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Aberrant motor cortex plasticity is hypothesised to contribute to chronic musculoskeletal pain, but evidence is limited. Critically, studies have not considered individual differences in motor plasticity or how this relates to pain susceptibility. Here we examined the relationship between corticomotor excitability and an individual's susceptibility to pain as pain developed, was sustained and resolved over 21 days. Nerve growth factor was injected into the right extensor carpi radialis brevis muscle of 20 healthy individuals on day 0, 2 and 4. Corticomotor excitability, pressure pain thresholds (PPTs) and performance on a cognitive conflict task were examined longitudinally (day 0, 2, 4, 6 and 14). Pain and disability were assessed on each alternate day (1,3…21). Two patterns of motor plasticity were observed in response to pain – corticomotor depression or corticomotor facilitation (p=0.009). Individuals who displayed corticomotor depression experienced greater pain (p=0.027), and had worse cognitive task performance (p=0.038), than those who displayed facilitation. PPTs were reduced to a similar magnitude in both groups. Corticomotor depression in the early stage of pain could indicate a higher susceptibility to pain. Further work is required to determine whether corticomotor depression is a marker of pain susceptibility in musculoskeletal conditions. Perspective: This article explores individual differences in motor plasticity in the transition to sustained pain. Individuals who developed corticomotor depression experienced higher pain and worse cognitive task performance than those who developed corticomotor facilitation. Corticomotor depression in the early stage of pain could indicate a higher susceptibility to pain.
Chronic pain is common in patients with prescription opioid use disorder (OUD), and pain severity has been shown to predict opioid use for those with chronic pain. However, recent research suggests that focusing on pain status (i.e., the presence or absence of chronic pain) at treatment initiation may not reflect the clinical significance of pain over the long-term course of OUD. Reports of variability in chronic pain and its clinical significance over time have yet to be investigated in patients with prescription OUD. The present study examined variability in chronic pain status from entry into prescription OUD treatment through 3.5-year follow-up. Additionally, we examined the association between concurrent chronic pain and opioid use at three follow-up time points.
Levcromakalim opens ATP-sensitive potassium channels (K channel) and induces head pain in healthy volunteers and migraine headache in migraine patients, but no pain in other parts of the body. K channels are expressed in C- and Aδ-fibers, and these channels might directly activate nociceptors and thereby evoke pain in humans.
Patients treated in interdisciplinary chronic pain rehabilitation programs (ICPRPs) show long-term improvements in symptoms, however outcomes may vary across heterogenous patient subpopulations. This longitudinal retrospective study characterizes the influence of opioids, mood, patient characteristics and baseline symptoms on pain and functional impairment (FI) in 1681 patients 6-months to 12-months post-treatment in an ICPRP incorporating opioid weaning. Linear mixed models showed immediate and durable treatment benefits with non-uniform worsening at follow up which slowed over time. Latent class growth analysis identified three post-treatment trajectories of pain and FI: mild symptoms and durable benefits, moderate symptoms and durable benefits, and intractable symptoms. A fourth pain trajectory showed immediate post-treatment improvement and worsening at follow up. Whether a patient was weaned from opioids was not predictive of treatment trajectory. Racial ethnic minority status, higher levels of post-treatment depression, and lower perceived treatment response were associated with less resolution (moderate symptoms) or intractable symptoms. Not having a college education was predictive of intractable or worsening pain and a moderate course of FI. Older age and male gender was associated with intractable FI. Treatment outcomes may be improved by the development of targeted interventions for patients at risk of poor recovery and/or deteriorating long-term course. Perspective: This study examined predictors of treatment response in 1681 patients treated in an interdisciplinary chronic pain rehabilitation program incorporating opioid weaning. Opioid weaning did not predict outcome. Higher levels of symptoms, lower levels of education, and being a racial-ethnic minority were associated with a less salubrious long-term treatment response.
Complex regional pain syndrome (CRPS) is a painful condition of a limb characterized by a constellation of symptoms. Little is known about the clinical features of pediatric CRPS, with fewer than a dozen studies published to date. The aim of this study was to explore the clinical course of pediatric CRPS, with emphasis on clinical features and disease outcomes. A secondary aim was to discern differences in clinical features of pediatric CRPS with and without related movement disorders, and between children who had a favorable and unfavorable outcome.
Aprepitant is a neurokinin 1 receptor (NK1R) antagonist used for its antipruritic properties in dermatoses and systemic diseases. The mode of action is still unclear. A peripheral effect is assumed as aprepitant shows efficacy in inflammatory skin diseases including prurigo nodularis (PN).
Although depression and chronic pain often coexist, few studies have examined antidepressant use among people with pain. This study examines the prevalence and characteristics associated with antidepressant use among people prescribed opioids for chronic noncancer pain (CNCP).
Current theories associated with the cause of tension type headache are mostly focused on muscle tissues. No study has investigated the presence of role of nerve tissues in this population.
Non-adherence to prescribed pain medication is common in chronic non-malignant pain patients. Beliefs about pain medication have been reported to be associated with non-adherence behaviour in cross-sectional studies. The aim of this study was to prospectively investigate the relation between patients' beliefs about pain medication and their medication adherence and treatment outcome.
Due to the current absence of a standardized guide for activity pacing, the concept of pacing is interpreted in various ways by healthcare professionals, patients and researchers. Consequently, the effects of pacing across different conditions are unclear. The present study aimed to undertake the second stage in the development of an activity pacing framework for chronic pain/fatigue.