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Emotional approach coping (EAC) is a potentially adaptive emotion-focused coping style that involves understanding or processing one's emotions and expressing them appropriately. Although EAC has been studied in various populations, little is known about this construct among people with chronic pain, including potential mediators such as negative affect, which might link EAC to pain-related variables, and moderators of these relationships.
Learn More >The aim of this study is to systematically review and critically assess the methodological quality of literature regarding prevalence, characteristics and factors influencing pain, other than phantom limb pain (PLP) in persons with lower limb amputation (LLA). A systematic review was performed (PROSPERO CRD42019138018). Literature was searched using PubMed, EMBASE, PsycINFO, and PEDro. Studies were included if describing pain other than PLP at least three months after amputation. For residual limb pain (RLP) and back pain, a meta-regression was performed. Fifty-one studies were included in which predominantly young males with a unilateral traumatic amputation using a prosthesis were investigated. Pooled prevalence of RLP was 0.51 (95% CI 0.40-0.62) with a positive association with presence of back pain ( = 0.044) in the univariate meta-regression. Pooled prevalence of back pain was 0.55 (95% CI 0.45-0.64), with a positive association of time since amputation ( < 0.001) and co-occurrence of RLP ( = 0.050). Back pain and RLP are common after LLA. The prevalence of back pain was positively associated with the presence of RLP, and vice versa. Future studies should give more attention to other chronic pain types, to persons with a diabetic or vascular cause of amputation, and to pain-related interference.Implications for RehabilitationBoth back pain and residual limb pain occur in more than 50% of persons with lower limb amputation (LLA), and both pain types are positively associated.Clinicians should be aware that chronic pain is common after LLA and can have a significant impact on the functioning of persons with LLA.Future research on this topic should give more attention to other chronic pain types, to persons with a diabetic or vascular cause of amputation, and to pain-related interference.
Learn More >To review the literature on the mechanism of action of onabotulinumtoxinA in chronic migraine.
Learn More >Sensory information is transmitted from peripheral nerves, through the spinal cord, and up to the brain. Sensory information may be modulated by projections from the brain to the spinal cord, but the neural substrates for top-down sensory control are incompletely understood. We identified a novel population of inhibitory neurons in the mouse brainstem, distinguished by their expression of prodynorphin, which we named LJA5. Here, we identify a similar group of pdyn+ neurons in the human brainstem, and we define the efferent and afferent projection patterns of LJA5 neurons in mouse. Using specific genetic tools, we selectively traced the projections of the pdyn-expressing LJA5 neurons through the brain and spinal cord. Terminal fields were densest in the lateral and ventrolateral periaqueductal grey (PAG), lateral parabrachial nucleus (LPB), caudal pressor area, and lamina I of the spinal trigeminal nucleus and all levels of the spinal cord. We then labeled cell types in the PAG, LPB, medulla, and spinal cord to better define the specific targets of LJA5 boutons. LJA5 neurons send the only known inhibitory descending projection specifically to lamina I of the spinal cord, which transmits afferent pain, temperature, and itch information up to the brain. Using retrograde tracing, we found LJA5 neurons receive inputs from sensory and stress areas such as somatosensory/insular cortex, preoptic area, paraventricular nucleus, dorsomedial nucleus and lateral hypothalamus, PAG, and LPB. This pattern of inputs and outputs suggest LJA5 neurons are uniquely positioned to be activated by sensation and stress, and in turn, inhibit pain and itch. This article is protected by copyright. All rights reserved.
Learn More >Female C57BL6 mice exhibit less severe chondropathy compared with male mice. We tests the robustness of this observation and explore underlying mechanisms.
Learn More >Women experience many pain conditions more frequently when compared with men, but the biological mechanisms underlying sex differences in pain remain poorly understood. In particular, little is known about possible sex differences in peripheral nociceptors, the fundamental building blocks of pain transmission. Emerging evidence reveals that prolactin (PRL) signaling at its cognate prolactin receptor (PRLR) in primary afferents promotes nociceptor sensitization and pain in a female-selective fashion. In this review, we summarize recent progress in understanding the female-selective role of PRL/PRLR in nociceptor sensitization and in pathological pain conditions, including postoperative, inflammatory, neuropathic, and migraine pain, as well as opioid-induced hyperalgesia. The clinical implications of the peripheral PRL/PRLR system for the discovery of new therapies for pain control in women are also discussed.
Learn More >Sleep deficiency, psychological distress, daytime dysfunction and abdominal pain are common in adults with irritable bowel syndrome (IBS). Prior research on individuals with chronic pain has identified the indirect effect of sleep on pain through psychological distress or daytime dysfunction; however, it is less clear in IBS. The purpose of this study was to examine potential indirect effects of sleep on abdominal pain symptoms simultaneously through psychological distress and daytime dysfunction in adults with IBS.
Learn More >The roles of serotonin and noradrenaline in the modulation of chronic pruriceptive processing currently remain unclear. To clarify the contribution of serotonin and noradrenaline to chronic itch, the effects of the administration of antidepressants or noradrenaline reuptake inhibitors were evaluated in the present study. A pretreatment with milnacipran, a serotonin and noradrenaline reuptake inhibitor, and mirtazapine, a noradrenergic and specific serotonergic antidepressant, attenuated the induction of spontaneous scratching behavior in mice with chronic itch. The administration of a serotonin reuptake inhibitor, such as fluvoxamine and paroxetine, but not escitalopram, or a noradrenaline reuptake inhibitor, such as atomoxetine and nisoxetine, ameliorated the induction of spontaneous scratching behavior in mice with chronic itch. Furthermore, this attenuation was reversed by the administration of yohimbine, a selective α-adrenoceptor antagonist, or methysergide, a non-selective serotonin receptor antagonist. These results suggest that elevated serotonin and noradrenaline levels are involved in the attenuation of scratching behavior induced by chronic itch, and serotonin receptors and an α-adrenoceptor play a crucial role in chronic pruriceptive processing.
Learn More >Spinal cord stimulation (SCS) is an established treatment of chronic neuropathic pain. Although a temporary SCS screening trial is widely used to determine whether a patient should receive permanent SCS implant, its evidence base is limited. We aimed to establish the clinical utility, diagnostic accuracy, and cost-effectiveness of an SCS screening trial. A multicentre single-blind, parallel two-group randomised controlled superiority trial was undertaken at three centres in United Kingdom. Patients were randomised 1:1 to either SCS screening trial strategy (TG) or no trial screening strategy (NTG). Treatment was open label, but outcome assessors were masked. The primary outcome measure was numerical rating scale (NRS) pain at six-months follow-up. Between June 2017 and September 2018, 105 participants were enrolled and randomised (TG=54, NTG=51). Mean NRS pain decreased from 7.47 at baseline (before SCS implantation) to 4.28 at 6-months in TG and from 7.54 to 4.49 in NTG (mean group difference: 0.2, 95% CI: -1.2 to 0.9, p=0.89). We found no difference between TG and NTG in the proportion of pain responders or other secondary outcomes. SCS screening trial had a sensitivity of 100% (95% CI: 78 to 100) and specificity of 8% (95% CI: 1 to 25). The mean incremental cost-effectiveness ratio of TG versus NTG was £78,895 per additional quality-adjusted life-year (QALY) gained. In conclusion, although the SCS screening trial may have some diagnostic utility, there was no evidence that an SCS screening trial strategy provides superior patient outcomes or is cost-effective compared to a no trial screening approach.
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