The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Reduction of bodily pain in response to an online positive activities intervention.
Inducing temporary positive states reduces pain and increases pain tolerance in laboratory studies. We tested whether completing positive activities in one's daily life produces long-term reductions in self-reported bodily pain in a randomized controlled trial of an online positive activities intervention. Participants recruited via the Web were randomly assigned to complete 0, 2, 4, or 6 positive activities administered online over a 6-week period. Follow-up assessments were collected at the end of 6 weeks and at 1, 3, and 6 months postintervention. We used linear mixed effects models to examine whether the intervention reduced pain over time among those who had a score <67 on the bodily pain subscale of the Short Form-36 at baseline (N = 417; pain scores range from 0 to 100; higher scores indicate less pain). Mean pain scores improved from baseline to 6 months in the 2-activity (55.7 to 67.4), 4-activity (54.2 to 71.0), and 6-activity (50.9 to 67.9) groups. Improvements were significantly greater (P < .05) in the 4-activity and 6-activity groups than in the 0-activity control group (54.1 to 62.2) in unadjusted and adjusted models. This study suggests that positive activities administered online can reduce bodily pain in adults with at least mild to moderate baseline pain. ⋯ This study demonstrates that teaching people simple positive activities can decrease reported levels of bodily pain; moreover, these activities can be administered over the internet, a potential avenue for broadly disseminating health interventions at relatively low costs and with high sustainability.
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Randomized Controlled Trial
Dexketoprofen trometamol in the acute treatment of migraine attack: a phase II, randomized, double-blind, crossover, placebo-controlled, dose optimization study.
Migraine is a disabling disease that can significantly affect a person's quality of life. This study assessed the efficacy and tolerability of the 2 doses of dexketoprofen trometamol (DKP) compared to placebo for migraine treatment. Ninety-three patients with at least 1 migraine attack per month in the preceding 6 months were enrolled and randomized to 25 mg DKP, 50 mg DKP, and placebo in a randomized, double-blind, single-center, crossover, placebo-controlled study. Primary endpoint was pain-free episodes 2 hours after drug intake. The presence of accompanying symptoms and adverse effects was also recorded. Seventy-six patients (mean age 40.5 ± 10.9 and 61% female) completed the study. At baseline, mean number of attacks/month was 3.7 ± 1.3, with a mean duration of 15.4 ± 13.5 hours. Prevalence of pain-free episodes after drug intake was significantly reduced by 50 mg DKP vs placebo (33.8 vs 14.7%, P = .0065) whereas the dose of DKP 25 mg was better than placebo but did not reach statistical significance (23 vs 14.7%, P = .1182). Both 25 mg DKP (56.8 vs 25.3%, P = .0002) and 50 mg DKP improved headache relief compared to placebo. Furthermore, both doses of DKP increased the absence of functional disability (25 mg DKP, 39.7 vs 24%, P = .045; and 50 mg DKP, 45.9 vs 24%, P < .0004). Both doses of DKP were effective and well tolerated for acute migraine treatment. ⋯ This article demonstrates the efficacy and tolerability of DKP in the treatment of migraine without and with aura attacks. Its rapid absorption rate with higher maximum plasma concentrations and shorter time to maximum values suggest that this drug is a good option for acute migraine treatment.
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Randomized Controlled Trial
Latent myofascial trigger points are associated with an increased intramuscular electromyographic activity during synergistic muscle activation.
