Pain
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The aim of the current study was to determine the course of back pain in older patients and identify prognostic factors for non-recovery at 3 months' follow-up. We conducted a prospective cohort study (the BACE study) of patients aged >55 years visiting a general practitioner (GP) with a new episode of back pain in the Netherlands. The course of back pain was described in terms of self-perceived recovery, pain severity, disability, pain medication, and GP visits at 6 weeks' and 3 months' follow-up. ⋯ At 3 months' follow-up 61% still reported non-recovery, but only 26% of these patients had revisited the GP. Longer duration of the back pain, severity of back pain, history of back pain, absence of radiating pain in the leg below the knee, number of comorbidities, patients' expectation of non-recovery, and a longer duration of the timed 'Up and Go' test were significantly associated with non-recovery in a multiple regression model (AUC 0.79). This information can help GPs identify older back pain patients at risk for non-recovery.
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When a newly developed experimental method to vibrate vellus hairs on human skin was applied to the face and arm in healthy subjects, intense itch was reproducibly induced on the face, but not on the arm, without any flare reactions. In contrast to histamine-induced itch, mechanically evoked itch was not characterized as burning or stinging by any subjects, and was resistant to histamine H1-receptor antagonists. When the stimulation was continued for 10 min, mechanically evoked itch reached the maximum intensity within 10 s, but gradually attenuated after 60 to 90 s and was rarely perceivable at the end of stimulation. ⋯ Touch-alloknesis was present in the adjacent skin area until mechanically evoked itch completely diminished, supporting the hypothesis that itch sensitization can be caused by a continuous activation of peripheral itch neurons whether or not they are histamine-sensitive C nerves. In conclusion, this study provides direct evidence of mechanosensitive nerves involved in itch in human skin. The purity of mechanically evoked itch without any pain-related sensory components is a major advantage for investigating the differentiation of itch from pain.
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Randomized Controlled Trial
Self-management intervention for chronic pain in older adults: a randomised controlled trial.
This study compared an outpatient pain self-management (PSM) program, using cognitive-behavioural therapy and exercises, with 2 control conditions in 141 chronic pain patients aged > 65 years. Results immediately posttreatment indicated that relative to the Exercise-Attention Control (EAC) group, the PSM group was significantly improved on measures of pain distress, disability, mood, unhelpful pain beliefs, and functional reach. The mean effect size for these gains was 0.52 (range: 0.44-0.68). ⋯ At 1-month follow-up, the mean proportion of reliably improved cases (across outcome variables) was 41% (range: 16-60%) for the PSM group, twice that of those who met this criterion in the 2 control conditions (and this difference was statistically significant). Similarly, significantly more (44%) of the PSM group (vs 22% and 20% for the control groups) achieved a clinically significant improvement on pain disability. In the short term at least, cognitive-behavioural therapy-based PSM was more effective than exercises and usual care.
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Despite similar behavioral hypersensitivity, acute and chronic pain have distinct neural bases. We used intraplantar injection of complete Freund's adjuvant to directly compare activity of pain-modulating neurons in the rostral ventromedial medulla (RVM) in acute vs chronic inflammation. Heat-evoked and von Frey-evoked withdrawal reflexes and corresponding RVM neuronal activity were recorded in lightly anesthetized animals either during the first hour after complete Freund's adjuvant injection (acute) or 3 to 10 days later (chronic). ⋯ During early immune-mediated inflammation, ON-cell spontaneous activity promotes hyperalgesia. After inflammation is established, the antinociceptive influence of OFF-cells is dominant, yet the lowered threshold for the OFF-cell pause allows behavioral responses to stimuli that would normally be considered innocuous. The efficacy of OFF-cells in counteracting sensitization of ascending transmission pathways could therefore be an important determining factor in development of chronic inflammatory pain.