The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
J Neurotrauma. 2012 Mar 20;29(5):915-24. doi: 10.1089/neu.2010.1549. Epub 2011 Dec 1.
Clonus can interfere with self-care and rehabilitation of people with spinal cord injury. Our aim was to characterize clonus and to evaluate factors that influence clonus duration in muscles paralyzed chronically by spinal cord injury. Electromyographic activity was recorded from soleus and 7 other limb muscles (5 ipsilateral, 2 contralateral) during clonus. In 14 subjects, clonus frequency in soleus averaged 5.4±0.9 Hz and was slower when the reflex path was longer. Contraction frequency slowed at the beginning and end of clonus (sometimes by 2 Hz). The magnitude of one cycle changed the timing and magnitude of the next cycle. These data suggest that afferent input influences the frequency and maintenance of clonus. Recording from many muscles revealed that clonus was prolonged (>40 sec) when only ipsilateral triceps surae or triceps surae and tibialis anterior were involved. Therefore, localized inputs to spinal circuits were important to sustain clonus. Clonus was intermediate (median: 21 sec) with activation of three or four ipsilateral muscles and these contractions were associated with greater activation of ipsilateral flexors. Clonus was short (<5 sec) when ipsilateral and contralateral muscles were activated (five or six muscles). Activation of extraneous afferent input, particularly contralateral muscles, may provide a way to shorten clonus after spinal cord injury.
痉挛会干扰脊髓损伤患者的自理和康复。我们的目的是描述痉挛的特征，并评估影响脊髓损伤慢性瘫痪肌肉痉挛持续时间的因素。在痉挛过程中，从比目鱼肌和其他 7 块肢体肌肉（5 块同侧，2 块对侧）记录肌电图活动。在 14 名受试者中，比目鱼肌的痉挛频率平均为 5.4±0.9 Hz，当反射路径较长时，痉挛频率较慢。在痉挛的开始和结束时，收缩频率会减慢（有时减慢 2 Hz）。一个周期的幅度改变了下一个周期的时间和幅度。这些数据表明，传入输入会影响痉挛的频率和维持。从许多肌肉记录显示，当只有同侧三头肌或三头肌和胫骨前肌参与时，痉挛会延长（>40 秒）。因此，局部传入到脊髓回路对于维持痉挛很重要。当激活三个或四个同侧肌肉时，痉挛为中等（中位数：21 秒），这些收缩与同侧屈肌的更大激活有关。当同侧和对侧肌肉（五或六块肌肉）激活时，痉挛很短（<5 秒）。激活额外的传入输入，特别是对侧肌肉，可能是脊髓损伤后缩短痉挛的一种方法。
