Effects of InterX therapy in myofascial pain syndrome: a randomized controlled simple blind clinical trial

The obtained data was examined with repeated measures analysis of variance (ANOVA). Results: In Cycle 1, G1 vs. G2 and G2 vs. placebo, the difference was significant (P< 0.05). In Cycle 3, G1 vs. G3, G1 vs. G4, G1 vs. placebo, the difference was significant (P< 0.001). In Cycle 4, G1 vs. G2, G1 vs. G3, G1 vs. G4, G1 vs. placebo, the difference was very significant (P< 0.001). In Cycle 5, G1 vs. G3, G1 vs. G4, G1 vs. placebo, the difference was significant (P< 0.05). The analysis of all the other comparisons between groups was not significant. Conclusion(s): The results show that the most effective waveform for pain treatment, in the cold induced pain model, is the biphasic symmetrical with 100 us of phase duration. More investigations are needed with other models to provide more support. Implications: TENS is one of the most used therapies for analgesia. This research provides evidence that biphasic symmetrical TENS may produce better clinical results. The acquisition of low-cost equipment with monophasic waveform is not recommended. The best phase duration is 100 s, so a device with variable phase width is the most suitable choice.