European journal of pain : EJP
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Following amputation, nearly all amputees report nonpainful phantom phenomena and many of them suffer from chronic phantom limb pain (PLP) and residual limb pain (RLP). The aetiology of PLP remains elusive and there is an ongoing debate on the role of peripheral and central mechanisms. Few studies have examined the entire somatosensory pathway from the truncated nerves to the cortex in amputees with PLP compared to those without PLP. The relationship among afferent input, somatosensory responses and the change in PLP remains unclear. ⋯ Peripheral afferent input plays a role in PLP and has been assumed to be sufficient to generate PLP. In this study we found no significant differences in the electrical potentials generated by peripheral stimulation from the truncated nerve and the skin of the residual limb in amputees with and without PLP. Peripheral input could enhance existing PLP but could not cause it. These findings indicate the multifactorial complexity of PLP and an important role of central processes in PLP.
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Stress-related dissociation has been shown to negatively co-vary with pain perception in current borderline personality disorder (cBPD). While remission of the disorder (rBPD) is associated with normalized pain perception, it remains unclear whether dissociation proneness is still enhanced in this group and how this feature interacts with pain sensitivity. ⋯ Both current (cBPD) and remitted borderline personality disorder (rBPD) patients show enhanced proneness to dissociation. This feature is significantly linked with pain hyposensitivity in cBPD in a paradigm that induces stress using a script-driven imagery approach, whereas this connection cannot be observed in rBPD. However, in the stress compared to the neutral condition, rBPD participants also show pain hyposensitivity compared to healthy controls. This study provides new insights into the pain processing mechanisms of BPD and its remission.
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As the development of neuropathic symptoms contributes to pain severity and chronification after surgery, their early prediction is important to allow targeted treatment. ⋯ Development of neuropathies contributes to pain severity and pain chronification after surgery. Here we demonstrate trajectories of quantitative sensory tests (assessed at monthly intervals for 6 months after surgery) that reveal accurate time courses of gain/loss of nerve function following thoracotomy. Independent of the degree of neuropathic signs after surgery, the main predictors for post-surgical neuropathic pain are self-reported neuropathic pain before surgery and sleep quality shortly after surgery.
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Recent evidence suggests that insomnia negatively influences the occurrence of generalized pain. This study examined whether insomnia is a risk factor for the transition from local pain (LP) to generalized pain (i.e. spreading of pain). ⋯ This study shows that people with LP conditions are at much higher risk of developing WSP if they also have significant insomnia symptoms. The elevated risk is evident after 24 months and increases in a dose-dependent manner regarding the degree of exposure to insomnia symptoms. Local pain conditions are quite common in primary care, and an evaluation of the insomnia symptoms is highly recommended since the most common sleep problems can be treated effectively if detected.
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Theories propose that interpretation biases and attentional biases might account for the maintenance of chronic pain symptoms, but the interactions between these two forms of biases in the context of chronic pain are understudied. ⋯ In summary, the present study provided evidence for the interplay between multiple forms of cognitive biases. Future studies should investigate whether this interaction might influence subsequent functioning in people with chronic pain.