Jadidi Armita Faghani, Asghar Zarei Ali, Lontis Romulus, Jensen Winnie
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:3573-3576. doi: 10.1109/EMBC44109.2020.9175393.
Following amputation, almost two-thirds of amputees experience unpleasant to painful sensations in the area of the missing limb. Whereas the mechanism of phantom limb pain (PLP) remains unknown, it has been shown that maladaptive cortical plasticity plays a major role in PLP. Transcutaneous electrical nerve stimulation (TENS) generating sensory input is believed to be beneficial for PLP relief. TENS effect may be caused by possible reversing reorganization at the cortical level that can be evaluated by changes in the excitability of the corticospinal (CS) pathway. Excitability changes are dependent on the chosen stimulation patterns and parameters. The aim of this study was to investigate the effect of two TENS patterns on the excitability of the CS tract among healthy subjects. We compared a non-modulated TENS as a conventional pattern with pulse width modulated TENS pattern. Motor evoked potentials (MEPs) from APB muscles of stimulated arm (TENS-APB) and contralateral arm (Control-APB) were recorded. We applied single TMS pulses on two subjects for each TENS pattern. The results showed that both patterns increase the CS excitability, while the effects of the conventional TENS is stronger. However, the amplitude of MEPs from control-APB after TENS delivery remained almost the same.Clinical Relevance- The primary results revealed changes in the activity of CS pathway for both patterns. A future study on a larger population is needed to provide strong evidence on the changes in CS excitability. The evaluation part with more factors such as changes in intracortical inhibition (ICI) may be beneficial to find an optimal modulated TENS pattern to enhance pain alleviation process in PLP.
截肢后，近三分之二的截肢者在缺失肢体的部位会经历不愉快甚至疼痛的感觉。虽然幻肢痛（PLP）的机制尚不清楚，但已有研究表明，适应性不良的皮质可塑性在PLP中起主要作用。产生感觉输入的经皮电神经刺激（TENS）被认为对缓解PLP有益。TENS的效果可能是由于皮质水平上可能的反向重组引起的，这可以通过皮质脊髓（CS）通路兴奋性的变化来评估。兴奋性变化取决于所选择的刺激模式和参数。本研究的目的是调查两种TENS模式对健康受试者CS束兴奋性的影响。我们将非调制TENS作为传统模式与脉宽调制TENS模式进行了比较。记录了受刺激手臂（TENS-APB）和对侧手臂（对照-APB）的拇短展肌的运动诱发电位（MEP）。对于每种TENS模式，我们对两名受试者施加了单个TMS脉冲。结果表明，两种模式均增加了CS兴奋性，而传统TENS的效果更强。然而，TENS传递后对照-APB的MEP幅度几乎保持不变。临床相关性——主要结果揭示了两种模式下CS通路活动的变化。需要对更多人群进行进一步研究，以提供关于CS兴奋性变化的有力证据。评估部分纳入更多因素，如皮质内抑制（ICI）的变化，可能有助于找到最佳的调制TENS模式，以加强PLP的疼痛缓解过程。
