Pain
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Carpal tunnel syndrome (CTS), a common entrapment neuropathy involving the median nerve at the wrist, frequently manifests with neuropathic pain. We sought information on pain mechanisms in CTS. We studied 70 patients with a diagnosis of CTS (117 CTS hands). ⋯ We sought possible correlations between neurophysiological data and the various qualities of neuropathic pain as assessed by the NPSI. We found that the median nerve sensory conduction velocity correlated with paroxysmal pain and abnormal sensations, whereas LEP amplitude correlated with spontaneous constant pain. Our findings suggest that whereas paroxysmal pain and abnormal sensations reflect demyelination of non-nociceptive Abeta-fibres, spontaneous constant pain arises from damage to nociceptive Adelta-fibres.
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Pain is a largely subjective experience, and one which is difficult to convey to others, and relies significantly on language to be communicated. The language used to describe pain is therefore an important aspect of understanding and assessing another's pain. A growing body of research has reported differences in the pain experienced by men and women. ⋯ Men used fewer words, less descriptive language, and focused on events and emotions. Common themes were the functional limitations caused by pain, difficulty in describing pain, and the dual nature of pain. Clinical implications include the value of gathering free pain descriptions as part of assessment, and the use of written pain descriptions.
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Randomized Controlled Trial
Activation of the prostaglandin system in response to sleep loss in healthy humans: potential mediator of increased spontaneous pain.
Insufficient duration of sleep is a highly prevalent behavioral pattern in society that has been shown to cause an increase in spontaneous pain and sensitivity to noxious stimuli. Prostaglandins (PGs), in particular PGE2, are key mediators of inflammation and pain, and we investigated whether PGE2 is a potential mediator in sleep-loss-induced changes in nociceptive processing. Twenty-four participants (7 females, age 35.1+/-7.1 years) stayed for 7 days in the Clinical Research Center. ⋯ Urinary PGE2 metabolite significantly increased by about 30% in TSD over sleep condition. TSD-induced increase in spontaneous pain, in particular headache and muscle pain, was significantly correlated with increase in PGE2 metabolite. Activation of the PGE2 system appears to be a potential mediator of increased spontaneous pain in response to insufficient sleep.
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The nociceptive flexion reflex (NFR) has been used as a psychophysiological tool to study spinal nociceptive processes in numerous clinical and experimental studies. Despite widespread use of the NFR, few attempts have been made to empirically test and compare different scoring criteria to detect the presence/absence of the reflex. The present studies were conducted to address this issue. ⋯ In both studies, receiver operating characteristics (ROCs) analyses were used to evaluate and compare different scoring methods. The results indicate that a number of different criteria were acceptable for defining an NFR threshold based on the area under the ROC curve and its statistical significance; however, NFR Interval z score [(NFR Interval Mean-baseline mean)/baseline SD] emerged as the scoring criterion with the greatest accuracy and with cut-points that are reliable across samples. These findings support the application of a common NFR scoring criterion to enhance direct comparison of results across different research laboratories and study samples.