The journal of pain : official journal of the American Pain Society
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Movement limitation is a common characteristic of chronic pain such that pain prevents the very movement and activity that is most likely to promote recovery. This is particularly the case for pathological pain states such as complex regional pain syndrome (CRPS). One clinical approach to CRPS that has growing evidence of efficacy involves progressive movement imagery training. ⋯ We then review the neuropathological targets of GMI and current thought on its effects on neurophysiological biomarkers. PERSPECTIVE: This article provides an overview of our experiences with graded motor imagery training over the last 20 years focussing on the treatment of CRPS. It does both cover the theoretical underpinnings for this treatment approach, biomarkers which indicate potential changes driven by GMI, and experiences for achieving optimal treatment results.
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Quantitative sensory testing (QST) allows researchers to evaluate associations between noxious stimuli and acute pain in clinical populations and healthy participants. Despite its widespread use, our understanding of QST's reliability is limited, as reliability studies have used small samples and restricted time windows. We examined the reliability of pain ratings in response to noxious thermal stimulation in 171 healthy volunteers (n = 99 female, n = 72 male) who completed QST on multiple visits ranging from 1 day to 952 days between visits. ⋯ PERSPECTIVE: This article assesses the reliability of an adaptive thermal pain calibration procedure. We find that pain threshold and tolerance are moderately reliable whereas the correlation between pain rating and stimulus temperature has low reliability. Female participants were more reliable than male participants on all pain sensitivity measures.
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Three categories of pain mechanisms are recognized as contributing to pain perception: nociceptive, neuropathic, and nociplastic (ie, central nervous system augmented pain processing). We use validated questionnaires to identify pain mechanisms in Urologic Chronic Pelvic Pain Syndrome (UCCPS) patients (n = 568, female = 378, male = 190) taking part in the Symptom Patterns Study of the Multidisciplinary Approach to the study of chronic Pelvic Pain Research Network. A cutoff score of 12 on the painDETECT questionnaire (-1 to 38) was used to classify patients into the neuropathic category while the median score of 7 on the fibromyalgia survey criteria (0-31) was used to classify patients into the nociplastic category. ⋯ A self-report method classifying individuals on pain mechanisms reveals clinical differences that could inform clinical trials and novel targets for treatment. PERSPECTIVE: This article presents differences in clinical characteristics based on a simple self-report method of classifying pain mechanisms for Urologic Chronic Pelvic Pain Syndrome patients. This method can be easily applied to other chronic pain conditions and may be useful for exploring pathophysiology in pain subtypes.
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In the lexical assessment of pain, an offshoot of the McGill Pain Questionnaire is the Pain Descriptor System (PDS) which assesses sensory, affective, and overall intensity of pain. To determine if sensory versus affective pain components might be selectively related to different aspects of disability, PDS scores were examined in relation to functional status and psychosocial impairment on the Pain Disability Questionnaire (PDQ). A sample of 629 chronic pain patients rated the degree to which each of 36 PDS words described their pain and also rated 15 items of the PDQ. ⋯ Clinically, the patient's description of pain sensation may hold valuable clues to physical impairment, whereas the communication of affect/suffering is more likely to connote psychosocial difficulties in functioning. PERSPECTIVE: Regression models (including Group Lasso) were applied to data on pain and disability from 629 patients. Findings support the Pain Descriptor System in assessing pain but further suggest that sensory descriptors are predictive of physical impairment from chronic pain, whereas affective descriptors are more predictive of psychologically-related disability.
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Neural systems play important roles in the functions of acupuncture. But the unclear structure and mechanism of acupoints hinder acupuncture standardization and cause the acupuncture effects to be varying or even paradoxical. It has been broadly assumed that the efficacy of acupuncture depends on the biological signals triggered at acupoints and passed up along neural systems. ⋯ Further, we found that 4 types of adenosine receptors were all expressed by ST36 DRG neurons, and A1, A2b, and A3 receptors were the principal reactors to adenosine. PERSPECTIVE: This study provides the major characteristics of ST36 DRG neurons, which will help to analyze the neural pathway of acupuncture signals. At the same time, these findings could provide a new possible therapy for pain relief, such as injecting adenosine or corresponding agonists into acupoints.