of peripheral vasomotor training as a general relaxation technique.     

Finger pulse amplitude and frontalis EMG biofeedback effects of single- and two-system training.

The relationship between finger pulse amplitude (PA) and frontalis EMG was studied first by looking at general physiological changes accompanying successful bidirectional PA control. Seven successful subjects were then asked to produce two patterns of PA and EMG (PAincEMGdec and PAdecEMGdec) while receiving both PA and frontalis EMG biofeedback. Results indicate subjects can easily produce the differentiation pattern of PAdecEMGdec but cannot produce the integration pattern of PAincEMGdec. These rather paradoxical results may indicate subjects were using an "attentional" rather than "arousal" strategy for controlling PA and have implications for the use of peripheral vasomotor training as a general relaxation technique.     

Flexibility development in sprinters using EMG biofeedback and relaxation training

This study compared the effectiveness of electromyographic (EMG) biofeedback and relaxation treatment in producing flexibility increases at the hip joint. Retention of flexibility gains and changes in sprinting performance were also examined. Fifteen male and 15 female athletes, predominantly sprinters, were matched according to age, sex, and flexibility and were randomly assigned to one of three groups. The control group received only the testing, the biofeedback group received visual and auditory EMG training, and the relaxation group received modified PMR and imagery exercises. Subjects in the two experimental groups were given eight twice-weekly 10-minute sessions and then were retested for flexibility. Retention of flexibility was reassessed 2 and 4 weeks later. Sprint performance improved for all groups. EMG biofeedback and relaxation treatment methods were no more effective than stretching exercises used by the control group for improving flexibility during the treatment period, but they did produce evidence of superior flexibility gains in the retention period. This may be important as flexibility has been reported to be related to the incidence of injuries.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.     

Model analyses of visual biofeedback training for EEG-based brain-computer interface

The primary goal of this study was to construct a simulation model of a biofeedback brain-computer interface (BCI) system to analyze the effect of biofeedback training on BCI users. A mathematical model of a man-machine visual-biofeedback BCI system was constructed to simulate a subject using a BCI system to control cursor movements. The model consisted of a visual tracking system, a thalamo-cortical model for EEG generation, and a BCI system. The BCI system in the model was realized for real experiments of visual biofeedback training. Ten sessions of visual biofeedback training were performed in eight normal subjects during a 3-week period. The task was to move a cursor horizontally across a screen, or to hold it at the screen’s center. Experimental conditions and EEG data obtained from real experiments were then simulated with the model. Three model parameters, representing the adaptation rate of gain in the visual tracking system and the relative synaptic strength between the thalamic reticular and thalamo-cortical cells in the Rolandic areas, were estimated by optimization techniques so that the performance of the model best fitted the experimental results. The serial changes of these parameters over the ten sessions, reflecting the effects of biofeedback training, were analyzed. The model simulation could reproduce results similar to the experimental data. The group mean success rate and information transfer rate improved significantly after training (56.6 to 81.1% and 0.19 to 0.76 bits/trial, respectively). All three model parameters displayed similar and statistically significant increasing trends with time. Extensive simulation with systematic changes of these parameters also demonstrated that assigning larger values to the parameters improved the BCI performance. We constructed a model of a biofeedback BCI system that could simulate experimental data and the effect of training. The simulation results implied that the improvement was achieved through a quicker adaptation rate in visual tracking gain and a larger synaptic gain from the visual tracking system to the thalamic reticular cells. In addition to the purpose of this study, the constructed biofeedback BCI model can also be used both to investigate the effects of different biofeedback paradigms and to test, estimate, or predict the performances of other newly developed BCI signal processing algorithms.     

