European journal of pain : EJP
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Randomized Controlled Trial
Catastrophizing moderates the effect of exposure in vivo for back pain patients with pain-related fear.
This investigation was an initial attempt to explore psychological factors that might help or hinder the effect of exposure in vivo for patients with musculoskeletal pain and pain-related fear. The study was based on data from a randomized-controlled trial for patients with non-specific spinal pain (Linton et al., 2008). First, catastrophizing, anxiety, and depression were studied as possible treatment moderators. ⋯ Next, patients were divided into high change participants and low change participants based on their improvement in disability after treatment in order to investigate the change in psychological variables during treatment. Descriptive data indicated that high change participants had large improvements across treatment on depression, anxiety, catastrophizing, and fear-avoidance beliefs whereas low change participants virtually did not change at all on these variables across treatment. These findings denote that catastrophizing is a moderator of treatment outcome in exposure whereas several psychological variables might be important for the treatment process.
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Randomized Controlled Trial
Driving plasticity in the motor cortex in recurrent low back pain.
The sensory and motor systems can reorganise following injury and learning of new motor skills. Recently we observed adaptive changes in motor cortical organisation in patients with recurrent low back pain (LBP), which are linked to altered motor coordination. Although changes in motor coordination can be trained and are associated with improved symptoms and function, it remains unclear whether these training-induced changes are related to reorganisation of the motor cortex. ⋯ Changes were not observed following unskilled walking exercise. This is the first observation that motor training can reverse reorganisation of neuronal networks of the motor cortex in people with recurrent pain. The observed relationship between cortical reorganisation and changes in motor coordination following motor training provides unique insight into potential mechanisms that underlie recovery.
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Two studies are reported that tested the fear-avoidance (FA) model using path analytic techniques. In study 1, 429 employees with back pain at baseline and back pain at 18 months follow-up completed questionnaires assessing sociodemographic information, pain severity, negative affect, pain-related fear, and disability. Results indicated that pain severity at baseline predicted pain-related fear and disability at follow-up, and that pain-related fear is rather a consequence than an antecedent of pain severity. ⋯ A similar model as in study 1 was tested. Overall, results are in line with those of study 1. Results are discussed in terms of theoretical relevance and clinical implications.
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Previous evaluations of the 20-item Neck Pain and Disability Scale (NPAD) were indicative of excessive redundancy of the measure. The aim of this study was to develop a shortened version of the NPAD (sf-NPAD) based on results of item-to-total-score correlations and factor analysis as published by the developers of the original NPAD. Two items with the highest item-to-total score correlation were selected per factor subscale with the exception of one factor consisting of only one item. ⋯ The sf-NPAD scores of patient subgroups were significantly different showing good discriminative validity. In conclusion, the sf-NPAD demonstrated good validity and internal consistency in this general practice setting. The abbreviated version may facilitate applicability of the scale in clinical and research settings.
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Central sensitization is believed to be one of the key mechanisms behind chronic pain conditions, and several models have been developed in order to characterize this phenomenon in humans. One of these models relies on conditioning electrical stimulation to elicit long-lasting effects on the nociceptive system. The aim of this study was to evaluate these effects using an objective electrophysiological measurement, the nociceptive withdrawal reflex (NWR). ⋯ To evaluate the excitability of the nociceptive system, the NWR was elicited within the same innervation area (superficial peroneal nerve) at graded stimulation intensities and recorded in the hamstrings. Following low-frequency stimulation, an intensity-independent long-lasting facilitation of the NWR was observed, with a significant increase in the reflex size (average of 31+/-4%, p<0.001) and in the number of reflexes (average increase of 22+/-10%, p<0.01), accompanied by a significant increase in the blood flow (average increase of 40+/-10%, p<0.001). These findings suggest that activity-dependent central sensitization can be elicited using conditioning electrical stimulation with a stimulation frequency that lies within the physiological firing range of primary afferents, and that it can be objectively assessed in humans using the NWR.