The journal of pain : official journal of the American Pain Society
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The Centrality of Pain Scale (COPS) is a recently developed patient-centered, 10-item self-report measure designed to assess how central, or dominating, in their lives individuals with chronic pain perceive pain to be. The COPS underwent initial development and validation previously; preliminary results suggested that the measure had excellent psychometric properties and that COPS scores were associated with important clinical factors. The purpose of the present study was to examine the psychometric properties of the COPS in a sample of individuals with mixed chronic pain diagnoses (N = 178) being treated at a U.S. Veterans Affairs Medical Center. Principal components analysis of COPS items revealed a single factor, and all items loaded highly. The COPS had high internal consistency (Cronbach's alpha = .902) and was significantly correlated with other measures of pain, mental health, psychological factors associated with pain, and chronic pain coping styles, suggesting convergent and divergent validity. Hierarchical linear regression analyses indicated that COPS score was independently associated with both pain severity and interference. Future research should evaluate the generalizability of the COPS in different samples, its responsiveness to treatment, and the extent to which pain centrality may be a focus of nonpharmacologic interventions for chronic pain. ⋯ We conducted psychometric testing of the COPS, a recently developed patient-centered self-report measure designed to examine how central or dominating pain is to a person's life. Study results indicated a reliable and valid measure, which was significantly associated with pain severity and interference, even after controlling for demographic and clinical factors.
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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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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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Injury- or disease-induced artemin (ARTN) signaling can sensitize primary afferents and contribute to persistent pain. We demonstrate that administration of an ARTN neutralizing antibody, anti-artemin (α-ARTN), can block the development of, and reverse already established, bladder hyperalgesia associated with cyclophosphamide-induced cystitis in mice. We further demonstrate that α-ARTN therapy blocks upregulation of TRPA1, an ion channel contributing to persistent bladder pain during cyclophosphamide-induced cystitis, and decreases phospho-ERK1/2 immunoreactivity in regions of the spinal cord receiving bladder afferent input. Thus, α-ARTN is a promising novel therapeutic approach for treatment of bladder hyperalgesia that may be associated with interstitial cystitis/painful bladder syndrome, as well as cystitis associated with antitumor or immunosuppressive cyclophosphamide therapy. ⋯ α-ARTN therapy effectively prevented and reversed ongoing bladder hyperalgesia in an animal model of cystitis, indicating its potential as an efficacious treatment strategy for ongoing bladder pain associated with interstitial cystitis/painful bladder syndrome.
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The study explored the analgesic effects of transcranial direct current stimulation (tDCS) over the motor cortex on postamputation phantom limb pain (PLP). Eight subjects with unilateral lower or upper limb amputation and chronic PLP were enrolled in a crossover, double-blind, sham-controlled treatment program. For 5 consecutive days, anodal (active or sham) tDCS was applied over the motor cortex for 15 minutes at an intensity of 1.5 mA. The 5-day treatment with active, but not sham, tDCS induced a sustained decrease in background PLP and in the frequency of PLP paroxysms, which lasted for 1 week after the end of treatment. Moreover, on each day of active tDCS, patients reported an immediate PLP relief, along with an increased ability to move their phantom limb. Patients' immediate responses to sham tDCS, on the contrary, were variable, marked by an increase or decrease of PLP levels from baseline. These results show that a 5-day treatment of motor cortex stimulation with tDCS can induce stable relief from PLP in amputees. Neuromodulation targeting the motor cortex appears to be a promising option for the management of this debilitating neuropathic pain condition, which is often refractory to classic pharmacologic and surgical treatments. ⋯ The study describes sustained and immediate effects of motor cortex stimulation by tDCS on postamputation PLP, whose analgesic action seems linked to the motor reactivation of the phantom limb. These results are helpful for the exploitation of tDCS as a therapeutic tool for the management of neuropathic pain.