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首页> 外文会议>Engineering in Medicine and Biology Society, 1998. Proceedings of the 20th Annual International Conference of the IEEE >Abnormal passive and intrinsic stiffness in the spastic ankle
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Abnormal passive and intrinsic stiffness in the spastic ankle

机译：痉挛性踝关节的被动和固有僵硬异常

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A parallel-cascade system identification method was used to measure dynamic ankle stiffness in normal and spastic spinal cord injured (SCI) subjects. Modulation of passive and intrinsic stiffness gain of ankle extensor muscles (GS) was studied by applying perturbations to the ankle at different positions under passive (relaxed) and active (10% extensor maximum voluntary contraction) conditions. Both passive and intrinsic stiffness were described well by a linear second-order model having elastic, viscous and inertia parameters. For passive stiffness the elastic and viscous parameters increased with ankle dorsiflexion in both groups; in addition, both parameters were larger in SCI than in control subjects as ankle dorsiflexed. For intrinsic stiffness (1) the elastic parameter increased with ankle position until neutral position (90/spl deg/) in both groups, it then saturated in control subjects, but decreased as ankle moved to dorsiflexion in SCI subjects; (2) it was always smaller in SCI subjects; (3) the intrinsic viscous parameter increased at the beginning of plantarflexion then decreased slightly until maximum dorsiflexion in both groups. However, it was lower than in control subjects as the ankle moved from neutral position to maximum dorsiflexion. The results indicate that abnormal non-reflex mechanics are due to enhanced passive stiffness and reduced intrinsic stiffness.
机译：并行级联系统识别方法用于测量正常和痉挛性脊髓损伤（SCI）受试者的动态踝关节僵硬程度。通过在被动（放松）和主动（10％伸肌最大自主收缩）条件下对踝关节的不同位置施加扰动，研究了踝伸肌（GS）被动和固有刚度增益的调制。被动刚度和固有刚度都可以通过具有弹性，粘性和惯性参数的线性二阶模型很好地描述。对于被动刚度，两组的弹性和粘性参数均随踝背屈而增加;此外，由于踝背屈，两个参数在SCI中都比对照组大。对于固有刚度（1），两组的弹性参数都随脚踝位置的增加而增加，直到中立位置（90 / spl deg /），然后在对照受试者中达到饱和，但在SCI受试者中随着踝关节向背屈运动而减小; （2）在SCI学科中总是较小; （3）固有挠性参数在plant屈开始时先增加，然后略有下降，直到两组的最大背屈为止。但是，由于踝关节从中立位置移至最大背屈，因此该比例低于对照组。结果表明，异常的非反射力学是由于增强的被动刚度和减小的固有刚度引起的。

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