Müller R, Dietz V
Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland.
Clin Neurophysiol. 2006 Jul;117(7):1499-507. doi: 10.1016/j.clinph.2006.03.022. Epub 2006 May 11.
Knowledge about the long-term course of spinal neuronal function after spinal cord injury (SCI) is important if regeneration therapies become available in the future. The objective of this study was to examine the behavior of locomotor EMG activity and of spinal reflexes in patients with chronic motor-complete SCI.
EMG activity from rectus femoris (RF), biceps femoris (BF), medial gastrocnemius (GM) and tibialis anterior (TA) of both sides was investigated during locomotor movements assisted by a robotic device in 10 chronic (>1 year after accident) complete SCI and 5 healthy subjects. H-reflexes (recorded from GM) were induced during the onset and flexion reflexes (recorded from BF and TA) at the end of the stance phase.
Only in the chronic SCI subjects an exhaustion of EMG activity--i.e. a decrease in amplitude--occurred within a few minutes in all leg muscles. The EMG exhaustion was not associated with a change in the H- or flexion reflex amplitude during a walking session.
Exhaustion of neuronal function in chronic complete SCI might be restricted to unused motor tasks, i.e. locomotion. The fact that H- and flexion reflexes show a normal behavior might be due to the fact that they still become activated.
Training/pharmalogical approaches may be required to maintain neuronal function of unused tasks as a basis for future successful regeneration therapies.
如果未来再生疗法可用，了解脊髓损伤（SCI）后脊髓神经元功能的长期病程很重要。本研究的目的是检查慢性运动完全性SCI患者的运动肌电图活动和脊髓反射的行为。
在机器人设备辅助的运动过程中，对10例慢性（事故发生后>1年）完全性SCI患者和5名健康受试者双侧股直肌（RF）、股二头肌（BF）、腓肠肌内侧头（GM）和胫骨前肌（TA）的肌电图活动进行了研究。在站立期开始时诱发H反射（从GM记录），在站立期末诱发屈曲反射（从BF和TA记录）。
仅在慢性SCI受试者中，所有腿部肌肉的肌电图活动在几分钟内出现耗尽，即振幅降低。在步行过程中，肌电图耗尽与H反射或屈曲反射振幅的变化无关。
慢性完全性SCI中神经元功能的耗尽可能仅限于未使用的运动任务，即运动。H反射和屈曲反射表现正常的事实可能是由于它们仍然会被激活。
可能需要训练/药物方法来维持未使用任务的神经元功能，作为未来成功再生疗法的基础。
