Abstract - The purpose of this study was to determine weather auditory information could substitute for missing vestibular information to improve postural stability. Specifically we developed an audio-biofeedback (ABF) that signaled anterior-posterior (AP) and medial-lateral (ML) body sway. ABF consisted of a stereo sound consisting of two different sine waves, modulated in frequency and volume. The frequency and volume modulation signaled AP sway and the volume balance signaled the ML sway. The sound dynamics were processed as a function of anthropometric parameters. A 1 degree threshold region was defined around the natural posture of each subject. Nine subjects with profound bilateral vestibular loss (VS) and nine control subjects (CS) performed several trials standing on a force plate with and without ABF. We investigated the effect of using ABF in different randomized conditions, such as eyes closed and standing on a foam surface. When stand on foam with eyes closed using ABF, subjects: 1) decreased their CoP sway area (23% CS, 38% VS); 2) increased the time that they swayed inside the threshold region (103% CS, 196% VS); 3) decreased the mean displacement of CoP outside the threshold region (16% CS, 25% VS). ABF improved postural stability more in VS than in CS thus balance prosthesis based on ABF seems promising for balance rehabilitation.

Supported by NIH DC01849 and DC06201.