European journal of pain : EJP
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Randomized Controlled Trial
Laser-evoked potentials as a tool for assessing the efficacy of antinociceptive drugs.
Laser-evoked potentials (LEPs) are brain responses to laser radiant heat pulses and reflect the activation of Adelta nociceptors. LEPs are to date the reference standard technique for studying nociceptive pathway function in patients with neuropathic pain. ⋯ The opioid antagonist naloxone partially reversed the tramadol-induced LEP amplitude decrease. We conclude that LEPs may be reliably used in clinical practice and research for assessing the efficacy of antinociceptive drugs.
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Randomized Controlled Trial
What factors influence the measurement properties of the Roland-Morris disability questionnaire?
Although the Roland disability questionnaire (RDQ) is a commonly used questionnaire for patients with low back pain (LBP), several important issues remain understudied. The purposes of this study were to investigate the impact that several parameters (length of test-retest interval, interpretation of the global perceived effect (GPE) scores, methods to estimate standard error of measurement (SEM), intervention and baseline scores) have on various measurement properties, such as agreement (Limits of Agreement (LOA), SEM(agreement)), responsiveness (area under the ROC curve, sensitivity, specificity) and interpretability (optimal cut-off point, Minimal Detectable Change), of the RDQ. RDQ was administered four times to 212 patients with chronic non-specific LBP (first consultation (T-1), eligibility check (T0), randomization/start of treatment (T1) and end of treatment (T2)). ⋯ Results revealed that agreement parameters decreased with increasing time interval between test-retest. They confirmed the influence of the interpretation of the GPE as well as of the method to calculate the SEM on the magnitude of the Minimal Detectable Change and ROC parameters. Baseline RDQ scores and the way to cluster patients with regard to baseline scores influenced mainly the optimal cut-off point and responsiveness parameters; intervention did not affect the magnitude of the Minimal Detectable Change.
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Chronic pain is often associated with comorbidities such as anxiety and depression, resulting in a low health-related quality of life. The mechanisms underlying this association are not clear, but a disturbance in the pain control systems from the brain stem has been suggested. Thirty neuropathic pain (NP) patients, 28 patients with fibromyalgia (FM), and 26 pain-free age- and gender-matched controls were included and examined with respect to mental distress (self-rated Symptom Checklist-92), depression (doctor-rated Hamilton Depression Scale and self-rated Major Depression Inventory), and anxiety (doctor-rated Hamilton Anxiety Scale and self-rated Anxiety Inventory). ⋯ However, these scores are low compared to other studies on mental distress in chronic pain patients. Only few chronic pain patients meet the diagnostic criteria for depression (NP 3.3%, FM 7.1%), and associations between pain and mental symptoms were only found in the FM group despite similar pain intensities. The findings suggest that different mechanisms are responsible for the development of mood disorders in the two patient groups.
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Diffusion Tensor Imaging (DTI) is a promising new imaging method allowing in vivo mapping of anatomical connections in the living human brain. We combined DTI with functional magnetic resonance imaging (fMRI) to investigate the anatomical relationships between areas involved in visceral sensations in humans. Non-painful and moderately painful rectal distensions were performed in 11 healthy women (38.4+/-3.1years). fMRI was used to analyse the changes in brain activity during both types of distension. ⋯ DTI revealed direct connections between insula, and the four areas more frequently activated in this study, i.e. ACC, thalamus, S1, S2 and PFC. The combined use of fMRI and DTI in healthy subjects during rectal distension revealed a neural network of visceral sensory perception involving the insula, thalamus, somatosensory cortices, ACC and PFC.
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An increasing body of research demonstrates that acceptance of pain is significantly associated with the quality of daily functioning in people with chronic pain. The aim of the present study was to examine acceptance more broadly in relation to a wider range of undesirable experiences these people may encounter, such as other physical symptoms, experiences of emotional distress, or distressing thoughts. One hundred forty-four, consecutive, adult patients attending interdisciplinary treatment for chronic pain participated in this study. ⋯ Hierarchical regression analyses showed that general psychological acceptance added a significant increment of explained variance to the prediction of patient functioning, independent of patient background characteristics, pain, acceptance of pain, and mindfulness. These results suggest that, when people with chronic pain are willing to have undesirable psychological experiences without attempting to control them, they may function better and suffer less. General acceptance may have a unique role to play in the disability and suffering of chronic pain beyond similar processes such as acceptance of pain or mindfulness.