Pain
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Disrupted sleep has long been associated with physical functioning and disability in chronic pain populations and recent research shows that patterns of sleep and rest can predict physical disability, independent of depression and pain levels in this group. However, it is unknown whether sleep quality may independently predict disability in this way. The aim of the present study was to examine the self-reported relationship between sleep and disability in 155 chronic pain patients attending a pain management service. ⋯ These findings highlight the important role of sleep in chronic pain suffering. However, due to the cross sectional nature of this study, the mediation pathways proposed require testing by further research adopting a prospective design. Ideally, future research should evaluate whether targeted interventions to improve sleep can reduce pain severity, depression and ultimately, pain-related disability.
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Multicenter Study
Pain-related catastrophizing and perceived social responses: Inter-relationships in the context of chronic pain.
Pain-related coping, particularly catastrophizing, plays a significant role in shaping pain responses. One way catastrophizing is hypothesized to amplify pain and disability is via its effect on patients' social environments (e.g., communal coping model), though empirical support is limited. The present study tested whether the association between catastrophizing and deleterious pain-related outcomes was mediated by patients' perceptions of significant others' responses to their pain in a sample of 1356 pain patients. ⋯ In sum, perceived social responses were found to play a small role in mediating the relationship between catastrophizing and pain-related outcomes, and these mediational effects may be strongest in particular patient subgroups. The present data suggest that interpersonal mechanisms may not constitute a primary route by which catastrophizing exerts its maladaptive effects on pain responses. The study and further understanding of what principal factors mediate catastrophizing's deleterious effects on pain will be important in illuminating the biopsychosocial model of pain.
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There is evidence that patients with Complex Regional Pain Syndrome (CRPS) have altered central sensorimotor processing. Sensory input can influence motor output either through indirect pathways or through direct connections from the sensory to motor cortex. The purpose of this study was to investigate sensorimotor interaction via direct connections in patients with CRPS and to compare the results with normal subjects'. ⋯ In seven of the eight CRPS patients EMG responses to TMS were suppressed when paired with median nerve stimulation. Only one CRPS patient's results showed no suppression of EMG responses. These results suggest that the disease mechanisms of CRPS1 do not typically affect the direct neural circuit between sensory and motor cortex and that normal sensorimotor interaction is occurring via this route.
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Randomized Controlled Trial
Pain relief by applying transcutaneous electrical nerve stimulation (TENS) on acupuncture points during the first stage of labor: a randomized double-blind placebo-controlled trial.
Transcutaneous electrical nerve stimulation (TENS) is one of the non-pharmacological means of pain relief for labor and delivery. We aimed to investigate the efficacy and safety of TENS on specific acupuncture points for reducing pain in the first stage of labor. In this double-blind, placebo-controlled trial, we randomly assigned healthy full-term parturients in active phase of first-stage labor to either TENS on four acupuncture points (Hegu [Li 4] and Sanyinjiao [Sp 6]) (n=52) or the TENS placebo (n=53). ⋯ Willingness of using the same analgesic method for a future childbirth was also significantly different (TENS: 48/50 [96%] vs TENS placebo: 33/50 [66%], P<0.001). Operative delivery was increased in the TENS group (12/50 [24%] vs 4/50 [8%], P=0.05), but the neonatal outcomes were not different. The application of TENS on specific acupuncture points could be a non-invasive adjunct for pain relief in the first stage of labor.