Pain
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Randomized Controlled Trial Multicenter Study Clinical Trial
Prediction of physician visits and prescription medicine use for back pain.
The primary purpose of this study was to examine the extent to which specific patient attitudes and beliefs about medical care and self-care for back pain predict future healthcare use. An automated database allowed examination of the predictive relationships in two primary care patient samples. In general, beliefs that physicians should find a definitive cause and permanent cure for back pain predicted neither physician visits nor prescription medication fills. ⋯ Factor analyses of the item set yielded three factors, but inconclusive results; the internal consistency of the identified sub-scales was only moderate. However, findings that a subset of items predicted physician visits and prescriptions medication fills, and was sensitive to change following a self-care intervention, suggest avenues for improving measurement of self-care orientation. These findings help clarify specific patient attitudes and beliefs that are related to healthcare utilization and suggest that a subset of these beliefs can be modified through a brief educational intervention.
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Comparative Study
An analysis of factors that contribute to the magnitude of placebo analgesia in an experimental paradigm.
Placebo analgesia was produced by conditioning trials wherein heat induced experimental pain was surreptitiously reduced in order to test psychological factors of expectancy and desire for pain reduction as possible mediators of placebo analgesia. The magnitudes of placebo effects were assessed after these conditioning trials and during trials wherein stimulus intensities were reestablished to original baseline levels. In addition, analyses were made of the influence of these psychological factors on concurrently assessed pain and remembered pain intensities. ⋯ The results further demonstrated that placebo effects based on remembered pain were 3 to 4 times greater than those based on concurrently assessed placebo effects, primarily because baseline pain was remembered as being much more intense than it actually was. However, similar to concurrent placebo effects, remembered placebo effects were strongly associated with expected pain levels that occurred just after conditioning. Taken together, these results suggest that magnitudes of placebo effect are dependent on multiple factors, including conditioning, expectancy, and whether analgesia is assessed concurrently or retrospectively.
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The whiplash syndrome has immense socio-economic impact. Despite extensive studies over the past years, the mechanisms involved in maintaining the pain in chronic whiplash patients are poorly understood. The aim of the present experimental study was to examine the muscular sensibility in areas within and outside the region involved in the whiplash trauma. ⋯ In the present study, muscular hyperalgesia and large referred pain areas were found in patients with chronic whiplash syndrome compared to control subjects both within and outside the traumatised area. The findings suggest a generalised central hyperexcitability in patients suffering from chronic whiplash syndrome. This indicates that the pain might be considered as a neurogenic type of pain, and new pharmacological treatments should be investigated accordingly.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Comparative reliability and validity of chronic pain intensity measures.
Reliable and valid measures of pain are essential for conducting research on chronic pain. The purpose of this longitudinal study was to compare the reliability and validity of several measures of pain intensity. One hundred twenty-three patients with chronic pain were administered telephone interview versions of 0-10 scales of current, worst, least and average pain, immediately prior to beginning a multidisciplinary treatment program. ⋯ Contrary to prediction, the composite measures did not show a statistically significant superiority to the individual ratings in terms of their ability to detect change in pain intensity from pre-treatment to various points after treatment. The composite scores did, however, show greater stability than did the individual ratings after treatment. The practical conclusions of this study are; (1), individual 0-10 pain intensity ratings have sufficient psychometric strengths to be used in chronic pain research, especially research that involves group comparison designs with relatively large sample sizes, but, (2), composites of 0-10 ratings may be more useful when maximal reliability is necessary, (e.g. in studies with relatively small sample sizes, or in clinical settings where monitoring of changes in pain intensity in individuals is needed).
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Randomized Controlled Trial Multicenter Study Clinical Trial
N of 1 randomised controlled trials of oral ketamine in patients with chronic pain.
Anecdotal reports suggest that the general anaesthetic drug ketamine, taken orally in low doses, can give rise to some extra analgesia in patients with refractory neuropathic pain. This study was designed to determine the proportion of patients with chronic neuropathic pain responding to oral ketamine, and then to separate the true treatment effect from non-specific effects by means of an n of 1 randomised controlled trial. Twenty-one patients gave informed consent and completed daily pain diaries and continued on their usual treatments (drug and non-drug) for the duration of the study. ⋯ We conclude that oral ketamine only gave rise to an extra analgesic response in three out of 21 patients with chronic neuropathic pain (14%). Adverse effects limited the use of the drug in almost half of the patients. The n of 1 trial was useful in demonstrating no true therapeutic effect for the ketamine in two thirds of the patients progressing to that part of the trial.