UPMC Univ Paris 06, ER 6, F-75005, Paris, France.
Clin Neurophysiol. 2010 Jun;121(6):930-8. doi: 10.1016/j.clinph.2009.12.037. Epub 2010 Feb 11.
It is still unclear to what an extent altered reflex activity contributes to gait deficit following stroke. Spinal group I and group II excitations from ankle dorsiflexors to knee extensors were investigated during post-stroke walking.
Electrical stimulation was applied to the common peroneal nerve (CPN) in the early stance, and the short-latency biphasic excitation in Quadriceps motoneurones was evaluated from the Vastus Lateralis (VL) rectified and averaged (N=50) EMG activity in 14 stroke patients walking at 0.6-1.6 km/h, and 14 control subjects walking at 3.2-4.8 and at 1 km/h.
The second peak of the CPN-induced biphasic facilitation in VL EMG activity, which is likely mediated by group II excitatory pathways, was larger on the paretic side of the patients, as compared to their nonparetic side or control subjects, whatever their walking speed.
The spinal, presumed group II, excitation from ankle dorsiflexors to knee extensors is particularly enhanced during post-stroke walking probably due to plastic adaptations in the descending control.
This adaptation may help to stabilize the knee in early stance when the patients have recover ankle dorsiflexor functions.
目前仍不清楚反射活动的改变在多大程度上导致了中风后的步态缺陷。本研究在中风后行走期间研究了踝背屈肌到伸膝肌的脊髓 I 群和 II 群兴奋。
在早期站立时对腓总神经（CPN）施加电刺激，并从股外侧肌（VL）的直整流和平均（N=50）EMG 活动中评估股四头肌运动神经元的短潜伏期双相兴奋，14 例中风患者以 0.6-1.6km/h 的速度行走，14 例对照受试者以 3.2-4.8km/h 和 1km/h 的速度行走。
与非瘫痪侧或对照组相比，患者瘫痪侧的 CP 诱导的双相易化在 VL EMG 活动中的第二峰更大，这可能是由 II 群兴奋性途径介导的。无论行走速度如何，结果都是如此。
从踝背屈肌到伸膝肌的脊髓、推测的 II 群兴奋在中风后行走期间特别增强，可能是由于下行控制的可塑性适应。
这种适应可能有助于在患者恢复踝背屈功能时稳定早期站立时的膝盖。
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