Transcutaneous electrical nerve stimulation (TENS) can relieve the movement-related pain experienced by people with fibromyalgia that limits their uptake of guideline recommended exercise, a randomised controlled trial has shown.
US researchers found that a four week program of daily TENS treatment relieved movement-evoked pain and fatigue in women with fibromyalgia, compared to a placebo TENS group and a no-treatment control group.
In the study involving 352 women with fibromyalgia, the use of TENS for up to two hours per day resulted in 44% of women achieving a clinically significant benefit in pain (>30% reduction in pain) and 45% had a clinically significant improvement in fatigue (>20% less fatigue), compared to rates of 22% and 26% with placebo TENS.
However the TENS intervention had no apparent effect on function or medication usage, which the study authors said may have been due to the short term duration of the trial.
Writing in the journal Arthritis and Rheumatology, researchers from the University of Iowa said pain and fatigue during physical activity are key features of fibromyalgia, and the association of pain with movement is a major reason why people with the condition are unable to participate in exercise that is recommended as an evidence-based non-drug treatment for fibromyalgia.
They noted that several small, poorly controlled trials had found mixed effects of TENS in fibromyalgia, and so they designed a larger trial with an adequate placebo group to try overcome these issues.
In their study, 352 women with fibromyalgia confirmed by ACR criteria were randomised to either active TENS (n= 103) applied at the cervicothoracic junction and lower back for two hours per day, or a placebo TENS unit (n= 99) or no treatment (n = 99) for four weeks.
For the primary outcome of movement‐evoked pain and fatigue following a 6-minute walking test the active TENS group showed a significant reduction compared to placebo (pain ‐1.0, fatigue ‐1.4) and no‐treatment groups (pain: ‐1.8, fatigue: ‐1.9).
A greater percentage of the active‐TENS group reported improvement on the global impression of change when compared to placebo‐TENS (70% vs. 31%) and no‐TENS (9%).
However there was no effect of TENS on function, rescue medication usage, or psychological outcomes.
“It is possible that longer treatment is necessary to see effects on these other outcomes and thus future experiments will be needed to examine more long-term impact of TENS use,” the researchers said.
“Further research is needed to examine effectiveness in a real world, pragmatic setting to establish clinical importance of these findings,” they concluded.