European journal of pain : EJP
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Comparative Study
Brain activity for chronic knee osteoarthritis: dissociating evoked pain from spontaneous pain.
Chronic pain is a hallmark of osteoarthritis (OA), yet little is known about its properties and representation in the brain. Here we use fMRI combined with psychophysics to study knee pain in fourteen OA patients and nine healthy controls. Mechanical painful pressure stimuli were applied to the knee in both groups and ratings of evoked pain and related brain activity examined. ⋯ In a subgroup of patients (n=6) we examined brain activity changes for a 2-week, repeat measure, cyclooxygenase-2 inhibitor (valdecoxib) therapy. Treatment decreased spontaneous pain for the worse knee and clinical characteristics of OA, and increased blood and csf levels of the drug which correlated positively with prefrontal-limbic brain activity. These findings indicate dissociation between mechanically induced and spontaneous OA knee pain, the latter engaging brain regions involved in emotional assessment of the self, and challenge the standard clinical view regarding the nature of OA pain.
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Although many studies have investigated the effectiveness of distraction as a method of pain control, the cognitive processes by which attentional re-direction is achieved, remain unclear. In this study the role of executive functioning abilities (inhibition, task switching and working memory) in the effectiveness of distraction is investigated. We hypothesized that the effectiveness of distraction in terms of pain reduction would be larger in participants with better executive functioning abilities. ⋯ Participants were randomly assigned to (1) a distraction group, in which an attention-demanding tone-detection task was performed during the CPT, or (2) a control group, in which no distraction task was performed. Participants in the distraction group reported significantly less pain during the CPT, but the pain experience was not influenced by executive functioning abilities. However, the performance on the distraction task improved with better inhibition abilities, indicating that inhibition abilities might be important in focussing on a task despite the pain.
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Half of female migraineurs in childbearing age use combined oral contraceptives (COCs), but the influence of COCs on perimenstrual migraine is still unclear. We therefore aimed to analyze the risk of occurrence and persistence (i.e. presence for more than 1 day) of headache and migraine before and during menstruation in women with migraine, comparing users of COCs to non-users. We included 184 women with at least 1 day of menstruation recorded in a 90-day diary. ⋯ In both groups, risk of any headache as well as that of migraine was highest during the first 3 days of menstruation with a hazard ratio of 1.9 and 2.1 for non-users and 2.1 and 2.2 for users. Although use of COCs showed no statistically significant overall effect, users were at higher risk for any headache premenstrually and non-users at higher risk for migraine on days 4+ of menstruation. In conclusion, use of COCs exerts only subtle differences on the course of perimenstrual migraine in menstruating women with migraine.
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The daily patient flow at dental emergency departments is subject to fluctuations. The aim of the present study was to investigate whether meteorological parameters were associated with the number of patients reporting acute pain in the oral cavity. ⋯ These findings suggest that changes in barometric pressure were the reason for the observed initiation and/or exacerbation of the various oral pains observed in the emergency room setting. This association has been considered to be rare, with most reports suggesting this phenomenon primarily affects divers and aircraft personnel. Our data suggests otherwise, by providing clear evidence that atmospheric pressure changes commonly influences painful oral conditions.
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Pain and the conscious mind (or the self) are experienced in our body. Both are intimately linked to the subjective quality of conscious experience. Here, we used virtual reality technology and visuo-tactile conflicts in healthy subjects to test whether experimentally induced changes of bodily self-consciousness (self-location; self-identification) lead to changes in pain perception. ⋯ This increase was not modulated by the synchrony of stroking as predicted based on earlier work. This differed for self-identification where we found as predicted that synchrony of stroking increased self-identification with the virtual body (but not a control object), and positively correlated with an increase in pain thresholds. We discuss the functional mechanisms of self-identification, self-location, and the visual perception of human bodies with respect to pain perception.