Faculty Bibliography

This third paper in the "Confronting Racism in All Forms of Pain Research" series discusses adopting an antiracism framework across all pain research disciplines and highlights the significant benefits of doing so. We build upon the previous call to action and the proposed reframing of study designs articulated in the other papers in the series and seek to confront and eradicate racism through a shared commitment to change current research practices. Specifically, we emphasize the systematic disadvantage created by racialization (ie, the Eurocentric social and political process of ascribing racialized identities to a relationship, social practice, or group) and discuss how engaging communities in partnership can increase the participation of racialized groups in research studies and enrich the knowledge gained. Alongside this critical work, we indicate why diversifying the research environment (ie, research teams, labs, departments, and culture) enriches our scientific discovery and promotes recruitment and retention of participants from racialized groups. Finally, we recommend changes in reporting and dissemination practices so that we do not stigmatize or reproduce oppressive forms of power for racialized groups. Although this shift may be challenging in some cases, the increase in equity, generalizability, and credibility of the data produced will expand our knowledge and reflect the pain experiences of all communities more accurately. PERSPECTIVE: Perspective: In this third paper in our series, we advocate for a shared commitment toward an antiracism framework in pain research. We identify community partnerships, diversification of research environments, and changes to our dissemination practices as areas where oppressive forms of power can be reduced.

BACKGROUND:Everyday experiences with racial (RD) and weight discrimination (WD) are risk factors for chronic pain in ethnically diverse adults with obesity. However, the individual or combined effects of RD and WD on pain in adults with obesity is not well understood. There are gender differences and sexual dimorphisms in nociception and pain, but the effect of gender on relationships between RD, WD, and pain outcomes in ethnically diverse adults with obesity is unclear. Thus, the purposes of this study were to: 1) examine whether RD and WD are associated with pain intensity and interference, and 2) explore gender as a moderator of the associations between RD, WD, and pain. METHODS:with weight-related comorbidity. RD and WD were measured using questions derived from the Experiences of Discrimination questionnaire (EOD). Pain interference and intensity were measured using the PROMIS 29 adult profile V2.1. Linear regression models were performed to determine the associations between WD, RD, gender, and pain outcomes. RESULTS:Participants (n = 483) reported mild pain interference (T-score: 52.65 ± 10.29) and moderate pain intensity (4.23 ± 3.15). RD was more strongly associated with pain interference in women (b = .47, SE = .08, p < 001), compared to men (b = .14, SE = .07, p = .06). Also, there were no significant interaction effects between RD and gender on pain intensity, or between WD and gender on pain interference or pain intensity. CONCLUSIONS:Pain is highly prevalent in adults with obesity, and is impacted by the frequencies of experiences with RD and WD. Further, discrimination against adults with obesity and chronic pain could exacerbate existing racial disparities in pain and weight management. Asking ethnically diverse adults with obesity about their pain and their experiences of RD and WD could help clinicians make culturally informed assessment and intervention decisions that address barriers to pain relief and weight loss. TRIAL REGISTRATION:NCT03006328.

Fibromyalgia (FM) is characterized by widespread chronic pain, fatigue, and somatic symptoms. The influence of phenotypic changes in monocytes on symptoms associated with FM are not fully understood. The primary aim of this study was to take a comprehensive whole-body to molecular approach in characterizing relationships between monocyte phenotype and FM symptoms in relevant clinical populations. LPS-evoked and spontaneous secretion of IL-5 and other select cytokines from circulating monocytes was higher in women with FM compared to women without pain. Additionally, greater secretion of IL-5 was significantly associated with pain and other clinically relevant psychological and somatic symptoms of FM. Further, higher levels of pain and pain-related symptoms were associated with a lower percentage of intermediate monocytes (CD14/CD16) and a greater percentage of non-classical monocytes (CD14/CD16) in women with FM. Based on findings from individuals with FM, we examined the role of IL-5, an atypical cytokine secreted from monocytes, in an animal model of widespread muscle pain. Results from the animal model show that IL-5 produces analgesia and polarizes monocytes toward an anti-inflammatory phenotype (CD206). Taken together, our data suggest that monocyte phenotype and their cytokine profiles are associated with pain-related symptoms in individuals with FM. Furthermore, our data show that IL-5 has a potential role in analgesia in an animal model of FM. Thus, targeting anti-inflammatory cytokines such as IL-5 in secreted by circulating leukocytes could serve as a promising intervention to control pain and other somatic symptoms associated with FM.

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. METHOD/METHODS:The scoping review utilized six databases to identify original studies that targeted pain or movement-related outcomes. Our search returned 7,322 articles that were screened by title and abstract by two reviewers. The inclusion criteria focused on measurement of MEP before, during and after movement tasks in adults with chronic pain. Studies of children < 18 years of age or with non-human 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. Additionally, studies collectively illuminated differences in MEP compared to rest pain, movement provocation methods, and pain intensity as the primary outcome. DISCUSSION/CONCLUSIONS: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. Based on the findings, we have put forth a preliminary definition MEP which may benefit from continued scholarly dialogue.

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 4weeks. 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/CONCLUSIONS: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.

