Aim: This systematic review and meta-analysis investigated neurophysiological responses using transcranial magnetic stimulation (TMS) following a concussion or sub-concussion. Methods: A systematic searching of relevant databases for peer-reviewed literature quantifying motor evoked potentials from TMS between 1999 and 2019 was performed. A meta-analysis quantified pooled data for measures including motor threshold, motor latency, and motor evoked potential amplitude and for inhibitory measures such as cortical silent period duration, short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI) ratios. Results: Fifteen articles met the inclusion criteria. The studies were arbitrarily classified into the groups, based on time post-concussion, “acute” (subjects 0–3 months post-injury, n = 8) and “post-acute” (3 months−2 years post-concussion, n = 7). A TMS quality of study checklist rated studies from moderate to high in methodological quality; however, the risk of bias analysis found that the included studies were categorised as high risk of bias, particularly for a lack of allocation concealment and blinding of participants in the methodologies. A meta-analysis showed no differences in excitability measures, apart from a decreased motor threshold that was observed in the concussed group (SMD −0.28, 95% CI −0.51 to −0.04; P = 0.02) for the post-acute time frame. Conversely, all inhibitory measures showed differences between groups. Cortical silent period duration was found to be significantly increased in the acute (SMD 1.19, 95% CI 0.58–1.81; P < 0.001) and post-acute (SMD 0.55, 95% CI 0.12–0.98; P = 0.01) time frames. The SICI (SMD −1.15, 95% CI −1.95 to −0.34; P = 0.005) and LICI (SMD −1.95, 95% CI −3.04 to −0.85; P = 0.005) ratios were reduced, inferring increased inhibition, for the post-acute time frame. Conclusion: This systematic review and meta-analysis demonstrates that inhibitory pathways are affected in the acute period post-concussion. However, persistent alterations in cortical excitability remain, with increased intracortical inhibition. While TMS should be considered as a reliable technique to measure the functional integrity of the central nervous system, the high risk of bias and heterogeneity in data suggest that future studies should aim to incorporate standardised methodological techniques, particularly with threshold determination and stimulus intervals for paired-pulse measures.

中文翻译：

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脑震荡的神经生理反应：经颅磁刺激研究的系统评价和元分析

目的：这项系统评价和荟萃分析研究了脑震荡或亚脑震荡后使用经颅磁刺激 (TMS) 的神经生理反应。方法：对相关数据库进行系统搜索，以获取 1999 年至 2019 年间量化 TMS 运动诱发电位的同行评审文献。一项荟萃分析量化了汇总数据，包括运动阈值、运动潜伏期和运动诱发电位幅度等指标，以及皮质静默期持续时间、短间隔皮质内抑制 (SICI) 和长间隔皮质内抑制 (LICI) 等抑制性指标比率。结果：15篇文章符合纳入标准。根据脑震荡后的时间、“急性”（受伤后 0-3 个月、n = 8）和“急性后”（脑震荡后 3 个月 - 2 年，n = 7）。TMS 质量研究清单将研究的方法学质量从中到高评级；然而，偏倚风险分析发现，纳入的研究被归类为高偏倚风险，尤其是在方法学中缺乏分配隐藏和参与者盲法。一项荟萃分析显示，除了在急性后时间范围内，在脑震荡组中观察到的运动阈值降低（SMD -0.28，95% CI -0.51 至 -0.04；P = 0.02）外，兴奋性测量没有差异。相反，所有抑制措施都显示出组间差异。发现皮质静默期持续时间在急性 (SMD 1.19, 95% CI 0.58–1.81; P < 0.001) 和急性后 (SMD 0.55, 95% CI 0.12–0.98; P = 0.01) 时间范围内显着增加。SICI（SMD -1.15，95% CI -1.95 至 -0.34；P = 0.005）和 LICI（SMD -1.95，95% CI -3.04 至 -0.85；P = 0.005）比率降低，推断抑制增加，对于急性期后。结论：这项系统评价和荟萃分析表明，抑制途径在脑震荡后的急性期受到影响。然而，皮质兴奋性的持续改变仍然存在，皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。005) 和 LICI (SMD -1.95, 95% CI -3.04 至 -0.85; P = 0.005) 比率降低，推断在急性后时间范围内抑制增加。结论：这项系统评价和荟萃分析表明，抑制途径在脑震荡后的急性期受到影响。然而，皮质兴奋性的持续改变仍然存在，皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。005) 和 LICI (SMD -1.95, 95% CI -3.04 至 -0.85; P = 0.005) 比率降低，推断在急性后时间范围内抑制增加。结论：这项系统评价和荟萃分析表明，抑制途径在脑震荡后的急性期受到影响。然而，皮质兴奋性的持续改变仍然存在，皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。对于急性后时间范围。结论：这项系统评价和荟萃分析表明，抑制途径在脑震荡后的急性期受到影响。然而，皮质兴奋性的持续改变仍然存在，皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。对于急性后时间范围。结论：这项系统评价和荟萃分析表明，抑制途径在脑震荡后的急性期受到影响。然而，皮质兴奋性的持续改变仍然存在，皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。皮质内抑制增加。虽然 TMS 应被视为测量中枢神经系统功能完整性的可靠技术，但数据中偏倚和异质性的高风险表明，未来的研究应旨在纳入标准化的方法学技术，尤其是阈值确定和刺激间隔的配对-脉冲措施。