European journal of pain : EJP
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Response biases are systematic biases in responding to test items that are unrelated to the content of the items. Examples often reported in young children include choosing only the lowest or highest anchors of a scale, or choosing a left-to-right sequence of responses. We investigated the presence of response biases in young children's ratings of pain in hypothetical situations, as a way of gauging their developing understanding of a pain scale over the preschool years. ⋯ These results reveal that response biases are common in children under 5 years. Clinicians should consider self-report pain ratings from preschoolers with caution, seek complementary observational assessment, and investigate discrepancies between self-report and observational estimates of pain. Simplified forms, instructions, and methods of administration for self-report scales should be developed and validated for use with 3- and 4-year-olds.
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Little is known about the variables that account for why parents underestimate the pain of their child. In the present experiment, the joint impact of parental catastrophizing about their child's pain and children's facial pain expressions was examined upon pain estimates of their child undergoing a pressure pain test. ⋯ An intriguing finding was that catastrophizing about their child's pain was related to less parent-child incongruence in pain ratings. The discussion addresses the possible functions of catastrophizing of parents about their children's pain, and delineates avenues for future research.
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The present study investigated the effects of different doses of intrathecal lidocaine on established thermal hyperalgesia and tactile allodynia in the chronic constriction injury model of neuropathic pain, defined the effective drug dose range, the duration of pain-relief effects, and the influence of this treatment on the body and tissues. Male Sprague-Dawley rats were divided into five groups and received intrathecal saline or lidocaine (2, 6.5, 15, and 35 mg/kg) 7 days after loose sciatic ligation. Respiratory depression and hemodynamic instability were found to become more severe as doses of lidocaine increased during intrathecal therapy. ⋯ These findings indicate that intrathecal lidocaine has prolonged therapeutic effects on established neuropathic pain. The balance between sympathetic and parasympathetic nervous activities could be well preserved in most cases, except for 35 mg/kg. Considering the ratio between useful effects and side effects, doses of 15 mg/kg are suitable for intrathecal injection for relief of neuropathic pain.
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Electrical low-frequency stimulation (LFS) of spinal afferents induces long-term depression (LTD) of nociceptive processing in rodents. LTD and its parameters in man are largely unknown. This study addresses the hypothesis that LTD of spinal nociception and pain in man depends on LFS frequency (0.5, 1, 2 Hz), number of electrical pulses (300, 600, 1200), intensity (relating to pain threshold I(P): 1 x I(P), 2 x I(P), 4 x I(P)), and on LFS repetition. ⋯ LFS with intensities 2 x I(P) and 4 x I(P) evoked sustained depression of SEP and pain perception in comparison to Control and 1 x I(P) LFS. Established LTD after single LFS was amplified by an additional second LFS. Hence this study provides electrophysiological and psychophysical evidence for LTD of spinal nociceptive processing and pain perception in man and indicates appropriate LFS parameters 1 Hz, 1200 pulses and 4 x I(P) for future studies on human LTD.
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The amygdala plays an important role in the processing of chronic pain and pain memory formation. Particularly, it is involved in the emotional and affective components of the pain circuitry. The role of kappa opioid receptors in these pain conditions is only partly known. The present study investigates the effect of kappa receptor activation on synaptic transmission and synaptic plasticity in the amygdala. ⋯ Kappa opioid receptor activation decreases synaptic transmission and inhibits the induction of LTP in the BLA of the mouse. These findings may be associated with the effects of kappa opioid agonists in chronic pain and pain memory formation.