The minimal number of TMS trials required for the reliable assessment of corticospinal excitability, short interval intracortical inhibition, and intracortical facilitation
The minimal number of TMS trials required for the reliable assessment of corticospinal excitability, short interval intracortical inhibition, and intracortical facilitation
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DOI：
10.1016/j.neulet.2018.03.026
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发表时间：
2018-05-01
影响因子：
2.5
通讯作者：
Jaberzadeh, Shapour
中科院分区：
文献类型：
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作者：
Biabani, Mana;Farrell, Michael;Jaberzadeh, Shapour
经颅磁刺激（TMS）诱导的运动诱发电位（MEP）经常用于评估皮质脊髓和皮质间活动。通常观察到电位的试验间方差，并且通常报告多个MEP的平均值。多项试验涉及资源问题，并且与某些实验方案不兼容。本研究调查了可靠评估皮质脊髓兴奋性（CSE）、短间期皮质内抑制（SICI）和皮质间易化（ICF）所需的最少MEP数量。15名健康志愿者接受了35次单脉冲TMS用于CSE评估，35次双脉冲TMS用于SICI和ICF测量。使用类内相关系数检验检查会话内和会话间的可靠性，并使用一般方程估计分析评估措施的稳定性。变异系数用于探讨个体间变异性对可靠性结果的影响。所有分析均基于累积平均值进行。为了确保“优秀”的会话内和会话间可靠性，低个体间变异性和最高水平的稳定性，发现CSE和SICI评估的最佳试验数量分别为20和26。尽管30项连续试验在一个疗程内产生了高度可靠的ICF测量结果，但在35项试验中，疗程间的可靠性并不显著。这些发现对提高TMS实验的时间效率而不影响会话内或会话间的可靠性具有重要意义。
Transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) are frequently used to assess corticospinal and intercortical activities. Trial to trial variance of the potentials is commonly observed, and averages of multiple MEPs are usually reported. Multiple trials have resources implications and are not compatible with some experimental protocols. This study investigated the minimum number of MEPs required to reliably assess corticospinal excitability (CSE), short interval intracortical inhibition (SICI) and intercortical facilitation (ICF), within and between sessions. Fifteen healthy volunteers received 35 single-pulse TMS for CSE assessments and 35 paired-pulse TMS for SICI and ICF measurements. Intra- and intersession reliability were examined using intra-class correlation coefficient tests, and stability of the measures was assessed using a general equation estimation analysis. Coefficients of variation were used to probe the effects of inter-individual variability on reliability results. All analyses were carried out on cumulative averages. The optimal number of trials to ensure "excellent" intra and inter-session reliability with low inter-individual variability and the highest level of stability was found to be 20 for CSE and 26 for SICI assessments. Although 30 consecutive trials produced highly reliable ICF measures within a session, inter-session reliability was not significant across 35 trials. These findings have significant implications for improving time efficiency of TMS experiments without compromising intra- or intersession reliability.