The aim of this study was to evaluate intramuscular muscle activity from a latent myofascial trigger point (MTP) in a synergistic muscle during isometric muscle contraction. Intramuscular activity was recorded with an intramuscular electromyographic (EMG) needle inserted into a latent MTP or a non-MTP in the upper trapezius at rest and during isometric shoulder abduction at 90° performed at 25% of maximum voluntary contraction in 15 healthy subjects. Surface EMG activities were recorded from the middle deltoid muscle and the upper, middle, and lower parts of the trapezius muscle. Maximal pain intensity and referred pain induced by EMG needle insertion and maximal pain intensity during contraction were recorded on a visual analog scale. The results showed that higher visual analog scale scores were observed following needle insertion and during muscle contraction for latent MTPs than non-MTPs (P < .01). The intramuscular EMG activity in the upper trapezius muscle was significantly higher at rest and during shoulder abduction at latent MTPs compared with non-MTPs (P < .001). This study provides evidence that latent MTPs are associated with increased intramuscular, but not surface, EMG amplitude of synergist activation. The increased amplitude of synergistic muscle activation may result in incoherent muscle activation pattern of synergists inducing spatial development of new MTPs and the progress to active MTPs. ⋯ This article presents evidence of increased intramuscular, but not surface, muscle activity of latent MTPs during synergistic muscle activation. This incoherent muscle activation pattern may overload muscle fibers in synergists during muscle contraction and may contribute to spatial pain propagation.
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Randomized Controlled Trial
Spinal manipulative therapy-specific changes in pain sensitivity in individuals with low back pain (NCT01168999).
Spinal manipulative therapy (SMT) is effective for some individuals experiencing low back pain; however, the mechanisms are not established regarding the role of placebo. SMT is associated with changes in pain sensitivity, suggesting related altered central nervous system response or processing of afferent nociceptive input. Placebo is also associated with changes in pain sensitivity, and the efficacy of SMT for changes in pain sensitivity beyond placebo has not been adequately considered. We randomly assigned 110 participants with low back pain to receive SMT, placebo SMT, placebo SMT with the instructional set "The manual therapy technique you will receive has been shown to significantly reduce low back pain in some people," or no intervention. Participants receiving the SMT and placebo SMT received their assigned intervention 6 times over 2 weeks. Pain sensitivity was assessed prior to and immediately following the assigned intervention during the first session. Clinical outcomes were assessed at baseline and following 2 weeks of participation in the study. Immediate attenuation of suprathreshold heat response was greatest following SMT (P = .05, partial η(2) = .07). Group-dependent differences were not observed for changes in pain intensity and disability at 2 weeks. Participant satisfaction was greatest following the enhanced placebo SMT. This study was registered at www.clinicaltrials.gov under the identifier NCT01168999. ⋯ The results of this study indicate attenuation of pain sensitivity is greater in response to SMT than the expectation of receiving an SMT. These findings suggest a potential mechanism of SMT related to lessening of central sensitization and may indicate a preclinical effect beyond the expectations of receiving SMT.
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Randomized Controlled Trial Multicenter Study
Determination of the effective dose of pregabalin on human experimental pain using the sequential up-down method.
The intradermal capsaicin pain model has been used to evaluate analgesic effects of a variety of drugs. Using the sequential up-down method, we examined the analgesic effects of pregabalin on intradermal capsaicin pain. Using a double-blind, placebo-controlled, crossover study, healthy adult men were randomized to oral pregabalin or placebo on the first visit and returned for the opposite treatment after a washout period. Dosing was set by the Dixon sequential up-down method; that is, a greater or less than 30% reduction in capsaicin pain decreased or increased the dose, respectively, by a fixed interval for the next subject. The median effective dose (ED50) was derived once 7 changes in dose direction occurred. Secondary outcome measures included secondary hyperalgesia and tactile and thermal allodynia, and their respective areas (cm(2)). Thirteen subjects were required to derive the pregabalin ED50: 252 mg (95% confidence interval 194, 310 mg). Most common side effects were drowsiness (46%), euphoria (31%), and dizziness (7%). Those with ≥30% pain reduction as compared to placebo also had similar reductions in secondary outcome measures. The intradermal capsaicin pain model can be used to efficiently derive the pregabalin ED50, but well-powered dose-response curve studies are needed for comparison and validation. ⋯ Using the Dixon sequential up-down method, the ED50 of pregabalin on intradermal capsaicin induced pain was successfully calculated (252 mg) using only 13 subjects.