The journal of pain : official journal of the American Pain Society
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Nociceptin/orphanin FQ (N/OFQ) is the endogenous peptide for the NOP receptors. Depending on the doses, intrathecal administration of N/OFQ has dual actions (ie, hyperalgesia and antinociception) in rodents. However, the pharmacological profile of intrathecal N/OFQ is not fully known in primates. The aim of this study was to investigate behavioral effects of intrathecal N/OFQ over a wide dose range and to compare its effects with ligands known to produce hyperalgesia or antinociception in monkeys. Intrathecal N/OFQ from 1 fmol to 1 nmol did not produce any hyperalgesic or scratching responses. In contrast, intrathecal substance P 100 nmol produced hyperalgesia, and intrathecal DAMGO 10 nmol produced antinociception. At the dose range between 10 nmol and 1 micromol, intrathecal N/OFQ dose-dependently produced thermal antinociception against a noxious stimulus in 2 intensities. More importantly, N/OFQ in combined with intrathecal morphine dose-dependently potentiated morphine-induced antinociception without inhibiting morphine-induced itch/scratching. Taken together, this study is the first to provide a unique functional profile of intrathecal N/OFQ over a wide dose range in primates. Intrathecal N/OFQ produces thermal antinociception without anti-morphine actions or scratching responses, indicating that N/OFQ or NOP receptor agonists represent a promising target as spinal analgesics. ⋯ Intrathecal administration of N/OFQ only produced thermal antinociception, not hyperalgesia, in monkeys. In addition, intrathecal N/OFQ does not have anti-morphine actions or itch/scratching responses. This study strongly supports the therapeutic potential of N/OFQ or NOP receptor agonists as spinal analgesics for clinical trials.
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Despite enhanced interest in manifestations of pain in adults with intellectual and developmental disabilities (IDD), the characteristics of pain behavior in this group have seldom been examined. The aim of the present study was to provide a sensitive pain behavior scale for adults with IDD. The participants, 228 adults (mean age, 38.7 years) with different levels of IDD, were videotaped before and during an influenza vaccination and scored using the Non-Communicating Children's Pain Checklist-Revised (NCCPC-R). Observed pain behaviors not captured by the NCCPC-R, was also registered. Sensitivity to pain of all 27 items was examined by Signed Rank test, internal consistency by Cronbach's alpha, and sensitivity to change of the total scale by Standardized Response Mean (SRM). Thirteen items were excluded from the original NCCPC-R scale; 4 new items were added, making a modified scale of 18 items. This scale, named the Non-Communicating Adults Pain Checklist-Revised (NCAPC), was rescored and examined for psychometric properties in a random sample (N = 89). Sensitivity to pain of all items (P < .05) and high internal consistency (alpha = 0.773) were demonstrated. Large sensitivity to pain at all levels of IDD was shown (SRM, 1.20 to 2.07). Better psychometric properties were demonstrated for NCAPC than NCCPC-R in the target population. ⋯ This article presents initial psychometric properties of a new measure, the NCAPC, evaluating pain behavior in adults with IDD. This measure could help clinicians to better capture pain expressions in this population and contribute to better pain management for this group of patients.
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A systematic literature review was conducted to determine the diagnostic validity of the criteria for sacroiliac (SI) joint pain as proposed by the International Association for the Study of Pain (IASP). Databases were searched up to September 2007. Quality of the studies was assessed using a Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Sensitivity, specificity, and diagnostic odds ratios (DOR) were calculated together with 95% confidence intervals (CI). Statistical pooling was conducted for results of provocative tests. Eighteen studies were included. Five studies examined the pattern of SI joint pain, whereas another 5 examined stressing test specific for SI joint pain. None of the studies evaluated the diagnostic validity of the SI joint infiltration or the diagnostic validity of the IASP criteria set as a whole. In all studies, the SI joint selective infiltration was used as a gold standard; however, the technique, medications, and required pain relief after the infiltration varied considerably between the studies. Taking the double infiltration technique as reference test, the pooled data of the thigh thrust test (DOR, 18.461; CI, 5.82 to 58.53), compression test (DOR, 3.88; CI, 1.7 to 8.9), and 3 or more positive stressing tests (DOR, 17.16; CI, 7.6 to 39) showed discriminative power for diagnosing SI joint pain. ⋯ This review of clinical studies focused on the diagnostic validity of the IASP criteria for diagnosing SI joint pain. A meta-analysis showed that the thigh thrust test, the compression test, and 3 or more positive stressing tests have discriminative power for diagnosing SI joint pain. Because a gold standard for SI joint pain diagnosis is lacking, the diagnostic validity of tests related to the IASP criteria for SI joint pain should be regarded with care.
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The current study tested whether the effectiveness of distraction using virtual reality (VR) technology in reducing cold pressor pain would maintain over the course of 8 weekly exposures. Twenty-eight adults, 18 to 23 years of age, underwent 1 baseline cold pressor trial and 1 VR distraction trial in randomized order each week. VR distraction led to significant increases in pain threshold and pain tolerance and significant decreases in pain intensity, time spent thinking about pain, and self-reported anxiety, relative to baseline. Repeated exposure did not appear to affect the benefits of VR. Implications for the long-term use of VR distraction as a nonpharmacological analgesic are discussed. ⋯ This article addresses the concern that the efficacy of virtual reality-assisted distraction from pain could potentially decrease with repeated exposure. The current finding that efficacy did not diminish over several repeated exposures provides support for the use of virtual reality as an adjuvant treatment of pain.
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People often respond with distress and avoidance to their own negative experiences, such as the physical, cognitive, and emotional aspects of depression or anxiety. When people with chronic pain respond this way, their overall level of distress may increase, they may struggle to avoid their emotional experiences, and their daily functioning may decrease. The purpose of this study was to examine the role of anxiety sensitivity (AS), or "fear of anxiety," in relation to these processes. It was predicted that those persons with chronic pain who report higher AS will also report higher emotional distress and greater disability caused by chronic pain. A second purpose was to examine whether therapeutic processes designed to reduce emotional avoidance, namely, acceptance, mindfulness, and values, could be demonstrated to reduce the role of AS in relation to this distress and disability based on a statistical model including these variables. Subjects were 125 consecutive adult patients (64.8% women) seeking services from a specialty pain service in the United Kingdom. All patients completed a standard set of measures of AS, acceptance of pain, mindfulness, and values-based action, as well as measures of pain, disability, and emotional functioning, at their initial consultation, and these data formed the basis for the current study. In correlation and regression analyses, AS was associated with greater pain, disability, and distress. In regression analyses, the 3 proposed therapeutic processes reduced the average variance accounted for by AS in patient functioning from DeltaR(2) = .21 to DeltaR(2) = .048. This means that when the 3 therapeutic variables are taken into account statistically, AS alone retained relatively little association with patient functioning. These results suggest that AS may amplify the impact of emotional distress on patient functioning in chronic pain and that processes of acceptance, mindfulness, and values-based action may reduce this effect. ⋯ Humans can fear and struggle to avoid their own emotional experiences, even when these cannot harm them. Data presented here show individuals with chronic pain have more distress and disability when they manifest more fear of anxiety symptoms, and behavior patterns of "acceptance" and "mindfulness" may reduce this effect.