Choi J C, Kim J, Kang E, Lee J-M, Cha J, Kim Y J, Lee H G, Choi J-H, Yi D-J
Department of Anesthesiology and Pain Medicine, Intensive Care Unit, Brain Research Group, Yonsei University Wonju College of Medicine, South Korea.
Department of Psychology, Kangwon National University, Chuncheon, South Korea.
Eur J Pain. 2016 Jan;20(1):92-105. doi: 10.1002/ejp.696. Epub 2015 Apr 2.
Although the exact mechanism of TENS pain relief is unknown, it is believed that TENS impulses interrupt nociceptive signals at the dorsal horn of the spinal cord.
To evaluate the hypotheses that during pain caused by noxious stimuli, brain responses, temporal summation and brain functional connectivity are modulated by TENS, and that mechanisms of pain relief by TENS differ between men and women.
During fMRI scanning, the same noxious stimuli were delivered to each participant in pain-only and pain+TENS conditions. In the pain-only condition, noxious stimuli were presented without TENS. In the pain+TENS condition, participants received noxious stimuli and TENS concurrently. Participants were initially presented with TENS at an intensity that was just below that causing discomfort. TENS intensity was presented in a step-wise fashion to prevent temporal summation from repetitive noxious stimuli.
Pain and unpleasantness ratings were significantly higher in the pain-only than the pain+TENS condition. With non-painful TENS, primary and secondary somatosensory and parietal cortices were activated, and temporal summation from repetitive noxious stimuli was prevented. Periaqueductal gray (PAG) and lateral prefrontal cortex functional connectivity was increased by TENS, and modulated by testosterone and cortisol. Women reported greater pain during TENS than men, and showed greater activation in the temporoparietal junction cortex and increased PAG functional connectivity with the orbitofrontal cortex.
TENS led to pain reduction, probably due to activation of the descending pain-inhibitory pathway, indicating that this TENS method may be applied in clinical practice.
尽管经皮电刺激神经疗法（TENS）缓解疼痛的确切机制尚不清楚，但人们认为TENS脉冲在脊髓背角中断伤害性信号。
评估以下假设：在有害刺激引起疼痛期间，TENS可调节大脑反应、时间总和及大脑功能连接，且TENS缓解疼痛的机制在男性和女性之间存在差异。
在功能磁共振成像（fMRI）扫描期间，在仅疼痛和疼痛+TENS两种条件下，向每位参与者施加相同的有害刺激。在仅疼痛条件下，不使用TENS施加有害刺激。在疼痛+TENS条件下，参与者同时接受有害刺激和TENS。最初以略低于引起不适的强度向参与者施加TENS。TENS强度以逐步方式呈现，以防止重复有害刺激导致时间总和。
仅疼痛条件下的疼痛和不愉快评分显著高于疼痛+TENS条件。使用非疼痛性TENS时，初级和次级体感皮层以及顶叶皮层被激活，并且防止了重复有害刺激引起的时间总和。TENS增加了导水管周围灰质（PAG）和外侧前额叶皮层的功能连接，并受睾酮和皮质醇调节。女性在TENS期间报告的疼痛比男性更强烈，并且在颞顶叶交界皮层表现出更大的激活，以及PAG与眶额皮层之间的功能连接增加。
TENS导致疼痛减轻，可能是由于下行疼痛抑制通路的激活，表明这种TENS方法可应用于临床实践。
