The journal of pain : official journal of the American Pain Society
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Self-reported pain intensity assessments are central to chronic pain research. Ecological momentary assessment (EMA) methodologies are uniquely positioned to collect these data, and are indeed being used in the field. However, EMA protocols are complex, and many decisions are necessary in the design of EMA research studies. A systematic literature review identified 105 articles drawing from 62 quantitative EMA research projects examining pain intensity in adult chronic pain patients. Study characteristics were tabulated to summarize and describe the use of EMA, with an emphasis placed on various dimensions of decision-making involved in executing EMA methodologies. Most identified studies considered within-person relationships between pain and other variables, and a few examined interventions on chronic pain. There was a trend toward the use of smartphones as EMA data collection devices more recently, and completion rates were not reported in nearly one third of studies. Pain intensity items varied widely with respect to number of scale points, anchor labels, and length of reporting period; most used numeric rating scales. Recommendations are provided for reporting to improve reproducibility, comparability, and interpretation of results, and for opportunities to clarify the importance of design decisions. ⋯ Studies that use EMA methodologies to assess pain intensity are heterogeneous. Aspects of protocol design, including data input modality and pain item construction, have the potential to influence the data collected. Thorough reporting on design features and completion rates therefore facilitates reproducibility, comparability, and interpretation of study results.
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Chronic stress produces maladaptive pain responses, manifested as alterations in pain processing and exacerbation of chronic pain conditions including irritable bowel syndrome. Female predominance, especially during reproductive years, strongly suggests a role of gonadal hormones. However, gonadal hormone modulation of stress-induced pain hypersensitivity is not well understood. ⋯ In addition, the presence of estradiol during stress increased spinal brain-derived neurotrophic factor (BDNF) expression independent of sex. In contrast, testosterone blocked the stress-induced increase in BDNF expression in female rats. These data suggest that estradiol facilitates and testosterone attenuates SIVH by modulating spinal excitatory and inhibitory glutamatergic receptor expression.
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Previous studies have shown increased pain sensitivity in fertile-aged women with endometriosis in response to mechanical stimuli. As yet, population-based studies on the association of endometriosis with pain sensation and pain symptoms in late fertile age are lacking. The main objective of this population-based cohort study was to investigate whether a history of endometriosis is associated with altered pain sensation and musculoskeletal pain symptoms at age 46 years. ⋯ The results were adjusted for body mass index, smoking, depressive/anxiety symptoms, education, and use of hormonal contraceptives. These unique data revealed an altered pain sensation and a greater likelihood of reporting musculoskeletal pain at age 46 years among women with a history of endometriosis. The results imply that endometriosis has a long-term footprint on affected women, thus underlying the need for psychological support and medical treatment beyond fertile age.
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Although the clinical application of opioids for pain management is often hindered by undesired behavioral impairment, preclinical assays of antinociception typically do not provide information regarding the behaviorally disruptive effects of opioids that may accompany their antinociceptive effects. To address this, we modified a warm water tail withdrawal procedure to determine concurrently the effects of opioids on tail withdrawal latency (antinociception) and indices of food-maintained operant behavior (rates of responding and reinforcement density) in squirrel monkeys. Six opioid agonists were tested, and all produced dose-dependent antinociception and impairment of operant behavior. ⋯ Oxycodone, heroin, buprenorphine, and methadone all produced similar ED50 ratios (.82-1.14), whereas butorphanol yielded a significantly lower ED50 ratio (.17) reflecting behavioral disruption at doses producing only minimal antinociception. The antinociceptive and behaviorally disruptive effects of oxycodone and buprenorphine were further characterized using Schild analysis to calculate apparent pA2 values for antagonism of the 2 drugs by naltrexone. These analyses suggest that µ-receptor mechanisms likely mediate the antinociceptive as well as behaviorally disruptive effects of oxycodone (pA2 values: 8.13 and 8.57) and buprenorphine (pA2 values: 8.6 and 7.9).
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Randomized Controlled Trial
Randomized Controlled Trial of Online Acceptance and Commitment Therapy for Fibromyalgia.
In this study, 67 participants (95% female) with fibromyalgia (FM) were randomly assigned to an online acceptance and commitment therapy (online ACT) and treatment as usual (TAU; ACT + TAU) protocol or a TAU control condition. Online ACT + TAU participants were asked to complete 7 modules over an 8-week period. Assessments were completed at pre-treatment, post-treatment, and 3-month follow-up periods and included measures of FM impact (primary outcome), depression, pain, sleep, 6-minute walk, sit to stand, pain acceptance (primary process variable), mindfulness, cognitive fusion, valued living, kinesiophobia, and pain catastrophizing. ⋯ Increases in pain acceptance significantly mediated these improvements (P = .005). Significant improvements in favor of online ACT + TAU were also found on measures of depression (P = .02), pain (P = .01), and kinesiophobia (P = .001). Although preliminary, this study highlights the potential for online ACT to be an efficacious, accessible, and cost-effective treatment for people with FM and other chronic pain conditions.