Schmid U D, Hess C W, Ludin H P
Neurologische und Neurochirurgische Universitätsklinik Bern.
EEG EMG Z Elektroenzephalogr Elektromyogr Verwandte Geb. 1989 Mar;20(1):39-49.
Following percutaneous stimulation over the cervical column, a compound action potential (CMAP) can be recorded from the muscles of the arm. The actual site of excitation is located on the spinal motor roots, probably near to their exit from the spinal column. This method allows the electroneurographical assessment of the proximal brachial plexus and is used to calculate a central motor conduction time following motor cortex stimulation. So far, the optimal placement of the stimulating electrodes is unknown, and normal values must be established. We measured onset latencies of CMAPs of Mm biceps brachii and abductor digiti minimi (ADM) after supramaximal cervical motor root stimulation in 31 healthy subjects. Distances between the stimulating electrodes varying from 3 to 12 cm were studied. With 6 cm interelectrode distance, the electrodes were then placed either in a longitudinal or in a transversal direction, with the cathode over the interspace C7/T1 or C6/7. In addition, for the longitudinal stimulation, the effect of cathodal versus anodal stimulation over the C7/T1 interspace was studied. The results of various stimulating electrode positions and directions over the lower cervical column were then compared statistically. With the longitudinal electrode position, the cathode over C7/T1 and the anode placed 6 cm cranially, it was always possible to excite muscles from both sides simultaneously. When a very proximal stimulation site at the nerve roots was required in both muscles after one single stimulus, this method was superior to the transversal electrode position with the cathode C6/7 or C7/T1, or to the longitudinal electrode position with the anode over C7/T1 and the cathode placed cranially. For the ADM (29 subjects, 58 sides), the mean onset latency was 13.795 +/- 1.307 ms (mean +/- 1 SD), the mean side-to-side difference (SSD) was 0.452 +/- 0.388 ms. The mean amplitude was 7.71 +/- 2.64 mV, the mean side-to-side quotient (SDQ) was 41.88 +/- 97.59%. For M. biceps (29 subjects, 58 sides), the mean onset latency was 5.138 +/- 0.582 ms, the mean SSD 0.166 +/- 0.193 ms. The mean amplitude was 7.91 +/- 3.45 mV, the mean SSQ was 55.42 +/- 67.94%.
在对颈椎进行经皮刺激后，可以从手臂肌肉记录复合动作电位（CMAP）。兴奋的实际部位位于脊髓运动神经根，可能靠近它们从脊柱穿出的位置。这种方法可以对臂丛神经近端进行神经电生理评估，并用于计算运动皮层刺激后的中枢运动传导时间。到目前为止，刺激电极的最佳放置位置尚不清楚，必须确定正常值。我们测量了31名健康受试者在最大强度刺激颈髓运动神经根后肱二头肌和小指展肌（ADM）的CMAP起始潜伏期。研究了刺激电极之间距离在3至12厘米之间变化的情况。当电极间距为6厘米时，然后将电极沿纵向或横向放置，阴极位于C7/T1或C6/7间隙上方。此外，对于纵向刺激，研究了在C7/T1间隙进行阴极刺激与阳极刺激的效果。然后对下颈椎上不同刺激电极位置和方向的结果进行统计学比较。在纵向电极位置，阴极位于C7/T1上方，阳极位于头侧6厘米处时，总是能够同时激发两侧肌肉。当单次刺激后需要在两块肌肉的神经根处进行非常近端的刺激部位时，这种方法优于阴极位于C6/7或C7/T1的横向电极位置，或阳极位于C7/T1上方且阴极位于头侧的纵向电极位置。对于ADM（29名受试者，58侧），平均起始潜伏期为13.795±1.307毫秒（平均值±1标准差），平均左右差异（SSD）为0.452±0.388毫秒。平均波幅为7.71±2.64毫伏，平均左右商（SDQ）为41.88±97.59%。对于肱二头肌（29名受试者，58侧），平均起始潜伏期为5.138±0.582毫秒，平均SSD为0.166±0.193毫秒。平均波幅为7.91±3.45毫伏，平均SSQ为55.
