The journal of pain : official journal of the American Pain Society
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Neonatal handling (NH) of male rat pups strongly attenuates stress response and stress-induced persistent muscle hyperalgesia in adults. Because female sex is a well established risk factor for stress-induced chronic muscle pain, we explored whether NH provides resilience to stress-induced hyperalgesia in adult female rats. Rat pups underwent NH, or standard (control) care. ⋯ The administration of the antiestrogen drug fulvestrant, in addition to gonadectomy, did not enhance the protective effect of NH in female rats. Finally, knockdown of the androgen receptor by intrathecal antisense treatment attenuated the protective effect of NH in intact male rats. Together, these data indicate that androgens play a key role in NH-induced resilience to WA stress-induced muscle hyperalgesia.
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The Modified Behavioral Pain Scale (MBPS) was designed to assess procedural pain in infants and is considered valid for assessing immunization pain. The aim of this study was to assess the practical and psychometric properties of the MBPS when applied to other commonly performed procedures. Twenty-six clinicians independently applied the MBPS scale to segments of video collected from 100 infants and children aged 6 to 42 months undergoing 1 of 4 procedures in the emergency department. ⋯ Finally, 28% of scores changed after the second viewing of a video segment. The MBPS appears reliable and sensitive to procedural pain when applied by clinicians. Results question the capacity of the scale to differentiate between pain- and nonpain-related distress, the feasibility of this scale, and the appropriateness of item descriptors for medical procedures.
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In this research, we examined effects of higher versus lower threat contexts on attention biases in more and less pain-fearful chronic pain subgroups via eye-tracking methodology. Within a mixed chronic pain sample (69 women, 29 men), biases in orienting and maintenance of visual attention were assessed during the standardized image pair presentation phase (2,000 ms) of a modified visual dot probe task featuring painful-neutral (P-N) image pairs (lower threat context) and a parallel task in which these P-N pairs cued potential pain (higher threat context). ⋯ Although trait-based fear of pain was not related to any gaze bias index in either task, between task analyses indicated the sample reported more state fear, directed their initial gaze less often, and displayed longer overall gaze durations toward pain images in the higher threat context in which P-N trials signaled potential pain. Results supported the threat interpretation model premise that persons with chronic pain have difficulty disengaging from moderately threatening visual painful cues.
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Complex regional pain syndrome (CRPS) is a complex pain disorder that can emerge after limb trauma or a lesion in the peripheral nervous system. Typical features include continuing pain, sensory, vasomotor, sudomotor, motor, and trophic changes as well as edema. These signs provide the basis of CRPS diagnosis. ⋯ We identified 11 distinct etiological triggers, which cover more than 99% of the study participants. We developed a weighted score on the basis of the most decisive data, which achieved a sensitivity of .869 and a specificity of .829, compared with .819 and .679 for the Budapest criteria. The weighted diagnostic criteria may help to better aid in distinguishing CRPS from other pain disorders.
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Musculoskeletal pain changes how people move. Although experimental pain is associated with increases in the variability of motor output, it is not clear whether motor-evoked pain in clinical conditions is also associated with increases in variability. In the current study, we measured jaw force production during a visually guided force paradigm in which individuals with chronic jaw pain and control subjects produced force at 2% of their maximum voluntary contraction (low target force level) and at 15% of their maximum voluntary contraction (high target force level). ⋯ We showed that the chronic jaw pain group exhibited greater force variability compared with controls irrespective of the force level, whereas the accuracy of force production did not differ between groups. Furthermore, predictors of force variability shifted from trait measures of pain intensity and pain interference at the low force level to state measures of pain intensity at the high force level. Our observations show that motor-evoked jaw pain is associated with increases in force variability that are predicted by a combination of trait measures and state measures of pain intensity and pain interference.