Success or failure of EEG feedback training for alpha self-control can depend on how alpha activity is quantified and fed back. Alpha self-control failures usually employ the envelope technique. A new method, namely anintegrated alpha feedback technique, has been developed in this study. The occipital EEG was filtered to extract alpha activity (8-13Hz), and a full wave rectified and integrated for every 5 s using an electric integrator. The integrated alpha value was used as a quantification of alpha wave activity. The threshold of the binary feedback signal depended upon the integrated alpha value of each subject. Forty-eight subjects went through both the alpha enhancement and suppression trials. The results showed a significant difference in the integrated alpha value between the enhancement task and suppression task and a tendency of the interaction effects of tasks and trials. These results have been discussed in relation to the mediator of alpha self-control and clinical application of feedback techique.
In biofeedback training, a subject is used to sit in a comfortable chair. The aim of our study is to assess the effectiveness of biofeedback training for alpha activity in an optional posture. Seven subjects who were trained previously to increase the amount of alpha activity participated in the experiments. They were measured their alpha activities during their biofeedback training periods in the sitting, standing, stepping and walking postures. The recording were made in a adjacent room by the experimenter. Simultaneously the percentage time alpha of the subjects were indicated by the digital counter. The subjects trained every other day using the auditory feedback telemeters. Fig. 3 and Fig. 4 summarize the mean percentage time alpha of "non-feedback" and "feedback" periods of the experimental group. Fig. 3 shows the percentage time alpha when the subjects were given instructions, "keep your eyes closed", whereas Fig. 4 shows the data when they were giveu instructions, "keep your eyes half close". The final vaues of the regression curves of the experimental data durinng the training periods are as follows : eyes closed (PTA) half eyes (PTA) sitting 80 65 stsnding 75 60 stepping 70 50 walking 50 30 (PTA ; percentage time alpha) The results of our experiments suggest that : l) A subject who was well trained in a sitting posture can enhance his alpha activity in a optional posture, for example, standing, stepping or walking by biofeedback training. 2) The effectiveness of biofeedback training in walking posture is remarkable greater than others. 3) In any posture, the effectiveness of biofeedback decrease trial by trial. 4) Even in walking posture, it is possible to increase EMG threshold by the subject himself. We suppose that feedback training promote to determine the optimum control parameter in individual nervous systems.
It has been made clear by some researches conducted in the past that SCL, as one of the indices of GSR, reflects psychological states. The present research attempted to inspect by the following experiments whether SCL can serve as a stable and sensitive index for psychophysiological states applicable to the biofeedback method. In Experiment I, the authors investigated to what extent SCL is influenced by the load voltage on organic bodies. Eight physically and mentally healthy men and women were used as subjects. The electrodes used in this experiment were the GSR Electrodes manufactured by Nihon Koden. Used as apparatus were the direct voltage source and resistance connected in series with organic bodies, and the volt meter connected in parallel with organic bodies. When the load voltage-SCL characteristics were examined by changing the amount of resistance, as a whole, no remarkable tendency of SCL changing with the change in load voltage was observed. In Experiment II, correlations between the spontaneous SCR while the subjects were at rest, and the SCL which was considered to be the background change of SCR, were examined. Eight physically and mentally healthy men and wome were chosen as subjects. The electrodes were the same as those used in Experiment I. Used as apparatus was the GSR detector manufactured by Nihon Koden, from which output was taken and recorded by the penrecorder. When spontaneous SCR appeared, some positive correlation was observed between the size of SCR and the SCL immediately before SCR appeared. However, after SCR became very large, the value of SCL was also influenced. Therefore, this SCR is regarded as one involving the change of SCL in the backgrond, rather than a mere transitory SCR. The change of SCL itself, when the subjects were at rest, was extremely slow ; and all subjects showed a tendency of decrease in SCL. This can be presumed as reflecting the slow change toward emotional stability. In Experiment III, some artificial manipulation, such as giving external stimuli--sound and mental calculation in this case・・・was made, in order