Pain
-
The magnitude of placebo response and its predictors in fibromyalgia syndrome (FMS) and painful peripheral diabetic neuropathy (DPN) had not been studied. We performed a systematic review by searching MEDLINE, CENTRAL, SCOPUS, and the databases of the U. S. ⋯ Placebo accounted for 45% of the response in the drug groups in FMS and for 62% in painful DPN. The placebo response was higher in painful DPN than in FMS (P<.001). The placebo response was not associated with age, sex, and race, but with year of study initiation, pain baseline, and effect size in active drug groups in both diseases.
-
Tissue injury during a critical period of early life can facilitate spontaneous glutamatergic transmission within developing pain circuits in the superficial dorsal horn (SDH) of the spinal cord. However, the extent to which neonatal tissue damage strengthens nociceptive synaptic input to specific subpopulations of SDH neurons, as well as the mechanisms underlying this distinct form of synaptic plasticity, remains unclear. Here we use in vitro whole-cell patch clamp recordings from rodent spinal cord slices to demonstrate that neonatal surgical injury selectively potentiates high-threshold primary afferent input to immature lamina II neurons. ⋯ This occurs in a widespread manner within the developing SDH, as incision elevated miniature excitatory postsynaptic current frequency in both GABAergic and presumed glutamatergic lamina II neurons of Gad-GFP transgenic mice. The administration of exogenous nerve growth factor into the rat hindpaw mimicked the effects of early tissue damage on excitatory synaptic function, while blocking trkA receptors in vivo abolished the changes in both spontaneous and primary afferent-evoked glutamatergic transmission following incision. These findings illustrate that neonatal tissue damage can alter the gain of developing pain pathways by activating nerve growth factor-dependent signaling cascades, which modify synaptic efficacy at the first site of nociceptive processing within the central nervous system.
-
Editorial Comment
A decade of effects on sickleave after multidisciplinary rehabilitation?
-
The attentional demand of pain has primarily been investigated within an intrapersonal context. Little is known about observers' attentional processing of another's pain. The present study investigated, within a sample of parents (n=65; 51 mothers, 14 fathers) of school children, parental selective attention to children's facial display of pain and the moderating role of child's facial expressiveness of pain and parental catastrophizing about their child's pain. ⋯ This interference effect was particularly pronounced for high-catastrophizing parents, suggesting that being confronted with increasing child pain displays becomes particularly demanding for high-catastrophizing parents. Finally, parents with higher levels of catastrophizing increasingly attended away from low pain expressions, whereas selective attention to high-pain expressions did not differ between high-catastrophizing and low-catastrophizing parents. Theoretical implications and further research directions are discussed.