The journal of pain : official journal of the American Pain Society
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The dominant socioaffective model of empathy has emphasized the overlap between brain mechanisms involved in the encoding and the decoding of internal states. The role of dispositional empathy has been extensively studied in this research, but several other individual factors fundamental to communication processes have been largely ignored. We studied the effects of dispositional expressiveness in chronic back pain patients to determine if the decoding of communicative and noncommunicative information signaling pain in others would be enhanced in individuals displaying a spontaneous propensity to consistently express more pain during a behavioral-observational naturalistic standardized lifting task performed on 2 separate occasions. Blood oxygenation level-dependent signal change was measured in response to pictures showing facial pain expressions and hands/feet in pain-evoking situations in chronic back pain patients and healthy controls. Vicarious brain responses to others' pain were comparable between groups. However, more expressive patients rated others' pain higher and showed stronger vicarious pain responses in the right ventral part of the inferior frontal gyrus, the right insula, and the midbrain. Activity in the right insula correlated positively with both the patients' expressiveness (encoding) and the intensity of the pain perceived in the images (decoding), suggesting that this structure linked the dispositional expressiveness with vicarious pain perception. Importantly, these effects were independent from dispositional empathy and were found with both communicative (facial expression) and noncommunicative (hand and foot) cues. These results suggest that dispositional expressiveness is a self-related factor that facilitates vicarious pain processing and might reflect individual tendencies to rely on social coping strategies. ⋯ This article shows that pain expressivity in chronic pain patients increased the vicarious brain responses and the sensibility to others' pain. These results may help provide empirical support for better defining models of pain communication in chronic pain patients.
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Although chronic pain in childhood can last into adulthood, few studies have evaluated the characteristics of adults with chronic pain who report childhood chronic pain. Thus, 1,045 new patients (mean age, 49.5 ± 15.4) at an academic tertiary care pain clinic were prospectively evaluated using validated self-report questionnaires. Patients also responded to questions about childhood pain. We found that almost 17% (n = 176) of adult chronic pain patients reported a history of chronic pain in childhood or adolescence, with close to 80% indicating that the pain in childhood continues today. Adults reporting childhood chronic pain were predominantly female (68%), commonly reported widespread pain (85%), and had almost 3 times the odds of meeting survey criteria for fibromyalgia (odds ratio [OR] = 2.94, 95% confidence interval [CI] = 2.04-4.23) than those denying childhood chronic pain. Similarly, those with childhood pain had twice the odds of having biological relatives with chronic pain (OR = 2.03, 95% CI = 1.39-2.96) and almost 3 times the odds of having relatives with psychiatric illness (OR = 2.85, 95% CI = 1.97-4.11). Lastly, compared to patients who did not report childhood chronic pain, those who did were more likely to use neuropathic descriptors for their pain (OR = 1.82, 95% CI = 1.26-2.64), have slightly worse functional status (B = -2.12, t = -3.10, P = .002), and have increased anxiety (OR = 1.77, 95% CI = 1.24-2.52). ⋯ Our study revealed that 1 in 6 adult pain patients reported pain that dated back to childhood or adolescence. In such patients, evidence suggested that their pain was more likely to be widespread, neuropathic in nature, and accompanied by psychological comorbidities and decreased functional status.
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Randomized Controlled Trial
A trial of a brief group-based form of acceptance and commitment therapy (ACT) for chronic pain in general practice: pilot outcome and process results.
