1975 Volume 3 Pages 30-33
Although many biofeedback experiments on EEG, EMG, skin temperature, heart rate, blood pressure, GSR, etc. have been made, so far the biofeedback study of postural sway is that of Litvinenkova and Hlavacka (1973). The purpose of our experiment was to test the hypothesis that postural sway can be controlled by using visual feedback procedures. The experimental procedure was as follows. The projection of the center of gravity to the horizontal plane of a standing subject was determined by measuring the weight at three points of the supporting plane. Each point was supported by three strain gauges. Any weight change was amplified and recorded on an X-Y recorder, and its area measured afterwards by a planimeter. Subjects were instructed to observe the pattern on the X-Y recorder and to try to minimize their postural sway as much as possible. One session consisted of 20 trials, each trial lasting for 30 seconds. Subjects were 40 healthy college students who were divided into two groups, the FC group and the CF group. In the FC group visual feedback was employed in the first session, but not in a subsequent (no feedback control) session. In the CF group, the order was reversed. The interval between two sessions was about six weeks. The results showed that the mean percentage changes of postural sway in the feedback session was significantly (p<0.01) less than that in the control session (Fig. 1). However, the mean area changes of each four sessions were not statistically significant (Fig. 2). Thus it is suggested that postural sway can be controlled by visual feedback procedures.
