Pain
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Worse executive function (EF) is associated with chronic pain and could mechanistically contribute to pain chronification. It is unclear whether there is overall impairment in EFs or whether there are impairments in specific cognitive domains. Furthermore, the possible genetic risk underlying these associations has not been tested. ⋯ A twin model indicated that pain and Updating-specific variance share genetic risk ( r A = -0.46, P = 0.005) but not environmental risk ( r E = 0.05, P = 0.844). Updating working memory shares a phenotypic and genetic relationship with pain in young adults. Impairments in gating or monitoring pain signals may play a mechanistic role in pain development.
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Pharmacological ablation of rostral ventromedial medulla (RVM) mu opioid receptor-expressing cells before peripheral nerve injury prevents the development of neuropathic pain. However, whether these neurons are required for the expression of established neuropathic pain is not known. Male Oprm1Cre heterozygous (MOR Cre ) or wild-type (MOR WT ) mice received AAV8-hSyn-DIO-hM4D(Gi)-mCherry in the RVM. ⋯ Sustained CNO in drinking water before PSNL prevented expression of chronic pain without affecting acute surgical pain; however, relief of chronic pain required sustained CNO treatment. Thus, in male mice, activity of spinally projecting RVM-MOR cells is required (1) for expression and manifestation of both sensory and affective dimensions of established neuropathic pain and (2) to promote descending facilitation that overcomes apparently intact descending inhibition to maintain chronic pain. Enhanced descending facilitation likely regulates the output signal from the spinal cord to the brain to shape the pain experience and may provide a mechanism for nonopioid management of pain.
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Randomized Controlled Trial
Independent effects of transcranial direct current stimulation and social influence on pain.
Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulatory technique with the potential to provide pain relief. However, tDCS effects on pain are variable across existing studies, possibly related to differences in stimulation protocols and expectancy effects. We investigated the independent and joint effects of contralateral motor cortex tDCS (anodal vs cathodal) and socially induced expectations (analgesia vs hyperalgesia) about tDCS on thermal pain. ⋯ The observed additive effects provide novel evidence that tDCS and socially induced expectations operate through independent processes. They extend clinical tDCS studies by showing tDCS effects on controlled nociceptive pain independent of expectancy effects. In addition, they show that social suggestions about neurostimulation effects can elicit potent placebo effects.
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Adolescent chronic pain may lead to persistent disability and long-term health impairments in adulthood. However, our understanding of which youth are more likely to experience adverse outcomes remains limited. To address this gap, this longitudinal cohort study examined adolescent predictors of various dimensions of young adult health and functioning, including pain, physical health, depression, anxiety, social isolation, and sleep disturbance. ⋯ Moreover, lower sleep quality, greater anxiety symptoms, and worse family functioning predicted worse physical and psychosocial health in adulthood. These findings represent an important first step toward identifying ways to optimize psychological pain interventions. Tailored psychological pain interventions can directly target adolescent vulnerabilities, including mood, sleep, and family risk factors, with the potential to disrupt a lifelong trajectory of pain and suffering.
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Quantitative sensory testing (QST) is a set of methods for quantifying somatosensory functioning. Limitations of laboratory-based QST (LQST) include high cost, complexity in training, lack of portability, and time requirements for testing. Translating QST to a home setting could facilitate future research and clinical care. ⋯ The participants rated the HQST protocol as highly acceptable and safe but can be improved in future implementations. Home QST was able to detect hypoesthesia to vibration after lidocaine cream application ( P = 0.024, d = 0.502) and could detect hypoalgesia and hyperalgesia to pressure and heat pain sensitivity tests after application of lidocaine and capsaicin creams, respectively ( P -value range = <0.001-0.036, d -value range = 0.563-0.901). Despite limitations, HQST tool-kits may become a cost-effective, convenient, and scalable approach for improving sensory profiling in clinical care and clinical research.