Increases in stimulation intensity for transcutaneous electrical nerve stimulation (TENS) may benefit women with fibromyalgia-related pain, particularly older women and women with anxiety, according to a study published in the Journal of Pain Research.
A total of 143 women with fibromyalgia were enrolled in this analysis of baseline data from the ongoing Fibromyalgia Activity Study with TENS trial (Clinicaltrials.gov identifier: NCT01888640). Researchers collected baseline data as well as data from the first and second visits. Participants were administered TENS using a Setting of Intensity of TENS (SIT) protocol, in which increasing stimulation intensities were delivered.
Participants were asked to identify sensory threshold, after which stimulation intensity was increased until being reported as “strong but comfortable” (SC1) and further increased to a “noxious” degree. Stimulation intensity was then decreased from that noxious threshold until participants reported experiencing a “strong but comfortable” sensation again (SC2).
Participants reported a mean increase in TENS intensity of 1.7 mA (95% CI, 1.5-2.2; P <.0001) from SC1 (37.5 mA; interquartile range [IQR], 35.6–39.0) to SC2 (39.2 mA; IQR: 37.1–45.3). Study participants with the greatest increase between SC1 and noxious stimulation intensity also had the greatest increase between SC1 and SC2. Participants age ≥40 vs <40 and participants with higher levels of anxiety had greater increases in final stimulation intensity (ie, between SC1 and SC2).
Study limitations include the sole inclusion of women.
“[These results suggest] that clinicians can be confident in the application of the SIT test to women with fibromyalgia,” the researchers noted. “It is unclear, however, what factors will be predictors of TENS effectiveness in women with fibromyalgia, or if the ability to achieve the greatest change in intensity between SC1 and SC2 is related to TENS effectiveness.”
Vance CG, Chimenti RL, Dailey DL, et al. Development of a method to maximize the transcutaneous electrical nerve stimulation intensity in women with fibromyalgia. J Pain Res. 2018;11:2269-2278.