Abstract
In previous research, we found that modulating the assistance timing of dorsiflexion may affect a user's voluntary efforts. This could constitute a focus area based on assistive strategies that could be developed to foster patients' voluntary efforts. In this present study, we conducted an experiment to verify the effects of ankle dorsiflexion assistance under different timings using a high-dorsiflexion assistive system. Nine healthy and young participants wore a dorsiflexion-restrictive device that enabled them to use circumduction or steppage gaits. On the basis of the transition from the stance to the swing phase of the gait, the assistance timings of the high-dorsiflexion assistive system were set to have delays, which ranged from 0 to 300 ms. The index results from eight out of nine participants evaluated compensatory movements and revealed positive strong/moderate correlations with assistance delay times (r = 0.627-0.965, p <.001), whereas the other participants also performed compensatory movement when dorsiflexion assistance timing was late. Meanwhile, the results from tibialis anterior surface electromyography from six out of nine participants showed positive strong/moderate correlations with dorsiflexion assistance delay times (r = 0.598-0.922, p <.001), indicating that tuning the assistance timing did foster these participants' voluntary dorsiflexion movements. This result indicates that there should be a trade-off between ensuring voluntary dorsiflexion movements and preventing incorrect gait patterns at different assistance timings. The findings of this feasibility study indicate the potential of developing an adaptive control method to ensure voluntary efforts during robot-assisted gait rehabilitation based on assistance timing modification. A new assistance mechanism should also be required to stimulate and motivate a patient's voluntary efforts and should reinforce the effects of active gait rehabilitation.
Highlights
T HE poststroke population has been increasing rapidly
To verify the compensatory movements used by each participant, the Student’s t-test was applied on maximum knee height in the swing phase, lateral pelvis tilt angle, swing width between Normal walk (NOR), and Simulated compensatory gait (SCG) conditions with significant differences set as p < 0.05
We have verified the effects of different dorsiflexion assistance timings on tibialis anterior surface electromyography (sEMG), minimum toe clearance (MTC), and compensatory movements
Summary
T HE poststroke population has been increasing rapidly. This has led to increased requirements for rehabilitation programs and follow-up care, which is a critical issue around the world [1]. A stroke survivor with hemiplegia experiences an enforced drop foot, “toe-down” posture on their paralyzed side during the swing phase of their gait [2]. This leads to insufficient minimum toe clearance (MTC), which is believed to create a high-stumbling risk [3]. A few PAFO studies have focused on providing sufficient dorsiflexion in the swing phase to ensure foot clearance [6]–[8]. It is hoped that through the intervention of PAFOs, patients can relearn how to practice sufficient MTC and lower their stumbling risk and prevent compensatory gaits. Two major challenges have arisen in the course of recent PAFO research
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Schedule a callMore From: IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society
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