The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Research Article: The prediction of the analgesic placebo response is moderated by outward-focused attention: a sham, randomized clinical trial of chronic back pain patients.
The within-subject variability (WSV) of pain-intensity reports has gained attention as a predictor of the placebo response but has demonstrated mixed results. We hypothesized that participants' inward- and outward-directed attention will moderate WSV's prediction of the analgesic placebo response. In this sham randomized clinical trial (protocol number NCT05994118); placebo response was induced in chronic back-pain patients (n=113) through a saline injection plus verbal suggestion. ⋯ Better understanding of factors shaping the placebo response could further contribute to both clinical practice and clinical trials. PERSPECTIVE: The current study demonstrates that the prediction of the analgesic placebo response could be improved if relevant personal characteristics are included as moderators of the prediction. Better predictions of the placebo response could contribute to improve both clinical research and clinical care.
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Randomized Controlled Trial Multicenter Study
The use of abstract animations and a graphical body image for assessing pain outcomes among adults with sickle cell disease.
Painimation, a novel digital pain assessment tool, allows patients to communicate their pain quality, intensity, and location using abstract animations (painimations) and a paintable body image. This study determined the construct validity of painimations and body image measures by testing correlations with validated pain outcomes in adults with sickle cell disease (SCD). Analyses used baseline data from a multisite randomized trial of 359 adults with SCD and chronic pain. ⋯ This demonstrates animations and body image data can assess SCD pain severity, potentially with more accuracy than a 0-10 scale. Future research will explore whether Painimation can differentiate biological and psychosocial pain components. PERSPECTIVE: This article presents the preliminary construct validity of Painimation in SCD by examining the associations of "painimations" and body area image data with daily e-diary and traditional self-report pain outcomes.
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Randomized Controlled Trial
Attention and Nocebo Hyperalgesia: Testing a Novel Virtual Reality Attention Bias Modification Paradigm.
Nocebo effects in pain (nocebo hyperalgesia) have received significant attention recently, with negative expectancies and anxiety proposed to be explanatory factors. While both expectancy and anxiety can bias attention, attention has been rarely explored as a potential mechanism involved in nocebo hyperalgesia. The present study aimed to explore whether attention bias modification (ABM) using an immersive, ecologically valid VR paradigm successfully induced attention biases (AB) and subsequently influenced nocebo hyperalgesia. ⋯ Unexpected effects of ABM were observed for state anxiety and anticipatory anxiety, whereby training away from pain exacerbated each, which necessitates further exploration. PERSPECTIVE: This article tests the efficacy of a novel attention bias modification paradigm, designed in virtual reality, for inducing pain-related biases, and whether these biases exacerbate or inoculate against nocebo hyperalgesia. While pain-related biases were successfully induced, there was no relationship with the strength of induced nocebo hyperalgesia.
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Randomized Controlled Trial
Tramadol effects on brain activity during cognitive and emotional empathy for pain: a randomized controlled study.
Pain is perceived not only by personal experience but also vicariously. Pain empathy is the ability to share and understand other's intentions and emotions in their painful conditions, which can be divided into cognitive and emotional empathy. It remains unclear how centrally acting analgesics would modulate brain activity related to pain empathy and which component of pain empathy would be altered by analgesics. ⋯ Supramarginal gyrus activation correlated negatively with the thermal pain threshold. In experiment 2, we found that tramadol decreased activation in angular gyrus in cognitive empathy for pain compared with placebo but did not change brain activity in emotional empathy for pain. PERSPECTIVE: Centrally acting analgesics such as tramadol may have not only analgesic effects on self-experienced pain but also on the complex neural processing of pain empathy.
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Randomized Controlled Trial
Comparable conditioned pain modulation and painful-exercise-induced hypoalgesia in healthy young adults: A randomised crossover trial.
Conditioned pain modulation and exercise-induced hypoalgesia reflect inhibitory pain controls emanating from the brain. The aim of this study was to compare the extent of pain inhibition from exercise-induced hypoalgesia (isometric wall squat), conditioned pain modulation (cold-water immersion), and their combination (wall squat followed by cold water in fixed order) in healthy pain-free adults. Sixty-one participants (median age 21 years) completed 3 sessions (wall-squat, cold-water, and combined) in random order. ⋯ Pressure pain in body regions remote from the exercised or conditioned sites may be weakly modulated. PERSPECTIVE: The current findings suggest that pain-inhibitory effects induced by painful wall squat and by cold-water immersion may overlap. The magnitude of pain inhibition in the forehead remote from the exercised thigh or the conditioned foot appears smaller, which could be examined further in future research.