European journal of pain : EJP
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Pain models are commonly used in drug development to demonstrate analgesic activity in healthy subjects and should therefore not cause long-term adverse effects. The ultraviolet B (UVB) model is a model for inflammatory pain in which three times the minimal erythema dose (3MED) is typically applied to induce sensitization. Based on reports of long-lasting postinflammatory hyperpigmentation (PIH) associated with 3MED, it was decided to investigate the prevalence of PIH among subjects who were previously exposed to 3MED at our research centre. In addition, re-evaluation of the UVB inflammation model using a reduced exposure paradigm (2MED) was performed in healthy subjects. ⋯ Postinflammatory hyperpigmentation is an unwanted long-term side effect associated with the UVB inflammation model using the 3× minimal erythema dose (3MED) paradigm. In contrast, using a 2MED paradigm results in hyperalgesia that is stable for 36 hr and has a lower risk of inducing postinflammatory hyperpigmentation.
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Controlled Clinical Trial
Assessing the efficacy of a manual-based intervention for improving the detection of facial pain expression.
This article presents the results of a parallel-group, non-randomized, controlled study that evaluated the feasibility of an online training program for improving observer detection of facial pain expression. ⋯ The index of facial pain expression (IFPE) is an online training program that can improve an observer's ability to reliably detect expressions of clinical pain after as few as 3.5-hr of training.
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Randomized Controlled Trial
The effect of total intravenous anaesthesia with propofol on postoperative pain after third molar surgery: a double blind randomized controlled trial.
Total intravenous anaesthesia (TIVA) with propofol may reduce pain after surgery compared with inhalational anaesthetic techniques. Whether propofol provides analgesic benefit may be influenced by the surgical procedure and anaesthetic/analgesic regime. Third molar surgery is a consistent and fairly standard surgical technique that provides a good model for postoperative pain. We investigated whether propofol TIVA or sevoflurane (SEVO) inhalational anaesthesia would produce better quality pain relief after third molar surgery. ⋯ Choice of general anaesthetic technique can affect postoperative analgesia. The results of this study suggest that propofol TIVA improves postoperative pain and patient satisfaction after third molar surgery compared to inhalational anaesthesia.
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Randomized Controlled Trial
Rewarded placebo analgesia: A new mechanism of placebo effects based on operant conditioning.
Placebo analgesia is explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. We aimed to induce placebo analgesia by operant conditioning. ⋯ According to the current placebo literature, placebo analgesia can be explained by two learning processes: classical conditioning and observational learning. A third learning process, operant conditioning, has not previously been investigated as a mechanism of placebo effects. Our study reveals that patients can learn placebo analgesia as a result of operant conditioning, suggesting that randomized controlled trials could be improved by controlling the reinforcement that might occur spontaneously when patients interact with, for example, medical personnel.
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Randomized Controlled Trial
Eye-movement behaviours when viewing real-world pain-related images.
Pain-related cues are evolutionarily primed to capture attention, although evidence of attentional biases towards pain-related information is mixed in healthy individuals. The present study explores whether healthy individuals show significantly different eye-movement behaviours when viewing real-world pain-related scenes compared to neutral scenes. The effect of manipulating via written information the threat value of the pain-related scenes on eye-movement behaviours was also assessed. ⋯ Healthy individuals show different eye-movement behaviours when viewing pain-related scenes than neutral scenes, supporting evolutionary accounts of pain. Implications for the onset and/or maintenance of chronic pain need to be explored.