Effects of alternative control procedures for electromyographic biofeedback relaxation training

Twenty-four college students participated in a single session of electromyographic (EMG) biofeedback in a comparison of three experimental control procedures commonly employed in biofeedback relaxation training research. One group received contingent EMG biofeedback from the forehead area, and each subject in this group served as his or her own control. Subjects in a second group received noncontingent EMG feedback from a tape recorder but were instructed to use the feedback signal to relax their forehead muscles (single blind). Subjects in a third group received the same auditory feedback as those in the second group but were not told the purpose or source of the feedback stimulus (yoked control). The contingent feedback group showed significantly less EMG activity when compared to the other two groups. However, this group did not exhibit significant EMG level decrements from the beginning to end of the session. This seemingly contradictory finding may have been due to statistically capitalizing on the artifactually high EMG level of the experimental and control groups, although the single-blind and yoked-control groups showed nonsignificant increases across the session. The single-blind group's data had a variance several times larger than the other two groups' variance. Findings are discussed with respect to a probing hypothesis as opposed to the previously offered frustration hypothesis. Of the three control procedures, the data suggest the yoked control as the procedure of choice for EMG biofeedback relaxation research.The authors would like to thank David Kazar and Claudia Coleman for their technical assistance with this article.     

A simple EMG—Reward system for biofeedback training of children

An automated reward system to be used with standard electromyographic (EMG) biofeedback instrumentation is described. The on-line reward system, when coupled with standard biofeedback instrumentation and procedures, constitutes instrumental conditioning. In addition to describing the EMG—reward interface circuity, a study demonstrating the efficacy of the instrumental conditioning approach with cerebral-palsied children is presented.This research was aided by a grant from the Easter Seal Research Foundation of the National Easter Seal Society for Crippled Children and Adults, and by a grant from the Tulsa Cerebral Palsy Association.     

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.     

The effectiveness of EMG biofeedback training in low back pain

Eighteen patients with chronic low back pain(lbp) of muscle tension origin were given an EMG biofeedback training. Compared to seven controls they showed a significant decrease during training in muscle tension and subsequently in pain. However, at follow-up EMG levels dropped to the initial(high) level. Pain scores of patients with high pain decrements during training showed further improvement during follow-up, which was not the case with patients showing less substantial improvement. The importance of cognitions was discussed.We wish to express our thanks to Marijke Höweler-van Dalen for supervising this investigation, to Arnold Goedhart for statistical advice, to Dr. Orlebeke for his critical remarks, and to Dr. Penders for referring the patients in Amsterdam. We are particularly indebted to the general practitioners Paul Kreutzer and Jan Huls for referring the Andijk patients. Without their support this investigation would not have been possible.     

Clinical and electromyographic effects of biofeedback training in mandibular dysfunction

Twenty patients with mandibular dysfunction, 10 acute and 10 chronic, were trained with electromyographic biofeedback from either m. masseter or m. frontalis area. The electromyographic activity in both muscle areas were recorded during six training sessions. The mean electromyographic activity decreased significantly within the sessions for both muscle areas, progressively more often for the m. masseter area. The activity did not decrease significantly between sessions for any muscle area. The clinical and subjective symptoms of mandibular dysfunction improved significantly after the training. No differences, electromyographically or clinically, among acute, chronic, m. masseter area, or m. frontalis area feedback patients could be observed. No correlation between decrease in electromyographic activity and symptoms could be established. Since a simplistic neuromuscular learning model for biofeedback training gains little support from these results, alternative views are discussed.This research was supported by grants to Sven G. Carlsson and Elliot N. Gale from the Swedish Council for Research in the Humanities and Social Sciences.     

Analysis of EEG characteristic at early stages of depression using method of independent components

Independent Component Analysis (ICA) was used for 19-channel resting EEG analysis 111 patients at early stages of depressive disorder and 526 age-matched healthy subjects. Comparison of independent components power spectra in depressed patients and healthy subjects in two states: Eyes closed and Eyes open, has revealed significant differences between groups for three frequency bands: Theta (4-7.5 Hz), Alpha (7.5-14 Hz), and Beta (14-20 Hz). Increased power of alpha and theta activity in depressed patients at parietal and occipital sites may be caused by decreased cortical activation of these regions. Diffuse enhancement of beta activity level can correlate with anxiety symptoms which take an important place in clinical picture of depressive disorder at early stages. Using of ICA method for comparison of spectral characteristics of EEG in groups of patients with different brain pathology and healthy subjects gives a possibility to localize more precisely the discovered differences as compare to traditional analysis of EEG spectra.     

