Pain
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Review Meta Analysis
Randomized controlled trials of psychological therapies for management of chronic pain in children and adolescents: an updated meta-analytic review.
The purpose of this meta-analytic review was to quantify the effects of psychological therapies for the management of chronic pain in youth. Specifically, in this review we updated previous systematic reviews of randomized controlled trials by including new trials, and by adding disability and emotional functioning to pain as treatment outcomes. Electronic searches of the Cochrane Register of Randomised Controlled Trials, MEDLINE, PsycLIT, EMBASE, and the Social Sciences Citation Index were conducted from inception through August 2008. ⋯ Studies directly comparing the effects of self-administered versus therapist-administered interventions found similar effects on pain reduction. Psychological therapies result in improvement in pain relief across several different pain conditions in children. Future trials are needed that incorporate non-pain outcome domains, that focus significant therapeutic content on reductions in disability, and that include extended follow-up to better understand maintenance of treatment effects.
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Multicenter Study
Distinctiveness of psychological obstacles to recovery in low back pain patients in primary care.
Many psychological factors have been suggested to be important obstacles to recovery from low back pain, yet most studies focus on a limited number of factors. We compared a more comprehensive range of 20 factors in predicting outcome in primary care. Consecutive patients consulting 8 general practices were eligible to take part in a prospective cohort study; 1591 provided data at baseline and 810 at 6 months. ⋯ Thus, a small number of psychological factors are strongly predictive of outcome in primary care low back pain patients. There is clear redundancy in the measurement of psychological factors. These findings should help to focus targeted interventions for back pain in the future.
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Clinical Trial
NGF induces non-inflammatory localized and lasting mechanical and thermal hypersensitivity in human skin.
Nerve growth factor (NGF) modulates sensitivity and sprouting of nociceptors. We explored the spatial and temporal sensitization induced by NGF injection (1 microg) in human skin. Hyperalgesia was investigated in 16 volunteers (36+/-9 years) at day 1, 3, 7, 21, and 49. ⋯ Spatially restricted hyperalgesia indicates a peripheral rather than central mechanism. The temporal profile of lasting nociceptor sensitization suggests an altered peripheral axonal expression of sensory proteins specifically leading to mechanical and thermal sensitization. Intradermal NGF administration provokes a pattern of sensitization that can be used as experimental model for neuropathic pain.
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Previous investigations of somatic hypersensitivity in IBS patients have typically involved only a single stimulus modality, and little information exists regarding whether patterns of somatic pain perception vary across stimulus modalities within a group of patients with IBS. Therefore, the current study was designed to characterize differences in perceptual responses to a battery of noxious somatic stimuli in IBS patients compared to controls. A total of 78 diarrhea-predominant and 57 controls participated in the study. ⋯ The somatic hypersensitivity in IBS patients was somatotopically organized in that the lower extremities that share viscerosomatic convergence with the colon demonstrate the greatest hypersensitivity. There were also changes in ACTH, cortisol, and systolic blood pressure in response to the ischemic pain testing in IBS patients when compared to controls. The results of this study suggest that a more widespread alteration in central pain processing in a subset of IBS patients may be present as they display hypersensitivity to heat, ischemic, and cold pressor stimuli.
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Expectations and beliefs modulate the experience of pain, which is particularly evident in placebo analgesia. The dorsolateral prefrontal cortex (DLPFC) has been associated with pain regulation and with the generation, maintenance and manipulation of cognitive representations, consistent with its role in expectation. ⋯ While rTMS did not affect pain experience, it completely blocked placebo analgesia. These findings suggest that expectation-induced placebo analgesia is mediated by symmetric prefrontal cortex function.