Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of diffuse noxious inhibitory controls on temporal summation of the RIII reflex in humans.
The aim of this study was to investigate the effects of diffuse noxious inhibitory controls (DNICs) on the temporal summation of the nociceptive flexion reflex (RIII reflex) in humans. Recordings were obtained from 36 healthy adults (16 M, 20 F), and the area and temporal summation threshold (TST) of the RIII reflex were measured. The subjective intensity of the painful sensation was rated on an 11-point visual analogue scale (VAS). ⋯ To summarize, activation of DNICs through the CPT significantly increased the TST of the RIII reflex in healthy subjects. This inhibitory effect was gender-specific. Whereas other findings are based on psychophysical evaluations, the results of this experimental study provide an objective neurophysiological demonstration that DNICs attenuate temporal summation in humans and confirm the presence of significant differences in pain modulation mechanisms between men and women.
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Comparative Study
Management of occupational back injuries: differences among African Americans and Caucasians.
This study examined differences in the case management of occupational low back injuries in a large, racially diverse population of Workers' Compensation claimants in Missouri. Participants were African Americans (N=580) and non-Hispanic whites (N=892) who had filed occupational injury claims that were settled over an 18-month period. Telephone interview data were gathered regarding diagnoses, legal representation, demographics, and socioeconomic status. ⋯ Simultaneous-entry, hierarchical multiple and logistic regression analyses showed significant and substantial effects for injury-related variables, socioeconomic status, and race across all Workers' Compensation variables. Differences remained for both injury and African Americans and lower socioeconomic status workers after controlling for injury, and for African Americans after controlling for both injury and socioeconomic status. Because Workers' Compensation mandates equal access to treatment and disability reimbursement for all injured workers, the differences observed in this study may reflect sociocultural biases in disability management among healthcare providers.
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Comparative Study
Laboratory pain perception and clinical pain in post-menopausal women and age-matched men with osteoarthritis: relationship to pain coping and hormonal status.
The present study examined relationships between pain coping, hormone replacement therapy, and laboratory and clinical pain reports in post-menopausal women and age-matched men with osteoarthritis. Assessment of nociceptive flexion reflex threshold was followed by an assessment of electrocutaneous pain threshold and tolerance. Participants rated their arthritis pain using the Arthritis Impact Measurement Scales. ⋯ A comparison of men (n=58), post-menopausal women receiving hormone replacement therapy (n=32), and post-menopausal women not receiving hormone replacement therapy (n=42) revealed no significant group differences in arthritis pain, electrocutaneous pain threshold or tolerance, or nociceptive flexion reflex threshold. Thus, older adults with osteoarthritis do not exhibit the pattern of sex differences in response to experimental pain procedures observed in prior studies, possibly due to the development of disease-related changes in pain coping strategies. Accordingly, individual differences in clinical and experimental pain may be better predicted by pain coping than by sex or hormonal differences.
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A clearer understanding of how pain intensity relates to disability could have important implications for pain treatment goals and definitions of treatment success. The objectives of this study were to determine the optimal pain intensity rating (0-10 scale) cutpoints for discriminating disability levels among individuals with work-related carpal tunnel syndrome (CTS) and low back (LB) injuries, whether these cutpoints differed for these conditions and for different disability measures, and whether the relationship between pain intensity and disability was linear in each injury group. Approximately 3 weeks after filing work injury claims, 2183 workers (1059 CTS; 1124 LB) who still had pain completed pain and disability measures. ⋯ For all disability measures examined, the relationship between pain intensity and disability level was linear in the CTS group, but nonlinear in the LB group. Among study participants with work-related back injuries, when pain level was 1-4, a decrease in pain of more than 1-point corresponded to clinically meaningful improvement in functioning, but when pain was rated as 5-10, a 2-point decrease was necessary for clinically meaningful improvement in functioning. The findings indicate that classifying numerical pain ratings into categories corresponding to levels of disability may be useful in establishing treatment goals, but that classification schemes must be validated separately for different pain conditions.
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Case Reports Comparative Study
Spinal cord stimulation in a patient with persistent oesophageal pain.
This study describes a man with a long history of oesophageal pain that led to inability to swallow food and drink. Over a period of 8 years, he had multiple oesophageal operations that were unsuccessful. He presented, to the pain management team, with persistent oesophageal pain and required jejunostomy tube feeding to maintain nutrition. ⋯ He feels that SCS has been worthwhile. The authors discuss the rationale for this treatment. The decision was based on the use of SCS for refractory angina, and the idea that the neural mechanisms that generate both these pain states may be similar.