Effects of practicing tandem gait with and without vibrotactile biofeedback in subjects with unilateral vestibular loss.

Subjects with unilateral vestibular loss exhibit motor control impairments as shown by body and limb deviation during gait. Biofeedback devices have been shown to improve stance postural control, especially when sensory information is limited by environmental conditions or pathologies such as unilateral vestibular loss. However, the extent to which biofeedback could improve motor performance or learning while practicing a dynamic task such as narrow gait is still unknown. In this cross-over design study, 9 unilateral vestibular loss subjects practiced narrow gait with and without wearing a trunk-tilt, biofeedback device in 2 practice sessions. The biofeedback device informed the subjects of their medial-lateral angular tilt and tilt velocity during gait via vibration of the trunk. From motion analysis and tilt data, the performance of the subjects practicing tandem gait were compared over time with and without biofeedback. By practicing tandem gait, subjects reduced their trunk-tilt, center of mass displacement, medial-lateral feet distance, and frequency of stepping error. In both groups, use of tactile biofeedback consistently increased postural stability during tandem gait, beyond the effects of practice alone. However, one single session of practice with biofeedback did not result in conclusive short-term after-effects consistent with short-term retention of motor performance without this additional biofeedback. Results from this study support the hypothesis that tactile biofeedback acts similar to natural sensory feedback to improve dynamic motor performance but does not facilitate a recalibration of motor performance to improve function after short-term use.