Locomotor adaptation to a powered ankle-foot orthosis depends on control method
Locomotor adaptation to a powered ankle-foot orthosis depends on control method
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DOI：
10.1186/1743-0003-4-48
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发表时间：
2007-12-21
影响因子：
5.1
通讯作者：
Ferris, Daniel P.
中科院分区：
文献类型：
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作者：
Cain, Stephen M.;Gordon, Keith E.;Ferris, Daniel P.
背景：我们研究了人类对动力踝足矫形器的运动适应性，目的是识别两种不同矫形器控制方法之间的差异。第一种矫形器控制方法使用脚踏开关提供“砰砰”控制（一种运动控制），第二种矫形器控制方法使用比目鱼肌的比例肌电信号（一种生理控制）。两个控制器都激活了一个人造气动肌肉，提供足底弯曲扭矩。方法：在脚踏开关控制（n = 6）或肌电控制（n = 6）下，受试者在跑步机上行走两次，每次30分钟，间隔三天。我们记录了下肢肌电图（EMG）、关节运动学和矫形器动力学。我们比较了姿态相位肌电图振幅，关节角度模式的相关性，以及两个控制器之间动力矫形器所做的机械功。结果：在第二阶段结束的稳定状态下，比例肌电控制组比目鱼肌和腓肠肌的激活明显低于脚开关控制组。三头肌表面活动的显著减少，使比例肌电控制受试者的踝关节运动接近正常，并减少矫形器带来的负面工作。脚开关控制组受试者行走时踝关节运动受到严重干扰，并且使用矫形器进行更多的负性工作。结论：这些结果提供了证据，证明矫形器控制方法的选择可以极大地改变人类在行走时对动力矫形器辅助的适应程度。具体来说，与脚开关控制相比，比例肌电控制导致肌肉激活和步态运动学更类似于正常情况的更大减少。
Background: We studied human locomotor adaptation to powered ankle-foot orthoses with the intent of identifying differences between two different orthosis control methods. The first orthosis control method used a footswitch to provide bang-bang control ( a kinematic control) and the second orthosis control method used a proportional myoelectric signal from the soleus ( a physiological control). Both controllers activated an artificial pneumatic muscle providing plantar flexion torque.Methods: Subjects walked on a treadmill for two thirty-minute sessions spaced three days apart under either footswitch control (n = 6) or myoelectric control ( n = 6). We recorded lower limb electromyography (EMG), joint kinematics, and orthosis kinetics. We compared stance phase EMG amplitudes, correlation of joint angle patterns, and mechanical work performed by the powered orthosis between the two controllers over time.Results: During steady state at the end of the second session, subjects using proportional myoelectric control had much lower soleus and gastrocnemius activation than the subjects using footswitch control. The substantial decrease in triceps surae recruitment allowed the proportional myoelectric control subjects to walk with ankle kinematics close to normal and reduce negative work performed by the orthosis. The footswitch control subjects walked with substantially perturbed ankle kinematics and performed more negative work with the orthosis.Conclusion: These results provide evidence that the choice of orthosis control method can greatly alter how humans adapt to powered orthosis assistance during walking. Specifically, proportional myoelectric control results in larger reductions in muscle activation and gait kinematics more similar to normal compared to footswitch control.