Pain
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Comparative Study
Comparison of verbal and visual analogue scales for measuring the intensity and unpleasantness of experimental pain.
Although the multidimensional nature of pain is now well recognized, there are, nevertheless, very few quantitative tests to measure the separate dimensions of pain and little data concerning their relative sensitivity. The present study compares 2 currently available methods, verbal descriptor and visual analogue scales. ⋯ However, data derived from the verbal descriptor scales revealed that subjects rated the painful temperatures as relatively more intense than unpleasant; this difference could not be detected using the visual analogue scales. These results confirm that both visual analogue and verbal descriptor techniques successfully quantify sensory intensity and affective aspects of pain, but that verbal descriptors may provide the more sensitive tool for separating intensity and unpleasantness.
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Pain patients' retrospective reports of pain are important to physicians and other health professionals in helping to decide on future treatment plans. Unfortunately patients' memory of pain can be inaccurate and subject to overestimation. This study examined variables which influenced accuracy of remembering pain in 93 chronic pain patients. ⋯ Results showed that most patients tended to overestimate their pain intensity levels. Cervical and low back pain patients were found to be more accurate than headache and abdominal pain patients in remembering their pain. Patients who reported more emotional distress, who had conflicts at home, who were less active and who relied on medication tended to be the most inaccurate in remembering their pain.
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Human pain responsivity was defined as the subject's behavioral pain endurance time (PET) to the 1 +/- 0.3 degrees C cold-pressor test, a naturalistic and clinical analogue tonic pain model. Over the past 2 years, we have consistently observed a behavioral dichotomy of pain responsivity in each of our 6 studies (all at P less than 0.000001 effect level), totaling 205 subjects. Overall, the pain-tolerant (PT) subjects could endure the whole 5 min (note that 3 min was the ceiling criterion in the last study) of cold-pressor test, while the pain-sensitive (PS) subjects could merely tolerate the test for an overall mean of 60 sec, 20% of PET in the PT group. ⋯ The psychological/physiological etiology of such drastic human pain responsivity requires intense systematic investigations. This report discusses the results in: (a) individual differences in pain responsivity, (b) characterization of the cold-pressor test as a model for tonic pain, (c) contrast between PS and PT groups of pain perception and state anxiety, and (d) psychological determinants of measures for cognitive, perceptual and affective domains. Discussion was also focused on the experimental tonic pain model and its generality for clinical pain, as well as the basic model of the cold-pressor test for human tonic pain responsivity.
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A transdermal formulation of fentanyl (TTS-fentanyl, Alza Corp., Palo Alto, CA) was evaluated in 13 surgical patients after an abdominal operation. An intraoperative dose of fentanyl (100-200 micrograms i.v.) was administered at the same time as the TTS-fentanyl systems (50-125 micrograms/h) were applied to the antero-lateral chest wall. The TTS-fentanyl systems remained in situ for 24 h and were then removed and a second lot of systems were applied to the contra-lateral chest wall. ⋯ These effects were due to the combined effects of a sustained blood fentanyl concentration and the intermittent supplementary pethidine doses. Side effects due to the topical formulation were transient and included erythema (8 patients) and a minor rash (2 patients) in the area occluded by the systems. The TTS-fentanyl systems provided a significant contribution to postoperative pain control but, at the TTS dose rates used, supplementary doses of pethidine were required by all patients probably to control 'incident' pain.
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Case Reports Comparative Study
Central post-stroke pain--a study of the mechanisms through analyses of the sensory abnormalities.
The somatosensory abnormalities in 20 men and 7 women (mean age 67 years, range 53-81) with central post-stroke pain (CPSP) have been analysed in detail with traditional neurological tests and quantitative methods. The cerebrovascular lesions were located in the lower brain-stem in 8 patients, involved the thalamus in 9 and in 6 were suprathalamic. In 4 patients the location of the CVL could not be determined. ⋯ The results indicate that all patients with CPSP have lesions that affect the major pathways for temperature and pain sensibility, i.e., the spino-thalamo-cortical pathways. Furthermore it appears that neither the level of the lesion along the neuraxis nor concomitant injury to the medial lemniscal pathways is crucial for the development of CPSP. The results confirm the notion that CPSP is a deafferentation syndrome, but they also provide evidence against the hypothesis that CPSP is a release phenomenon caused by a lesion that removes inhibitory influences of the lemniscal pathways on neurones that evoke pain.