低频磁刺激对人咬肌抑制反射及其恢复曲线的影响

Effect of Low r TMS on The Recovery of Masseter Inhibitory Reflect in Normal People

目的:研究低频经颅磁刺激下,健康人咬肌的抑制反射(masseter inhibitory reflex,MIR)及其恢复情况,以明确低频磁刺激下咬肌抑制反射兴奋性的变化规律。方法:选取20名健康受试者,在低频刺激(1Hz)前后,采用单脉冲模式刺激颏神经,记录咬肌肌电,统计分析早期静息期(the early silent period,SP1)及晚期静息期(the late silent period,SP2)的潜伏期和持续时间。再在双脉冲刺激模式下,条件刺激和测试刺激间设置不同的时间间隔(interstimulus interval,ISIs):100、200、300、400、500、600 ms。统计分析在不同时间点,双脉冲模式刺激下MIR的恢复情况。结果 :单脉冲刺激下,受试者SP1和SP2的潜伏期与持续时间都未发生变化(P>0.05)。双脉冲模式中,条件刺激下所得SP1和SP2都具有稳定的波段,而测试刺激中所得SP1波段较稳定,SP2发生变化。磁刺激下,随着间隔时间延长,测试刺激激发出的SP2面积会逐渐恢复,基础对照组在100 ms时,SP2面积恢复为16.6%,400 ms时为90.3%,600 ms时SP2面积几乎全完恢复。而低频组在100 ms时,SP2面积恢复仅为3.9%,400 ms时为49.7%,600 ms时为74.2%。结论:低频重复经颅磁刺激后,受试者短时间内MIR恢复程度受到显著抑制,提示低频重复经颅磁刺激可以显著干扰脑干反射通路的兴奋性。

Objective：To investigate the changes in the masseter inhibitory reflect （MIR） and the recovery of the MIR by repetitive transcranial magnetic stimulation （rTMS） of low stimulate frequency. Figure out the varying pattern of the MIR under low rTMS. Method：Twenty healthy subjects provided informed consents and participated in the study. Before and after the low frequency stimulation. Single magnetic stimulation and paired stimuli technique were used to evoke the nervus mentalis. The paired stimuli technique, two stimulus were set in different intervals, i. e. 100, 200, 300, 400, 500, and 600 ms. Then the early silent period （SP1）, the late silent period （SP2） and MIR were recorded and analyzed. Results： In single magnetic stimulation, the difference of SP1 and SP2 between basal group and post-rTMS group was insignificant （P〉0.05）. With paired stimuli, SP1 and SP2 evoked by conditioning stimulation were stable, but the area of SP2 evoked by test stimulation reduced. In basal group, the SP2 amplitude percent was 16.6%at 100 ms, 90.3%at 400 ms, and fully recovered at 600 ms. However, in post-rTMS group, the SP2 amplitude percent was just 3.9%at 100 ms, 49.7%at 400 ms, and even only 74.2%at 600 ms. Conclusion：Compared with basal group, the recovery degree of MIR in post-rTMS group was significantlylower. Our findings indicate that the excitement of brainstem reflexes was inhibited by low frequency rTMS.