Pain
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Few studies have investigated whether prognostic indicators, which contribute to the transition from acute to chronic low back pain (LBP), are also those which contribute to continuing persistence of chronic LBP. We compared the contribution of physical, psychological and social indicators to predicting disability after one year between consulters with LBP of less than 3 months duration and more than 3 months duration. Data from two large prospective cohort studies of consecutive patients consulting with LBP in general practices were merged, providing complete data for 258 cases with acute/subacute LBP and 668 cases with chronic LBP at 12 months follow-up. ⋯ Fear of pain was significantly associated with disability in chronic LBP. Importantly, beyond baseline disability, the effect size of the other prognostic indicators for poor outcome was rather low. These findings must continue to challenge researchers to identify useful early predictors of outcome in persons with disabling back pain, as screening and targeted treatment approaches are dependent upon prognostic indicators with clinical significance.
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Clinical use of quantitative sensory testing (QST) requires standardization. The German research network on neuropathic pain (DFNS) solves this problem by defining reference data stratified for test site, gender and age for a standardized QST protocol. In this report we have targeted two further problems: how to adjust for age-related sensory changes, and how to compare groups of patients with the reference database. ⋯ Simulations for various sample sizes and variances showed that method B was more conservative than method A. We present a simple way of calculating method B for data that have been z-normalized. This technique makes the DFNS reference data bank applicable for researchers beyond the DFNS community without a need for subsampling of subjects from the database.
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Pain behaviors provide meaningful information about adolescents in chronic pain, enhancing their verbal report of pain intensity with information about the global pain experience. Caregivers likely consider these expressions when making judgments about their adolescents' medical or emotional needs. Current validated measures of pain behavior target acute or procedural pain and young or non-verbal children, while observation systems may be too cumbersome for clinical practice. ⋯ However, significant correlations were found between parent-reported pain behaviors and parent- and adolescent-reported functional disability, pain catastrophizing, depressive symptoms, and poorer quality of life. The assessment of pain behaviors provides qualitatively different information than solely recording pain intensity and disability. It has clinical utility for use in behavioral treatments seeking to reduce disability, poor coping, and distress.
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Following upper limb peripheral nerve transection and surgical repair (PNIr) patients frequently exhibit sensory and motor deficits, but only some develop chronic neuropathic pain. Thus, the sensorimotor outcome of PNIr may be impacted by individual factors. Therefore, our aims were to determine if patients with chronic neuropathic pain (PNI-P) following PNIr (1) are distinguished from patients without pain (PNI-NP) and healthy controls (HCs) by the psychological factors of pain catastrophizing, neuroticism or extraversion, and (2) exhibit more severe sensorimotor deficits than patients who did not develop chronic pain (PNI-NP). ⋯ Compared to PNI-NP patients, PNI-P patients had higher vibration detection thresholds, performed worse on sensory-motor integration tasks, had greater motor impairment, and showed more impaired nerve conduction. Furthermore, PNI-P patients had reduced cold pain tolerance, elevated pain intensity and unpleasantness during the cold pressor test, and they scored higher on neuroticism and pain-catastrophizing scales. These data demonstrate that chronic neuropathic pain following PNIr is associated with impaired nerve regeneration, profound sensorimotor deficits and a different psychological profile that may be predictive of poor recovery after injury.
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Widespread central hypersensitivity is present in chronic pain and contributes to pain and disability. According to animal studies, expansion of receptive fields of spinal cord neurons is involved in central hypersensitivity. We recently developed a method to quantify nociceptive receptive fields in humans using spinal withdrawal reflexes. ⋯ This study provides for the first time evidence for widespread expansion of reflex receptive fields in chronic pain patients. It thereby identifies a mechanism involved in central hypersensitivity in human chronic pain. Reverting the expansion of nociceptive receptive fields and exploring the prognostic meaning of this phenomenon may become future targets of clinical research.