European journal of pain : EJP
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Recent research suggests that changes in cortical structures can contribute to the pathophysiology of Complex Regional Pain Syndrome (CRPS). This review provides an overview of studies showing cortical involvement in CRPS, including mislocalizations of tactile stimuli, changes in size and organization of the somatosensory map, changes in motor cortex representation and body perception disturbances. In addition, we review experimental treatment approaches, such as mirror therapy and motor imagery programs, aimed at restoring the integrity of neural processing in the sensory-motor cortex in individuals with CRPS. The intervention effects are promising and can be theoretically motivated on the basis of established principles of neural organization, although important questions concerning the precise neural mechanisms of action remain unanswered.
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The aim was to study the introduction of the new low dose transdermal buprenorphine (LD-TD-BUP) in Norway, particularly with regard to former use and co-medication with other potentially addictive drugs. The nationwide Norwegian Prescription Database contains information on all prescription drugs dispensed to individual non-institutionalised patients, and we may follow all individuals who received LD-TD-BUP (Norspan) after marketing on the Norwegian market on 15/11/05. We studied all prescriptions of opioids and other potentially addictive drugs to patients receiving at least two LD-TD-BUP prescriptions during 2004-2006. ⋯ Of the LD-TD-BUP users who received more than one prescription, 60% co-medicated with at least one other potentially addictive drug, and 24% with at least two. In the multivariate analysis, the variables associated with a higher likelihood of using co-medicated drugs were: previous use of benzodiazepines/carisoprodol relative risk RR=16.7 (95% CI 10.4-26.9), previous use of opioids RR=4.0 (1.9-8.7) and younger age 20-40 years RR=1.9 (1.6-2.3). So far, it is questionable whether the introduction of LD-TD-BUP actually has stabilised opioids consumption or whether it has complicated and increased the consumption of potentially addictive drugs.
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Comparative Study
Stress and thermoregulation: different sympathetic responses and different effects on experimental pain.
Stress and thermoregulation both activate the sympathetic nervous system (SNS) but might differently affect pain. Studies investigating possible interactions in patients are problematic because of the high prevalence of SNS disturbances in patients. We therefore analyzed the influence of these different sympathetic challenges on experimentally-induced pain in healthy subjects. ⋯ The control tasks neither activated the SNS nor altered pain perception. Our results suggest that (1) different patterns of sympathetic activation can be recorded after stress and thermoregulatory challenges and (2) that only stress is able to interfere with sensation of experimental pain. Whether SNS activation is causally responsible for analgesia needs to be further investigated.
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This study investigated attentional biases for linguistic pain-related stimuli in individuals suffering from chronic headaches and healthy controls. Attentional bias was assessed using a visual probe (also reported as dot probe in previous investigations) task which presented pain-related (sensory and affective) and neutral words at two exposure duration conditions, 500 and 1250 ms. ⋯ No significant differences between groups were found in attentional bias scores at the shorter stimulus duration of 500 ms, which instead correlated significantly with trait anxiety. Results are discussed in relation to research into pain-related and anxiety-related biases in initial orienting and maintained attention.