Pain
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Comparative Study
Variability of "optimal" cut points for mild, moderate, and severe pain: neglected problems when comparing groups.
Defining cut points for mild, moderate, and severe pain intensity on the basis of differences in functional interference has an intuitive appeal. The statistical procedure to derive them proposed in 1995 by Serlin et al. has been widely used. Contrasting cut points between populations have been interpreted as meaningful differences between different chronic pain populations. ⋯ Optimal cut points are strongly influenced by random fluctuations within a sample. Differences in optimal cut points between study groups may be explained by chance variation; no other substantial explanation is required. Future studies that aim to interpret differences between groups need to include measures of variability for optimal cut points.
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The influence of pain descriptors and mechanical hypersensitivity on pain severity in neuropathic pain has not been well researched and is poorly understood. The aim of this study was to determine the relationship between pain severity and other factors describing chronic neuropathic pain in a large cohort of patients with self-reported neuropathic pain potentially recruited as subjects for a Phase IIa study. A questionnaire specific to the study parameters covering demographics and pain characteristics was sent to potential participants. ⋯ Having 3 or 4 pain descriptors was also strongly indicative of both moderate and severe pain. Female gender, age, and history of serious mental disorders were found to be weaker indicators of both moderate and severe pain. Given the large and varied population with many neuropathic pain diagnoses in the study, the findings are not likely to be merely chance, but are likely to reflect important relationships between pain severity and other factors in those who suffer from chronic neuropathic pain.
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The interaction between intensity of nociceptive stimuli and cognitive load in a concomitant task is still a challenging and complex topic. Here, we investigated the interaction between top-down factors (i.e., perceptual load), induced by a visual task, and bottom-up factors (i.e., intensity of nociceptive stimuli that implicitly modifies saliency of input). Using a new experimental paradigm, in which perceptual load is varied while laser heat stimuli of different intensities are processed; we show a significant interaction between intensity of nociceptive stimuli and perceptual load on both pain ratings and task performance. ⋯ However, under this condition, task performance was impaired, regardless of interindividual differences in motivation and pain catastrophizing. Thus, we showed that pain ratings can be reduced by increasing the load of attentional resources at the perceptual level of a non-pain-related task. Nevertheless, the disruptive effect of highly intensive nociceptive stimuli on the performance of the perceptual task was evident only under high load.
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Comparative Study
Ethnic differences in physical pain sensitivity: role of acculturation.
Although research suggests that Asian Americans are more reactive to physical pain than European Americans, some evidence suggests that the observed differences in ethnicity may actually reflect Asian Americans' differing levels of acculturation. Two studies were conducted to test this hypothesis. ⋯ Study 2 further controlled for ethnicity and replicated this pattern in finding heightened pain reactions among mainland Chinese students in Hong Kong relative to Hong Kong Chinese students. These findings suggest a role for acculturation in accounting for ethnic differences in physical pain sensitivity.