to create mental excitement momentarily in the minds of the subjects while they were at rest in an effort to examine the correlation between the transitory SCR at that moment and the SCL, which was considered to be a background change, as well as the process of change in SCL itself. Used as subjects were five mentally and physically healthy men and women ; and the electrodes and the apparatus were the same as those used in Experiment II. The sound stimulus used was a pure tone of 1000 cycles ; and it was given the subjects from the speaker fixed 1.2 meters diagonally above their ears. Used as the mental calculation stimulus was a multiplicaion of two two-dit numbers, which was given by human voice through a communication hole. When the sound stimulus was given, a positive correlation similar to the spontaneous change when the subjects were at rest was observed between SCL and SCR ; but the value of SCR was larger than that obtained when the subjects were at rest. The change of SCR to the sound stimulus was slow, and it took 15 to 20 seconds before the value returned to the level before the stimulus was given. When the mental calculation stimulus was given, a positive correlation simlar to that obtained when the sound stimulus was given was observed, but the value of SCR was larger than in the case of sound stimulus. A large change in SCL was still observed in three of the five subjects even 20 seconds later, which indicated that the change of SCR and that of SCL itself were occurring simultaneously ; while in the two other subjects, a slow change of SCL was ob-served for more than 20 seconds, indicating that mental calculation was continuing during that time. From the above three experiments, it is presumed that although SCL is correlated with SCR, the former changes considerably more slowly than the latter. In
In order to study an effective way of reducing tension of the masseter muscle, biofeedback training from the frontal muscle, the masseter muscle, and simple relaxation training of the frontal muscle were done, and compared in relation to their mean integral EMG of the masseter muscle. Biofeedback information from the frontal muscle was found to consistently inhibit the masseter muscle. Furthermore, even when the biofeedback information was cut off, the frontal muscle still had the ability to continue it's acquired traning, indicating a learned effect. On the other hand, biofeedback information from the masseter muscle showed a slight inhibition of the masseter muscle. However, no acquired training effect was revealed after the biofeedback information was cut off. Although the relaxation training of the frontal muscle was inconsistent, compared to the previous frontal muscle biofeedback information, this does not necessary disprove the effect of inhibition of the masseter muscle. Thus, biofeedback information from the masseter muscle plays an important role in control of the masseter muscle, indicating it to be a valuable source for the mandibular dysfunction therapy.
Oral dyskiesia is one of the most refractory symptoms in geriatrics. This pilot study was undertaken to elucidate whether EMG-biofeedback training works on this symptom. Biofeedback training to aged people has been positive only in only in patients with sequelae of cerebrovascular accidents and fecal incontinence sofar. 3 subjects (male ; 1,female ; 2) were between 71 and 76 yeas old. They suffered from oral dyskinesia for 1 to 6 years. Electrodes were fixed on the skin surface of the cow muscle in the case of munching, and the muscles around the hyoid bone in grinding and thrusting of the tongue. They received from 18 to 38 sessions of EMG-biofeedback training. The results showed that all patients improved dyskinetic symptoms with the decreased EMG-threshold and were free from 2 months to 6 months. These findings suggest that EMG-biofeedback training is useful to improve oral dyskinesia in some geriatric patients. Further study should be necessary to evaluate the efficacy of this technique on oral dyskinesia of aged people.
Eight cancer patients receiving chemotherapy were given either electromyographic (EMG) biofeedback plus progressive muscle relaxation training (PMRT) or skin temperature biofeedback plus PMRT in order to reduce their nausea, vomitng, and dysphoria. Four additional patients received no behavioral intervention and served as a control group. Biofeedback patients participated in four training sessions and one follow-up session held in conjunction with their chemotherapy treatments. Physiological meaures of arousal, self-report scales of affect, and patient-reported and nurse-reported ratings of nausea, anxiety, and vomiting were collected before, during, and/or after each chemotherapy session. Inspection of the data suggests that EMG biofeedback and skin temperature biofeedback, in combination with PMRT, can be effective techniques for helping to reduce some of the adverse side effects of cancer chemotherapy.