Pain
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This study examined within- and across-session consistency of visual analog scale (VAS) pain intensity and unpleasantness ratings of contact heat stimuli in 64 subjects (32 male). Subjects participated in four sessions over 14 days, with three stimulus series per session. Two levels of painful heat (pain-lo: rated 40, and pain-hi: rated 70 on a 0-100 VAS) were delivered in randomized order during each series, with temperatures selected on an individual subject basis to equalize pain perception across subjects. ⋯ Across- and within-session CVs were significantly negatively correlated with individual ratings of the stimuli, but were not correlated with demographic or psychosocial factors. Furthermore, sex did not impact consistency of ratings, demonstrating that neither sex is more variable in ratings than the other over time. Taken together, these findings suggest that VAS ratings of painful contact heat are relatively stable over time but the variability of these ratings is significantly impacted by the perceived intensity of the stimulus.
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Despite the frequent use of pain recall ratings in clinical research, there remains doubt about the ability of individuals to accurately recall their pain. In particular, previous research indicates the possibility that the most pain experienced during a recall period and the most recent pain experienced (known as peak and end effects, respectively) might bias recall ratings. ⋯ Also, the influence of peak pain was stronger than that of end pain. However, the biasing impact of both peak and end pain together was very small, suggesting that 24-h recall ratings are adequately valid indicants of average pain for patients participating in post-surgery clinical pain trials.
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This two-phase study was conducted to identify relevant domains of patient-reported outcomes from the perspective of people who experience chronic pain. In Phase 1, focus groups were conducted to generate a pool of patient outcome-related domains and their components. The results of the focus groups identified 19 aspects of their lives that were significantly impacted by the presence of their symptoms and for which improvements were important criteria they would use in evaluating the effectiveness of any treatment. ⋯ Chronic pain clearly impacts health-related quality of life. The results of the two phases of the study indicate that people with chronic pain consider functioning and well-being as important areas affected by the presence of symptoms and as appropriate targets of treatment. These multiple outcomes should be considered when evaluating the efficacy and effectiveness of chronic pain treatments.
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The aims of this study were to replicate and extend previous observations on the relationship between enmeshment of the self and pain and measures of adjustment [Morley et al., Possible selves in chronic pain: self-pain enmeshment, adjustment and acceptance, Pain 2005;115:84-94], and to test the hypothesis that individual variation in motivational preferences interacts with enmeshment. 82 chronic pain patients completed standardized self-report measures of depression, anxiety, acceptance and the possible selves interview which generated measures of their hoped-for (own and other perspectives) and feared-for selves. They made judgments about the conditionality of each self on the continuing presence of pain as a measure of self-pain enmeshment. A series of hierarchical regression analyses, that adjusted for demographics, pain characteristics and disability, confirmed the relationship between self enmeshment and depression and acceptance. When anxiety was considered, there was no main effect for any of the self aspects but there were specific interactions between the hoped-for (own) and (other) selves and two motivational preferences--autonomy and sociotropy.
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Since neuropathic pain is resistant to conventional analgesics such as opiates and non-steroidal anti-inflammatory drugs, the development of new types of drugs for its treatment has been awaited. Several key molecules associated with nociception have been suggested as potential targets for new analgesics. Glial cell line-derived neurotrophic factor (GDNF) has a variety of functions affecting the survival and development of specified neural cell populations, mediated via transmission of intracellular signals through binding to its high-affinity receptor, GFR*1, and subsequent activation of a tyrosine receptor kinase, RET, neural cell adhesion molecule (NCAM), or other signaling molecules. ⋯ Reduction of NCAM expression by NCAM antisense oligodeoxynucleotide administration to CCI rats abolished the analgesic effect of GDNF without affecting RET signaling activation. An NCAM mimetic peptide, C3d, partially reduced the chronic pain induced by CCI. These findings suggest that NCAM signaling plays a critical role in the analgesic effect of GDNF and that development of new drugs activating GDNF-NCAM signaling may represent a new strategy for the relief of intractable pain.