Pain
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Electrical high-frequency stimulation (HFS) of skin afferents elicits long-term potentiation (LTP)-like hyperalgesia in humans. Time courses were evaluated in the facilitating (homotopic) or facilitated (heterotopic) pathways to delineate the relative contributions of early or late LTP-like pain plasticity. HFS in healthy subjects (n=55) elicited highly significant pain increases to electrical stimuli via the conditioning electrode (to 145% of control, homotopic pain LTP) and to pinprick stimuli in adjacent skin (to 190% of control, secondary hyperalgesia). ⋯ Dynamic mechanical allodynia (only present in 16 of 55 subjects) lasted for a shorter time than secondary hyperalgesia. Three different readouts of nociceptive central sensitization suggest that brief intense nociceptive input elicits early LTP1 of pain sensation (based on posttranslational modifications), but susceptible subjects may already develop longer-lasting late LTP2 (based on transcriptional modifications). These findings support the hypothesis that LTP may contribute to the development of persistent pain disorders.
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Multicenter Study
Clinical utility and validity of the Functional Disability Inventory among a multicenter sample of youth with chronic pain.
The Functional Disability Inventory (FDI) is a well-established and commonly used measure of physical functioning and disability in youth with chronic pain. Further validation of the measure has been called for, in particular, examination of the clinical utility and factor structure of the measure. To address this need, we utilized a large multicenter dataset of pediatric patients with chronic pain who had completed the FDI and other measures assessing pain and emotional functioning. ⋯ Our findings provide important new information regarding the clinical utility and validity of the FDI. This will greatly enhance the interpretability of scores for research and clinical use in a wide range of pediatric pain conditions. In particular, these findings will facilitate use of the FDI as an outcome measure in future clinical trials.
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Multicenter Study
Elevated levels of gonadotrophins but not sex steroids are associated with musculoskeletal pain in middle-aged and older European men.
The aim of this study was to determine the association of hormone levels with the occurrence of musculoskeletal pain. Men ages 40 to 79 years were recruited from population registers in 8 European centres. Subjects were asked to complete a postal questionnaire, which enquired about lifestyle and the occurrence of musculoskeletal pain over the past month. ⋯ Compared with those in the lowest tertile of LH, those in the highest tertile were more likely to report some pain (vs no pain, RRR=1.28; 95% CI 1.09 to 1.50) and also CWP (vs no pain, RRR=1.51; 95% CI 1.10 to 2.07). Similar results were found for FSH. Gonadotrophins, but not sex steroid hormone levels, are associated with musculoskeletal pain in men.