European journal of pain : EJP
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Pressure pain thresholds (PPTs) in distal limbs have been under-investigated despite their potential clinical importance. Therefore, we compared PPTs over nail bed, bony prominences, and muscle in distal parts of upper and lower limbs. We investigated 12 healthy subjects using three handheld devices: a spring-loaded, analogue pressure threshold meter (PTM) with two operating ranges, and an electronic Algometer. ⋯ PPTs over distal muscles were comparable to published values on proximal limb and trunk muscles. These findings suggest that pressure pain testing over distal muscles may be a sensitive test for deep pain sensitivity and that the simple and less expensive devices are sufficient for testing this tissue type. Intra-individual site-to-site comparisons will be more sensitive than absolute normative values.
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Evidence of cognitive bias in depression and anxiety has sparked an increasing interest in the potential for pain-related bias in patients suffering from chronic pain and/or illness. Research to date has been somewhat inconsistent, and the vast majority has been conducted on just two patient populations: rheumatoid arthritis (RA) and chronic pain patients. The present study investigates cognitive bias in Systemic Lupus Erythematosus (SLE) patients, particularly in relation to disease activity and depression. ⋯ Groups did not differ in their recall patterns, although all groups demonstrated a recall bias for positive words and illness words. Post-hoc analyses revealed a significant recall bias for disability-related illness words compared to sensory pain words in ill, depressed patients compared to ill, non-depressed patients and healthy controls. Consistent with the most recent research, it appears to be both the nature of the illness stimuli and the depression status of the patient that determines cognitive bias in chronically ill populations.
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A systematic evaluation of nociceptive withdrawal reflexes and pain rating was undertaken in order to explore the mechanisms underlying temporal summation of repetitive electrocutaneous stimulation in healthy individuals (n=12; age=27.5+/-1.5 years). Five-second subreflex threshold (RT) electrocutaneous stimulation at different frequencies (single stimulus, 5, 10, and 20 Hz) and intensities (0.6RT and 0.8RT) was applied on the dorsum of the foot, and the withdrawal reflex from the ipsilateral biceps femoris muscle was measured. The subjects scored the pain intensity on a visual analogue scale (0-100 mm) for the beginning, the middle and the end phase of the 5 s series of stimulation, and the respective averaged reflex size was calculated. ⋯ Profound activation of inhibition following electrocutaneous pain stimuli was demonstrated by reduction in pain intensity and reflex size during the last second as compared with the first second at 0.6RT current intensity (SNK, P<0.05). The pain intensity peaked between 5 and 10 Hz (P<0.05) and was reduced at 20 Hz for current intensities at 0.8RT (P<0.05). This study provides evidence for both frequency dependent central integration of the repetitive electrocutaneous stimuli and activation of a pain inhibitory system by psychophysical and electrophysiological means, demonstrating the delicate balance between neuronal facilitation and inhibition in the human pain system.
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Spinal cord stimulation (SCS) is a useful option in selected patients with chronic neuropathic pain. The aim of this questionnaire-based survey was to determine what assessment methods are used for patients being considered for SCS in pain management centres in the United Kingdom. This was in relation to the recommendations produced by the Task Force of the European Federation of IASP chapters (1998) on neuromodulation. ⋯ There was significant variation concerning absolute contraindications. The majority of respondents worked in a multi-disciplinary team and 61% stated their patients received a psychological assessment but although 96% of individuals worked with a specialist nurse only 25% reported that the nurse had an active role in the pre-assessment of patients for SCS. The development of national guidelines may provide a more standardised approach but further research into the role of the specialist nurse and the benefits of psychological assessment would also be useful.