European journal of pain : EJP
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In patients with low back pain (LBP), physical functioning may be negatively influenced by both expectations on pain and pain-related fear. It is unclear whether these factors influence both physical functioning in the laboratory as well as in daily life. The aim of this study was to test if a combination of persistent overprediction of pain and fear of movement predicts lab-based performance and whether these factors are relevant for predicting daily-life functioning. ⋯ No significant association between fear and performance or daily-life functioning were found in correct predictors. In contrast to correct predictors, in overpredictors lab-based performance and daily-life functioning was additionally explained by fear of movement. Thus it appears that fear of movement is only predictive of performance in patients with LBP who simultaneously overpredict the consequences of movements in terms of painfulness.
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Patients with neuropathy, report changes in sensory perception, particularly mechanical and thermal allodynia, and spontaneous pain. Similar sensory changes are seen in experimental neuropathies, in which alteration in primary afferent properties can also be determined. The neural correlate of spontaneous pain is ongoing activity in sensory afferents. ⋯ The afferent barrage associated with mechano-cooling-sensitive afferents was increased 26-fold 7 days after nerve injury. We observed no differences in the properties of intact A fibre mechanosensitive afferents. These studies demonstrate for the first time that the altered nociception seen after PSNI is associated with ongoing activity and enhanced cooling-evoked activity in intact C fibre afferents in the saphenous nerve, with no concurrent alteration in A fibre afferents.