Pain
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The Tampa scale for kinesiophobia (TSK) was developed to measure fear of movement/(re)injury in chronic pain patients. Although studies of the Dutch adaptation of the TSK have identified fear of movement/(re)injury as an important predictor of chronic pain, pain-related avoidance behaviour, and disability, surprisingly little data on the psychometric properties of the original English version of the TSK are available. The present study examined the reliability, construct validity and factor structure of the TSK in a sample of chronic pain patients (n=200) presenting for an interdisciplinary functional restoration program. ⋯ The TSK was not related to individual differences in physical performance testing as assessed using standardised treadmill and lifting tasks. Confirmatory factor analyses suggest that the TSK is best characterized by a three-factor trait method model that includes all 17 of the original scale items and takes into account the distinction between positively and negatively keyed items. The results of the present study provide important details regarding the psychometric properties of the original English version of the TSK and suggest that it may be unnecessary to remove the negatively keyed items in an attempt to improve scale validity.
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Controlled Clinical Trial
Placebo analgesia is accompanied by large reductions in pain-related brain activity in irritable bowel syndrome patients.
Previous experiments found that placebos produced small decreases in neural activity of pain-related areas of the brain, yet decreases were only statistically significant after termination of stimuli and in proximity to when subjects rated them. These changes could reflect report bias rather than analgesia. This functional magnetic resonance imaging (fMRI) study examined whether placebo analgesia is accompanied by reductions in neural activity in pain-related areas of the brain during the time of stimulation. ⋯ Large reductions in pain and in brain activation within pain-related regions (thalamus, somatosensory cortices, insula, and anterior cingulate cortex) occurred during the placebo condition. Results indicate that decreases in activity were related to placebo suggestion and a second factor (habituation/attention/conditioning). Although many factors influence placebo analgesia, it is accompanied by reduction in pain processing within the brain in clinically relevant conditions.
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Biopsychosocial models of chronic pain that recognize psychological and environmental factors as important aspects of adjustment to pain have been proposed for understanding chronic pain and related suffering in persons with multiple sclerosis (MS), but such models have not been empirically tested. The objective of this study was to test such a model by evaluating the associations of several psychosocial variables (i.e., pain-related catastrophizing, perceived social support, pain beliefs, and pain coping) with pain intensity, pain interference with functioning, and psychological functioning in persons with chronic pain and MS, after controlling for demographic and disease-related factors. Participants were 125 community-dwelling persons with MS and pain who completed a mailed questionnaire that included measures of pain intensity and interference, psychological functioning, catastrophizing, social support, and pain beliefs and coping. ⋯ These variables explained an additional 22% of the variance in pain-related interference (p<.001) and 43% of the variance in psychological functioning (p<.001), after adjusting for demographic and MS-related variables and average pain intensity. Catastrophizing was consistently and independently associated with all criterion measures, whereas social support, pain beliefs, and pain coping were associated with some criterion measures but not others. The results provide empirical support for a biopsychosocial understanding of chronic pain in MS and suggest that specific psychosocial factors (e.g., catastrophizing) may be important regarding adjustment to pain in persons with MS.
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The theory of chemical radiculitis had been put forward about 30 years ago, but as yet it has not been proved by clinical studies. The aim of the current studies was to determine whether the annular tear of a painful disc proved by discography is the cause of radiating leg pain (radiculopathy) in patients with discogenic low back pain. Forty-two patients with discogenic low back pain at single disc level with concomitant radiating leg pain were studied in order to analyse the relationship between site of annular tear and side of radiating leg pain. ⋯ The current studies found that there was a significant positive correlation between the site of annular tear and the side of radiation pain. Abnormalities of electromyogram and reduction of motor nerve conduction velocity were found on the side of radiating leg pain. The studies indicated that leakage of chemical mediators or inflammatory cytokines, which are produced in the painful disc, into epidural space through annular tear could lead to injury to adjacent nerve roots, and it might constitute the primary pathophysiologic mechanism of radiating leg pain in patients with discogenic low back pain but with no disc herniation.
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Previous studies using a primary task procedure have demonstrated that an experimental pain stimulus interrupts ongoing task performance in healthy volunteers and patients, and that this interruption is intensified by catastrophic thinking about pain and the perceived threat value of the pain stimulus. However, no studies have investigated the interruption of attention by relevant threatening stimuli in specific patient samples. ⋯ The patients showed a more pronounced deterioration of performance compared to controls when the neck rotation and extension fixations were introduced. Within the groups, neither catastrophic thinking nor fear predicted the magnitude of the performance deterioration.