The journal of pain : official journal of the American Pain Society
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There is growing evidence that fear-learning abnormalities are involved in the development of posttraumatic stress disorder (PTSD) and chronic pain. More than 50% of PTSD patients suffer from chronic pain. This study aimed to examine the role of fear-learning deficits in the link between pain perception and PTSD. ⋯ Fear-learning deficits are a potentially promising, specific psychopathological factor in altered pain perception associated with PTSD. Deficits in safety learning may increase fear and, consequently, pain sensations. These findings may contribute to elucidating the pathogenesis behind the highly prevalent comorbidity that exists between PTSD and pain disorders, and to developing new treatments.
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This study aimed to understand the relationship between caregiver culture and infant pain expression at the 12-month immunization and discern if a mechanism subsuming this relationship was the quality of caregiver behaviors (emotional availability). Infants (N = 393) with immunization data at 12 months of age were examined. On the basis of the Development of Infant Acute Pain Responding model, a mediation model was developed to examine how caregiver behaviors mediate the relationship between caregiver heritage culture and infant pain. ⋯ Two mediation models were estimated, examining infant pain expression at 1 and 2 minutes post-needle. Caregivers who self-reported heritage cultures that were more highly individualistic tended to show greater emotional availability, which in turn predicted decreased infant pain expression at 1 and 2 minutes post-needle. The present findings further our understanding of one mechanism by which caregiver culture affects infant acute pain expression.
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The prevalence of chronic pain rises with increasing age. It has been suggested that the mechanisms responsible for the development of chronic pain overlap with mechanisms involved in aging, potentially implicating age-related changes in descending modulatory pathways. This observation raises the question whether other forms of endogenous pain modulation, in particular placebo analgesia, become compromised with age. ⋯ We observed increased heat pain thresholds and higher pain intensity ratings (in response to physically identical heat stimulation) in the older compared with the younger group. However, the placebo analgesic response was comparable between both age groups of healthy participants. The preserved capacity for placebo analgesia in our sample of older participants highlights the potential to use nonpharmacological analgesic treatment strategies in this age group and to exploit placebo mechanisms as an add-on to existing analgesic (pharmacological) treatment strategies.
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Somatic awareness (SA) refers to heightened sensitivity to a variety of physical sensations and symptoms. Few attempts have been made to dissociate the relationship of SA and affective symptoms with pain outcomes. We used a validated measure of mood and anxiety symptoms that includes questions related to SA to predict the number of tender points found on physical examination in a large cross-sectional community sample (the Midlife in the United States [MIDUS] Biomarker study). ⋯ Follow-up mediation analyses indicated that the relationship between general distress and tender points was partially mediated by levels of SA. Our primary finding was that SA is strongly related to the number of tender points in a community sample. Mechanisms linking SA to the spatial distribution of pain sensitivity should be investigated further.
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Dorsal root ganglion (DRG) electrical stimulation (ganglionic field stimulation [GFS]) is effective in relieving clinical pain, but its mechanism is unknown. We therefore developed a rat model for GFS to test analgesic effects in the context of neuropathic pain. GFS was applied with a bipolar electrode at L4, using parameters replicating clinical use (20 Hz, 150-μs pulse width, current at 80% of motor threshold). ⋯ Conditioned place preference showed that GFS was not rewarding in uninjured control animals but was rewarding in animals subjected to TNI, which reveals analgesic efficacy of GFS for spontaneous pain. We conclude that GFS relieves neuropathic pain in rats. This model may provide a platform for identifying mechanisms and novel applications of GFS.