Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94304, USA.
Sensors (Basel). 2022 Feb 24;22(5):1762. doi: 10.3390/s22051762.
The impact of repetitive magnetic stimulation (rTMS) on cortex varies with stimulation parameters, so it would be useful to develop a biomarker to rapidly judge effects on cortical activity, including regions other than motor cortex. This study evaluated rTMS-evoked EEG potentials (TEP) after 1 Hz of motor cortex stimulation. New features are controls for baseline amplitude and comparison to control groups of sham stimulation. We delivered 200 test pulses at 0.20 Hz before and after 1500 treatment pulses at 1 Hz. Sequences comprised AAA = active stimulation with the same coil for test-treat-test phases ( = 22); PPP = realistic placebo coil stimulation for all three phases ( = 10); and APA = active coil stimulation for tests and placebo coil stimulation for treatment ( = 15). Signal processing displayed the evoked EEG waveforms, and peaks were measured by software. ANCOVA was used to measure differences in TEP peak amplitudes in post-rTMS trials while controlling for pre-rTMS TEP peak amplitude. Post hoc analysis showed reduced P60 amplitude in the active (AAA) rTMS group versus the placebo (APA) group. The N100 peak showed a treatment effect compared to the placebo groups, but no pairwise post hoc differences. N40 showed a trend toward increase. Changes were seen in widespread EEG leads, mostly ipsilaterally. TMS-evoked EEG potentials showed reduction of the P60 peak and increase of the N100 peak, both possibly reflecting increased slow inhibition after 1 Hz of rTMS. TMS-EEG may be a useful biomarker to assay brain excitability at a seizure focus and elsewhere, but individual responses are highly variable, and the difficulty of distinguishing merged peaks complicates interpretation.
重复经颅磁刺激 (rTMS) 对皮层的影响因刺激参数而异，因此开发一种生物标志物来快速判断皮层活动的影响（包括运动皮层以外的区域）将是有用的。本研究评估了 1 Hz 运动皮层刺激后的 rTMS 诱发脑电电位 (TEP)。新特征是用于基线幅度的对照，并与假刺激对照组进行比较。我们在 1 Hz 治疗脉冲之前和之后以 0.20 Hz 施加 200 个测试脉冲。序列包括 AAA = 用于测试-治疗-测试阶段的同线圈主动刺激（= 22）；PPP = 用于所有三个阶段的现实假线圈刺激（= 10）；APA = 测试时使用主动线圈刺激，治疗时使用假线圈刺激（= 15）。信号处理显示了诱发的脑电波形，并通过软件测量了峰值。ANCOVA 用于测量 rTMS 后试验中 TEP 峰值幅度的差异，同时控制 rTMS 前 TEP 峰值幅度。事后分析显示，与假刺激（APA）组相比，主动（AAA）rTMS 组的 P60 幅度降低。与安慰剂组相比，N100 峰值显示出治疗效果，但没有两两事后差异。N40 呈增加趋势。变化发生在广泛的脑电导联上，主要是同侧。TMS 诱发的脑电电位显示 P60 峰值降低和 N100 峰值增加，这两者都可能反映出 1 Hz rTMS 后慢抑制增加。TMS-EEG 可能是一种有用的生物标志物，用于检测癫痫灶和其他部位的大脑兴奋性，但个体反应高度可变，合并峰的区分难度增加了解释的复杂性。
