Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom.
Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom; Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa.
J Neurol Sci. 2018 Nov 15;394:45-56. doi: 10.1016/j.jns.2018.09.001. Epub 2018 Sep 5.
The study aimed to determine the optimal application of single- and paired-pulse transcranial magnetic stimulation (TMS) in the rectus femoris. Twenty-nine male adults participated in the study, which involved 5 separate experiments. Experiments 1 to 3 assessed the effect of conditioning stimulus (CS) intensity (60, 70, 80 and 90% active motor threshold, AMT), contraction strength (5, 10, 20 and 50% maximum voluntary contraction, MVC), and inter-stimulus interval (ISI, 2-5 ms for short-interval intracortical inhibition, SICI and 10-15 ms for intracortical facilitation, ICF) on SICI and ICF. In Experiment 4, 30 measurements of corticospinal excitability (CSE), SICI and ICF were recorded, with the minimum number of consecutive measurements required as a probability of falling within the 95% CI determined. In Experiment 5, within- and between-day reliability of CSE, SICI and ICF was assessed. The results suggest that for SICI, a CS of 70% AMT, ISI of 2 ms, and contraction strength of 5 or 10% MVC induces the greatest level of inhibition. Negligible differences in ICF were seen across stimulus variables. The minimum number of measurements required to obtain an accurate estimate of CSE, SICI and ICF was 21, 18 and 17, respectively. Using the optimal stimulus variables and number of measurements, CSE, SICI and ICF can be measured reliably both within- and between-days (intraclass correlation coefficient, ICC ≥ 0.87, ≥0.74, and ≥0.61, respectively). The current findings can be used to guide future investigations using single- and paired-pulse TMS to elicit responses in the rectus femoris.
本研究旨在确定单脉冲和双脉冲经颅磁刺激（TMS）在股直肌中的最佳应用。29 名成年男性参与了这项研究，该研究涉及 5 项独立的实验。实验 1 至 3 评估了刺激条件（CS）强度（60%、70%、80%和 90%主动运动阈值，AMT）、收缩强度（5%、10%、20%和 50%最大随意收缩，MVC）和刺激间间隔（ISIs，2-5 ms 用于短程皮质内抑制，SICI 和 10-15 ms 用于皮质内易化，ICF）对 SICI 和 ICF 的影响。在实验 4 中，记录了 30 次皮质脊髓兴奋性（CSE）、SICI 和 ICF 的测量值，所需的连续测量次数最少，作为概率落入 95%置信区间内的确定值。在实验 5 中，评估了 CSE、SICI 和 ICF 的日内和日间可靠性。结果表明，对于 SICI，CS 为 70% AMT、ISI 为 2 ms、收缩强度为 5%或 10% MVC 可引起最大抑制水平。在刺激变量方面，ICF 差异可以忽略不计。获得 CSE、SICI 和 ICF 准确估计所需的最小测量次数分别为 21、18 和 17。使用最佳刺激变量和测量次数，可以在日内和日间可靠地测量 CSE、SICI 和 ICF（组内相关系数，ICC≥0.87、≥0.74 和≥0.61）。目前的研究结果可以用于指导未来使用单脉冲和双脉冲 TMS 刺激股直肌以引出反应的研究。
