Dietz V, Zijlstra W, Prokop T, Berger W
Paraplegic Centre, University Hospital Balgrist, Zurich, Switzerland.
Electroencephalogr Clin Neurophysiol. 1995 Dec;97(6):408-15. doi: 10.1016/0924-980x(95)00109-x.
Adaptation in leg muscle activity and coordination between lower limbs were studied during walking on a treadmill with split belts in one group of parkinsonian patients and one of age-matched healthy subjects. Four different belt speeds (0.25/0.5/0.75/1.0 m/sec) were applied in selected combinations to the left and right leg. While these walking conditions were easily tolerated by the healthy subjects, the parkinsonian patients usually reached the limits of their walking capabilities. Both groups adapted automatically to a change in belt speed within approximately 20 stride cycles. Healthy subjects adapted by reorganizing their stride cycle with a relative shortening of duration of support and lengthening of the swing phase of the "fast" leg and vice versa on the "slow" leg. The patients showed a restricted range of stride frequencies for the various belt speeds during normal and split-belt walking with consequent deviations in the reorganization of the stride cycle. In both healthy subjects and patients, ipsilateral gastrocnemius and contralateral tibialis anterior electromyographic (EMG) activity increased predominantly with an ipsilateral increase in belt speed. Two main differences were observed in the EMG patterns: (1) In the patients leg muscle EMG activity was less modulated and gastrocnemius EMG amplitude was small during normal and split-belt walking. However, there was no significant difference between the two groups in respect to the reorganization of the EMG pattern required for the various split-belt walking conditions. (2) The amount of co-activation of antagonistic leg muscles during the support phase of the stride cycle was greater in the patients compared to the healthy subjects during normal and split-belt walking. It is suggested that reduced EMG modulation and recruitment in the leg extensors may contribute to the impaired walking of the patients. This in turn is a result of an impaired proprioceptive feedback from extensor load receptors. This defective control is partially compensated for in parkinsonian patients by a greater amount of leg flexor activation which leads to a higher degree of co-activation. Visual input plays a role in the control of this increased activation.
在一组帕金森病患者和一组年龄匹配的健康受试者中，研究了他们在跑步机上使用分离式跑带行走时腿部肌肉活动的适应性以及下肢之间的协调性。将四种不同的跑带速度（0.25/0.5/0.75/1.0米/秒）以选定的组合分别应用于左腿和右腿。虽然这些行走条件健康受试者很容易耐受，但帕金森病患者通常会达到其行走能力的极限。两组受试者均在大约20个步幅周期内自动适应跑带速度的变化。健康受试者通过重新组织步幅周期来适应，“快”腿支撑期持续时间相对缩短，摆动期延长，而“慢”腿则相反。在正常和分离式跑带行走过程中，患者在不同跑带速度下的步频范围受限，步幅周期的重新组织也随之出现偏差。在健康受试者和患者中，同侧腓肠肌和对侧胫骨前肌的肌电图（EMG）活动主要随着同侧跑带速度的增加而增加。在肌电图模式上观察到两个主要差异：（1）在患者中，正常和分离式跑带行走时腿部肌肉的肌电图活动调节较少，腓肠肌肌电图幅度较小。然而，在各种分离式跑带行走条件下所需的肌电图模式重新组织方面，两组之间没有显著差异。（2）在正常和分离式跑带行走过程中，与健康受试者相比，患者在步幅周期支撑期拮抗腿部肌肉的共同激活量更大。研究表明，腿部伸肌的肌电图调节和募集减少可能导致患者行走功能受损。这反过来又是伸肌负荷感受器本体感觉反馈受损的结果。这种缺陷性控制在帕金森病患者中部分通过更大程度的腿部屈肌激活得到补偿，这导致了更高程度的共同激活。视觉输入在这种增加的激活控制中起作用。
