Pain
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This experiment was set up to test the hypothesis that confrontation with feared movements would lead to symptom-specific muscular reactivity in chronic low back pain patients who report high fear of movement/(re)injury. Thirty-one chronic low back pain patients were asked to watch a neutral nature documentary, followed by a fear-eliciting video-presentation, while surface electromyography (EMG) recordings were made from the lower paraspinal and the tibialis anterior muscles. It was further hypothesized that negative affectivity (NA) would moderate the effects of fear on symptom-specific muscular reactivity, as well as the effects of muscular reactivity on pain report. ⋯ As predicted, there was a significant covariation between left paralumbar muscular activity and pain report. This association was moderated by NA, but in the opposite direction. The findings extend the symptom-specificity model of psychophysiological reactivity, and support the idea that pain-related fear perpetuates pain and pain disability through muscular reactivity.
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The exteroceptive suppression periods (ES) in human jaw-closing muscles can be conditioned by a wide range of somatosensory stimuli and cognitive states. The aim of this study was to examine the effects of tonic experimental jaw-muscle pain versus remote muscle pain on the short-latency (ES1) and long-latency (ES2) reflex in the jaw-closing muscles. Twelve healthy subjects participated in the first experiment with jaw-muscle pain. ⋯ In experiment 3, no significant effects on ES1 and ES2 were observed during painful infusion of hypertonic saline into the leg muscle. These results indicate that the effects of tonic jaw-muscle pain on ES2 can be distinguished from a generalized effect of muscle pain. Furthermore, there seems to be a differential and lateralized effect of jaw-muscle pain on the brain stem reflex circuits involved in the generation of ES1 and ES2 probably through a presynaptic mechanism.
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The objective of this study was to investigate how economic compensation for disability (disability pensions) to chronic pain patients affected their utilisation of health care services. The study was carried out as a register investigation. Inclusion of 144 study patients was based on records from 1989 and 1990 of the Rehabilitation and Pension Board in the Municipality of Copenhagen. ⋯ Chronic pain patients who did not get a disability pension and those who were not satisfied with the level of the pension awarded, maintained their health care utilisation after the decision. The mean health care use by the patients who appealed the level of the pension was three times higher than the mean health care use by the patients who accepted the level of the pension awarded. The study may indicate that lack of or insufficient economic compensation from the social system in chronic pain patients contribute to an inexpedient pain behaviour resulting in increased expenses for the health care sector.
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The present paper presents the relationship between the total body-pain (TBP) score, defined as the total number of areas shaded on a pain drawing, and the pain from one area, the Shoulder-Neck (SN), among subjects in or out of full-time gainful work respectively. Furthermore, relationships between pain-score, self-experienced health (SEH) and level of mental distress, measured with the General Health Questionnaire (GHQ) were investigated. The analyses is based on a general population sample of 8,116 men and women, 45-60 years of age, completing a questionnaire in the Malmö Shoulder Neck Study. ⋯ If such data are not collected in epidemiological studies on causes for musculoskeletal pain it will at best lead to unnoticed effect modifications. At worst a potential confounding situation may occur. The relationship between the self-experienced health, mental distress and chronic pain identifies chronic pain as a major public-health problem and suggests a multidisciplinary approach in the treatment and rehabilitation already before work capacity is lost.
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This electrophysiological study examined the effects of NSAID administration on synaptically-elicited responses of rat single spinal dorsal horn neurons to natural stimulation of peripheral receptive fields. Nociceptive responses consisted of a fast initial discharge during the stimulus followed by a slowly-decaying afterdischarge. The cyclooxygenase inhibitor, indomethacin (2.0-8.0 mg/kg, i.v.), was without effect on the on-going rate of discharge but dose-dependently inhibited synaptically-elicited responses to noxious cutaneous mechanical stimulation (fast initial discharge: n = 3/3 with 2 mg/kg, 5/8 with 4 mg/kg, 5/6 with 8 mg/kg; slowly-decaying afterdischarge: n = 3/3 with 2 mg/kg, 6/8 with 4 mg/kg, 6/6 with 8 mg/kg) and thermal (fast initial discharge: n = 7/9 with 8 mg/kg; slowly-decaying afterdischarge: n = 3/4 with 4 mg/kg, n = 7/9 with 8 mg/kg). ⋯ The data are interpreted to suggest that sensory inputs are more involved than input-independent excitation of dorsal horn neurons in leading to de novo synthesis of eicosanoids and that the time course of this synthesis brings the levels to a point where COX inhibition can have an observable effect during prolonged excitation. Although the data suggest that COX inhibition differentially inhibits nociceptive versus non-nociceptive mechanisms at the cellular level, irrespective of the modality of the stimulus, this is the first direct demonstration that prolonged activation of synaptic mechanisms are preferentially inhibited. According to this it would be predictable that NSAIDs would be more effective on nociceptive types of pain characterized by time or prolonged inputs of primary afferents.