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Imaging of the living human brain is a powerful tool to probe the interactions between brain, gut and microbiome in health and in disorders of brain-gut interactions, in particular IBS. While altered signals from the viscera contribute to clinical symptoms, the brain integrates these interoceptive signals with emotional, cognitive and memory related inputs in a non-linear fashion to produce symptoms. Tremendous progress has occurred in the development of new imaging techniques that look at structural, functional and metabolic properties of brain regions and networks. Standardisation in image acquisition and advances in computational approaches has made it possible to study large data sets of imaging studies, identify network properties and integrate them with non-imaging data. These approaches are beginning to generate brain signatures in IBS that share some features with those obtained in other often overlapping chronic pain disorders such as urological pelvic pain syndromes and vulvodynia, suggesting shared mechanisms. Despite this progress, the identification of preclinical vulnerability factors and outcome predictors has been slow. To overcome current obstacles, the creation of consortia and the generation of standardised multisite repositories for brain imaging and metadata from multisite studies are required.
Learn More >As a complex multidimensional construct, fatigue may play an important role in the physical and psychosocial functioning of youth with chronic pain. Based on a model previously tested in adults, the current study similarly utilized Patient-Reported Outcomes Measurement System (PROMIS) to examine how fatigue contributes to functional outcomes for youth with chronic pain. The model tested self-reported ratings of pain intensity, depressive symptoms, and sleep disturbance as predictors of outcomes (mobility, pain-related interference, and school functioning) as mediated by ratings of fatigue.
Learn More >Consultation-based reassurance for patients with low back pain (LBP) in primary care has been shown to be associated with patients' outcomes. Little is known about the role of reassurance in people with LBP consulting with orthopaedic spinal care teams. Reassurance may be important, especially in cases where surgery is not indicated and patients are discharged without treatment.
Learn More >Experimental and clinical studies suggest that the low-affinity N-methyl-d-aspartate (NMDA) receptor open-channel blockers Mg and memantine are effective in reducing trigeminal nociceptive activation. The aim of the present study was to investigate the apparent effectiveness of these channel blockers using a model of trigeminal activation in vivo. Rats were anesthetized before electrically stimulating the dura mater adjacent the middle meningeal artery. Neurons responding to stimulation were recorded extracellularly using electrophysiological methods while l-glutamate or NMDA and Mg , memantine, or sodium controls were applied locally using microiontophoresis. Microiontophoretic application of Mg or memantine into the trigeminocervical complex inhibited mechanically and electrically-stimulated craniovascular afferent, l-glutamate, or NMDA-evoked neuronal activity at the second order trigeminal synapse of craniovascular afferents. By contrast, intravenous administration of MgSO (100 mg/kg) or memantine (10 mg/kg) did not significantly affect electrically-stimulated afferent-evoked activity within the trigeminocervical complex. The Mg and memantine concentrations achieved after systemic administration may not effectively inhibit activation of the trigeminocervical complex, perhaps providing an explanation for the relatively poor efficacy of these NMDA receptor open-channel blockers for headache treatment in clinical studies. Nevertheless, the present results suggest blocking of NMDA-receptor open channels inhibits nociceptive activation of the trigeminocervical complex. Further exploration of such channel blockers as a therapeutic strategy for primary head pain is warranted. This article is protected by copyright. All rights reserved.
Learn More >Nocebo hyperalgesia (i.e., increased pain sensitivity based on expectations) can be induced by conditioning, but is supposed to be mediated by conscious expectation. Although recent evidence points to the feasibility of subliminal conditioning of nocebo hyperalgesia with masked faces, face processing might be a special case and the practical implications of subliminal conditioning remain questionable. This study aimed to implicitly condition nocebo hyperalgesia using supraliminal cues.
Learn More >Temporomandibular joint osteoarthritis (TMJOA) is a prevalent source of temporomandibular joint disorder (TMD). Women are more commonly diagnosed with TMD and are more likely to seek care at tertiary orofacial pain clinics. Limited knowledge regarding mechanisms underlying temporomandibular joint (TMJ) pain impairs development of improved pain management strategies. In a rat model of unilateral TMJOA, monosodium iodoacetate (MIA) produces joint pathology in a concentration-dependent manner. Unilateral MIA produces alterations in meal patterns in males and females without altering overnight time spent eating or weight across 2 weeks. Monosodium iodoacetate (80 mg/mL)-treated males develop ongoing pain within 2 weeks after MIA injection. Females develop ongoing pain at a 5-fold lower MIA concentration (16.6 mg/m). Monosodium iodoacetate (80 mg/mL)-treated males show spread of tactile hypersensitivity across the face during the first week after injection and then to the fore paws and hind paws during the second week after injection, indicating development of central sensitization. At the lower dose, female rats demonstrate a similar spread of tactile hypersensitivity, whereas male rats do not develop ongoing pain or spread of tactile hypersensitivity outside the area of the ipsilateral temporomandibular joint. These observations indicate that females have a higher susceptibility to development of ongoing pain and central sensitization compared with male rats that is not due to differences in MIA-induced joint pathology. This model of TMJOA pain can be used to explore sex differences in pain processes implicated in development of neuropathic pain, ongoing pain, and central sensitization, allowing for development of individualized strategies for prevention and treatment of TMD joint pain.
Learn More >Chronic pain is extremely prevalent in older adults and is associated with significant morbidity, including limited mobility, social isolation, and depressed mood. Pain is defined by a biopsychosocial model highlighting the importance of a multidisciplinary approach to treatment, including multimodal medications, selected interventions, physical therapy and rehabilitation, and psychological treatments. In this narrative review, the authors highlight the use of these approaches in older adults with specific attention paid to considerations unique to aging, including alterations in drug metabolism, avoidance of polypharmacy, and physiologic changes predisposing to painful conditions.
Learn More >To measure and compare the total and normalised tibial nerve movements during forward bending in patients with and without failed back surgery syndrome (FBSS) and persistent leg pain following anatomically successful lumbar decompression surgery and demonstrated no psychological stress. Nerve pathomechanics may contribute to FBSS with persistent leg pain following anatomically successful lumbar decompression surgery.
Learn More >Cluster headache is the most severe primary headache disorder. A genetic basis has long been suggested by family and twin studies; however, little is understood about the genetic variants that contribute to cluster headache susceptibility.
Learn More >The aim of this study was to determine whether post-traumatic stress disorder (PTSD) moderates treatment outcomes in Acceptance and Commitment Therapy for chronic pain.
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