Balance control enhancement using sub-sensory stimulation and visual-auditory biofeedback strategies for amputee subjects

A computerized foot pressure activated sensory compensation system using sub-sensory electrical stimulation combined with visual-auditory biofeedback was developed. The proposed system was used for enhancing standing balance and gait performance for amputees. In this pilot study, we hypothesized that the static balance with single limb support and gait performance during treadmill walking could be improved by providing proprioceptive neuromuscular facilitation using sub-sensory stimulation and visual-auditory biofeedback in amputee respectively. To test this hypothesis, five unilateral trans-tibial amputees who consecutively wore prosthetics over two years were recruited. Experimental results show that reduction in all of the postural sway indices and increase in single leg support time index during single leg quiet standing by applying sub-sensory stimulation. With visual-auditory biofeedback for providing clue for heel contact and toe push off condition during treadmill ambulation, the improvement of all four dynamic gait performance indices in amputees was verified. These findings suggest that proposed system with sub-sensory electrical stimulation and visual-auditory biofeedback mechanisms may be effective in compensating sensory loss and improving posture control for amputees.