The journal of pain : official journal of the American Pain Society
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Review Meta Analysis
Do People With Chronic Musculoskeletal Pain Have Impaired Motor Imagery? A Meta-analytical Systematic Review of the Left/Right Judgment Task.
The left/right judgment task (LRJT) is the most commonly used method of assessing motor imagery performance. Abnormally long response times are thought to reflect delayed processing of body/spatial representations, and poor accuracy is thought to reflect disrupted cortical proprioceptive representations or body schema. Slower and less accurate responses on the LRJT have been reported in a variety of chronic musculoskeletal pain conditions. ⋯ PERSPECTIVES: This review synthesizes evidence of altered motor imagery performance using the LRJT across chronic musculoskeletal pain conditions. Consistent evidence was found for altered motor imagery performance in peripheral pain conditions, but evidence was less consistent for axial conditions. Treatment to restore a normal body schema may be beneficial in chronic limb and facial pain.
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Observational Study
SELF-MEDICATION WITH OVER-THE-COUNTER ANALGESICS: A SURVEY OF PATIENT CHARACTERISTICS AND CONCERNS ABOUT PAIN MEDICATION.
Pain is a common reason for self-medication with over-the-counter (OTC) analgesics. However, this self-treating population has remained largely uncharacterized. This cross-sectional observational study investigated individuals who self-medicate their pain with OTC analgesics to elucidate their pain characteristics and medication use. ⋯ Perspective: This study found that the clinical picture of people who self-medicate their pain with OTC analgesics looked worse than expected. We also identified substantial concerns about pain medication. Therefore, we recommend that health professionals systematically probe pain patients about their self-medication practices and explore concerns about pain medication.
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Clinical guidelines discourage prescribing opioids for chronic pain, but give minimal advice about how to discuss opioid tapering with patients. We conducted focus groups and interviews involving 21 adults with chronic back or neck pain in different stages of opioid tapering. Transcripts were qualitatively analyzed to characterize patients' tapering experiences, build a conceptual model of these experiences, and identify strategies for promoting productive discussions of opioid tapering. ⋯ Recommendations for promoting productive tapering discussions include understanding the social and emotional dynamics likely to impact patients' tapering, addressing patient fears, focusing on patients' best interests, providing anticipatory guidance about tapering, and developing an individualized tapering plan that can be adjusted based on patient response. Perspective: This study used interview and focus group data to characterize patients' experiences with opioid tapering and identify communication strategies that are likely to foster productive, patient-centered discussions of opioid tapering. Findings will inform further research on tapering and help primary care clinicians to address this important, often challenging topic.
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We showed previously that spinal metabotropic glutamate receptor 1 (mGluR1) signaling suppresses or facilitates (depending on the stage of estrous cycle) analgesic responsiveness to intrathecal endomorphin 2, a highly mu-opioid receptor-selective endogenous opioid. Spinal endomorphin 2 antinociception is suppressed during diestrus by mGluR1 when it is activated by membrane estrogen receptor alpha (mERα) and is facilitated during proestrus when mGluR1 is activated by glutamate. In the current study, we tested the hypothesis that in female rats subjected to spinal nerve ligation (SNL), the inhibition of spinal estrogen synthesis or blockade of spinal mERα/mGluR1 would be antiallodynic during diestrus, whereas during proestrus, mGluR1 blockade would worsen the mechanical allodynia. ⋯ Findings suggest menstrual cycle stage-specific drug targets for and the putative clinical utility of harnessing endogenous opioids for chronic pain management in women, as well as the value of, if not the necessity for, considering menstrual cycle stage in clinical trials thereof. PERSPECTIVE: Intrathecal treatments that enhance spinal endomorphin 2 analgesic responsiveness under basal conditions lessen mechanical allodynia in a chronic pain model. Findings provide a foundation for developing drugs that harness endogenous opioid antinociception for chronic pain relief, lessening the need for exogenous opioids and thus prescription opioid abuse.
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Pain sensitivity is characterized by interindividual variability, determined by factors including genetic variation of nociceptive receptors and pathways. The sigma-1 receptor (SIGMAR1) is involved in pain modulation especially under pre-sensitized conditions. However, the contribution of SIGMAR1 genetic variants to pain generation and sensitivity is unknown yet. ⋯ This study indicates lack of association of SIGMAR1 -297G>T and 5A>C genetic variants to susceptibility to develop chronic pain, but significant modulation of somatosensory function in neuropathic pain patients. PERSPECTIVE: This article presents the first study indicating a modulation of somatosensory function in neuropathic pain patients by selected genetic variants in SIGMAR1. As our findings could contribute to the explanation of interindividual differences in drug response they might help to improve the treatment of neuropathic pain.