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

Abstract

Sub-sensory electrical or mechanical stimulation can enhance the sensitivity of the human somatosensory system to improve the balance control capabilities of elderly. In addition, clinical studies suggest that visual-auditory biofeedback can improve sensory compensation for the elderly. This study hypothesizes that the static balance and gait performance of single leg quiet standing and treadmill walking could be improved for providing proprioceptive neuromuscular facilitation using sub-sensory stimulation and visual-auditory biofeedback in amputee subjects. To test this, a computerized foot pressure biofeedback sensory compensation system using sub-threshold low-level electrical stimulation combined with visualauditory biofeedback was developed. Seven unilateral trans-tibial amputees who wore prostheses over 2 years were recruited. The subjects performed multiple single leg quiet standing trials with sub-sensory electrical stimulation applied at the quadriceps muscle during half of the trials. Static balance performance was characterized by using a Zebris motion analysis system to measure the sway distance and duration of the centre of mass on the second sacral (S2) of the subjects. In addition, multiple treadmill ambulatory trials with or without visual-auditory biofeedback was performed. Dynamic gait performance was characterized with a Zebris instrumented insole to measure the temporal responses of foot pressure sensors. Experimental results showed an improvement in three balance performance indices (Holding Time Index, HTI, Maximum Sway Distance Index, MSDI, and Average Sway Distance Index, ASDI) during single leg quiet standing by applying sub-sensory stimulation. The improvement ratio of these balance performance indices across subjects for single leg quiet standing tests resulted in 132.34% in HTI, 44.61% in MSDI, and 61.45% in ASDI. With visual-auditory biofeedback as a cue for heel contact and toe push-off condition during treadmill ambulation, the improvement of four dynamic gait performance measures (Double Support Period, DSP, Constant Time Cadence, CTC, Single Support Period, SSP, and Stance/Swing Ratio, SSR) in amputees was verified. This resulted in 7.89% in DSP (affected side), 5.09% in CTC, 16.67% in SSP (sound side), 45.30% in SSR (sound side), and 40.30% in SSR (affected side) respectively. These findings suggest that sub-threshold electrical stimulation and visual-auditory biofeedback rehabilitation strategies may be effective in compensating sensory loss and improving static balance and dynamic ambulation performance for amputees.

Test‐Retest Reliability of the Sensory Organization Test in Older Persons With a Transtibial Amputation

“…These clinical tools are easy to administer and are an attractive option for clinicians who wish to monitor balance performance in the rehabilitation setting [16,17]. More recently, sophisticated laboratory instruments such as the force platform [18‐21], motion analysis technology [22‐24], and computerized dynamic posturography (CDP) [25,26] have been used to objectively quantify balance performance in individuals with an LLA. The detailed information obtained by objective and systematic testing from such instruments has the potential to significantly advance the understanding of individual impairments underlying the balance control system.…”

Quantitative Assessment of Postural Stability and Balance Between Persons with Lower Limb Amputation and Normal Subjects by using Dynamic Posturography

“…Sub-threshold electrical stimulation and visual-auditory biofeedback rehabilitation strategies may be effective in compensating sensory loss and improving static balance and dynamic ambulation performance for persons with amputation [14].…”

A wearable skin stretch haptic feedback device: Towards improving balance control in lower limb amputees

“…Previously, the use of tactile feedback for balance and postural control has been investigated for patients with vestibular disease where reduction of sway during locomotion [17] and postural stability improvement [18] were reported. At least one study [19] described work with above knee amputees to investigate the effect of providing IC and TO (detected using foot sensors) cues during ambulation, however, using visual and auditory feedback. The authors reported improvement in several dynamic gait performance measures.…”