Motor Evoked Potential by Magnetic Stimulation

运动诱发电位（MEP）已被记录高压电刺激。与电刺激相比，磁刺激是非侵入性的。本文首先对磁刺激产生的电磁力分布进行了研究，然后在犬的肱肌和颈段硬膜外腔进行了经颅磁刺激MEP的记录，并对偏瘫患者双侧肱肌MEP的波幅和潜伏期进行了临床研究，结果如下：1.线圈边缘的磁感应通量密度大于中心。2：在麻醉的狗中，从肱肌记录MEP，其潜伏期约为6 - 8msec。硬膜外腔记录到的MEP由两个负峰组成，与电刺激相对应。3：偏瘫患者MEP未记录。在轻偏瘫患者中，MEP有低幅、潜伏期延长的趋势，但不能准确评价运动功能。磁刺激MEP可用于运动功能的研究。

Motor evoked potential (MEP) has been recorded by high voltage electrical stimulation. Magnetic stimulation, in contrast with electrical stimulation, is non invasive. But distribution of magnetic force generated by the coil has not been studied accurately.And then in dogs, MEP by transcranial magnetic stimulation is recorded from brachial muscle and epidural space at cervical level.Next, as clinical study, amplitude and latency of MEP recorded from the bilateral thiner muscle are investigated in the patients with hemiparesis.The following results are obtained.1 : Magnetic induction flux density is greater at the edge of the coil than center. 2 : In anesthesied dogs, MEP is recorded from the brachial muscle, which latency is about 6-8msec. And MEP recorded from epidural space consist of two negative peaks corresponding to the electrical stimulation. 3 : In the patients with hemiplegia, MEP is not recorded. In the patients with hemiparesis, MEP has a tendency to be low amplitude and prolongation of latency, but it is not possible to evaluate motor function precisely.Transcranial magnetic stimulation is non invasive. MEP by magnetic stimulation will be useful for investigation of motor function.