Pain
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Observational Study
The responsiveness of quantitative sensory testing-derived sensory phenotype to disease-modifying intervention in patients with entrapment neuropathy: a longitudinal study.
The German Research Network on Neuropathic Pain (DFNS) quantitative sensory testing (QST) method for sensory phenotyping is used to stratify patients by mechanism-associated sensory phenotype, theorised to be predictive of intervention efficacy. We hypothesised that change in pain and sensory dysfunction would relate to change in sensory phenotype. We investigated the responsiveness of sensory phenotype to surgery in patients with an entrapment neuropathy. ⋯ Quantitative sensory testing-derived sensory phenotype is sensitive to clinically important change. In an entrapment neuropathy model, sensory phenotype was associated with patient-reported symptoms and demonstrated statistically significant, clinically relevant change after disease-modifying intervention. Sensory phenotype was independent of disease severity and may reflect underlying neuropathophysiology.
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This study investigated the association between COVID-related myalgia experienced by patients at hospital admission and the presence of post-COVID symptoms. A case-control study including patients hospitalised due to COVID-19 between February 20 and May 31, 2020, was conducted. Patients reporting myalgia and patients without myalgia at hospital admission were scheduled for a telephone interview 7 months after hospital discharge. ⋯ The presence of myalgia at hospital admission was associated with preexisting history of musculoskeletal pain (OR 1.62, 95% confidence interval 1.10-2.40). In conclusion, myalgia at the acute phase was associated with musculoskeletal pain as long-term post-COVID sequelae. In addition, half of the patients with preexisting pain conditions experienced a persistent exacerbation of their previous syndromes.
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Randomized Controlled Trial
Internet-delivered cognitive behavioral therapy for youth with functional abdominal pain: a randomized clinical trial testing differential efficacy by patient subgroup.
Inconsistent results of psychological treatments for pediatric functional abdominal pain (FAP) may be due to heterogeneity of patients' pain-related psychological characteristics. This randomized controlled trial tested whether statistically derived patient subgroups (high pain dysfunctional [HPD], high pain adaptive [HPA], and low pain adaptive [LPA]) moderated response to cognitive behavior therapy (CBT) for adolescents with FAP and their parents (n = 278 dyads; patients were 66% female, mean [SD] age was 14.62 [1.88] years, and parents were 95% female). Randomization to Internet-delivered CBT vs Internet-delivered pain education (EDU) was stratified by patient subgroup. ⋯ Furthermore, among all patients assigned to CBT, HPD youth demonstrated significantly greater reductions in GI symptoms compared with HPA and LPA youth and greater reductions in abdominal pain compared with LPA youth. All subgroups maintained symptom reductions throughout the follow-up period. Results suggest that subgrouping FAP patients may inform treatment allocation and optimize treatment response.
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Brain biomarkers of pain, including pain-predictive "signatures" based on brain activity, can provide measures of neurophysiological processes and potential targets for interventions. A central issue relates to the specificity of such measures, and understanding their current limits will both advance their development and explore potentially generalizable properties of pain to other states. Here, we used 2 data sets to test the neurologic pain signature (NPS), an established pain neuromarker. ⋯ Local NPS patterns in anterior or midinsula, S2, and dorsal anterior cingulate responded to breathlessness and finger opposition and were reduced by remifentanil. Local NPS responses in the dorsal posterior insula did not respond to any manipulations. Therefore, significant global NPS activity alone is not specific for pain, and we offer insight into the overlap between NPS responses, breathlessness, and somatomotor demand.
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Endogenous opioids mediate the pleasurable responses to positively reinforcing stimuli such as palatable food. Yet, the reduction or omission of a negative experience can also be rewarding (negative reinforcement). As such, pain relief leads to negative reinforcement and evokes a pleasant feeling in humans. ⋯ Endogenous opioid blockade by naltrexone decreased relief and pleasantness ratings compared with placebo (P = 0.0027). This study provides evidence that endogenous opioids play a role in mediating the pleasant feeling of pain relief in humans. Clinically, the rewarding nature of pain relief and its underlying mechanisms require consideration because of their potential reinforcing effects on behaviors that might be beneficial short-term but maladaptive long-term.