Motor Evoked Potential by Magnetic Stimulation

在高压电刺激下记录了运动诱发电位（MEP）。与电刺激相比，磁刺激是非侵入性的。但线圈产生的磁力分布还没有得到准确的研究。经颅磁刺激在犬颈水平臂肌和硬膜外间隙处记录MEP。接下来，作为临床研究，研究偏瘫患者双侧较薄肌肉记录的MEP振幅和潜伏期。得到如下结果：1：线圈边缘的磁感应磁通密度大于中心。2：麻醉犬MEP记录于臂肌，潜伏期约6-8msec。硬膜外腔记录的MEP有两个与电刺激相对应的负峰。3：偏瘫患者未记录MEP。在偏瘫患者中，MEP有低振幅和延迟延长的趋势，但无法准确评价运动功能。经颅磁刺激是无创的。磁刺激的MEP将有助于运动功能的研究。

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.