Pain
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Behavioral and neurochemical studies have shown that the coeruleospinal modulation system is activated by peripheral inflammation, and that this modulation system is active in only the dorsal horn ipsilateral, but not in the dorsal horn contralateral, to the site of inflammation; the present study was designed to confirm electrophysiologically this previous finding. Extracellular recordings from dorsal horn neurons were continued for at least 4 h after the induction of inflammation. Unilateral hindpaw inflammation was produced by a subcutaneous injection of carrageenan (2 mg in 0.15 ml saline). ⋯ Four hours after the induction of inflammation, there was a significant increase in both the background activity and heat-evoked response in neurons in LC/SC-lesioned compared to LC/SC-intact rats. In neurons located in the dorsal horn contralateral to the inflamed paw, 4 h after inflammation, no significant increase in either the background activity or the heat-evoked response in neurons in LC/SC-lesioned rats was observed, as well as in the case before inflammation. These results suggest that the coeruleospinal modulation system is active in only the dorsal horn ipsilateral, but not in the dorsal horn contralateral, to the site of inflammation during the development of unilateral hindpaw inflammation.
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Coping responses have been shown to be associated with physical and psychological functioning in patients with chronic pain. Assessment of coping strategies has received increasing attention, with several measures of cognitive and behavioral coping showing promise. One such instrument is the Chronic Pain Coping Inventory (Pain 60 (1995) 203), a 65-item measure of behavioral and cognitive pain coping strategies often targeted as part of multidisciplinary pain treatment. ⋯ This article describes the development of an abbreviated (42-item) CPCI. The results demonstrate very high correlations between the original and abbreviated CPCI scales, as well as comparable internal consistency, test-retest stability, and validity coefficients. The findings support the reliability and validity of the abbreviated CPCI, and suggest that it could be substituted for the CPCI without sacrificing reliability and validity in situations where a briefer measure of coping with chronic pain is preferable.
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Comparative Study
Functional self-efficacy and pain-related disability among older veterans with chronic pain in a primary care setting.
We examined the relationship between functional self-efficacy and pain-related disability in a sample of older veterans with chronic pain. A total of 1045 veterans aged 65 years or older who received primary care at the VA Connecticut Healthcare System in West Haven, CT, were assessed for the presence of chronic pain (i.e. pain due to a non-cancer cause for >/=3 consecutive months in the past 12 months); 303 (26%) screened positive; and 245 (81%) participated. Using a ten-item functional self-efficacy questionnaire (scale: 0-40), participants were categorized into three functional self-efficacy groups: low, score =26; moderate, score 27-38; and high, score 39-40. ⋯ The prevalence of pain-related disability was 56%. After adjusting for potential confounders, the likelihood of pain-related disability was significantly higher for those with moderate vs. high (OR=2.05, 95% CI 1.03-4.06) and low vs. high (OR=4.77, 95% CI 1.96-11.61) functional self-efficacy. Functional self-efficacy was a strong and independent factor associated with pain-related disability among older veterans with chronic pain.
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Comparative Study
Heat pain thresholds and cerebral event-related potentials following painful CO2 laser stimulation in chronic tension-type headache.
Current opinion concerning the pathophysiology of tension-type headache (TTH) and its related pericranial muscle tenderness proposes a primary role of central sensitization at the level of dorsalhorn/trigeminal nucleus as well as the supraspinal level. Investigation of these phenomena can be conducted using laser-evoked potentials (LEPs), which are objective and quantitative neurophysiological tools for the assessment of pain perception. In the present study we examined features of LEPs, as well as cutaneous heat-pain thresholds to laser stimulation, in relation to the tenderness of pericranial muscles in chronic TTH resulting from pericranial muscle disorder, during a pain-free phase. ⋯ The TTS scores at almost all pericranial sites were higher in TTH patients than in normal controls. The amplitude of the N2a-P2 complex elicited by stimulation of the pericranial zone was greater in TTH patients than in controls; the amplitude increase was significantly associated with the TTS score. Our findings suggest that pericranial tenderness may be a primary phenomenon that precedes headache, and is mediated by a greater pain-specific hypervigilance at the cortical level.