The journal of pain : official journal of the American Pain Society
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Review
Using Screening Tests to Predict Aberrant Use of Opioids in Chronic Pain Patients: Caveat Emptor.
Screening tests represent a critical tool in chronic pain treatment for predicting aberrant opioid use, which has emerged as a significant public health issue. Nevertheless, there remains a significant potential for the misapplication of screeners in this context. The potential difficulties in evaluating the diagnostic efficiency of screeners have been well established, particularly with regard to the effect that the prevalence of a disorder has on predictive value. ⋯ Given the prevalence of opioid problems, however, formulating clear clinical guidelines on such screeners appears highly important. The aims of the present report include: 1) providing a review of the salient issues necessary for interpreting diagnostic efficiency statistics of screening tests, 2) identifying the critical differences between sensitivity, specificity, and predictive value, and 3) discussing the characteristic effects that disease prevalence has on statistical prediction. The article also reviews key processes in screening measure development and highlights several key considerations relevant to their appropriate use in clinical decision-making.
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Central neuropathic pain, which is pain caused by a lesion or disease of the central somatosensory nervous system, is a serious consequence of spinal cord injury, stroke, multiple sclerosis, and other conditions affecting the central nervous system. A collaborative effort between the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks public-private partnership and the American Pain Society, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society Pain Taxonomy (AAPT) initiative, invited a working group to develop diagnostic criteria for central neuropathic pain. ⋯ This article focuses on central neuropathic pain associated with spinal cord injury, stroke, and multiple sclerosis, but the AAPT framework can be extended to central pain due to other causes such as traumatic brain injury. The classification of central neuropathic pain is organized according to the AAPT multidimensional framework, specifically: 1) core diagnostic criteria, 2) common features, 3) common medical and psychiatric comorbidities, 4) neurobiological, psychosocial, and functional consequences, and 5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors.
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An age-related decline in endogenous pain inhibitory processes likely places older adults at an increased risk for chronic pain. Limited research indicates that older adults may be characterized by deficient offset analgesia, an inhibitory temporal sharpening mechanism that increases the detectability of minor decreases in noxious stimulus intensity. The primary purpose of the study was to examine age differences in offset analgesia in community-dwelling younger, middle-aged, and older adults. ⋯ The results indicated that older and middle-aged adults showed reduced offset analgesia compared with younger adults in the 1.0°C and .4°C offset trials. Furthermore, the magnitude of offset analgesia predicted self-reported bodily pain, with those exhibiting reduced offset analgesia reporting greater bodily pain. Dysfunction of this endogenous inhibitory system could increase the risk of developing chronic pain for middle-aged and older adults.
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Temporal summation of second pain (TSSP) is a psychophysical indication of a central pain encoding mechanism, potentially enhanced in pathological pain conditions. Low-frequency repetitive stimulation of unmyelinated (C) nociceptors results in a progressive increase of pain intensity when thermal stimulation intensity remains constant. However, when using different methods of nociceptive delivery to the skin, regularity as well as rate of pain enhancement with repetition varies between experiments. ⋯ In the present study, TSSP by the intermittent contact with a preheated thermode and constant contact, ramp and hold methods were compared during 10 iterations of stimulation of glabrous skin of the hand or hairy forearm skin, with an onset to onset interval of 3.3 seconds and stimulus interval of .8 seconds. Significantly greater TSSP was observed for intermittent contact stimulation at both sites (P < .001). Differential activation of myelinated and unmyelinated nociceptors by ramping and tapping may account for different rates of temporal summation of heat pain.
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The Acquisition and Extinction of Fear of Painful Touch: a Novel Tactile Fear Conditioning Paradigm.
Fear of touch, due to allodynia and spontaneous pain, is not well understood. Experimental methods to advance this topic are lacking, and therefore we propose a novel tactile conditioning paradigm. Seventy-six pain-free participants underwent acquisition in a predictable as well as an unpredictable pain context. ⋯ Cue exposure reduced fear of touch, whereas context exposure reduced contextual fear. Thus, painful touch leads to increased fear, as does touch in the same context as unpredictable pain, and extinction protocols can reduce this fear. We conclude that tactile conditioning is valuable for investigating fear of touch and can advance our understanding of chronic pain.