On the Biofeedback Using the Integrated Percent Time Alpha as Index

Abstract

In auditory alpha feedback, we have told the subjects to increase the amount of alpha activities as much as they can. In these sessions, at least some subjects have found the increases clearly undesirable, because they have experienced uneasiness or impatient emotions with the increases in alpha activities. In this study, we examined one's ability to voluntarily make the alpha activity (percent time alpha) in the desired character rather than increasing it. To control the alpha activity in the desired chara2cter would be useful for stabilizing our daily emotions. For the biofeedback training, we set the desired value and threshold of feedback signals according to subjects' personalities. In this experiment, it was necessary for the subject to grasp his alpha activity at just the precise moment. We gave the integrated percent time alpha by voice from the voice synthesiser for the feedback signals. For the preliminary experiment, we examined the effect of feedback training "to increase the alpha activity as much as you can" using the above mentiond feedback technique. From the result of this experiment, it was found this technique was rather effective for increasing the alpha activity than the usual feedback technique. Consequentry, in the main experiment "to increase your percent time alpha up to the desired value during the measuring period (100sec.)", we used this technique. In the experiment, we designed the following three sessions, (1) self-control without feedback, (2) feedback control using the usual technique, (3) feedback control using "the integrated percent time alpha" technique. The result's of these experiments suggested the following : We were able to control the alpha activities in the desired character by self-control, especially by auditory alpha feedback. And the feedback using "the integrated percent time alpha" technique was more effective than that using the usual technique. But the effects were different individually from the subjects' personalities.