EXPLORATION OF VIBROTACTILE BIOFEEDBACK STRATEGIES TO INDUCE STANCE TIME ASYMMETRIES
Bibliographic record
Abstract
BACKGROUND: Gait symmetry is the degree of equality of biomechanical parameters between limbs within a gait cycle. Human gait is highly symmetrical; however, in the presence of pathology, gait often lacks symmetry. Biofeedback (BFB) systems have demonstrated the potential to reduce gait asymmetry, improve gait function, and benefit overall long-term musculoskeletal health. OBJECTIVE(S): The aim of this study was to develop a BFB system and evaluate three unique BFB strategies, including bidirectional control – constant vibration (BC), bidirectional control – variable vibration (BV), and unidirectional control – variable vibration (UV) relevant to gait symmetry. The assessed feedback strategies were a combination of vibration frequency/amplitude levels, vibration thresholds, and vibrotactile stimuli from one and two vibrating motors (tactors). Learning effect and short-term retention were also assessed. METHODOLOGY: Testing was performed using a custom BFB system that induces stance time asymmetries to modulate temporal gait symmetry. The BFB system continuously monitors specific gait events (heel-strike and toe-off) and calculates the symmetry ratio, based on the stance time of both limbs to provide real-time biomechanical information via the vibrating motors. Overall walking performance of ten (n=10) able-bodied individuals (age 24.8 ± 4.4 years) was assessed via metrics of symmetry ratio, symmetry ratio error, walking speed, and motor's vibration percentages. FINDINGS: All participants utilized BFB somatosensory information to modulate their symmetry ratio. UV feedback produced a greater change in symmetry ratio, and it came closer to the targeted symmetry ratio. Learning or short-term retention effects were minimal. Walking speeds were reduced with feedback compared to no feedback; however, UV walking speeds were significantly faster compared to BV and BC. CONCLUSION: The outcomes of this study provide new insights into the development and implementation of feedback strategies for gait retraining BFB systems that may ultimately benefit individuals with pathological gait. Future work should assess longer-term use and long-term learning and retention effects of BFB systems in the populations of interest. Layman's Abstract Healthy walking is usually highly symmetrical with the same movements occurring on both sides of the body. However, certain disorders can cause abnormal and asymmetrical walking movements. Biofeedback can improve the movements during walking. This study used a custom biofeedback system to test three ways of applying biofeedback including having one and two motors that vibrated in unique ways. The biofeedback system was set up to guide participants to change their normal walking pattern to be less symmetrical. Walking movements of ten young able-bodied individuals were measured while walking with the biofeedback system. The results showed a change in walking symmetry for all participants. Using a single vibrating motor resulted in the greatest changes in walking symmetry. The changes in walking symmetry occurred only when using biofeedback, and walking patterns quickly returned to normal when the biofeedback was turned off. Overall, all feedback methods caused the users to walk slower than their typical walking speed. These findings provide important new information about the changes in walking caused by different biofeedback methods. Future work should evaluate long-term effects of biofeedback methods in the populations of interest. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36744/28677 How To Cite: Escamilla-Nunez R, Sivasambu H, Andrysek J. Exploration of vibrotactile biofeedback strategies to induce stance time asymmetries. Canadian Prosthetics & Orthotics Journal. 2022; Volume 5, Issue 1, No.2. https://doi.org/10.33137/cpoj.v5i1.36744 Corresponding Author: Rafael Escamilla-Nunez, Institute of Biomedical Engineering, University of Toronto, Toronto, Canada.E-Mail: rafael.escamilla@mail.utoronto.caORCID ID: https://orcid.org/0000-0002-2739-878X
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".