Pain
-
Comparative Study
P300-amplitudes in upper limb amputees with and without phantom limb pain in a visual oddball paradigm.
The aim of the study was to investigate to what extent cortical hyper-reactivity to visual stimuli is present in upper limb amputees. Five amputees with phantom limb pain (PLP), five amputees without PLP (Non-PLP) and 10 healthy controls (HC) were investigated using a visual oddball paradigm. Two hundred visual stimuli were presented with target stimuli occurring at a probability of 25% and standard stimuli at a probability of 75%. ⋯ The size of the P300-amplitude was positively correlated with the intensity of PLP. These findings suggest a higher magnitude of non-specific cortical excitability in amputees with PLP and a reduced excitability in amputees without PLP. This extends previous findings of differences in cortical excitability in PLP and non-PLP patients in the sensorimotor domain.
-
Comparative Study
Distraction from chronic pain during a pain-inducing activity is associated with greater post-activity pain.
The aim of this study was to investigate the effects of distraction from pain during and after a pain-inducing lifting task in a sample of chronic low back pain (CLBP) patients. Fifty-two CLBP patients (25 males, 27 females; mean age=46.30 years) performed a pain-inducing lifting task twice, once alone and once with a simultaneous cognitive distraction task. ⋯ Further investigation of the catastrophizing data showed that the effect of catastrophizing about pain during the lifting task on the cognitive distraction task was mediated by the amount of attention paid to pain. Clinical implications of these findings are discussed.
-
Comparative Study
Comparison of two psychometric scaling methods for ratings of acute musculoskeletal pain.
Psychometric theory allows interindividual comparisons by scaling differences among subjects with respect to some psychological attribute. The most widely used psychometric scaling method is classical test theory. The properties of classical test theory pain scores are limited to the observed range of pain scores in a given sample, to the specific conditions in a given sample that are the source of pain (e.g. surgery vs. cancer), and to a particular pain survey. ⋯ The psychometric scaling methods were compared using standardized residuals (data fit), standard errors of measurement (score precision), and a graphical plot of predicted scores against scale scores (bias). The item response theory scores demonstrated better data fit and less bias than did the classical test theory scores. In addition to superior psychometric properties, item response theory scores have several other important theoretical and practical advantages.
-
Comparative Study
Pain-related fear and daily functioning in patients with osteoarthritis.
There is growing evidence supporting the relationship between pain-related fear and functional disability in chronic musculoskeletal pain conditions. In osteoarthritis (OA) patients the role of pain-related fear and avoidance has received little research attention so far. The present study investigates the degree to which pain-related fear, measured with the Tampa Scale for Kinesiophobia (TSK), influences daily functioning in OA patients. ⋯ Radiological findings were not significant predictors and when compared to pain-related fear they were not significant. These findings underscore the importance of pain-related fear in daily functioning of OA patients. Therefore, treatment strategies aiming at reduction of pain-related fear in OA patients need to be developed and investigated.
-
Comparative Study
State-dependent block of voltage-gated Na+ channels by amitriptyline via the local anesthetic receptor and its implication for neuropathic pain.
Amitriptyline is a tricyclic antidepressant, which also alleviates various pain syndromes at its therapeutic plasma concentration (0.36-0.90 microM). Accumulated evidence suggests that such efficacy may be due to block of voltage-gated Na(+) channels. The Na(+) channel alpha-subunit protein consists of four homologous domains (D1-D4), each with six transmembrane segments (S1-S6). ⋯ The open-channel block by amitriptyline has the highest affinity, with a 50% inhibitory concentration (IC(50)) of 0.26 microM. The inactivated-channel block by amitriptyline had a weaker affinity (0.51 microM), whereas the resting-channel displayed the weakest affinity (33 microM). We hypothesize that selective block of both persistent late openings and the inactivated state of neuronal Na(+) channel isoforms by amitriptyline also occurs at its therapeutic concentration and likely contributes to its efficacy in pain syndromes.