Bioengineering Unit, University of Strathclyde, Glasgow, United Kingdom.
Phys Ther. 2012 Jul;92(7):911-23. doi: 10.2522/ptj.20110104. Epub 2012 Apr 5.
Little evidence exists regarding parameter selection for hypoalgesia using interferential therapy (IFT).
This study investigated segmental and extrasegmental hypoalgesic effects of different IFT parameter combinations upon experimentally induced pressure pain threshold (PPT) in pain-free volunteers.
The participants were randomly assigned to 6 groups: control, placebo, bipolar constant amplitude modulation frequency (AMF), bipolar sweep AMF, quadripolar constant AMF, and quadripolar sweep AMF.
The study was conducted in a university laboratory.
One hundred eighty adults who were healthy and pain-free participated in the study.
Interferential therapy was delivered to all groups at high, to-tolerance intensity and at high AMF. Stimulation to the dominant forearm was delivered for 30 minutes, with monitoring for a further 30 minutes.
Pain pressure threshold was measured at the area of first dorsal interosseous muscle of the dominant and nondominant hands (segmental measurements) and over the tibialis anterior muscle (extrasegmental measurement) at baseline and at 10-minute intervals using a pressure algometer. Square root transformed PPT data were analyzed using repeated-measures analysis of variance.
There was a significant change in PPT over time, but no significant between-subjects difference in segmental or extrasegmental PPT between any of the IFT groups and the placebo or control group. Thus, IFT delivered in any of these parameter combinations did not significantly affect the PPT of pain-free participants compared with the control or placebo group.
Success of blinding was not evaluated.
This study showed that IFT delivered at high, to-tolerance intensity and high AMF does not produce significant segmental and extrasegmental hypoalgesic effects on PPT in participants who were healthy compared with a control or placebo group. Further research is warranted to investigate the hypoalgesic effect of different IFT parameter combinations and to explain its possible mechanism of action.
关于使用干扰电疗法（IFT）产生的痛觉减退的参数选择，证据很少。
本研究旨在调查在无痛志愿者中，不同 IFT 参数组合对实验诱导的压力疼痛阈值（PPT）的节段和节段外痛觉减退效应。
参与者被随机分配到 6 组：对照组、安慰剂组、双极恒幅调制频率（AMF）组、双极扫描 AMF 组、四极恒幅 AMF 组和四极扫描 AMF 组。
该研究在一所大学的实验室进行。
180 名健康无痛的成年人参加了这项研究。
所有组均在高耐受强度和高 AMF 下接受 IFT 治疗。对优势前臂进行 30 分钟的刺激，并在随后的 30 分钟内进行监测。
使用压力测痛计在优势和非优势手的第一背间骨间肌区域（节段性测量）和胫骨前肌（节段外测量）测量疼痛压力阈值，在基线和 10 分钟间隔测量。使用重复测量方差分析对平方根变换后的 PPT 数据进行分析。
PPT 随时间发生显著变化，但在 IFT 组与安慰剂或对照组之间，任何 IFT 组在节段或节段外 PPT 方面均无显著的受试者间差异。因此，与对照组或安慰剂组相比，任何这些参数组合的 IFT 治疗都不会显著影响健康参与者的 PPT。
未评估盲法的成功率。
本研究表明，在高耐受强度和高 AMF 下给予 IFT 治疗，与对照组或安慰剂组相比，不会对健康参与者的 PPT 产生显著的节段和节段外的痛觉减退效应。需要进一步研究以调查不同 IFT 参数组合的痛觉减退效应，并解释其可能的作用机制。
