Pain
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This study aimed to identify self-report correlates of central pain augmentation in individuals with knee pain. A subset of participants (n = 420) in the Knee Pain and related health In the Community (KPIC) baseline survey undertook pressure pain detection threshold (PPT) assessments. Items measuring specific traits related to central pain mechanisms were selected from the survey based on expert consensus, face validity, item association with underlying constructs measured by originating host questionnaires, adequate targeting, and PPT correlations. ⋯ Pain distribution classified as "pain below the waist additional to knee pain" was more strongly associated with low PPT than were alternative classifications of pain distribution. A single factor, interpreted as "central pain mechanisms," was identified across the 8 selected items and explained variation in PPT (R = 0.17) better than did any originating scale (R = 0.10-0.13). In conclusion, including representative items within a composite self-report tool might help identify people with centrally augmented knee pain.
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A great need exists for the identification of new effective analgesics to treat sustained pain. However, most preclinical nociceptive assays measure behavioral responses evoked by noxious stimuli (ie, pain-stimulated behavior), which presents a challenge to distinguish between motor impairing and antinociceptive effects of drugs. Here, we demonstrate that chronic constriction injury (CCI) of the sciatic nerve elicits common pain-stimulated responses (ie, mechanical allodynia and thermal hyperalgesia) as well as reduces marble burying/digging behaviors that occur during the early stages of the neuropathy and resolve within 1 week. ⋯ Each of these drugs reversed all CCI-induced nociceptive measures, with the exception of the fatty acid amide hydrolase inhibitor that reversed pain-stimulated behaviors, only. These findings support the use of the mouse marble-burying assay as a model of pain-depressed behavior within the first week of sciatic nerve injury to examine candidate analgesics. These data also support existing preclinical research that cannabinoid receptor agonists and inhibitors of endocannabinoid-regulating enzymes merit consideration for the treatment of pain.
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Multicenter Study
Dyadic differences in friendships of adolescents with chronic pain compared with pain-free peers.
A multisite cross-sectional study was conducted to examine dyadic friendship features between adolescents with chronic pain (ACP) and their friends compared with non-pain adolescent friendship dyads and the association of these friendship features with loneliness and depressive symptoms. Participants completed a battery of standardized measures to capture friendship features (friendship quality, closeness, and perceived social support from friends) and indices of social-emotional well-being. Sixty-one same sex friendship dyads (122 adolescents) participated; 30 friendship dyads included an adolescent with chronic pain and 52 dyads were female. ⋯ Further research is needed to understand whether pain-related social support improves loneliness and depressive symptoms for ACP. Furthermore, a more nuanced understanding of loneliness in this population is warranted. Strategies to help ACP garner needed social support from friends are needed to decrease rates of loneliness to improve long-term outcomes.
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Randomized Controlled Trial
Effectiveness of a healthy lifestyle intervention for chronic low back pain: a randomised controlled trial.
We assessed the effectiveness of a 6-month healthy lifestyle intervention, on pain intensity in patients with chronic low back pain who were overweight or obese. We conducted a pragmatic randomised controlled trial, embedded within a cohort multiple randomised controlled trial of patients on a waiting list for outpatient orthopaedic consultation at a tertiary hospital in NSW, Australia. Eligible patients with chronic low back pain (>3 months in duration) and body mass index ≥27 kg/m and <40 kg/m were randomly allocated, using a central concealed random allocation process, to receive advice and education and referral to a 6-month telephone-based healthy lifestyle coaching service, or usual care. ⋯ In the intervention group, 41% (n = 32) of participants reported an adverse event compared with 56% (n = 45) in the control group. Our findings show that providing education and advice and telephone-based healthy lifestyle coaching did not benefit patients with low back pain who were overweight or obese, compared with usual care. The intervention did not influence the targeted healthy lifestyle behaviours proposed to improve pain in this patient group.
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We describe the mixed-methods (qualitative and quantitative) development and preliminary validation of the Patient Assessment for Low Back Pain-Symptoms (PAL-S), a patient-reported outcome measure for use in chronic low back pain (cLBP) clinical trials. Qualitative methods (concept elicitation and cognitive interviews) were used to identify and refine symptom concepts and quantitative methods (classical test theory and Rasch measurement theory) were used to evaluate item- and scale-level performance of the measure using an iterative approach. Patients with cLBP participated in concept elicitation interviews (N = 43), cognitive interviews (N = 38), and interview-based assessment of paper-to-electronic mode equivalence (N = 8). ⋯ Individual item scores and total score discriminated between numeric rating scale tertile groups and painDETECT categories. Respondent interpretation of paper and electronic administration modes was equivalent. The PAL-S has demonstrated content validity and is potentially useful to assess treatment benefit in cLBP clinical trials.