Multi-site kinetic Biofeedback for Contorol of the Standing Posture of Cerebral Palsied Children

Abstract

Three cerebral palsied subjects with spasticity were given multi-site kinetic biofeedback (BF) training in a standing posture. A multi-site kinetic biofeedback system included handrails with strain gauge mounted isometric force sensors, and plates with linear potentiometers and springs for measurement of hip and knee displacement in the horizontal direction. From the displacement data and a known stiffness value of the spring, force was calculated. An experimental design used was an A-B-A time-series(pre-nofeedback, multi-site kinetic BF, post-nofeedback). In the multi-site kinetic BF condition, a body stick figure of a standing man whose posture could change by given force signals from the handrails, and hip and knee plates was displayed on the CRT of a micro-computer. The hands, knees, and hips of the stick figure were marked with circles. A posture of the stick figure could alter depending on the force created by the postural changes of the subject himself. For example, if the subject lean backward, width of the hip and legs became wider. If there was knee flexion, the distance between the knees in the stick figure widened. Forces on the handrails changes the position of the hand in the stick figure. The subjects were instructed to have a good body stick figure on the CRT by maintaining body coordination. At the same time, binary feedback was used to monitor overall success during training. For each of the hands, knees, and hips, a mean force was computed for the pre-nofeedback condition as a threshold value. This mean value was used as a criterion of binary feedback. During training, the color of the circles changed to provide binary feedback information (white = success, red = failure). During the time all six criteria were met, a beep sounded repeatedly. Results showed that all subjects improved his/her postural controlling capacity due to the training of multi-site kinetic BF. The multi-site kinetic BF as shown in this experimental paradigm seems to be a viable method for training of gross motor systems in cerebral palsied children.