Article
Improving impaired balance function: real-time versus carry-over effects of prosthetic feedback
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Published: | September 21, 2011 |
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Aim: Given the correlation between the frequency of falls and excessive trunk sway, this study investigated whether training with real-time prosthetic biofeedback (BF) of trunk sway induces a carry-over improvement in balance control once BF is removed.
Methods: 12 healthy older adults and 8 chronic uncompensated vestibular loss patients were tested. All participants performed a battery of 14 balance and gait tasks (pre-test) upon their initial lab visit during which trunk angular sway in the pitch (AP direction) and roll (ML direction) was measured at L1–3 with a SwayStarTM system. They then received balance BF training on a subset of 7 tasks, three times per week, for two consecutive weeks. BF was provided using a multi-modal biofeedback system with graded head vibrotactile, bone-conducting auditory, and visual cues in relation to subject-specific angular displacement thresholds. Performance on the battery of the 14 balance and gait tasks was re-assessed without FB immediately after the 2 week training period, as well as 1 and 4 weeks later to examine BF carry-over effects.
Results: Significant 30–40% reductions in trunk angular displacement were observed with the real-time BF, compared to the pre-test trials. The effects of BF persisted when BF was removed immediately after the final training session. BF carry-over effects were slightly less evident at 1 and 4 weeks post-training.
Conclusions: This evidence supports the potential short-term effects of BF training in a number of stance and gait tasks after the BF is removed in healthy elderly subjects and those with vestibular loss. However, the prospect for longer term (>4 weeks) effects of prosthetic training on balance control remains currently unknown. Developing a more effective real time feedback device and improving its carry-over effects both seem to be viable options.