AUDIO BIOFEEDBACK OF TRUNK ACCELERATIONS IMPROVES BALANCE IN SUBJECTS WITH BILATERAL VESTIBULAR LOSS

Humans maintain balance based on the information provided by the visual, vestibular and somatosensory systems. When one or more of these sensory systems is not available, balance is affected. Subjects who have lost vestibular function lack linear and angular head acceleration which provides information correlated with body sway and orientation with respect to gravity. Visual biofeedback of standing subjects’ center of pressure (CoP) has been used successfully to reduce postural sway in stroke patients [Shumway-Cook et al, 1988]. Technological advances in the last few years provide new low-cost, portable sensors able to acquire kinematic data. In particular, data from accelerometers have been validated by comparing them with force plate and motion analysis data [Mayagoitia et al. 2002]. We developed an audio biofeedback device that encodes trunk biaxial accelerations into stereo sound. Our hypothesis is that audio information can improve balance in patients with profound bilateral loss of vestibular function (BVL).