Articles: hyperalgesia.
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Randomized Controlled Trial
Independent effects of transcranial direct current stimulation and social influence on pain.
Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulatory technique with the potential to provide pain relief. However, tDCS effects on pain are variable across existing studies, possibly related to differences in stimulation protocols and expectancy effects. We investigated the independent and joint effects of contralateral motor cortex tDCS (anodal vs cathodal) and socially induced expectations (analgesia vs hyperalgesia) about tDCS on thermal pain. ⋯ The observed additive effects provide novel evidence that tDCS and socially induced expectations operate through independent processes. They extend clinical tDCS studies by showing tDCS effects on controlled nociceptive pain independent of expectancy effects. In addition, they show that social suggestions about neurostimulation effects can elicit potent placebo effects.
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Opioids, which are widely used during surgery in perioperative settings, may cause hyperalgesia, especially when the opioid employed is remifentanil. Opioid-induced hyperalgesia may increase the length of a patient's hospital stay and negatively affect enhanced recovery after surgery and the patient's prognosis. Currently, there is no consensus on treatment strategies for remifentanil-induced postoperative hyperalgesia (RIPH). ⋯ Our results demonstrated that the upregulation of LCN2 in the ACC plays a crucial role in the occurrence of RIPH, suggesting that LCN2 potentially be a therapeutic target for alleviating RIPH.
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Randomized Controlled Trial
Attention and Nocebo Hyperalgesia: Testing a Novel Virtual Reality Attention Bias Modification Paradigm.
Nocebo effects in pain (nocebo hyperalgesia) have received significant attention recently, with negative expectancies and anxiety proposed to be explanatory factors. While both expectancy and anxiety can bias attention, attention has been rarely explored as a potential mechanism involved in nocebo hyperalgesia. The present study aimed to explore whether attention bias modification (ABM) using an immersive, ecologically valid VR paradigm successfully induced attention biases (AB) and subsequently influenced nocebo hyperalgesia. ⋯ Unexpected effects of ABM were observed for state anxiety and anticipatory anxiety, whereby training away from pain exacerbated each, which necessitates further exploration. PERSPECTIVE: This article tests the efficacy of a novel attention bias modification paradigm, designed in virtual reality, for inducing pain-related biases, and whether these biases exacerbate or inoculate against nocebo hyperalgesia. While pain-related biases were successfully induced, there was no relationship with the strength of induced nocebo hyperalgesia.
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Quantitative sensory testing (QST) is a set of methods for quantifying somatosensory functioning. Limitations of laboratory-based QST (LQST) include high cost, complexity in training, lack of portability, and time requirements for testing. Translating QST to a home setting could facilitate future research and clinical care. ⋯ The participants rated the HQST protocol as highly acceptable and safe but can be improved in future implementations. Home QST was able to detect hypoesthesia to vibration after lidocaine cream application ( P = 0.024, d = 0.502) and could detect hypoalgesia and hyperalgesia to pressure and heat pain sensitivity tests after application of lidocaine and capsaicin creams, respectively ( P -value range = <0.001-0.036, d -value range = 0.563-0.901). Despite limitations, HQST tool-kits may become a cost-effective, convenient, and scalable approach for improving sensory profiling in clinical care and clinical research.
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Identifying the subset of patients at risk for developing persistent pain after surgery is clinically important as they could benefit from targeted prevention measures. In this prospective study, we investigated if the preoperative assessment of the individual susceptibility to developing experimentally induced secondary hyperalgesia is associated with post-thoracotomy pain at 2 months. ⋯ Our data suggests that preoperatively assessed experimentally induced secondary hyperalgesia displays excellent discriminative power for the presence or absence of cough-evoked pain 2 months after thoracotomy.