Pain
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Randomized Controlled Trial
Validating a biosignature predicting placebo pill response in chronic pain in the settings of a randomized controlled trial.
The objective of this study is to validate a placebo pill response predictive model-a biosignature-that classifies chronic pain patients into placebo responders (predicted-PTxResp) and nonresponders (predicted-PTxNonR) and test whether it can dissociate placebo and active treatment responses. The model, based on psychological and brain functional connectivity, was derived in our previous study and blindly applied to current trial participants. Ninety-four chronic low back pain (CLBP) patients were classified into predicted-PTxResp or predicted-PTxNonR and randomized into no treatment, placebo treatment, or naproxen treatment. ⋯ At a single subject level, the biosignature better predicted placebo nonresponders, with poor accuracy. One component of the biosignature (dorsolateral prefrontal cortex-precentral gyrus functional connectivity) could be generalized across 3 placebo studies and in 2 different cohorts-CLBP and osteoarthritis pain patients. This study shows that a biosignature can predict placebo response at a group level in the setting of a randomized controlled trial.
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Randomized Controlled Trial
Effectiveness of training physical therapists in pain neuroscience education for patients with chronic spine pain: cluster-randomized trial.
Chronic spinal pain poses complex challenges for health care around the world and is in need of effective interventions. Pain neuroscience education (PNE) is a promising intervention hypothesized to improve pain and disability by changing individuals' beliefs, perceptions, and expectations about pain. Pain neuroscience education has shown promise in small, controlled trials when implemented in tightly controlled situations. ⋯ The PNE group demonstrated significant greater improvements in pain self-efficacy at 12 and 2 weeks compared with no intervention (mean difference = 3.65 [95% CI: 0.00-7.29], P = 0.049 and = 3.08 [95% CI: 0.07 to -6.09], P = 0.045, respectively). However, a similar percentage of participants in both control (41.1%) and treatment (44.4%) groups reported having received the treatment per fidelity question (yes or no to pain discussed as a perceived threat) at 2 weeks. Pragmatic PT PNE training and delivery failed to produce significant functional changes in patients with chronic spinal pain but did produce significant improvement in pain self-efficacy over UC PT.
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Many analgesics inadequately address the psychiatric comorbidities of chronic and persistent pain, but there is no standard preclinical model of pain-altered behavior to support the development of new therapies. To explore this conflicting and inconclusive literature, we conducted a focused systematic review and meta-analysis on the effect of complete Freund adjuvant-induced (CFA) rodent hind paw inflammation on multiple classical indicators of exploratory behavior, stress coping, and naturalistic behavior. Our primary objective was to define CFA's effect on assays including, but not limited to, the elevated plus maze and forced swim test. ⋯ Complete Freund adjuvant modestly but significantly decreased exploratory behavior, significantly increased passive stress coping in the tail suspension test but not the forced swim test, and significantly decreased preference for sucrose and naturally rewarding activity. Subgroup analyses revealed significant differences between species and animal sourcing. Based on the evidence provided here, we conclude future studies should focus on CFA's effect on natural rewards and naturalistic behaviors.
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Activation of toll-like receptor 4 (TLR4) in the dorsal root ganglion (DRG) and spinal cord contributes to the generation of paclitaxel-related chemotherapy-induced peripheral neuropathy (CIPN). Generalizability of TLR4 signaling in oxaliplatin-induced CIPN was tested here. Mechanical hypersensitivity developed in male SD rats by day 1 after oxaliplatin treatment, reached maximum intensity by day 14, and persisted through day 35. ⋯ Finally, there was no significant difference in oxaliplatin-induced mechanical hypersensitivity between male and female rats when observed for 2 weeks. Furthermore, upregulation of TLR4 was detected in both sexes when tested 14 days after treatment with oxaliplatin. These findings suggest that the activation of TLR4 signaling in DRG neurons is a common mechanism in CIPN induced by multiple cancer chemotherapy agents.