Treatment of posttraumatic stress disorder with relaxation and biofeedback training

This study investigated the use of biofeedback and relaxation training on six patients with posttraumatic stress disorder (PTSD) referred routinely for biofeedback treatment in a VA medical center. Subjects received between 8 and 14 sessions of training overall, as well as concurrent individual and group therapy. Measures used to assess treatment outcome include pre- and posttreatment MMPI, State-Trait Anxiety Inventory, Beck Depression Inventory, and Multidimensional Health Locus of Control scores, as well as electromyographic and subjective measures of tension within each session. Additionally, an overall posttreatment clinical rating of change and 1- to 2-year follow-up data were obtained for each subject. Slight to marked improvements were demonstrated for each subject, as evidenced by improvements on the State Anxiety Inventory Scale and the Beck Depression Inventory, a decrease in overall MMPI scores, and lowered EMG and subjective tension ratings for all participants. Possible alternative explanations for improvement (situational demand characteristics, regression toward the mean, lack of independent subject evaluation) are described, along with other study limitations. This preliminary investigation suggests that the use of relaxation training and biofeedback may be a particularly useful component within a comprehensive treatment program for this disorder.     

Treatment of posttraumatic stress disorder with relaxation and biofeedback training

This study investigated the use of biofeedback and relaxation training on six patients with posttraumatic stress disorder (PTSD) referred routinely for biofeedback treatment in a VA medical center. Subjects received between 8 and 14 sessions of training overall, as well as concurrent individual and group therapy. Measures used to assess treatment outcome include pre- and posttreatment MMPI, State-Trait Anxiety Inventory, Beck Depression Inventory, and Multidimensional Health Locus of Control scores, as well as electromyographic and subjective measures of tension within each session. Additionally, an overall posttreatment clinical rating of change and 1- to 2-year follow-up data were obtained for each subject. Slight to marked improvements were demonstrated for each subject, as evidenced by improvements on the State Anxiety Inventory Scale and the Beck Depression Inventory, a decrease in overall MMPI scores, and lowered EMG and subjective tension ratings for all participants. Possible alternative explanations for improvement (situational demand characteristics, regression toward the mean, lack of independent subject evaluation) are described, along with other study limitations. This preliminary investigation suggests that the use of relaxation training and biofeedback may be a particularly useful component within a comprehensive treatment program for this disorder.     

Clinical and electromyographic effects of biofeedback training in mandibular dysfunction

Twenty patients with mandibular dysfunction, 10 acute and 10 chronic, were trained with electromyographic biofeedback from either m. masseter or m. frontalis area. The electromyographic activity in both muscle areas were recorded during six training sessions. The mean electromyographic activity decreased significantly within the sessions for both muscle areas, progressively more often for the m. masseter area. The activity did not decrease significantly between sessions for any muscle area. The clinical and subjective symptoms of mandibular dysfunction improved significantly after the training. No differences, electromyographically or clinically, among acute, chronic, m. masseter area, or m. frontalis area feedback patients could be observed. No correlation between decrease in electromyographic activity and symptoms could be established. Since a simplistic neuromuscular learning model for biofeedback training gains little support from these results, alternative views are discussed.     

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.     

Electromyographic biofeedback training for tension headache in the elderly: A prospective study

This study evaluated the effects of a 12-session frontal electromyographic biofeedback training regimen on the headache activity of eight tension headache sufferers aged 62 and older. The biofeedback sessions were slightly modified for a geriatric population, essentially to increase comprehension and retention of rationale and instructions. Post-treatment assessment at three months revealed significant decreases in overall headache activity (50% or greater) in 50% of the subjects, and moderate improvement (35%–45%) in three of the remaining four subjects. Significant clinical and/or statistical prepost differences were also found for the number of headache-free days, peak headache activity, and medication index. This is the first prospective study of biofeedback training for tension headache in an elderly population and, unlike previous retrospective studies, suggests that such therapy may be an effective intervention in the treatment of tension headaches in the elderly.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Department of Veterans Affairs. This study was supported by a Department of Veterans Affairs MERIT-Review awarded to the first author.