Lourenço G, Bleton J-P, Iglesias C, Vidailhet M, Marchand-Pauvert V
INSERM, U731, Paris F-75013, France.
Clin Neurophysiol. 2007 Oct;118(10):2215-26. doi: 10.1016/j.clinph.2007.07.009. Epub 2007 Sep 4.
Spinal reflexes from hand to wrist muscles were investigated in writer's cramp.
Stimulus-triggered rectified EMG averages after ulnar nerve and cutaneous stimulation, in wrist flexors and extensors during tonic contraction, were compared in 18 controls and 19 patients.
On the patient dystonic side, ulnar-induced EMG suppression was decreased in wrist extensors, and facilitation in wrist flexors modified dependent on the dystonic wrist posture during writing. No change was found on the patient non-dystonic side. Cutaneous stimulation increased wrist flexor EMG on both sides of the patients with normal wrist posture during writing, but had no effect in controls and patients with abnormal wrist posture.
Comparison between cutaneous and mixed nerve stimuli suggests that spindle afferents from intrinsic hand muscles may mediate patients' ulnar-induced EMG modulations. Abnormal proprioceptive control was only observed on dystonic side, while bilateral unusual cutaneous control was found in patients. Changes in spinal transmission were partly related to the dystonic wrist posture, suggesting that systems involved in sensory processing can be differentially altered in writer's cramp.
Changes in spinal transmission, probably related to peripheral and/or cortical inputs, might either take part in primary or adaptive mechanisms underlying writer's cramp.
研究书写痉挛患者手部至腕部肌肉的脊髓反射。
比较18名对照组和19名患者在尺神经和皮肤刺激后，在腕部屈肌和伸肌强直性收缩期间的刺激触发整流肌电图平均值。
在患者肌张力障碍侧，腕部伸肌中尺神经诱发的肌电图抑制减弱，而腕部屈肌中的易化作用根据书写时肌张力障碍性腕部姿势而改变。在患者非肌张力障碍侧未发现变化。在书写时腕部姿势正常的患者两侧，皮肤刺激均增加了腕部屈肌肌电图，但对对照组和腕部姿势异常的患者无影响。
皮肤和混合神经刺激的比较表明，手部固有肌的肌梭传入可能介导了患者尺神经诱发的肌电图调制。异常的本体感觉控制仅在肌张力障碍侧观察到，而在患者中发现双侧异常的皮肤控制。脊髓传导的变化部分与肌张力障碍性腕部姿势有关，表明感觉处理相关系统在书写痉挛中可能存在不同程度的改变。
脊髓传导的变化可能与外周和/或皮层输入有关，可能参与了书写痉挛的原发性或适应性机制。
