A Randomized Controlled Trial of TENS for Movement‐Evoked Pain in Women With Fibromyalgia

Objective

Fibromyalgia (FM) is characterized by pain and fatigue, particularly during physical activity. Transcutaneous electrical nerve stimulation (TENS) activates endogenous pain inhibitory mechanisms. We evaluated if using TENS during activity would improve movement‐evoked pain and other patient‐reported outcomes in women with FM.

Methods

Participants were randomly assigned to receive active‐TENS (n=103), placebo‐TENS (n=99), or no‐TENS (n=99) and instructed to use it at home 2h/day during activity for 4‐ weeks. TENS was applied to the lumbar and cervicothoracic regions using a modulated frequency (2‐125Hz) at the highest tolerable intensity. Participants rated movement‐evoked pain (primary outcome) and fatigue on an 11‐point scale before and during application of TENS. Primary and secondary patient‐reported outcomes were assessed at randomization and 4 weeks.

Results

After 4‐weeks, the active‐TENS group reported a greater reduction in movement‐evoked pain and fatigue than placebo‐TENS (Pain, Group mean difference (95% CI): ‐1.0(‐1.8, ‐0.2), P=0.008; Fatigue: ‐1.4(‐2.4, ‐0.4), P=0.001) and no‐TENS groups (Pain: ‐1.8(‐2.6. ‐1.0), P<0.0001; Fatigue: ‐1.9(‐2.9, ‐0.9), P=<0.0001). A greater percentage of the active‐TENS group reported improvement on the global impression of change when compared to placebo‐TENS (70% vs. 31%, P<0.0001) and no‐TENS (9%, P<0.0001). There were no TENS‐related serious adverse events and less than 5% of participants experienced minor adverse events from TENS.

Conclusion

Among women with FM and stable medication, 4‐weeks of active‐TENS use compared with placebo‐TENS or no‐TENS resulted in a significant improvement in movement‐evoked pain and other clinical outcomes. Further research is needed to examine effectiveness in a real world, pragmatic setting to establish clinical importance of these findings.

You can read an interview with the lead author of this study here and expert commentary about the clinical implications of the study here.