Pain
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In a longitudinal observational study of 94 patients (39 M:55 F, mean age 69) at elevated risk for developing post herpetic neuralgia (PHN), the natural history of pain during the first 6 months after herpes zoster (HZ) rash onset was determined. Pain severity and impact were rated using pain-VAS, SF-MPQ, and MPI. Applying a definition of PHN of average daily pain >0/100 on the pain VAS during the last 48 h, 30 subjects had PHN at 6 months. ⋯ At study inclusion, the SF-MPQ and MPI scores in our PHN group were similar to historical controls with chronic severe PHN enrolled in clinical trials, but by 6 months the scores in our PHN subjects were significantly lower than historic controls. Only two subjects met the more stringent criteria for 'clinically meaningful' PHN at 6 months (> or = 30/100 on the pain VAS). Defining PHN as average daily pain >0/100 at 6 months after rash onset appears to substantially overestimate the number of HZ patients negatively impacted by ongoing pain and disability.
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Clinical Trial
Brain activity for spontaneous pain of postherpetic neuralgia and its modulation by lidocaine patch therapy.
Postherpetic neuralgia (PHN) is a debilitating chronic pain condition, yet there is a lack of knowledge regarding underlying brain activity. Here we identify brain regions involved in spontaneous pain of PHN (n=11) and determine its modulation with Lidoderm therapy (patches of 5% lidocaine applied to the PHN affected body part). Continuous ratings of fluctuations of spontaneous pain during fMRI were contrasted to ratings of fluctuations of a bar observed during scanning, at three sessions: (1) pre-treatment baseline, (2) after 6h of Lidoderm treatment, and (3) after 2 weeks of Lidoderm use. ⋯ Pain properties: average magnitude of spontaneous pain, and responses on Neuropathic Pain Scale (NPS), decreased with treatment. The ventral striatal and amygdala activity best reflected changes in NPS, which was modulated only with longer-term treatment. The results show a specific brain activity pattern for PHN spontaneous pain, and implicate areas involved in emotions and reward as best reflecting changes in pain with treatment.
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Randomized Controlled Trial
Classical conditioning and expectancy in placebo hypoalgesia: a randomized controlled study in patients with atopic dermatitis and persons with healthy skin.
The effectiveness of placebos is unchallenged. However, it is still not clear on which mechanisms the placebo effect is based. Besides expectancy theories, classical conditioning is discussed as a major explanatory model. ⋯ However, conditioning processes seem to be necessary for a longer lasting effect. The extent of this effect seemed to be greater in atopics than in healthy controls. Expectancy, achieved through verbal instruction, might also be seen as a conditioned stimulus that reactivates earlier stimulus associations.
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We examined between and within-person variability, affective correlates, and diagnostic differences in daily fatigue in women with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia syndrome (FMS). Two hundred and fifty-five female patients recruited from the community served as participants for this project. The patients had a physician-confirmed diagnosis of RA (n=89), OA (n=76), or FMS (n=90). ⋯ Daily pain was associated with increased fatigue in all groups, although OA patients showed less pain reactivity than either FMS or RA patients. These findings indicate that fatigue is a common feature of rheumatologic conditions. Nonetheless, there are important differences between RA, OA, and FM patients in both the everyday manifestations and the biopsychosocial correlates of fatigue.
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Little is known about the pathway from musculoskeletal pain to mobility difficulty among older persons. We examined potential physical and psychological mediators of the pain-disability relationship in the Women's Health and Aging Study (WHAS), a cohort of women aged 65 who had at least mild disability at baseline. Pain was classified according to location and severity (widespread pain; lower extremity pain; other pain; none or mild pain in only one site). ⋯ Pain was not associated with increased risk for becoming unable to walk or climb stairs. The findings suggest that pain is a unique domain as a cause of disablement, independent of the usual pathway to disability via physical impairments. Research is needed to better understand the development of pain-related disability in order to determine optimum approaches to prevent and treat mobility disability in older persons with persistent pain.