Background:Repetitive transcranial magnetic stimulation (rTMS) has been applied for modulating cortical excitability and treating spasticity in neurological lesions. However, it is unclear which rTMS frequency is most effective in modulating cortical and spinal excitability in incomplete spinal cord injury (SCI). Objective:To evaluate electrophysiological and clinical repercussions of rTMS compared to sham stimulation when applied to the primary motor cortex (M1) in individuals with incomplete SCI. Methods:A total of 11 subjects (35±12 years) underwent three experimental sessions of rTMS (10 Hz, 1 Hz and sham stimulation) in a randomized order at 90%intensity of the resting motor threshold and interspersed by a seven-day interval between sessions. The following outcome measures were evaluated: M1 and spinal cord excitability and spasticity in the moments before (baseline), immediately after (T0), 30 (T30) and 60 (T60) minutes after rTMS. M1 excitability was obtained through the motor evoked potential (MEP); spinal cord excitability by the Hoffman reflex (H-reflex) and homosynaptic depression (HD); and spasticity by the modified Ashworth scale (MAS). Results:A significant increase in cortical excitability was observed in subjects submitted to 10 Hz rTMS at the T0 moment when compared to sham stimulation (p = 0.008); this increase was also significant at T0 (p = 0.009), T30 (p = 0.005) and T60 (p = 0.005) moments when compared to the baseline condition. No significant differences were observed after the 10 Hz rTMS on spinal excitability or on spasticity. No inter-group differences were detected, or in the time after application of 1 Hz rTMS, or after sham stimulation for any of the assessed outcomes. Conclusions:High-frequency rTMS applied to M1 was able to promote increased cortical excitability in individuals with incomplete SCI for at least 60 minutes; however, it did not modify spinal excitability or spasticity.

中文翻译：

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重复经颅磁刺激对脊髓损伤个体皮质和脊髓兴奋性的调节作用

背景：重复经颅磁刺激（rTMS）已被应用于调节皮质兴奋性和治疗神经病变的痉挛状态。然而，尚不清楚哪种 rTMS 频率在调节不完全脊髓损伤 (SCI) 中的皮质和脊髓兴奋性方面最有效。目的：评估 rTMS 与假刺激相比对不完全 SCI 个体初级运动皮层 (M1) 的电生理和临床影响。方法：共有 11 名受试者（35±12 岁）在 90% 的静息运动阈值强度下以 7 天的间隔以随机顺序进行 3 次 rTMS 实验（10 Hz、1 Hz 和假刺激）会话之间。评估了以下结果测量：rTMS 之前（基线）、之后（T0）、30（T30）和 60（T60）分钟的 M1 和脊髓兴奋性和痉挛。通过运动诱发电位 (MEP) 获得 M1 兴奋性；霍夫曼反射（H-反射）和同突触抑制（HD）的脊髓兴奋性；修正的 Ashworth 量表 (MAS) 和痉挛。结果：与假刺激相比，在 T0 时刻接受 10 Hz rTMS 的受试者观察到皮质兴奋性显着增加（p = 0.008）；与基线条件相比，这种增加在 T0 (p = 0.009)、T30 (p = 0.005) 和 T60 (p = 0.005) 时刻也很显着。在 10 Hz rTMS 后，在脊髓兴奋性或痉挛方面没有观察到显着差异。未检测到组间差异，或在应用 1 Hz rTMS 后的时间内，或在任何评估结果的假刺激后。结论：应用于 M1 的高频 rTMS 能够促进不完全 SCI 个体的皮质兴奋性增加至少 60 分钟；然而，它并没有改变脊柱的兴奋性或痉挛状态。