Pain
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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
A substance P receptor (NK1) antagonist can reverse vascular and nociceptive abnormalities in a rat model of complex regional pain syndrome type II.
Sciatic nerve section in rats evokes chronic hindlimb edema, pain behavior, and hyperalgesia, a syndrome resembling complex regional pain syndrome (CRPS II) in man. Furthermore, there is an increase in spontaneous protein extravasation in the hindpaw skin of rats after sciatic transection, similar to the increased protein extravasation observed in the edematous limbs of CRPS patients. Now we demonstrate that sciatic nerve section also generates chronic hindlimb warmth, distal articular tenderness, allodynia, and periarticular osteoporosis, sequelae of nerve injury resembling those observed in CRPS. ⋯ Systemic administration of LY303870 also reversed hindpaw edema and cutaneous warmth. Intrathecal, but not systemic administration of LY303870 reversed soft tissue and articular mechanical hyperalgesia in the hindpaw. Collectively, these data further support the hypothesis that the sciatic nerve transection model closely resembles CRPS and that substance P contributes to the spontaneous extravasation, edema, warmth, and mechanical hyperalgesia observed in this model.
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The aim of this study was to examine how men and women observe experimentally induced pain in male and female participants and to specifically determine the accuracy of observed pain ratings, the possible interactions between the sex of the viewer and the sex of the individual being observed, and the influence of gender role expectations on observed pain ratings. The sample comprised 29 participants (15 females). They each completed a battery of psychological questionnaires and viewed a presentation of 10 randomly ordered video clips. ⋯ When endurance expectations were controlled, sex of the viewer no longer significantly predicted observed pain ratings. The 'willingness to report pain' variable was not a significant predictor of observed pain ratings. Our results show that women are perceived to have more pain than men, that there was a tendency by both sexes to underestimate pain in others, but men showed even greater underestimation, and that gender role expectations of pain endurance given by the video observers accounted for substantial variance in their ratings of pain in the videos.
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Comparative Study
Fear of pain, physical performance, and attentional processes in patients with fibromyalgia.
Patients with fibromyalgia often present with increased levels of disability and physical functioning, for which the determinants are still unclear. In patients with other musculoskeletal pain syndromes, such as chronic low back pain, physical performance and disability levels are shown to be strongly associated with pain-related fear, and even stronger than pain severity. The present study was aimed at examining the role of pain-related fear and attentional processes on tolerance for physical activity in fibromyalgia patients. ⋯ The results showed that pain itself was a greater predictor of activity tolerance than pain-related fear, but that pain-related fear was the stronger predictor of reaction times on the cognitive task. Also, all groups showed equal improvement in physical performance in the dual task. The findings suggest that baseline pain acts as an occasion setter which determines the level of physical activity the patient is willing to perform, regardless of pain increase and threat-reducing instructions.
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GABA and glycine are inhibitory neurotransmitters used by many neurons in the spinal dorsal horn, and intrathecal administration of GABA(A) and glycine receptor antagonists produces behavioural signs of allodynia, suggesting that these transmitters have an important role in spinal pain mechanisms. Several studies have described a substantial loss of GABA-immunoreactive neurons from the dorsal horn in nerve injury models, and it has been suggested that this may be associated with a loss of inhibition, which contributes to the behavioural signs of neuropathic pain. We have carried out a quantitative stereological analysis of the proportions of neurons in laminae I, II and III of the rat dorsal horn that show GABA- and/or glycine-immunoreactivity 2 weeks after nerve ligation in the chronic constriction injury (CCI) model, as well as in sham-operated and nai;ve animals. ⋯ However, we did not observe any change in the proportion of neurons in laminae I-III of the ipsilateral dorsal horn that showed GABA- or glycine-immunoreactivity compared to the contralateral side in these animals, and these proportions did not differ significantly from those seen in sham-operated or nai;ve animals. In addition, we did not see any evidence for alterations of GABA- or glycine-immunostaining in the neuropil of laminae I-III in the animals that had undergone CCI. Our results suggest that significant loss of GABAergic or glycinergic neurons is not necessary for the development of thermal hyperalgesia in the CCI model of neuropathic pain.