Objective. Fibromyalgia (FM) is characterized by pain and fatigue, particularly during physical activity. Trans cutaneous electrical nerve stimulation (TENS) activates endogenous pain inhibitory mechanisms. This study was undertaken to investigate 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 during activity 2 hours each day for 4 weeks. TENS was applied to the lumbar and cervicothoracic regions using a modulated frequency (2-125 Hz) at the highest tolerable intensity. Participants rated movement evoked pain (primary outcome measure) and fatigue on an 11 point scale before and during application of TENS. The primary outcome measure and secondary patient reported outcomes were assessed at baseline (time of randomization) and at 4 weeks.Results. After 4 weeks, a greater reduction in movement evoked pain was reported in the active TENS group versus the placebo TENS group (group mean difference -1.0 [95% confidence interval -1.8, -0.2]; P = 0.008) and ver sus the no TENS group (group mean difference -1.8 [95% confidence interval -2.6, -1.0]; P < 0.0001). A reduction in movement evoked fatigue was also reported in the active TENS group versus the placebo TENS group (group mean difference -1.4 [95% confidence interval -2.4, -0.4]; P = 0.001) and versus the no TENS group (group mean difference -1.9 [95% confidence interval -2.9, -0.9]; P = <0.0001). A greater percentage of the patients in the active TENS group reported improvement on the global impression of change compared to the placebo TENS group (70% versus 31%; P < 0.0001) and the no TENS group (9%; P < 0.0001). There were no TENS related serious adverse events, and <5% of participants experienced minor adverse events from TENS.Conclusion. Among women who had FM and were on a stable medication regimen, 4 weeks of active TENS use compared to 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 setting to establish the clinical importance of these findings.

Objective: Individuals with chronic pain conditions often report movement as exacerbating pain. An increasing number of researchers and clinicians have recognized the importance of measuring and distinguishing between movement-evoked pain (MEP) and pain at rest as an outcome. This scoping review maps the literature and describes MEP measurement techniques. Materials and Methods: The scoping review utilized 6 databases to identify original studies that targeted pain or movement-related outcomes. Our search returned 7322 articles that were screened by title and abstract by 2 reviewers. The inclusion criteria focused on the measurement of MEP before, during, and after movement tasks in adults with chronic pain. Studies of children below 18 years of age or with nonhuman animals, case studies, qualitative studies, book chapters, cancer-related pain, non-English language, and abstracts with no full publish text were excluded from the study. Results: Results from 38 studies revealed great variation in the measurement of MEP, while almost all of the studies did not provide an explicit conceptual or operational definition for MEP. In addition, studies collectively illuminated differences in MEP compared with rest pain, movement provocation methods, and pain intensity as the primary outcome. Discussion: These results have clinically significant and research implications. To advance the study of MEP, we offer that consistent terminology, standardized measurement (appropriate for pain type/population), and clear methodological processes be provided in research publications. On the basis of the findings, we have put forth a preliminary definition of MEP that may benefit from the continued scholarly dialog.

These data highlight the need for additional high-quality RCTs to examine the effects of TENS in CLBP. Trials should consider intensity of stimulation, timing of outcome assessment and assessment of pain, disability and function.

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BackgroundFibromyalgia is a condition characterized by chronic widespread muscle pain and fatigue and associated with significant impairment in perceived function and reduced physical performance. The purpose of this study was to determine the degree to which pain and fatigue are associated with perceived function and physical performance in women with fibromyalgia.MethodsHierarchical linear regression determined the contribution of pain and fatigue (Numeric Rating Scale (NRS) for resting, movement and combined) to perceived function (Fibromyalgia Impact Questionnaire Revised - Function Subscale, FIQR-Function), Multidimensional Assessment of Fatigue - Activities of Daily Living (MAF-ADL) and SF-36 Physical Function Subscale (SF-36-PF) and physical performance (6-Minute Walk Test, 6MWT and Five Time Sit To Stand, 5TSTS) while controlling for age, body mass index, pain catastrophizing, fear of movement, anxiety, and depression in women with fibromyalgia (N = 94).ResultsFor perceived function, movement pain and movement fatigue together better predicted FIQR-function (adjusted R2 = 0.42, p ≤ 0.001); MAF-ADL (adjusted R2 = 0.41, p ≤ 0.001); and SF-36-PF function (adjusted R2 = 0.34, p ≤ 0.001). For physical performance measures, movement pain and fatigue together predicted 6MWT distance (adjusted R2 = 0.42, p ≤ 0.001) and movement fatigue alone predicted performance time on the 5TSTS (adjusted R2 = 0.20, p ≤ 0.001).ConclusionsPain and fatigue are significantly associated with and explain more than one-third of the variance in perceived function and physical performance in women with fibromyalgia.Trial registrationNIH Clinicaltrials.gov Registration: NCT01888640. Registered 13 June 2013.