Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
Different lipid profiles as constituencies of liquid formula diets do not influence pain perception and the efficacy of opioids in a human model of acute pain and hyperalgesia.
Nutritional support and pain control by medication are often used concomitantly, but interactions are hardly investigated. A randomised, double-blind, cross-over study in ten right-handed volunteers was performed evaluating the influence of cholecystokinin (CCK)-excretion on the perception of pain in a standardised model. CCK-excretion was induced by a liquid formula diet with either long- or medium-chain triglycerides (LCT, MCT). ⋯ In a second series of experiments, alfentanil (4.1+/-0.5 mg) was administered for 90 min using target-controlled infusions and measurements were performed as stated above. Oral administration of LCT as well as MCT may lead to different CCK blood levels, but we found no evidence for CCK-induced effects on pain sensation, touch-evoked allodynia, secondary hyperalgesia or morphine-induced anti-nociception in humans. In our studies, liquid formula diets did not influence acute pain perception or the efficacy of opioids in a human model of pain.
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Comparative Study
Differential effects of expressive anger regulation on chronic pain intensity in CRPS and non-CRPS limb pain patients.
Research has shown that the anger management styles of both anger-in (suppression of anger) and anger-out (direct verbal or physical expression of anger) may be associated with elevated chronic pain intensity. Only the effects of anger-out appear to be mediated by increased physiological stress responsiveness. Given the catecholamine-sensitive nature of pain mechanisms in complex regional pain syndrome (CRPS), it was hypothesized that anger-out, but not anger-in, would demonstrate a stronger relationship with chronic pain intensity in CRPS patients than in non-CRPS chronic pain patients. ⋯ The AIS main effect on MPQ-A ratings was accounted for entirely by overlap with negative affect. Results are consistent with a greater negative impact of anger-out on chronic pain intensity in conditions reflecting catecholamine-sensitive pain mechanisms, presumably due to the association between anger-out and elevated physiological stress responsiveness. These results further support previous suggestions that anger-in and anger-out may affect pain through different mechanisms.
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Hypersensitivity to a variety of sensory stimuli is a feature of persistent whiplash associated disorders (WAD). However, little is known about sensory disturbances from the time of injury until transition to either recovery or symptom persistence. Quantitative sensory testing (pressure and thermal pain thresholds, the brachial plexus provocation test), the sympathetic vasoconstrictor reflex and psychological distress (GHQ-28) were prospectively measured in 76 whiplash subjects within 1 month of injury and then 2, 3 and 6 months post-injury. ⋯ The differences in GHQ-28 did not impact on any of the sensory measures. These findings suggest that those with persistent moderate/severe symptoms at 6 months display, soon after injury, generalised hypersensitivity suggestive of changes in central pain processing mechanisms. This phenomenon did not occur in those who recover or those with persistent mild symptoms.
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We set out to determine whether observing one's mother's reaction during a cold pressor test changes ratings of pain threshold, pain intensity, and observed pain-related facial behavior during a cold pressor test, using a Repeated Measures Mixed Factorial design in the setting of the Psychology Department, Dalhousie University, Halifax, Canada. The participants were: 96 mothers (mean age 41 years,) and 96 children (48 males, mean age 12.6 years), all in good general health. Pain intensity was measured using a 0-10 rating scale. ⋯ No differences were observed in the self-report pain ratings of children between groups (F<1). CFCS Scores were significantly lower in the Minimize group compared to the Control group (95% CI 4.98-20.19, P=0.001), but no difference was noted between the Exaggerate and Control groups (95% CI -8.03-6.93, P=0.884). Children's pain threshold and their facial behavior are altered by exposure to mother's behavior during a cold pressor task suggesting that modeling has an impact on a child's pain behavior.
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Comparative Study
Contributing factors to chronic myofascial pain: a case-control study.
This case-control study was designed to investigate the contributing factors for chronic masticatory myofascial pain (MFP). Eighty-three patients with MFP, selected from the dental clinics of the Jewish General and Montreal General Hospitals, Montreal, Canada, and 100 concurrent controls selected only at the first clinic, participated in this study. The association with MFP was evaluated for bruxism, head-neck trauma, psychological factors (symptom check list 90 revised questionnaire, SCL-90R) and sociodemographic characteristics by using unconditional logistic regression. ⋯ In addition, female gender had almost three times the risk of chronic MFP than males when the model was also adjusted for psychological symptoms. Grinding-only, age, household income and education were not related with chronic MFP. Tooth clenching, trauma and female gender may contribute to MFP even when other psychological symptoms are similar between subjects.