Department of Neurology, Paracelsus Medical University Salzburg, Austria.
Clin Neurophysiol. 2012 Jan;123(1):193-9. doi: 10.1016/j.clinph.2011.06.010. Epub 2011 Jul 18.
In a previous transcranial magnetic stimulation (TMS) study we demonstrated that suprathreshold mesh-glove (MG) whole-hand stimulation elicits lasting changes in motor cortical excitability. Currently, there is no consensus with regard to the optimal parameters for the induction of sensorimotor cortical plasticity using peripheral electrical stimulation. Thus, in the present study we explore the modulatory effects of MG stimulation at different stimulus intensities and different frequencies in order to identify an optimal stimulation protocol.
MG stimulation was performed on 12 healthy subjects in separate sessions at different stimulation levels: sub-sensory at 50 Hz, sensory at 50 Hz and motor at 2 Hz. To verify if stimulation at lower frequencies is less effective, an additional experiment at sensory level with 2 Hz was performed. TMS was used to assess motor threshold (MT), motor evoked potentials (MEPs) recruitment curve (RC), short latency intracortical inhibition (SICI) and intracortical facilitation (ICF) to paired-pulse TMS at baseline (T0), immediately after (T1) and 1h (T2) after 30 min of MG stimulation. F-wave studies were performed to assess spinal motoneuron excitability.
MG stimulation at sub-sensory/50 Hz and sensory/2 Hz level determines no significant cortical excitability changes; at sensory/50 Hz level and at motor/2 Hz level we found decreased MT, increased MEP RC as well as reduced SICI and increased ICF at T1 and T2.
MG stimulation at sensory/50 Hz and motor/2 Hz level induces similar long-lasting modulatory effects on motor cortical excitability. Both the strength of the corticospinal projections and the intracortical networks are influenced to the same extend.
The study provides further evidence that stimulation intensity and frequency can independently modulate motor cortical plasticity. The selection of optimal stimulation parameters has potentially important implications for the neurorehabilitation of patients after brain damage (e.g. stroke, traumatic brain injury) with hand motor deficits.
在先前的经颅磁刺激（TMS）研究中，我们证明了阈上网格手套（MG）全手刺激会引起运动皮质兴奋性的持久变化。目前，对于使用外周电刺激诱导感觉运动皮质可塑性的最佳参数尚无共识。因此，在本研究中，我们探索了 MG 刺激在不同刺激强度和不同频率下的调节作用，以确定最佳的刺激方案。
在不同的刺激水平下，对 12 名健康受试者进行了单独的 MG 刺激：50 Hz 的亚感觉、50 Hz 的感觉和 2 Hz 的运动。为了验证低频刺激是否效果较差，还进行了感觉水平的 2 Hz 的附加实验。使用 TMS 评估运动阈值（MT）、运动诱发电位（MEP）募集曲线（RC）、短潜伏期皮质内抑制（SICI）和双脉冲 TMS 的皮质内易化（ICF），在基线（T0）、刺激后即刻（T1）和 30 分钟后 1 小时（T2）进行 MG 刺激。F 波研究用于评估脊髓运动神经元兴奋性。
MG 刺激在亚感觉/50 Hz 和感觉/2 Hz 水平下不会引起皮质兴奋性的显著变化；在感觉/50 Hz 和运动/2 Hz 水平下，我们发现 MT 降低，MEP RC 增加，SICI 减少，ICF 在 T1 和 T2 增加。
MG 刺激在感觉/50 Hz 和运动/2 Hz 水平下会引起运动皮质兴奋性的相似的持久调节作用。皮质脊髓投射和皮质内网络的强度都受到相同程度的影响。
该研究进一步证明，刺激强度和频率可以独立调节运动皮质可塑性。选择最佳的刺激参数对于脑损伤（如中风、创伤性脑损伤）后手运动障碍患者的神经康复具有潜在的重要意义。
