Plassman B L, Gandevia S C
Department of Neurology, Prince Henry Hospital, University of New South Wales, Sydney, Australia.
J Neurol Neurosurg Psychiatry. 1989 Feb;52(2):213-7. doi: 10.1136/jnnp.52.2.213.
Percutaneous electrical stimuli (up to 600 V) were applied over the cervical spinal cord to evoke responses in the biceps brachii and thenar muscles. Cathodal stimulation over the C7 spinous process was more effective than anodal stimulation or stimulation over the C5 or C3 spinous process. As the stimulus intensity was increased, the response amplitude increased and the latency decreased. When progressively higher levels of supramaximal stimuli were delivered the latency often decreased further. The shortest latencies evoked by stimulation over the C7 spinous process were close to the latencies of the responses evoked by supramaximal stimulation near Erb's point. Thus, with this type of stimulation, the site of nerve activation changes with different stimulus intensities. The variability in latency introduced by distal spread of the site of activation will affect measurements of central motor conduction time and should be considered in the diagnostic use of this technique.
经皮电刺激（高达600伏）施加于颈脊髓上，以诱发肱二头肌和鱼际肌的反应。在C7棘突上进行阴极刺激比在阳极刺激或C5或C3棘突上进行刺激更有效。随着刺激强度增加，反应幅度增大而潜伏期缩短。当给予逐渐增高的超强刺激水平时，潜伏期常常进一步缩短。在C7棘突上进行刺激所诱发的最短潜伏期接近在Erb点附近进行超强刺激所诱发反应的潜伏期。因此，采用这种类型的刺激，神经激活部位会随不同刺激强度而改变。激活部位向远端扩散所导致的潜伏期变异性将影响中枢运动传导时间的测量，在该技术的诊断应用中应予以考虑。
