磁刺激拇短展肌体感诱发电位的研究

A study of somatosensory potentials evoked by magnetic stimulation of abductor pollicis brevis

磁刺激34名健康成人拇短肌肌腹,分别在体感传导通路的各个水平(Erb's点,第7颈椎棘突及对侧原发感觉皮眉)记录诱发电位,并与电刺激正中神经进行比较,结果发现除P_9波幅和中枢传导时间磁、电刺激间有显著性差异外,其它峰-峰波幅、峰间期两者均无明显差异;两者的N_(20)峰潜伏时均与身高明显相关。研究表明,磁刺激肌肉体感诱发电位可为定量评定肌肉传入纤维功能提供一简单可行而无损伤的方法;其机制可能是通过收缩肌肉、间接兴奋肌肉感受器和Ia传入纤维;其P_9、P_(1a)的神经发生源可能与电刺激相同,而皮层早成分则有待进一步研究。

Magnetic stimulation of abductor pollicis brevis was performed in 34 healthy people to compare somatosensory potentials evoked by magnetic stimulation with that evoked by electrical stimulation of median nerve. The potentials were recorded from different levels of peripheral and central nervous system(Erb's point, 7th cervical spinous process and scalp primary sensory areas contraleteral to the stimulated side). It was found that:(l) The P_9 peak amplitude and the central conduction time of magnetic and electric stimulation showed significant difference,whereas the peak amplitude and interpeak latency of the other potential components did not show any difference; (2)Both the N_(20) peak latenev of magnetic and electric stimulation were significantly correlated with bodyheight. This finding suggested that: (1) In comparison with electric stimulation, magnetic stimulation is a simple, effective and noninvasive method for quantifying the function of muscle afferent fiber; (2)Magnetic stimulation may activate muscle receptor and their afferent fibers indirectly through muscle contraction; (3) The potentials P_9, P_(13) of magnetic stimulation may originate from the same sensory pathway as the electric, but the nature and origin of cortical potential components (N_(20)) need to be further studied.