The journal of pain : official journal of the American Pain Society
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There is increasing interest in the measurement of "readiness to change," or willingness to engage in a self-management approach to pain coping, as a predictor of treatment response in pediatric pain populations. The primary aim of the present study was to provide cross-validation of the Pain Stages of Change Questionnaire-Adolescent and -Parent versions in a new, independent pediatric chronic pain sample by examining aspects of reliability, validity, and generalizability of the factor structures identified in the initial validation study. Secondary aims were to 1) expand upon previously identified differences between the Pain Stages of Change Questionnaire-Adolescent and -Parent versions and 2) examine previously unreported aspects of father data. Although slight differences emerged, the factor structures identified in the initial validation were largely replicated, suggesting that the psychometric properties of the measure are robust across pediatric outpatient chronic pain samples. Variability between parent and adolescent reports suggests that there may be meaningful differences in the interpretation of each measure and that factors other than readiness to change may influence response patterns. Findings highlight the need for more fine-tuned analyses of the way the construct operates in youth with pediatric pain and their parents. ⋯ Findings provide further validation of the Pain Stages of Change Questionnaire-Adolescent and -Parent versions measures in a new outpatient pediatric chronic pain sample. Previously uninvestigated father data showed good reliability and patterns of findings similar to validated mother reports. Moreover, the study suggests that the adolescent and parent versions may function in meaningfully different ways.
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The μ-opioid receptor 1 (OPRM1) binds endogenous opioids. Increasing evidence suggests that endogenous OPRM1 agonists released at the time of trauma may contribute to the development of posttraumatic musculoskeletal pain (MSP). In this prospective observational study, we evaluated the hypothesis that individuals with an AG or GG genotype at the OPRM1 A118 G allele, which results in a reduced response to opioids, would have less severe MSP 6 weeks after motor vehicle collision (MVC). Based on previous evidence, we hypothesized that this effect would be sex-dependent and most pronounced among women with substantial peritraumatic distress. European American men and women ≥ 18 years of age presenting to the emergency department after MVC and discharged to home after evaluation (N = 948) were enrolled. Assessments included genotyping and 6-week evaluation of overall MSP severity (0-10 numeric rating scale). In linear regression modeling, a significant A118 G Allele × Sex interaction was observed: an AG/GG genotype predicted reduced MSP severity among women with substantial peritraumatic distress (β = -.925, P = .014) but not among all women. In contrast, men with an AG/GG genotype experienced increased MSP severity at 6 weeks (β = .827, P = .019). Further studies are needed to understand the biologic mechanisms mediating observed sex differences in A118 G effects. ⋯ These results suggest a sex-dependent mechanism by which an emotional response to trauma (distress) contributes to a biologic mechanism (endogenous opioid release) that increases MSP in the weeks after stress exposure. These results also support the hypothesis that endogenous opioids influence pain outcomes differently in men and women.
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Although nonnoxious, high-frequency electrical stimulation applied segmentally (ie, conventional transcutaneous electrical nerve stimulation [TENS]) has been proposed to modulate pain, the mechanisms underlying analgesia remain poorly understood. To further elucidate how TENS modulates pain, we examined evoked responses to noxious thermal stimuli after the induction of sensitization using capsaicin in healthy volunteers. We hypothesized that sensitization caused by capsaicin application would unmask TENS analgesia, which could not be detected in the absence of sensitization. Forty-nine healthy subjects took part in a series of experiments. The experiments comprised the application of topical capsaicin (.075%) on the left hand in the C6 dermatome, varying the location of TENS (segmental, left C6 dermatome, vs extrasegmental, right shoulder), and assessing rating of perception (numeric rating scale: 0-10) and evoked potentials to noxious contact heat stimuli. The extrasegmental site was included as a control condition because previous studies indicate no analgesic effect to remote conventional TENS. Conventional TENS had no significant effect on rating or sensory evoked potentials in subjects untreated with capsaicin. However, segmental TENS applied in conjunction with capsaicin significantly reduced sensation to noxious thermal stimuli following a 60-minute period of sensitization. ⋯ The study indicates that sensitization with capsaicin unmasks the analgesic effect of conventional TENS on perception of noxious contact heat stimuli. Our findings indicate that TENS may be interacting segmentally to modulate distinct aspects of sensitization, which in turn results in analgesia to thermal stimulation.
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The Mediating Role of Acceptance in Multidisciplinary Cognitive-Behavioral Therapy for Chronic Pain.
Cognitive-behavioral therapy (CBT) is the most frequently delivered psychological intervention for adults with chronic pain. The treatment yields modest effect sizes, and the mechanisms of action remain understudied and unclear. Efforts are needed to identify treatment mediators that could be used to refine CBT and improve outcomes. The primary aim of this study was to investigate whether pain-related acceptance, from the psychological flexibility model, mediates changes in outcome over time in a CBT-based treatment program. This includes comparing how this variable relates to 3 other variables posited as potential mediators in standard CBT: life control, affective distress, and social support. Participants attended a 5-week outpatient multidisciplinary program with self-report data collected at assessment, posttreatment, and 12-month follow-up. Multilevel structural equation modeling was used to test for mediation in relation to 3 outcomes: pain interference, pain intensity, and depression. Results indicate that effect sizes for the treatment were within the ranges reported in the CBT for pain literature. Pain-related acceptance was not related to pain intensity, which is in line with past empirical evidence and the treatment objectives in acceptance and commitment therapy. Otherwise, pain-related acceptance was the strongest mediator across the different indices of outcome. Accumulated results like these suggest that acceptance of pain may be a general mechanism by which CBT-based treatments achieve improvements in functioning. More specific targeting of pain-related acceptance in treatment may lead to further improvements in outcome. ⋯ Potential mediators of outcome in a CBT-based treatment for adult chronic pain were investigated using multilevel structural equation modeling. The results highlight the role of pain-related acceptance as an important treatment process even when not explicitly targeted during treatment. These data may help clinicians and researchers better understand processes of change and improve the choice and development of treatment methods.