Crenna P
Institute of Human Physiology, Faculty of Medicine, University of Genoa, Italy.
Neurosci Biobehav Rev. 1998 Jul;22(4):571-8. doi: 10.1016/s0149-7634(97)00046-8.
The current notion of spasticity as a velocity-dependent increase of muscle response to imposed stretch was mainly derived from studies performed under stationary experimental conditions. To address the issue of a spastic muscle behaviour under dynamic conditions, we conceived a novel approach, aimed at quantitatively assessing motor output over the lengthening periods which take place during unperturbed functional movements. Application to the analysis of overground walking in children with spastic cerebral palsy (CP) revealed that, for representative lower limb muscles, the relationship between EMG levels and estimated muscle lengthening rate displays either increased gain or reduced velocity threshold. Parallel measurement of gait kinetics frequently showed congruent increase of the mechanical resistance to joint rotation. Abnormalities preferentially targeted the lengthening contractions occurring around the ground contact period of the stride. The pathophysiological profile of what is clinically defined as 'spastic' gait in CP children did not only consist of dynamic spasticity, as described above. Most often it resulted from the simultaneous contribution of other factors, including paresis, co-contraction, immature and non-neural components.
目前将痉挛定义为肌肉对施加的牵伸反应随速度增加的概念，主要源自于在静态实验条件下进行的研究。为了解决动态条件下痉挛肌肉行为的问题，我们构思了一种新方法，旨在定量评估在无干扰功能运动期间发生的肌肉拉长阶段的运动输出。将该方法应用于痉挛型脑性瘫痪（CP）儿童的地面行走分析发现，对于具有代表性的下肢肌肉，肌电图（EMG）水平与估计的肌肉拉长率之间的关系显示出增益增加或速度阈值降低。步态动力学的并行测量经常显示出对关节旋转的机械阻力同步增加。异常情况优先针对步幅着地期前后发生的拉长收缩。CP儿童临床上定义为“痉挛性”步态的病理生理特征不仅包括上述动态痉挛。大多数情况下，它是由其他因素共同作用导致的，包括轻瘫、共同收缩、不成熟和非神经成分。
