Pain
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Comparative Study
The functional expression of mu opioid receptors on sensory neurons is developmentally regulated; morphine analgesia is less selective in the neonate.
Opioid requirements in neonatal patients are reported to be lower than older infants and this may be a reflection of the developmental regulation of opioid receptors. In this study we have investigated the postnatal regulation of Mu opioid receptor (MOR) function in both rat lumbar dorsal root ganglion (DRG) cultures and behavioural mechanical and thermal reflex tests in rat pups. Immunostaining with MOR and selective neurofilament (NF200) antibodies was combined with calcium imaging of MOR function in cultured neonatal and adult rat dorsal root ganglion cells. ⋯ These experiments show that the MOR expressed on large DRG neurons in neonates are functional and are subject to postnatal developmental regulation. This changing functional receptor profile is consistent with greater morphine potency in mechanical, but not thermal, sensory tests in young animals. These results have important clinical implications for the use of morphine in neonates and provide a possible explanation for the differences in morphine requirements observed in the youngest patients.
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Clinical Trial Controlled Clinical Trial
Manipulating presence influences the magnitude of virtual reality analgesia.
Excessive pain during medical procedures performed in unanesthetized patients is frequently reported, but can be reduced with virtual reality (VR) distraction. Increasing the person's illusion of going into the virtual world may increase how effectively VR distracts pain. Healthy volunteers aged 18-20 years participated in a double-blind between-groups design. ⋯ Each subject provided subjective 0-10 ratings of cognitive, sensory and affective components of pain, and rated their illusion of going inside the virtual world. Subjects in the High Tech VR group reported a stronger illusion of going into the virtual world (VR presence) than subjects in the Low Tech VR group, (4.2 vs. 2.5, respectively, P = 0.009) and more pain reduction (reduction of worst pain is 3.1 for High Tech VR vs. 0.7 for Low Tech VR, P < 0.001). Across groups, the amount of pain reduction was positively and significantly correlated with VR presence levels reported by subjects ( r = 0.48 for 'worst pain', P < 0.005).
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The main objective of this research was to determine the initial psychometric properties of the Faces Pain Scale - Revised (FPS-R) as a measure of pain intensity for use with Catalan children and adolescents. Results of the Catalan version of this scale (FPS-R-C) are similar to those obtained with the original instrument. In order to assess the validity and reliability of the FPS-R-C, two different samples were studied. ⋯ Overall, these results provide preliminary evidence of the reliability, and convergent and criterion-related validity of the FPS-R-C. Moreover, all participating subjects were asked to choose the pain scale they preferred the most. Our data suggest that, regardless of their age and/or gender, the subjects prefer the FPS-R-C to the CAS.
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Randomized Controlled Trial Clinical Trial
Effects of exposure on perception of pain expression.
The present study evaluated the effects of exposure to facial expression of pain, on observers' perceptions of pain expression. Thirty-one male and 49 female observers judged 1-s video excerpts in a signal detection paradigm. The excerpts showed facial expressions of shoulder-pain patients displaying no pain or moderate pain. ⋯ There was a linear relationship between the density of exposure to strong pain and observers' response criteria: greater exposure was associated with more conservative decisions. On average, participants showed very high levels of sensitivity to pain expression, with women significantly outperforming men. Results are discussed in terms of their implications for pain judgments of health care professionals, adaptation-level theory, and the psychophysical method of selective adaptation.
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Pain perception and autonomic responses to pain are known to be altered in dementia, although the mechanisms are poorly understood. We studied patients with Alzheimer's disease (AD) whose cognitive status was assessed through the Mini Mental State Examination test and whose brain electrical activity was measured by means of quantitative electroencephalography. After assessment of both cognitive impairment and brain electrical activity deterioration, these patients underwent sensory measurements in which the minimum stimulus intensity for both stimulus detection and pain sensation was determined. ⋯ These results indicate that pain anticipation and reactivity depend on both the cognitive status and the frequency bands of the electroencephalogram, whereas both stimulus detection and pain threshold are not affected by the progression of AD. These findings indicate that, whereas the sensory-discriminative components of pain are preserved even in advanced stages of AD, the cognitive and affective functions, which are related to both anticipation and autonomic reactivity, are severely affected. This sensory-affective dissociation is well correlated with the neuropathological findings in AD.