Bara-Jimenez W, Aksu M, Graham B, Sato S, Hallett M
Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA.
Neurology. 2000 Apr 25;54(8):1609-16. doi: 10.1212/wnl.54.8.1609.
To test the hypothesis that periodic limb movements (PLMs) are related to spinal flexor reflexes (FRs), the authors compared the state-dependent changes in FR excitability in 10 patients with restless legs syndrome (RLS) and PLMs with those from matched controls.
PLM is a disorder of motor control during sleep, frequently occurring in RLS. Clinically, PLMs resemble spinal FRs.
FRs were obtained by electrically stimulating the medial plantar nerve and recording from antagonist leg and thigh muscles bilaterally.
Compared with controls, patients had significantly increased spinal cord excitability, as indicated by lower threshold and greater spatial spread of the FR, which was more prominent during sleep. Multiple late responses were seen during sleep in all patients and in some controls at higher threshold. The most prominent of these responses had a very long duration and a latency range of 250 to 800 msec, and because of its close temporal relationship to the FR stimulus, the authors considered it was a late, high-threshold component of the FR (FR3). The authors also found a similarity between the pattern of muscle recruitment and spatial spread of late components of the FR and those of spontaneous PLMs.
The results support the hypothesis that PLMs in RLS and FRs share common spinal mechanisms and suggest that PLMs may result from enhanced spinal cord excitability in RLS patients. Because dopaminergic mechanisms are involved in spinal FR control, the results are consistent with the current view that RLS is a disorder of dopaminergic function.
为验证周期性肢体运动（PLMs）与脊髓屈肌反射（FRs）相关这一假说，作者比较了10例不宁腿综合征（RLS）伴PLMs患者与匹配对照组的FR兴奋性的状态依赖性变化。
PLM是睡眠期间的一种运动控制障碍，常见于RLS。临床上，PLMs类似于脊髓FRs。
通过电刺激足底内侧神经并双侧记录拮抗肌腿部和大腿肌肉来获取FRs。
与对照组相比，患者脊髓兴奋性显著增加，表现为FR阈值降低和空间扩散增大，睡眠期间更为明显。所有患者睡眠期间以及部分阈值较高的对照组均可见多个迟发反应。其中最显著的反应持续时间很长，潜伏期范围为250至800毫秒，由于其与FR刺激的时间关系密切，作者认为它是FR的一个迟发、高阈值成分（FR3）。作者还发现FR迟发成分的肌肉募集模式和空间扩散与自发PLMs的相似。
结果支持RLS中的PLMs与FRs具有共同脊髓机制这一假说，并提示PLMs可能源于RLS患者脊髓兴奋性增强。由于多巴胺能机制参与脊髓FR控制，结果与当前认为RLS是一种多巴胺能功能障碍的观点一致。
