The journal of pain : official journal of the American Pain Society
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Comparative Study
Results of the Leeds assessment of neuropathic symptoms and signs pain scale in Turkey: a validation study.
Classification of pain and identification of the specific pain mechanisms through utilization of clinical data are helpful to the physician in choosing the appropriate treatment model. For discrimination between different pain types, various tests could be used. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Pain Scale is a scale based on the analysis of data obtained during bedside examination. The LANSS Pain Scale, as first used by Bennett, is a very useful tool that provides immediate information in the clinical setting and helps distinguish nociceptive pain from neuropathic pain. In this study we targeted validation of the LANSS Pain Scale in the Turkish population. A total of 104 patients who consulted the Algology Department of Istanbul Faculty of Medicine Outpatient Clinic were enrolled in our validation study. The sensitivity and specificity of the scale were found to be 89.9% and 94.2%, respectively. These results suggest a high validity level for the Turkish version of the LANSS Pain Scale. We believe that this scale is a useful tool for the differential diagnosis of neuropathic pain and can be used in future pharmacologic studies. ⋯ Any measures that aid in differentiating neuropathic pain from nociceptive pain would facilitate effective management of pain. In daily practice the simplicity of the classification method is important. The present study suggests that Turkish version of LANSS can be used for the discrimination between neuropathic and nociceptive types of pain.
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Sex differences in clinical and experimental pain responses have been widely reported; however, few studies have examined sex differences in outcomes from interventional pain treatment and the predictors thereof. The aims of this study were to examine sex differences in (1) the acute pain produced by epidural steroid injections (ESIs), (2) clinical improvements in pain and pain-related psychological distress and disability after ESIs, and (3) predictors of the clinical response to ESIs. A total of 57 patients (37 menopausal women and 20 men), seen in the pain clinic of a regional medical center for ESI therapy, participated. Patients rated the painfulness of the ESI procedure itself. Also, clinical pain, depression, and disability were assessed before treatment and at 2 weeks and 2 months after the ESIs. Participants also were queried about their expectations of successful pain relief, coping strategies, and pain-related anxiety, which were examined as predictors of treatment outcome. Men reported significantly greater pain intensity and unpleasantness than women for the first injection only. All groups showed significant reductions in clinical pain, depression, and disability at 2 weeks compared to baseline, but minimal change occurred between 2 weeks and 2 months past baseline. No sex differences in the magnitude of treatment response emerged; however, specific dimensions of pain coping were associated with treatment responses in a sex-dependent manner. These findings suggest that the determinants of ESI pain and treatment outcome might differ across sex. ⋯ Sex-related influences on pain responses have been widely reported, but few studies have explored sex-dependent predictors of treatment response. These findings indicate that pain coping was differentially associated with outcomes after ESI in women versus men.
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Comparative Study
Neonatal hind paw injury alters processing of visceral and somatic nociceptive stimuli in the adult rat.
Tissue damage during the first few weeks after birth can have profound effects on sensory processing in the adult. We have recently reported that a short-lasting inflammation of the neonatal rat hind paw produces baseline hypoalgesia and exacerbated hyperalgesia after reinflammation of that hind paw in the adult. Because the contralateral hind paw and forepaws also displayed hypoalgesia, we speculated that effects of the initial injury were not somatotopically restricted and would alter visceral sensory processing as well. In the present study we tested this hypothesis by examining the effects of neonatal hind paw injury at P3 or P14 on visceral and somatic sensitivity in the adult rat. In P3 rats, the visceromotor response evoked by colorectal distention in the absence of colonic inflammation was attenuated in carrageenan-treated neonatal rats compared to naive rats. Colonic inflammation in the adult reversed this hypoalgesia and evoked a level of visceral hyperalgesia similar to naive rats. There were no consequences of the P14 injury observed in the adult. In a second experiment, colonic inflammation in naive rats induced viscerosomatic inhibition to thermal stimulation of the forepaw and hind paw. This inhibition was reversed, and the paw withdrawal latency was slightly decreased in neonatal (P3) carrageenan-treated rats. Rats treated on P14 appeared similar to naive rats. These data support the hypothesis that neonatal hind paw injury during a critical period permanently alters sensory processing of multiple sensory modalities in the adult. Animals develop with greater inhibitory processing of somatic and visceral stimuli throughout the neuraxis. However, inflammation in the adult in previously uninjured tissue reverses the hypoalgesia and evokes development of normal hyperexcitability associated with tissue injury. ⋯ Trauma experienced by premature infants can lead to alterations in sensory processing throughout life. This study shows that short-term somatic tissue injury to neonatal rats during a well-defined critical period alters several aspects of viscerosensory processing in the adult, demonstrating that injury to one tissue affects sensory processing throughout the body.
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The purpose of this study was to examine sex differences in the stability of experimental pain responding across time. Stability was assessed by using 2 forehead cold pressor applications separated by 9 months. Twenty-eight men and 20 women completed both Session 1 and Session 2. Repeated measures analysis of variance showed a main effect for Session on maximum pain level. Women reported significantly more pain at Session 2, whereas men showed no difference between sessions. There were no differences on pain report between men and women at Session 1. A significant Session by Sex interaction was associated with perceived chronic stress and trait anxiety levels. At Session 2 but not Session 1, women endorsed a significantly greater expectation than men to experience unpleasant aftereffects from the cold pressor task. Additional analysis showed that chronic stress and trait anxiety were significantly associated with sex-specific pain responding. We propose that the influence of a prior painful incident on an identical repeated painful experience differs between men and women. We speculate that this influence is related to sex differences in psychological mechanisms used to interpret painful stimuli within the context of remembered experiences. To our knowledge, this is the first report of sex differences in the long-term stability of an experimental laboratory pain stimulus, controlling for follicular phase of the female menstrual cycle. ⋯ This study examines sex differences in the stability of experimental pain responding across a 9-month period. We speculate that psychological mechanisms influence one's interpretation of a prior painful incident and that this interpretation facilitates increased pain reporting in response to an identical repeated exposure, as was observed for women.
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Several investigators have reported weak or no associations between self-report and facial expression of pain, concluding that both parameters appear to be unrelated. However, studies so far have only focused on an overall association, not considering psychophysical relationships between stimulus intensities and pain responses while computing correlations. In the present study these psychophysical relationships, between stimulus intensity on the one hand and response magnitudes (of self-report and facial expression) on the other hand, were described in terms of intercept and slope. Correlation analyses were conducted between intercept and slope parameters of self-report and facial expression of pain. Forty young, pain-free individuals were investigated for their responses to mechanically and electrically induced pain. Self-report was assessed by Visual Analog Scales. Facial expression was examined by using the Facial Action Coding System. There were significant correlations between the linear slopes of the psychophysical functions of self-report and facial expression in pressure pain. Neither the intercepts nor overall mean responses in the 2 pain-signaling systems were significantly correlated. These findings suggest that the facial expression of pain appears to mirror self-report ratings, when their increases over a range of increasing stimulus intensities are considered in parallel. ⋯ In future studies, our psycho-physically derived observation that incremental changes in facial expression during developing pain are more characteristic for individuals than static levels needs further corroboration.