Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
The analgesic effect of codeine as compared to imipramine in different human experimental pain models.
The hypoalgesic effect of single oral doses of 100 mg imipramine and 125 mg codeine was evaluated in a randomised, placebo-controlled, double-blind, 3-way cross-over experiment including 18 healthy volunteers. Pain tests were performed before and 90, 180, 270, 360 and 450 min after medication. The tests included determination of pain tolerance thresholds to pressure, pain detection/tolerance thresholds to single electrical sural nerve stimulation and pain summation at tolerance threshold to repetitive electrical sural nerve stimulation (temporal summation) and pain experienced during the cold pressor test, rated as peak pain intensity, pain average intensity and discomfort. ⋯ Pain summation may be a key mechanism in neuropathic pain. Imipramine has a documented effect on such pain conditions on temporal summation. The present study showed that codeine also inhibits temporal summation, which is in line with the clinical observations indicating that opioids relieve neuropathic pain.
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Comparative Study Clinical Trial
Pain assessment in cognitively impaired and unimpaired older adults: a comparison of four scales.
The purpose of the study was to compare the psychometric properties of four established pain scales in a population of hospitalized older adults (mean age, 76 years) with varying levels of cognitive impairment. Patients made ratings of current pain three times/day for 7 days. They also made retrospective daily, weekly, and bi-weekly ratings of usual, worst, and least pain levels over a 14-day period. ⋯ Retrospective estimates of pain varied by mental status: a combination of usual/worst pain was best for cognitively impaired patients, while a combination of usual/least pain was best for unimpaired patients. These findings support the use of the 21-point box scale for pain assessment in older patients, including those with mild-to-moderate cognitive impairment. They also support the ability of older, cognitively impaired patients to rate pain reliably and validly.
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The traditional concept that pain is poorly localized has been challenged by recent studies, where subjects were able to point to the stimulated spot on the skin with an accuracy of 10-20 mm. Pointing movements themselves, however, have errors of about 15 mm. To determine the limits of sensory performance of the nociceptive system independent of motor performance, point localization of heat pain (540 mJ punctate laser stimuli, 5 mm diameter), mechanical pain (256 mN punctate probe, 200 microm diameter), and touch (16 mN von Frey probe, 1.1 mm diameter) were tested in a two-alternative forced-choice paradigm in 12 healthy subjects. ⋯ Sequential spatial discrimination for touch was significantly better than simultaneous spatial discrimination tested with a grating orientation task (18.9 mm), but both were one order of magnitude worse than at the finger tip (1.3 mm, 0.4 +/- 0.1 log2 units). In conclusion, pain evoked by radiant heat pulses and touch evoked by von Frey probes were localized with similar precision on the back of the hand. These findings indicate that outside the tactile fovea at finger tips or lips the spatial discrimination capacities of the nociceptive and tactile systems are about equal.
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This study describes the development and validation of a novel tool for identifying patients in whom neuropathic mechanisms dominate their pain experience. The Leeds assessment of neuropathic symptoms and signs (LANSS) Pain Scale is based on analysis of sensory description and bedside examination of sensory dysfunction, and provides immediate information in clinical settings. It was developed in two populations of chronic pain patients. ⋯ This data was used to derive a seven item pain scale, consisting of grouped sensory description and sensory examination with a simple scoring system. The LANSS Pain Scale was validated in a second group of patients (n = 40) by assessing discriminant ability, internal consistency and agreement by independent raters. Clinical and research applications of the LANSS Pain Scale are discussed.
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Evidence of the relationship between childhood abuse and pain problems in adulthood has been based on cross-sectional studies using retrospective self-reports of childhood victimization. The objective of the current study was to determine whether childhood victimization increases risk for adult pain complaints, using prospective information from documented cases of child abuse and neglect. Using a prospective cohort design, cases of early childhood abuse or neglect documented between 1967 and 1971 (n = 676) and demographically matched controls (n = 520) were followed into young adulthood. ⋯ These findings indicate that the relationship between childhood victimization and pain symptoms in adulthood is more complex than previously thought. The common assumption that medically unexplained pain is of psychological origin should be questioned. Additional research conducting comprehensive physical examinations with victims of childhood abuse and neglect is recommended.