A subthreshold pulse of transcranial magnetic stimulation (TMS) on the motor cortex can modulate the amplitude of the monosynaptic reflex (H-reflex) elicited in the flexor carpi radialis (FCR) muscle, a method known as TMS-conditioning of the H-reflex. The purpose of this study was to establish the intersession reliability of this method over the course of three sessions. Eleven healthy participants received either peripheral nerve stimulation (PNS), TMS or a combination of the two. The intensity of the PNS stimuli was set to evoke a monosynaptic response (H-reflex) corresponding to 10% of the maximum motor response (M_max), H_M10%. The conditioning effect of TMS on the monosynaptic reflex was assessed by delivering subthreshold cortical pulses at different conditioning-test intervals (from -7 ms to 7 ms) from peripheral nerve stimulation. The first interval at which facilitation could be observed was deemed early facilitation (EF). Using intraclass correlation coefficients (ICCs), we found excellent reliability for M_max amplitudes (ICC = 0.98), H_M10% amplitudes (ICC = 0.85) and TMS-conditioned H-reflexes recorded at the interval following EF (EF + 2 ms) (ICC = 0.87). Good reliability (ICCs ranging from 0.67 to 0.77) was found for the other conditioning-test intervals. We conclude that TMS-conditioned H-reflexes are reliable parameters to assess the excitability of corticospinal circuits.

运动皮层上的亚阈值经颅磁刺激（TMS）脉冲可调节radial腕腕（FCR）肌肉引起的单突触反射（H-反射）的振幅，该方法称为H-反射的TMS调节。这项研究的目的是在三个疗程的过程中建立该方法的疗程间可靠性。11名健康参与者接受了周围神经刺激（PNS），TMS或两者的结合。PNS刺激的强度设置为引起单突触反应（H反射），对应于最大运动反应（M _max）的10％，H _M10％。通过从周围神经刺激以不同的调节测试间隔（从-7毫秒到7毫秒）传递亚阈值皮层脉冲来评估TMS对单突触反射的调节作用。可以观察到促进作用的第一个间隔被认为是早期促进作用（EF）。使用类内相关系数（ICC），我们发现在EF（EF + 2 ms）后的间隔记录的M_最大振幅（ICC = 0.98），H _M10％振幅（ICC = 0.85）和TMS条件的H反射具有极好的可靠性。（ICC = 0.87）。对于其他条件测试间隔，发现其具有良好的可靠性（ICC在0.67至0.77之间）。我们得出结论，TMS条件H反射是评估皮质脊髓回路兴奋性的可靠参数。