Wischnewski Miles, Edwards Lauren, Revill Kate P, Drake Daniel, Hobbs Gerald, Buetefisch Cathrin M
Department of Neurology, Emory University, School of Medicine, Atlanta, GA, USA.
Department of Experimental Psychology, University of Groningen, Groningen, The Netherlands.
Neurorehabil Neural Repair. 2025 Jan;39(1):58-73. doi: 10.1177/15459683241292615. Epub 2024 Oct 27.
Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) protocols targeting primary motor cortex (M1) are used in rehabilitation of neurological diseases for their therapeutic potential, safety, and tolerability. Although lower intensity LF-rTMS can modulate M1 neurophysiology, results are variable, and a systematic assessment of its dose effect is lacking.
To determine the dose-response of LF-rTMS on stimulated and non-stimulated M1.
In a sham-controlled randomized double-blind crossover study the effect of LF-TMS protocols were determined in 20 right-handed older healthy participants. In 3 sessions, 1 Hz rTMS at 80% (rTMS), 90% (rTMS) of motor threshold or sham stimulation were applied to left upper extremity M1. Outcome measures were curve parameters of the stimulus-response curve (maximum motor evoked potential [MEP], slope and the intensity to evoke 50% MEP), short-interval intracortical inhibition (SICI), and interhemispheric inhibition (IHI).
Within LF-rTMS sessions, rTMS, increased MEP in the stimulated M1. Furthermore, rTMS, increased the slope in the non-stimulated M1. LF-rTMS effects on SICI were dependent on the participants' baseline SICI, hemisphere, and intensity of conditioning pulse. Finally, rTMS increased whereas rTMS decreased IHI, for both IHI directions. These changes were dependent on baseline IHI and hemisphere and were no longer significant when baseline IHI was accounted for.
Intensity of subthreshold LF-rTMS has differential effects on excitation and inhibition of stimulated and non-stimulated M1. The effects were small and were only demonstrated within the LF-rTMS sessions but were not different when compared to sham. rTMS related changes in SICI and IHI were dependent on baseline level.
CLINICALTRIALS.GOV IDENTIFIER: NCT02544503, NCT01726218.
针对初级运动皮层（M1）的低频重复经颅磁刺激（LF-rTMS）方案因其治疗潜力、安全性和耐受性而被用于神经疾病的康复治疗。尽管较低强度的LF-rTMS可以调节M1神经生理学，但结果存在差异，且缺乏对其剂量效应的系统评估。
确定LF-rTMS对受刺激和未受刺激的M1的剂量反应。
在一项假对照随机双盲交叉研究中，对20名右利手健康老年参与者测定了LF-TMS方案的效果。在3个疗程中，对左上肢M1施加80%（rTMS）、90%（rTMS）运动阈值的1 Hz rTMS或假刺激。结果指标为刺激反应曲线的曲线参数（最大运动诱发电位[MEP]、斜率和诱发50% MEP的强度）、短间隔皮质内抑制（SICI）和半球间抑制（IHI）。
在LF-rTMS疗程中，rTMS增加了受刺激M1中的MEP。此外，rTMS增加了未受刺激M1中的斜率。LF-rTMS对SICI的影响取决于参与者的基线SICI、半球和条件刺激脉冲的强度。最后，对于两个IHI方向，rTMS增加而rTMS降低IHI。这些变化取决于基线IHI和半球，当考虑基线IHI时不再显著。
阈下LF-rTMS的强度对受刺激和未受刺激的M1的兴奋和抑制有不同影响。这些影响较小，仅在LF-rTMS疗程内表现出来，但与假刺激相比并无差异。rTMS相关的SICI和IHI变化取决于基线水平。
NCT02544503，NCT01726218。
