Pain
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Comparative Study Clinical Trial Controlled Clinical Trial
Differences in patients' and family caregivers' perceptions of the pain experience influence patient and caregiver outcomes.
The purposes of this study were to determine if there were differences in pain intensity scores, pain duration scores, mood states, and quality of life of oncology outpatients whose pain intensity scores were congruent with their family caregivers compared to patients whose pain intensity scores were non-congruent and to determine if there were differences in mood states, health status, and caregiver strain between family caregivers whose pain intensity scores were congruent with their family members and those family caregivers whose pain intensity scores were non-congruent. A total of 78 patient-caregiver dyads participated in the study. Patients completed a Demographic Questionnaire, a Cancer Pain Questionnaire, the Profile of Mood States, and the Multidimensional Quality of Life Scale-Cancer 2. ⋯ Patients in the non-congruent dyads (i.e. difference of >10 on the VAS score) had significantly more mood disturbance and a poorer quality of life than patients in the congruent dyads. Family caregivers in the non-congruent dyads had significantly higher caregiver strain score than caregivers in the congruent dyads. These findings suggest that differences in the perception of the pain experience between patients and their family caregivers is associated with deleterious outcomes for the patient and their family caregivers.
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Randomized Controlled Trial Clinical Trial
Classical conditioning and the placebo effect.
Stimulus substitution models posit that placebo responses are due to pairings of conditional and unconditional stimuli. Expectancy theory maintains that conditioning trials produce placebo response expectancies, rather than placebo responses, and that the expectancies elicit the responses. ⋯ Verbal information reversed the effect of conditioning trials on both placebo expectancies and placebo responses, and the magnitude of the placebo effect increased significantly over 10 extinction trials. These data disconfirm a stimulus substitution explanation and provide strong support for an expectancy interpretation of the conditioned placebo enhancement produced by these methods.
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The present study found in lightly anesthetized rats that the radiant heat-evoked tail flick (TF) reflex was markedly inhibited by a unilateral electrical stimulation (a 20 ms train of 0.2 ms, 100 Hz, 30-100 microA pulses) of the ventrolateral orbital cortex (VLO), with the tail flick latency (TFL) being increased. The mean threshold of VLO stimulation for producing inhibition of the TF reflex was 39.2 +/- 8.7 microA (n = 26), and this inhibitory effect increased following increasing stimulation intensity from 40 to 70 microA. The inhibition developed and remained during the stimulation and disappeared rapidly after termination of the stimulation. ⋯ The difference was significant between the TFL changes produced by VLO stimulation before and after PAG lesion (P < 0.01). The results suggest that the antinociception elicited by VLO stimulation is mediated by PAG, leading to activation of the brainstem descending inhibitory system which depresses the nociceptive transmission at the spinal level. The role played by VLO in pain modulation was discussed in association with the proposed endogenous analgesic system consisting of spinal cord-Sm-VLO-PAG-spinal cord.
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Comparative Study
Do patients with chronic pain selectively attend to pain-related information?: preliminary evidence for the mediating role of fear.
Preliminary evidence from a study using a modified Stroop paradigm suggests that individuals with chronic pain selectively attend to pain-related information. The current study was conducted in an attempt to replicate and extend this finding. Nineteen patients with chronic pain stemming from musculoskeletal injury and 22 healthy control subjects participated. ⋯ Ther., 34 (1996) 545-554), those with low anxiety sensitivity shifted attention away from stimuli related to pain whereas those with high anxiety sensitivity responded similarly to dot-probes regardless of the parameters of presentation. These results suggest that the operation of the information processing system in patients with chronic pain may be dependent on a patient's trait predisposition to fear pain. Theoretical and ecological implications are discussed.
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Randomized Controlled Trial Clinical Trial
The visual analogue pain intensity scale: what is moderate pain in millimetres?
One way to ensure adequate sensitivity for analgesic trials is to test the intervention on patients who have established pain of moderate to severe intensity. The usual criterion is at least moderate pain on a categorical pain intensity scale. When visual analogue scales (VAS) are the only pain measure in trials we need to know what point on a VAS represents moderate pain, so that these trials can be included in meta-analysis when baseline pain of at least moderate intensity is an inclusion criterion. ⋯ For those reporting severe pain 85% scored over 54 mm with a mean score of 75 mm. There was no difference between the corresponding VAS scores of men and women. Our results indicate that if a patient records a baseline VAS score in excess of 30 mm they would probably have recorded at least moderate pain on a 4-point categorical scale.