OBJECTIVES/OBJECTIVE:Peripherally-directed treatments (targeted exercise, surgery) can reduce, but not fully eliminate, pain for up to 40% of patients with Achilles tendinopathy. The objectives were to: 1) Identify indicators of altered central processing in participants with Achilles tendinopathy compared to controls; and 2) determine which indicators of altered central processing persisted after a local anesthetic injection in patients with Achilles tendinopathy. DESIGN/METHODS:Mechanistic clinical trial. METHODS:46 adults participated (23 with chronic Achilles tendinopathy, 23 matched-controls; NCT03316378). All participants repeated: 1) movement-evoked pain rating, 2) motor performance, 3) pain psychology questionnaires; 4) quantitative sensory testing. Participants with Achilles tendinopathy received a local anesthetic injection before repeat testing and controls did not. Mixed-effects ANOVAs examined group, time, and group*time effects. RESULTS:>0.05). CONCLUSION/CONCLUSIONS:.

BACKGROUND:Although exercise is an effective treatment for fibromyalgia, the relationships between lifestyle physical activity and multiple symptomology domains of fibromyalgia are not clear. Thus, the purpose of this study was to comprehensively examine the relationships between lifestyle physical activity with multiple outcome domains in women with fibromyalgia, including pain, fatigue, function, pain-related psychological constructs, and quality of life. METHODS:Women (N = 171), aged 20 to 70 years, diagnosed with fibromyalgia, recruited from an ongoing two-site clinical trial were included in this prespecified subgroup analysis of baseline data. Physical activity was assessed using self-report and accelerometry. Symptomology was assessed using questionnaires of perceived physical function, quality of life, fatigue, pain intensity and interference, disease impact, pain catastrophizing, and fear of movement. In addition, quantitative sensory testing of pain sensitivity and performance-based physical function were assessed. Correlation coefficients, regression analyses and between-group differences in symptomology by activity level were assessed, controlling for age and body mass index (BMI). RESULTS:Lifestyle physical activity was most closely associated with select measures of physical function and fatigue, regardless of age and BMI. Those who performed the lowest levels of lifestyle physical activity had poorer functional outcomes and greater fatigue than those with higher physical activity participation. No relationships between lifestyle physical activity and pain, pain sensitivity, or pain-related psychological constructs were observed. CONCLUSIONS:Lifestyle physical activity is not equally related to all aspects of fibromyalgia symptomology. Lifestyle physical activity levels have the strongest correlations with function, physical quality of life, and movement fatigue in women with fibromyalgia. No relationships between lifestyle physical activity and pain, pain sensitivity, or psychological constructs were observed. These data suggest that physical activity levels are more likely to affect function and fatigue, but have negligible relationships with pain and pain-related psychological constructs, in women with fibromyalgia. TRIAL REGISTRATION/BACKGROUND:ClinicalTrials.gov, NCT01888640 . Registered on 28 June 2013.

We conducted a systematic review and meta-analysis analysing the existing data on transcutaneous electrical nerve stimulation (TENS) or interferential current (IFC) for chronic low back pain (CLBP) and/or neck pain (CNP) taking into account intensity and timing of stimulation, examining pain, function and disability. Seven electronic databases were searched for TENS or IFC treatment in non-specific CLBP or CNP. Four reviewers independently selected randomized controlled trials (RCTs) of TENS or IFC intervention in adult individuals with non-specific CLBP or CNP. Primary outcomes were for self-reported pain intensity and back-specific disability. Two reviewers performed quality assessment, and two reviewers extracted data using a standardized form. Nine RCTs were selected (eight CLBP; one CNP), and seven studies with complete data sets were included for meta-analysis (655 participants). For CLBP, meta-analysis shows TENS/IFC intervention, independent of time of assessment, was significantly different from placebo/control (p < 0.02). TENS/IFC intervention was better than placebo/control, during therapy (p = 0.02), but not immediately after therapy (p = 0.08), or 1-3 months after therapy (p = 0.99). Analysis for adequate stimulation parameters was not significantly different, and there was no effect on disability. This systematic review provides inconclusive evidence of TENS benefits in low back pain patients because the quality of the studies was low, and adequate parameters and timing of assessment were not uniformly used or reported. Without additional high-quality clinical trials using sufficient sample sizes and adequate parameters and outcome assessments, the outcomes of this review are likely to remain unchanged.

Introduction/UNASSIGNED:Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological intervention clinically used for pain relief. The importance of utilizing the adequate stimulation intensity is well documented; however, clinical methods to achieve the highest possible intensity are not established. Objectives/UNASSIGNED:Our primary aim was to determine if exposure to the full range of clinical levels of stimulation, from sensory threshold to noxious, would result in higher final stimulation intensities. A secondary aim explored the association of pain, disease severity, and psychological variables with the ability to achieve higher final stimulation intensity. Methods/UNASSIGNED:Women with fibromyalgia (N=143) were recruited for a dual-site randomized controlled trial - Fibromyalgia Activity Study with TENS (FAST). TENS electrodes and stimulation were applied to the lumbar area, and intensity was increased to sensory threshold (ST), then to "strong but comfortable" (SC1), then to "noxious" (N). This was followed by a reduction to the final stimulation intensity of "strong but comfortable" (SC2). We called this the Setting of Intensity of TENS (SIT) test. Results/UNASSIGNED:<0.0001) with a mean increase of 1.7 mA (95% CI: 1.5, 2.2). Linear regression analysis showed that those with the largest increase between SC1 and N had the largest increase in SC2-SC1. Further, those with older age and higher anxiety were able to achieve greater increases in intensity (SC2-SC1) using the SIT test. Conclusion/UNASSIGNED:The SC2-SC1 increase was significantly associated with age and anxiety, with greater mean increases associated with older age and higher anxiety. Thus, although all patients may benefit from this protocol, older women and women with elevated anxiety receive the greatest benefit.