European journal of pain : EJP
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Heritable phenotypes resulting from environment-caused changes in a chromosome without alterations in the DNA sequence are increasingly recognized as a basis of personalized therapy. Epigenetic mechanisms include covalent modifications of the DNA (methylation) or of the DNA-packaging histones (e.g., deacetylation or phosphorylation). In addition, regulatory non-coding RNA molecules (micro-RNAs) exert epigenetic actions. ⋯ Finally, epigenetic techniques such as RNA interference have been employed in pain research to proof the contribution of certain proteins to nociception. Thus, the new field of epigenetics becomes increasingly used in research and management of pain and will complement genetics. This article introduces epigenetics to pain and summarizes the current and future utility.
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The etiology of post-stroke shoulder pain (PSSP) is largely unclear and may involve both nociceptive and neuropathic mechanisms. No gold standard is present for PSSP diagnosis. The neuropathic pain diagnostic questionnaire (DN4), was originally developed to identify neuropathic pain in the clinical context. ⋯ Notably, several symptoms and signs suggestive of either neuropathic or nociceptive pain corresponded to the subgroups DN4+ and DN4- respectively. However, since the pathophysiological mechanisms remain unclear and none of the sensory signs could be exclusively related to either DN4+ or DN4-, PSSP prognosis and treatment should not be solely based on the DN4. Nonetheless, a thorough assessment of neuropathic and nociceptive pain complaints and somatosensory functions should be included in the diagnostic work-up of PSSP.
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This study investigated the role of anger in attentional bias for linguistic threat-related stimuli in individuals with chronic daily headache (CDH) tension type and healthy controls. Attentional bias was assessed using a visual probe task which presented pain-related (sensory and affective), social threat, anger-related, and neutral words at two exposure duration conditions: 500 ms and 1250 ms. Compared to healthy controls, individuals with CDH showed significantly greater attentional bias towards pain-related words at 1250 ms, indicating a bias in maintained attention to pain cues in this group. ⋯ Across the whole sample, pain bias scores at 1250 ms were significantly associated with anger out, whilst anger bias scores at both 500 ms and 1250 ms correlated significantly with trait anger. The results of the present investigation support the content-specificity hypothesis, according to which attentional bias in patients with chronic pain is shown only towards pain-related cues. Moreover, the current pattern of results highlights the importance of exploring further the role of anger in the aetiology and maintenance of chronic pain in general, and CDH tension type in particular.
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Multicenter Study
Does attrition bias longitudinal population-based studies on back pain?
Longitudinal population studies are a keystone in describing the course of back pain over time. Yet, potential bias because of repeated attrition has received little attention. This study aims to identify those back pain related indicators most susceptible to bias and to discuss practical consequences for back pain research. ⋯ The representativeness of the sample is consecutively reduced because of differential attrition over the different measurement points. Despite this, bias due to attrition has a marginal impact on the point estimates of virtually all back pain related outcomes.