The journal of pain : official journal of the American Pain Society
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Preoperative pain characteristics in patients with osteoarthritis may explain persistent pain after total knee replacement. Fifty patients awaiting total knee replacement and 22 asymptomatic controls were recruited to evaluate the degree of neuropathic pain symptoms and pain sensitization. Patients with OA were pain phenotyped into 2 groups based on the PainDETECT questionnaire: high PainDETECT group (scores ≥19) indicating neuropathic pain-like symptoms and low PainDETECT group (scores <19) indicating nociceptive or mixed pain. ⋯ Patients with OA with high PainDETECT scores had higher postoperative visual analogue scale pain scores than the low PainDETECT patients (P < .0001) and facilitated temporal summation of pain (P = .022) compared with healthy control subjects. Perspective: This study has found that preoperative PainDETECT scores independently predict postoperative pain. Patients with knee OA with neuropathic pain-like symptoms identified using the PainDETECT questionnaire are most at risk of developing chronic postoperative pain after TKR surgery.
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Changes in excitability of the sensorimotor cortex have been demonstrated in clinical musculoskeletal pain, although the timing is unknown. Eccentric exercise provokes delayed-onset muscle soreness providing a model to study the temporal profile of sensorimotor cortical plasticity during progressively developing muscle soreness. Twelve healthy participants performed eccentric exercise of the wrist extensors. ⋯ A decrease in the ECR pressure pain thresholds was correlated (P < .027) with an increase in the P45 amplitude at a centroparietal recording site. PERSPECTIVE: These novel data demonstrate that the somatosensory cortical excitability may be affected by muscle soreness developing over days in parallel with a deficit in the motor system. Cortical neuroplasticity may thus develop in the subacute phase and be relevant for understanding neural adaptation in the transition from acute to persistent pain.
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Spouse attributions regarding displays of pain behaviors by their partners with chronic pain may account for subsequent increases in spouse critical/hostile responses toward their partners. People with chronic low back pain (n = 105) and their pain-free spouses (n = 105) completed electronic diary measures 5 times per day for 14 consecutive days. Key items assessed spouse observations of patient pain behavior, attributions regarding these behaviors, and spouse critical/hostile responses toward patients. ⋯ A vital factor linking spouse scrutiny to spouse critical/hostile responses may be the spouse's ascribed reasons for the patient's grimacing, bracing, complaining, and so forth. Perspective: Results indicate that spouse internal and negative attributions for pain behaviors of their partners with chronic pain may influence subsequent spouse critical/hostile reactions to them. Findings suggest that replacing spouse internal and negative attributions with external, compassionate, and accepting explanations may be useful therapeutic targets for couples coping with chronic pain.
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It is widely believed that cortical changes are a consequence of longstanding neuropathic pain (NP). In this article, we demonstrate that NP in individuals with subacute spinal cord injury (SCI) has characteristic electroencephalography markers (EEG) that precede the onset of pain. EEG was recorded in a relaxed state and during motor imagination tasks in 10 able-bodied participants and 31 patients with subacute SCI (11 with NP, 10 without NP, and 10 who had pain develop within 6 months of EEG recording). ⋯ Clinical Trial Registration Number: NCT02178917 PERSPECTIVE: We demonstrate that brain activity in patients with subacute SCI reveals both early markers and predictors of NP, which may manifest before sensory discomfort. These markers and predictors may complement known sensory phenotypes of NP. They may exist in other patient groups suffering from NP of central origin.
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Pain is significantly impacted by the increasing epidemic of obesity and the metabolic syndrome. Our understanding of how these features impact pain is only beginning to be developed. Herein, we have investigated how small genetic differences among C57BL/6 mice from 2 different commercial vendors lead to important differences in the development of high-fat diet-induced mechanical sensitivity. ⋯ PERSPECTIVE: Obesity and the metabolic syndrome play an important role in pain. This study identifies key differences in the response to a high-fat diet among substrains of C57BL/6 mice and differences in intrinsic physical activity that may influence pain sensitivity. The results emphasize physical activity as a powerful modulator of obesity-related pain sensitivity.