Pain
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Comparative Study
Processing capacity in chronic pain patients: a visual event-related potentials study.
Chronic pain may impair performance on attentional processing capacity tasks. In the present study, event-related potentials were recorded to examine whether pain patients show performance decrements on attentional processing capacity tasks due to shared resources by pain and attention or, alternatively, due to deficits in allocating attentional resources during pain. Fourteen chronic pain patients and thirty age and education matched healthy controls were investigated. ⋯ For healthy controls, the expected decreased amplitude was found for probe stimuli in the difficult compared to the easy task. In contrast, the pain patients did not show decreased probe amplitudes with increasing task load. The data may imply that allocation of attentional resources is deficient in pain patients, instead of attentional capacity.
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Comparative Study
Local interactions between anandamide, an endocannabinoid, and ibuprofen, a nonsteroidal anti-inflammatory drug, in acute and inflammatory pain.
Anandamide, an endocannabinoid, is degraded by the enzyme fatty acid amide hydrolase which can be inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs). The present work was designed to study the peripheral interactions between anandamide and ibuprofen (a non-specific cyclooxygenase inhibitor) in the rat formalin test. We first determined the ED50 for anandamide (0.018 microg +/- 0.009), ibuprofen (0.18 microg +/- 0.09), and their combination (0.006 microg +/- 0.002). ⋯ In conclusion, locally (hind paw) injected anandamide, ibuprofen or combination thereof decreased pain behavior in the formalin test. The combination of anandamide with ibuprofen produced synergistic antinociceptive effects involving both cannabinoid CB1 and CB2 receptors. Comprehension of the mechanisms involved needs further investigation.
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Randomized Controlled Trial Comparative Study
Motor cortex stimulation for long-term relief of chronic neuropathic pain: a 10 year experience.
Chronic subthreshold stimulation of the contralateral precentral gyrus is used in patients with intractable neuropathic pain for more than 15 years. The aim of this study was to analyse retrospectively our own patient group with long term follow-up of 10 years. Seventeen patients with chronic neuropathic pain were treated with contralateral epidural stimulation electrodes. ⋯ Double-blind testing can identify non-responders. Patients with TNP profit more than patients with PSP. The positive effect can last for ten years in long-term follow-up.
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Randomized Controlled Trial Comparative Study Clinical Trial
Loss of expectation-related mechanisms in Alzheimer's disease makes analgesic therapies less effective.
Expectation/placebo-related mechanisms and specific effects of therapies show additive effects, such that a therapy is less effective if the placebo component is absent. So far, the placebo component has been disrupted experimentally by using covert administrations of treatments. Here, we show for the first time that disruption of expectation/placebo-related analgesic mechanisms may occur in a clinical condition, Alzheimer's disease (AD). ⋯ We also found that the disruption of the placebo component occurred when reduced connectivity of the prefrontal lobes with the rest of the brain was present. Remarkably, the loss of these placebo-related mechanisms reduced treatment efficacy, such that a dose increase was necessary to produce adequate analgesia. These findings highlight the active role of cognition and prefrontal lobes in the therapeutic outcome and underscore the need of considering a possible revision of the therapeutic approach in Alzheimer patients in order to compensate for the loss of the endogenous expectation and placebo mechanisms.
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Symptom duration is integral to clinical and epidemiological research on pain. It is widely used for sample selection and commonly assessed in clinical practice. However, there has been little specific investigation of the link between duration and outcome. ⋯ In conclusion, memory of LBP episode duration is associated with pain, disability and psychological status, and is an independent predictor of time to improvement. There are important differences between people who recall more or less than 3 years' duration. Mechanisms for these associations are poorly understood, but this research suggests that duration itself is an important focus for research.