Pain
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Chronic pain remains a significant problem due to its prevalence, impact, and limited therapeutic options. Progress in addressing chronic pain is dependent on a better understanding of underlying mechanisms. Although the available evidence suggests that changes within the central nervous system contribute to the initiation and maintenance of chronic pain, it also suggests that the primary afferent plays a critical role in all phases of the manifestation of chronic pain in most of those who suffer. ⋯ A mechanism of sensitization that has received far less attention, however, is the local or axonal translation of these signaling molecules. A growing body of evidence indicates that this process not only is dynamically regulated but also contributes to the initiation and maintenance of chronic pain. Here, we review the biology of local translation in primary afferents and its relevance to pain pathobiology.
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Placebos and their beneficial clinical and psychological effects are well-researched, but nocebo effects receive far less attention, despite being highly undesirable. The aim of this restricted scoping review was to examine how nocebo effects are represented in the biomedical literature and to identify the trends and gaps in existing knowledge. After searching 5 biomedical databases and 2 clinical trials registries (from their inception to December 23, 2020) for articles on nocebo effects or negative placebo effects, 1161 eligible publications were identified. ⋯ The nocebo effect was most frequently investigated in the context of pain. Studies were almost exclusively in adults and more often in healthy participants than in patients. In conclusion, in the biomedical literature, there is an overabundance of nonsystematic reviews and expert opinions and a lack of primary research and high-quality systematic reviews and meta-analyses specifically dealing with nocebo effects.
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Burrowing behaviour is used to assess pain-associated behaviour in laboratory rodents. To gain insight into how models of disease-associated persistent pain and analgesics affect burrowing behaviour, we performed a systematic review and meta-analysis of studies that assessed burrowing behaviour. A systematic search in March 2020 and update in September 2020 was conducted in 4 databases. ⋯ The findings indicate that burrowing could be used to assess pain-associated behaviour. We support the use of a portfolio of composite measures including spontaneous and stimulus-evoked tests. The information collected here could help in designing experiments involving burrowing assessment in models of disease-associated pain.
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This study examined the efficacy of internet-delivered cognitive and behavioural interventions for adults with chronic pain AND explored the role of clinical and study characteristics as moderators of treatment effects. PubMed, Embase, PsycINFO, CENTRAL and CINAHL were searched to identify randomized controlled trials published up to October 2021. A meta-analysis of 36 studies (5778 participants) was conducted, which found small effect sizes for interference/disability (Hedges' g = 0.28; 95% confidence interval [CI] 0.21-0.35), depression ( g = 0.43; 95% CI 0.33-0.54), anxiety ( g = 0.32; 95% CI 0.24-0.40), pain intensity ( g = 0.27; 95% CI 0.21-0.33), self-efficacy ( g = 0.39; 95% CI 0.27-0.52) and pain catastrophizing ( g = 0.31; 95% CI 0.22-0.39). ⋯ No differences were found between treatments based on traditional cognitive behaviour therapy vs acceptance and commitment therapy. Sample size, study year, and overall risk of bias (Cochrane rating) did not consistently moderate treatment effects. Overall, the results support the use of internet-delivered cognitive and behavioural interventions as efficacious and suggest guided interventions are associated with greater clinical gains for several key pain management outcomes.
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Meta Analysis
Pain mechanisms in carpal tunnel syndrome: a systematic review and meta-analysis of quantitative sensory testing outcomes.
Carpal tunnel syndrome (CTS) is the most common nerve compression in the arm. A mix of peripheral and central contributions on quantitative sensory testing (QST) has been reported in the literature. Thus, this systematic review or meta-analysis aimed to identify the dominant sensory phenotype and draw conclusive evidence about the presence of central sensitization (CS) in CTS. ⋯ Furthermore, there was a significant increase in mechanical pain sensitivity in median nerve territories and remotely in the forearm ( P < 0.05) and a significant gain in pressure and heat pain thresholds in the carpal area ( P < 0.05). Conditioned pain modulation was impaired in CTS. Hypoesthesia and increased thermal and mechanical pain ratings are the dominant sensory phenotype with inconclusive evidence about CS in CTS due to the heterogenous results of thermal and mechanical pain thresholds.