Pain
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Insomnia is a significant problem for many people with chronic pain. In this study, we used a combination of daily sleep diaries and ambulatory activity monitoring (actigraphy) to: (i) examine the nature and severity of the sleep disturbance in this patient group; (ii) determine the concordance between sleep diary and actigraph measures of different sleep parameters; (iii) assess the reliability of sleep parameters across nights; and (iv) identify the clinical correlates of insomnia severity. Forty subjects with insomnia associated with chronic musculoskeletal pain completed questionnaires addressing clinical issues of pain severity, medication use, sleep quality, and affective distress. ⋯ Subjects who reported high pain severity also reported greater sleep impairment than subjects with low pain severity, but this was not confirmed by actigraphy. In general, both methods of assessment point to the significance of insomnia associated with chronic musculoskeletal pain as a distinct clinical problem, but the activity monitoring and self-report procedures provide different information. These findings suggest that multi-method assessment is an important consideration for studies of insomnia in patients with chronic pain.
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Nociceptive electrical stimuli were applied to the sural nerve during hypnotically-suggested analgesia in the left lower limb of 18 highly susceptible subjects. During this procedure, the verbally reported pain threshold, the nociceptive flexion (RIII) reflex and late somatosensory evoked potentials were investigated in parallel with autonomic responses and the spontaneous electroencephalogram (EEG). The hypnotic suggestion of analgesia induced a significant increase in pain threshold in all the selected subjects. ⋯ No modification in the autonomic parameters or the EEG was observed. These data suggest that different strategies of modulation can be operative during effective hypnotic analgesia and that these are subject-dependent. Although all subjects may shift their attention away from the painful stimulus (which could explain the decrease of the late somatosensory evoked potentials), some of them inhibit their motor reaction to the stimulus at the spinal level, while in others, in contrast, this reaction is facilitated.
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Little is known concerning the mechanisms underlying the perception of cold pain in humans. An appreciation of these mechanisms is important to understand and possibly treat those disorders in which cold stimuli evoke unpleasant sensations. To study cold pain, I have conducted psychophysical experiments on 16 healthy subjects. ⋯ The block did not consistently affect the total pain at the hairy sites. However, most subjects reported more pain during the block at the glabrous sites. These data suggest that noxious cold stimuli affect a mosaic of primary afferent input and central processing resulting in a complex pain experience which may differ in glabrous and hairy skin.
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The objective of this study was to assess outcomes of pediatric day surgery tonsillectomy. A total of 129 children, aged 5-16 years, and their parents were recruited from three urban hospitals which provided pediatric day surgery. Children reported pain on a visual analogue scale (VAS) in day surgery and then daily at home for 7 days. ⋯ The increase in postoperative pain experienced by those who had the infiltration was attributed to quality of pain management. Children with persistent pain (those who did not follow the typical trajectory) were likely to be taken to a medical practitioner. One-third of the sample made unscheduled visits to practitioners with most occurring from Day 4 to Day 7 of the follow-up.
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Intraspinal injections of the AMPA-metabotropic receptor agonist quisqualic acid (QUIS) were made in an effort to simulate injury induced elevations of excitatory amino acids (EAAs), a well documented neurochemical change following spinal cord injury (SCI). The progressive pathological sequela associated with QUIS injections closely resembles the cascade of events described following ischemic and traumatic SCI and the pathogenesis of cavities in the clinical condition of post-traumatic syringomyelia. ⋯ Thus, the present results provide a morphological correlate of spontaneous and evoked pain related behaviors following excitotoxic SCI. The behavioral characteristics combined with the similarities between QUIS induced injury and the clinical pathology of SCI support the use of the excitotoxic model in studies related to the central mechanism(s) of altered sensation, including pain, following spinal injury.