Acceptance and commitment therapy (ACT) is a developing approach for chronic pain. The current study was designed to pilot test a brief, widely inclusive, local access format of ACT in a UK primary care setting. Seventy-three participants (68.5% women) were randomized to either ACT or treatment as usual (TAU). Many of the participants were aged 65 years or older (27.6%), were diagnosed with fibromyalgia (30.2%) and depression (40.3%), and had longstanding pain (median = 10 years). Standard clinical outcome measures included disability, depression, physical functioning, emotional functioning, and rated improvement. Process measures included pain-related and general psychological acceptance. The recruitment target was met within 6 months, and 72.9% of those allocated to ACT completed treatment. Immediately post treatment, relative to TAU, participants in ACT demonstrated lower depression and higher ratings of overall improvement. At a 3-month follow-up, again relative to TAU, those in ACT demonstrated lower disability, less depression, and significantly higher pain acceptance; d = .58, .59, and .64, respectively. Analyses based on intention-to-treat and on treatment "completers," perhaps predictably, revealed more sobering and more encouraging results, respectively. A larger trial of ACT delivered in primary care, in the format employed here, appears feasible with some recommended adjustments in the methods used here (Trial registration: ISRCTN49827391). ⋯ This article presents a pilot randomized controlled trial of ACT for chronic pain in a primary care setting in the United Kingdom. Both positive clinical outcomes and ways to improve future trials are reported.
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The present study examined whether the histone deacetylase inhibitor valproate prevents downregulation of glutamate transporters in the primary cultured astrocytes and in the spinal cord after L5-L6 spinal nerve ligation (SNL) and whether this action of valproate on spinal glutamate transporters prevents spinal glutamate dysregulation and development of hypersensitivity after SNL. In cultured astrocytes, valproate prevented downregulation of glutamate transporter-1 (GLT-1) and glutamate-aspartate transporter in a concentration-dependent manner. Repeated oral administration of valproate reduced the development of hypersensitivity and prevented the downregulation of spinal GLT-1 and glutamate-aspartate transporter expression in rats after SNL, but did not affect mechanical nociception and expression of those transporters in normal rats. Valproate's effects on hypersensitivity and spinal GLT-1 expression in SNL rats were blocked by intrathecal administration of the selective GLT-1 blocker dihydrokainic acid or the GLT-1 selective small interfering RNA (siRNA). Extracellular glutamate concentration in the spinal cord, measured by microdialysis, was increased in animals with SNL or after GLT-1 selective siRNA treatment, and valproate prevented the SNL-induced glutamate increase. These results suggest that valproate reduces the development of chronic pain after nerve injury in part by preventing downregulation of glutamate transporters, especially GLT-1, to maintain normal extracellular glutamate concentrations in the spinal cord. ⋯ This study demonstrates that valproate prevents the downregulation of glutamate transporters in the spinal cord, which contributes in part to the development of chronic pain after nerve injury. Given clinical availability and established safety profiles, perioperative use of valproate should be tested to prevent chronic pain after surgery.
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Factorial validity of the English-language version of the Pain Catastrophizing Scale--child version.
The Pain Catastrophizing Scale (PCS) was developed in English to assess 3 components of catastrophizing (rumination, magnification, helplessness). It has been adapted for use and validated with Flemish-speaking children (Pain Catastrophizing Scale for Children [PCS-C]) and French-speaking adolescents. The PCS-C has been back-translated to English and used extensively in research with English-speaking children; however, the factorial validity of the English PCS-C has not been empirically examined. This study assessed the factor structure of the English PCS-C among a community sample of 1,006 English-speaking children (aged 8-18 years). Exploratory factor analysis was conducted using a random subsample (n = 504) to assess the underlying factor structure. Items with poor factor loadings were removed. Confirmatory factor analysis, using the second subsample (n = 502), was used to cross-validate the factor structure revealed by exploratory factor analysis and compare it to the original 3-factor model and other model variants. Exploratory factor analysis revealed that the original PCS-C and a revised 3-factor model comprising 11 of the original 13 PCS-C items, all loading on their original factors, provided adequate fit to the data. The revised model provided statistically better fit to the data compared to all other model variants, suggesting that the English PCS-C may be better understood using a revised 11-item oblique 3-factor model. ⋯ This is the first examination of the factorial validity of the widely used English version of the PCS-C in a large community sample of English-speaking children. A revised 11-item, 3-factor model provided statistically better fit to the data compared to the original model and other model variants.