Centre for Physiotherapy Research, University of Otago, Dunedin, New Zealand.
Clin J Pain. 2013 Jun;29(6):533-9. doi: 10.1097/AJP.0b013e318262330f.
Transcutaneous electrical nerve stimulation (TENS) is a modality commonly used in pain management.
This study investigated the hypoalgesic effects of alternating-frequency TENS (4 Hz for 3 s/110 Hz for 3 s) on pressure pain threshold (PPT).
Two-hundred and eight healthy, pain-free volunteers (19 to 59 y old; 104 males, 104 females) were randomized to 8 groups: 6 active TENS groups, placebo, and control (n=26 per group). Parameter combinations were such that alternating-frequency TENS was combined with different levels of intensity "low" (strong but comfortable) or "high" (strong and uncomfortable but not painful). TENS was administered either at the forearm (segmental stimulation), at the ipsilateral leg (extrasegmental stimulation), or at both sites (dual-site stimulation) for 30 minutes and monitored for 30 further minutes. PPT measurements were taken bilaterally from the mid-point of first dorsal interosseous muscle, by an independent blinded rater, at baseline and at 6 subsequent 10-minute intervals. Square-root transformed data were analyzed using repeated measures analysis of covariance (baseline values and sex as covariates).
Alternating-frequency TENS groups did not achieve significant hypoalgesic effects compared with placebo or control (P>0.05). The largest increase in PPT (from baseline) was 76.6 kPa with low-intensity segmental alternating frequency TENS at the 20-minute stimulation time point. This change from baseline is below a difference of 100 kPa that is considered to be a clinically meaningful change in hypoalgesia.
The alternating-frequency setting does not result in large hypoalgesic effects such as those previously reported using fixed-frequency TENS.
经皮神经电刺激（TENS）是一种常用于疼痛管理的模式。
本研究旨在探讨交替频率 TENS（4 Hz 持续 3 秒/110 Hz 持续 3 秒）对压力疼痛阈值（PPT）的镇痛作用。
将 208 名健康、无痛的志愿者（19 至 59 岁；男性 104 名，女性 104 名）随机分为 8 组：6 个活性 TENS 组、安慰剂组和对照组（每组 26 名）。参数组合为，交替频率 TENS 与不同强度的“低”（强但舒适）或“高”（强且不适但不疼痛）相结合。TENS 在前臂（节段性刺激）、同侧腿部（非节段性刺激）或两个部位（双部位刺激）进行 30 分钟治疗，并监测 30 分钟。由独立的盲法评估者在基线和随后的 6 个 10 分钟间隔内，从第一骨间背侧肌中点的双侧测量 PPT。使用重复测量协方差分析（基线值和性别作为协变量）分析平方根转换后的数据。
与安慰剂或对照组相比，交替频率 TENS 组未达到显著的镇痛效果（P>0.05）。低强度节段性交替频率 TENS 在 20 分钟刺激时间点的 PPT 最大增加为 76.6 kPa。这一变化低于 100 kPa 的差异，被认为是镇痛作用的临床意义变化。
与之前使用固定频率 TENS 报道的那样，交替频率设置不会产生较大的镇痛效果。
