Pain
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Randomized Controlled Trial
A deeper look at pain variability and its relationship with the placebo response: results from a randomized, double-blind, placebo-controlled clinical trial of naproxen in osteoarthritis of the knee.
Previous studies have shown a robust correlation between variability of clinical pain scores and responsiveness to placebo (but not active drug) in pain studies, but explanations for these relationships are lacking. We investigated this further by assessing relationship between the Focused Analgesia Selection Test (FAST), a psychophysical method that quantifies pain reporting variability in response to experimental stimuli, variability of daily clinical pain scores as captured using diary, and response to treatment in the context of a randomized controlled crossover trial of naproxen vs placebo in knee osteoarthritis. Evoked pain using the Staircase-Evoked Pain Procedure served as the primary efficacy endpoint. ⋯ Both correlated with the placebo response (r = 0.393, P = 0.004; r =-0.371, P = 0.009; respectively), but only the FAST predicted the treatment difference between naproxen and placebo, as demonstrated both in a regression model (P = 0.002, Beta = 0.456, t = 3.342) and in a receiver operating characteristic curve (0.721) analysis. Our results extend previous findings to include a correlation between experimental pain variability and the placebo response and suggest that experimental pain variability is a better predictor of patients who respond preferentially to drug over placebo. A theoretical model unifying these observations is proposed, and practical implications are discussed.
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Multimodal neuroimaging studies provide support for a role of alterations in sensory processing circuits and endogenous pain modulatory systems in provoked vestibulodynia (PVD). In this study, we tested the hypotheses that PVD compared with healthy controls (HCs) would demonstrate gray matter volume (GMV) alterations in regions associated with sensorimotor, corticothalamic, and basal ganglia circuits. We also tested the replicability of previously reported gray matter increases in basal ganglia and hippocampal volumes in PVD vs HCs. ⋯ Regional GMV alterations were associated with patient reports of pain during intercourse and muscle tenderness. The current findings provide further evidence that GMV is increased in PVD compared with HCs in several regions of the sensorimotor network and the hippocampus in patients with PVD. In addition, GMV distinct alterations in the sensorimotor network were identified between 2 pelvic pain disorders, PVD compared with IBS.
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Chemotherapy-induced peripheral neuropathy (CIPN) is a severe adverse effect that occurs secondary to anticancer treatments and has no known preventive or therapeutic strategy. Therapeutic hypothermia has been shown to be effective in protecting against central and peripheral nervous system injuries. However, the effects of therapeutic hypothermia on CIPN have rarely been explored. ⋯ Finally, in NOD/SCID mice inoculated with cancer cells, the antiproliferative effect of paclitaxel was not affected by the distal application of LBH. In conclusion, our findings indicate that early exposure to regional hypothermia alleviates paclitaxel-induced peripheral neuropathy. Therapeutic hypothermia may therefore represent an economical and nonpharmaceutical preventive strategy for CIPN in patients with localized solid tumors.