Articles: pain-measurement.
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In a clinical trial one scale of pain relief is scored backwards relative to another (high on one corresponding to low on the other), with a consequent large negative correlation. But two derived scales of total pain, obtained by multiplying average pain relief on each scale by duration of pain (common to both pain relief measurements) gave an almost zero correlation. This apparent contradiction is explained by the inverse relationship between the pain relief scales and the large differences in duration of pain experienced by the patients.
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Multidimensional scaling was used to explore whether a single intensity dimension underlies the perception of both nonpainful and painful electrical stimuli, or whether separate dimensions are required. For the scaling (INDSCAL) procedure, 41 healthy volunteers judged the similarity between all pairs of 16 intensities, which ranged from imperceptible levels to pain tolerance. For the property mapping (PREFMAP) analysis, they rated each intensity on each of 16 property scales. ⋯ Third and fourth dimensions, which refined the scaling of nonpainful stimuli, were also found. Variability in the subjects' use of the painful and nonpainful dimensions was related to their choice of stimulus descriptors. Like clinical pain, laboratory pain requires multidimensional assessment.
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Patients with burns often suffer severe pain, especially during dressing of wounds, but there are no established alternatives to potent opiate analgesics, with their various side-effects. Intravenous lignocaine infusion strikingly reduced self-assessed pain scores in 7 patients during the first 3 days after second-degree burns, without need for supplementary opiate analgesia.
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Based upon a tripartite theoretical model of pain, the Pain Rating Index (PRI) of the McGill Pain Questionnaire (MPQ) continues to be one of the most frequently used instruments to measure clinical pain. Although a number of exploratory factor analytic studies have failed to consistently support the theoretical structure of the instrument, one previous confirmatory factor analytic study of chronic pain did statistically support the a priori model. Because it has been suggested that acute pain may not involve the same dimensions as chronic pain, this study provided a direct test of the theoretical structure of the MPQ through multi-sample confirmatory factor analysis (CFA) using data provided by women experiencing pain during labor (n = 185) and women experiencing acute postoperative pain (n = 192). Results of the LISREL CFA analysis indicated that the a priori, 3-factor, oblique model originally proposed by Melzack provided the most parsimonious representation of the data across the 2 samples of acute pain.
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There are many options available to measure a child's self-report of pain. Many factors should be considered when choosing a scale, including previous testing, ease of administration, age of the child, and type of pain experience. When selecting a measure, it is important to pretest it with a sample similar to that in the proposed study to evaluate these factors.