How Audio-biofeedback of Trunk Acceleration Affects Feed-forward and Feed-back Control of Posture

Introduction – The brain controls posture using feedforward (FF) (open loop) and feed-back (FB) (closed loop) control. FF control is based on the movements that the brain predicts. FB control is determined by the response of the brain to sensory information. It is unknown how the brain combines FF and FB control to maintain balance. While maintaining balance in different sensory conditions that that provide different amounts of available sensory information, the brain uses different degrees of FF and FB control. The effects of additional balance information provided by biofeedback systems have been widely studied, but the relative effect of biofeedback on FF and FB control is unknown. This study investigated how a portable, low-cost, audio-biofeedback (ABF) prototype (Chiari et al., 2004) affects the FF and FB control of posture in quiet stance. Our hypothesis was that ABF improves balance by increasing both FF and FB control.