Pain
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Randomized Controlled Trial Clinical Trial
Correlates of depression in chronic pain patients: a comprehensive examination.
This study examined the relations between depression and demographic, pain-related, and work-related variables in 254 chronic pain patients. Regression analyses were conducted, initially by category (i.e., demographic, pain-related, and work-related), and finally a comprehensive regression analysis was performed, containing the significant independent variables from each category. Among the demographic variables, education level and marital status were related to depression, and an interaction between age and gender was associated with depression, with younger women and older men reporting more depression. ⋯ Among the work-related variables, unemployment was associated with depression, and there was an interaction between work status and litigation status, with working and litigating being associated with depression and not working and not litigating being associated with depression. In the comprehensive analysis, work status, education level, and marital status accounted for a significant amount of the variance in depression scores. These findings, together with future research directions, are discussed.
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
Modulation of pressure pain thresholds during and following isometric contraction in patients with fibromyalgia and in healthy controls.
This study aimed at evaluating the influence of submaximal isometric contraction on pressure pain thresholds (PPTs) in 14 fibromyalgia (FM) patients and 14 healthy volunteers, before and after skin hypoesthesia. PPTs were determined with pressure algometry over m. quadriceps femoris before, during and following an isometric contraction. Maximum voluntary contraction (MVC) was assessed using a computerized dynamometer. ⋯ Anesthetic cream raised PPTs at rest in controls (P < 0.01) but not in FM patients, and did not influence contraction or post-contraction PPTs in either group. Therefore, the increased pressure pain sensibility in FM patients is more pronounced deep to the skin. The observed decrease of PPTs during isometric contraction in FM patients could be due to sensitization of mechanonociceptors caused by muscle ischemia and/or dysfunction in pain modulation during muscle contraction.
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Randomized Controlled Trial Clinical Trial
A new analogue scale for assessing children's pain: an initial validation study.
A new instrument was designed to provide a practical clinical measure for assessing children's pain intensity and pain affect. The pocket size measure includes a Coloured Analogue Scale (CAS) to assess intensity and a facial affective scale to assess the aversive component of pain. Both scales have numerical ratings on the back, so that the person administering it can quickly note the numbers that represent a child's pain. ⋯ The new instrument has equivalent psychometric properties to a 165 mm VAS. However, the CAS was rated as easier to administer and score than the VAS, so it may be more practical for routine clinical use. Since the CAS has fulfilled the first two criteria for a pain measure (psychophysical properties and discriminant validity), it is ethical to proceed with the formal definitive test for construct validity, in which children from various clinical populations use the CAS scale to assess their own pain.
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Randomized Controlled Trial Clinical Trial
Peripheral analgesic effect of intra-articular clonidine.
Sympathetic nervous system stimulation, which releases noradrenaline, influences the nociceptor activity which develops after tissue injury. The alpha 2-adrenergic agonist, clonidine, produces analgesia through a central mechanism but also inhibits noradrenaline release at terminal nerve fibre endings. Clonidine may induce analgesia when administered at peripheral sites. ⋯ The difference was not significant between group 4 (300 +/- 419 min) and the other groups. We conclude that a low dose of intra-articular clonidine produces analgesia unrelated to vascular uptake of the drug. This study further supports a peripheral analgesic effect of clonidine.
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Randomized Controlled Trial Clinical Trial
The opposite effects of the opiate antagonist naloxone and the cholecystokinin antagonist proglumide on placebo analgesia.
Discovery of the involvement of endogenous opiates in placebo analgesia represents an important step in understanding the mechanisms underlying placebo response. In the present study, we investigated the effects of the opiate antagonist naloxone and the cholecystokinin antagonist proglumide on placebo analgesia in a human model of experimentally induced ischemic pain. First, we found that part of the placebo response was reversed by naloxone, confirming previous studies on the role of opioids in the placebo phenomenon. ⋯ The placebo effect can thus be modulated in two opposite directions: it can be partially abolished by naloxone and potentiated by proglumide. The fact that placebo potentiation by proglumide occurred only in placebo responders, but not in non-responders, suggests that activation of an endogenous opiate system is a necessary condition for the action of proglumide. These results suggest an inhibitory role for cholecystokinin in placebo response, although the low affinity of proglumide for cholecystokinin receptors does not rule out the possibility of other mechanisms.