Marco Dozza - PhD in Bioengineering, 2003-2007

Biofeedback Systems for Postural Control

14th NCM Meeting 28 March · 3 April 2004 - Sitges, Spain

• F. Horak, M. Dozza, R. Peterka, and L. Chiari, “What do subjects learn from audiobiofeedback for postural verticality?”, Proc. Neural Control of Movement, Sitges, Spain, 28 March - 3 April 2004.



Abstract - The extent to which subjects with loss of sensory information can substitute audio information to control body sway is unknown. We developed an audio-biofeedback (ABF) system to investigate its effect on postural stability during stance. Audio biofeedback consisted of soundwaves representing 2D trunk kinematic (position, velocity and acceleration) information. When the subject sway was outside a 1 degree threshold area frequency and amplitude modulation signaled anterior-posterior trunk sway and left-right ear volume balance signaled left-right sway. Nine subjects with bilateral loss of vestibular function and nine age-matched control subjects attempted to use this biofeedback to minimize postural sway in stance with eyes closed and/or with foam under their feet, and during surface rotations. Results showed that audio biofeedback decreased center of pressure (CoP) sway area and decreased the mean displacement of CoP outside the threshold area. Patients with total vestibular loss who could not stand on foam with eyes closed were able to balance using audio-biofeedback. The relative effect of audio biofeedback for each subject depended on how much they benefited from alternative sensory information. For example, subjects who were very visually-dependent used audiobiofeedback more when eyes were closed whereas subjects who were very surface-dependent used audiobiofeedback more when on the foam. Subjects with vestibular loss also learned to use audiobiofeedback to prevent falls during surface rotations with eyes closed. Lasting effects of the audio biobfeedback training were also observed since they continued to be stable on the rotating surface even after the audio information was removed. These results suggest that providing alternative sensory information for postural vertical may calibrate or train latent somatosensory information to perform that function rather than simply providing sensory substitution.

Supported by NIH grants DC 01849 and DC06201.

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