European journal of pain : EJP
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Randomized Controlled Trial
Self-reported sleep duration associated with distraction analgesia, hyperemia, and secondary hyperalgesia in the heat-capsaicin nociceptive model.
Although sleep deprivation is known to heighten pain sensitivity, the mechanisms by which sleep modifies nociception are largely unknown. Few studies of sleep-pain interactions have utilized quantitative sensory testing models that implicate specific underlying physiologic mechanisms. One possibility, which is beginning to receive attention, is that differences in sleep may alter the analgesic effects of distraction. ⋯ Individuals who slept less than 6.5 h/night in the month prior to the study experienced significantly less behavioral analgesia, increased skin flare and augmented secondary hyperalgesia. These findings suggest that reduced sleep time is associated with diminished analgesic benefits from distraction and/or individuals obtaining less sleep have a reduced ability to disengage from pain-related sensations. The secondary hyperalgesia finding may implicate central involvement, whereas enhanced skin flare response suggests that sleep duration may also impact peripheral inflammatory mechanisms.
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The current study interviewed patients with chronic pain to: (1) identify the most common words used by patients in the samples to describe the "quality" of their pain (i.e. sharp, dull) and (2) evaluate the validity of existing pain quality measures. Two-hundred and thirteen individuals with pain associated with spinal cord injury (SCI) or multiple sclerosis (MS) were asked to describe their pain. Consistent with previous research that has shown that patients with different types of pain problems describe their pain using different pain quality descriptors, there was variability in the frequency of pain descriptors used by the study participants. ⋯ Regarding the validity of existing pain measures, only one pain quality measure assessed all 14 of the most common pain descriptors volunteered by the sample. Also, although a number of pain quality measures have been developed to discriminate neuropathic from nociceptive pain, there was surprisingly little overlap in descriptors between these measures. The results of the current study and other studies using similar procedures would be useful for evaluating and developing existing and future pain quality measures.
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To study the effects of occupational class, physical and psychosocial working conditions, health behaviours, and pain in the low back and the neck on sciatic pain among middle-aged employees. ⋯ Manual occupational class in both genders and semi-professional occupations in men, unhealthy behaviours and previous pain both in the neck and the lower back predicted sciatica, while physical and psychosocial working conditions had no independent effect.
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The demand-control-support "job strain" model is frequently used in occupational health research. We sought to explore the relationship between job strain and back pain. ⋯ Our results support the findings linking back pain to job strain. Moreover, the relationship between back pain and job strain is much stronger if job strain includes both psychological and physical demands. Results of this study suggest that workplace interventions that aim to reduce job strain may help prevent back pain and may alleviate the personal, social, and economic burden attributable to back pain.
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The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasympathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart rate variability, and correlated the results with the presence of cortical arousal measured in concomitant 32-channel EEG. Fourteen healthy volunteers underwent whole-night polysomnography during which nociceptive laser stimuli were applied over the hand. ⋯ This RR decrease was associated with an increase in sympathetic LF(WV) and LF(WV)/HF(WV) ratio without any parasympathetic HF(WV) change. Albeit RR decrease existed even in the absence of arousals, it was significantly higher when an arousal followed the noxious stimulus. These results suggest that the sympathetic-dependent cardiac activation induced by nociceptive stimuli is modulated by a sleep dependent phenomenon related to cortical activation and not by sleep itself, since it reaches a same intensity whatever the state of vigilance.