The journal of pain : official journal of the American Pain Society
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Cognitive biases that emphasize bodily harm, injury, and illness could play a role in the maintenance of chronic pain by facilitating fear and avoidance. Whereas extensive research has established attention, interpretation, and memory biases in adults with chronic pain, far less is known about these same biases in children and adolescents with pain. Studying cognitive biases in attention, interpretation, and memory in relation to pain occurring in youth is important because youth is a time when pain can first become chronic, and when relationships between cognitive biases and pain outcomes emerge and stabilize. ⋯ In this article, we summarize the growing corpus of data that have measured cognitive biases in relation to pediatric pain. We conclude that although biases in attention, interpretation, and memory characterize children and adolescents with varying pain experiences, questions regarding the direction, magnitude, nature, and role of these biases remain. We call for independent extension of cognitive bias research in children and adolescents, using well powered longitudinal studies with wide age ranges and psychometrically sound experimental measures to clarify these findings and any developmental trends in the links between cognitive biases and pain outcomes.
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Multicenter Study
Within-Person Pain Variability and Mental Health in Older Adults With Osteoarthritis: An Analysis Across 6 European Cohorts.
Pain is a key symptom of osteoarthritis (OA) and has been linked to poor mental health. Pain fluctuates over time within individuals, but a paucity of studies have considered day-to-day fluctuations of joint pain in relation to affective symptoms in older persons with OA. This study investigated the relationship of pain severity as well as within-person pain variability with anxiety and depression symptoms in 832 older adults with OA who participated in the European Project on OSteoArthritis (EPOSA): a 6-country cohort study. ⋯ Moreover, older-old participants experienced fewer symptoms of anxiety (ratio = .85, 95% confidence interval [CI], .77-.94), depression (ratio = .90, 95% CI, .82-.98), and total affective symptoms (ratio = .87, 95% CI, .79-.94) if their pain fluctuated more. No such association was evident in younger-old participants (65-74.0 years). These findings imply that stable pain levels are more detrimental to mental health than fluctuating pain levels in older persons.
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Increased HCN Channel Activity in the Gasserian Ganglion Contributes to Trigeminal Neuropathic Pain.
Orofacial neuropathic pain caused by trigeminal nerve injury is a debilitating condition with limited therapeutic options. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels regulate neuronal excitability and are involved in the development and maintenance of chronic pain. However, the effect of HCN channel activity in the Gasserian ganglion on trigeminal neuropathic pain has not been examined. We evaluated nociceptive behaviors after microinjection of the HCN channel blockers ZD7288 or ivabradine into the Gasserian ganglion in rats with trigeminal nerve injury. Both blockers dose-dependently ameliorated evoked and spontaneous nociceptive behavior in rats with trigeminal neuropathic pain. Moreover, the clinically available HCN channel blocker ivabradine showed a prolonged antinociceptive effect. In the Gasserian ganglion, HCN1 and HCN2 are major HCN isoforms. After trigeminal nerve injury, the counts of HCN1 as well as HCN2 immuno-positive punctae were increased in the ipsilateral Gasserian ganglions. These results indicate that the increased HCN channel activity in the Gasserian ganglion directly contributes to neuropathic pain resulting from trigeminal nerve injury. ⋯ Trigeminal nerve damage-induced orofacial pain is severe and more resistant to standard pharmacological treatment than other types of neuropathic pain. Our study suggests that targeting HCN channel activities in the Gasserian ganglion may provide an alternative treatment of trigeminal neuropathy including trigeminal neuralgia.
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Conditioned pain modulation (CPM), a psychophysical paradigm that is commonly used to infer the integrity of endogenous pain-altering systems by observation of the effect of one noxious stimulus on another, has previously identified deficient endogenous analgesia in fibromyalgia (FM) and other chronic pain conditions. The mechanisms underlying this deficiency, be they insufficient inhibition and/or active facilitation, are largely unknown. ⋯ Higher resting connectivity between this cluster and cortical pain processing regions was associated with more efficient inhibitory CPM in both groups, whereas PAG connectivity with the dorsal pons was associated with greater CPM inhibition only in HC. Greater PAG connectivity to the caudal pons/rostral medulla, which was pain-inhibitory in HC, was associated with pain facilitation in FM patients.
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In recent years, the disappointing history of translation in pain research has undergone significant scrutiny. The escalation of knowledge and understanding related to presumed pain in neuropathic and inflammatory animal models contrasted with the unsatisfactory record of "bench-to-bedside" translation has raised many questions about the validity and clinical relevance of preclinical models and methods of behavioral assessment. Although many opinions have been expressed one of the overriding concerns and greatest barriers to the widening gap between preclinical research and the development of new interventions has been the underappreciated distinction between pain and nociception. ⋯ Other issues important to the discussion include but are not limited to the predictive validity of preclinical models, and the neglect of gender, age, and comorbidities in the design of preclinical studies. On the clinical side, the lack of sanitization of phenotypes in clinical trials has also contributed to the insufficient success of efforts to translate basic research to the clinic. The current review will discuss these and other issues believed to have contributed to the existing obstacles and challenges facing pain research along with making recommendations for the future.