BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, P.O. Box 340, FI-00029, Helsinki, Finland.
Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, P.O. Box 372, FI-00029, Helsinki, Finland.
Sci Rep. 2019 Mar 7;9(1):3849. doi: 10.1038/s41598-019-40474-0.
Paired associative stimulation (PAS), a combination of transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS), is emerging as a promising tool for alleviation of motor deficits in neurological disorders. The effectiveness and feasibility of PAS protocols are essential for their use in clinical practice. Plasticity induction by conventional PAS can be variable and unstable. Protocols effective in challenging clinical conditions are needed. We have shown previously that PAS employing 50 Hz PNS enhances motor performance in chronic spinal cord injury patients and induces robust motor-evoked potential (MEP) potentiation in healthy subjects. Here we investigated whether the effectiveness of PAS can be further enhanced. Potentiation of MEPs up to 60 minutes after PAS with PNS frequencies of 25, 50, and 100 Hz was tested in healthy subjects. PAS with 100 Hz PNS was more effective than 50 (P = 0.009) and 25 Hz (P = 0.016) protocols. Moreover, when administered for 3 days, PAS with 100 Hz led to significant MEP potentiation on the 3 day (P = 0.043) even when the TMS target was selected suboptimally (modelling cases where finding an optimal site for TMS is problematic due to a neurological disease). PAS with 100 Hz PNS is thus effective and feasible for clinical applications.
成对关联刺激（PAS），即经颅磁刺激（TMS）与外周神经刺激（PNS）的结合，作为一种缓解神经障碍运动缺陷的有前途的工具正在出现。PAS 方案的有效性和可行性对于将其应用于临床实践至关重要。常规 PAS 诱导的可塑性可能是可变和不稳定的。需要在具有挑战性的临床条件下有效的方案。我们之前已经表明，采用 50 Hz PNS 的 PAS 可增强慢性脊髓损伤患者的运动表现，并在健康受试者中诱导出强大的运动诱发电位（MEP）增强。在这里，我们研究了 PAS 的有效性是否可以进一步增强。在健康受试者中测试了 25、50 和 100 Hz 的 PNS 频率的 PAS 后，MEP 的增强持续长达 60 分钟。与 50 Hz（P=0.009）和 25 Hz（P=0.016）方案相比，100 Hz PNS 的 PAS 更有效。此外，当连续 3 天给药时，即使 TMS 目标选择不佳（由于神经系统疾病，找到 TMS 的最佳部位存在问题），100 Hz 的 PAS 也会导致 3 天时 MEP 明显增强（P=0.043）。因此，100 Hz PNS 的 PAS 对临床应用是有效且可行的。
