Current pain and headache reports
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Curr Pain Headache Rep · Jun 2007
ReviewPhenotyping central nervous system circuitry in chronic pain using functional MRI: considerations and potential implications in the clinic.
Functional MRI (fMRI) has provided new insights into brain mechanisms in chronic pain. However, unlike acute pain measures in healthy volunteers, there are additional concerns relating to mapping brain circuits in these patients. ⋯ Nevertheless, our understanding of the centralization of pain with attendant changes in sensory, emotional, and autonomic function is being more clearly realized and has significant implications for defining the disease state and therapeutic interventions. It is possible that fMRI may become clinically useful.
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Curr Pain Headache Rep · Jun 2007
Review Meta AnalysisControlled trials in pediatric migraine: crossover versus parallel group.
Studies on the treatment of migraine in children and adolescents are rare and difficult to design. In particular, the high placebo response makes it difficult to show efficacy of a verum drug. When analyzing all published trials in the acute drug treatment of migraine in children, crossover trials show lower placebo rates and higher therapeutic gain, compared with parallel group trials. This should be considered in the future design of acute drug trials in childhood migraine.
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Curr Pain Headache Rep · Jun 2007
ReviewSpontaneous pain and brain activity in neuropathic pain: functional MRI and pharmacologic functional MRI studies.
Functional brain imaging studies in chronic neuropathic pain patients have lagged far behind equivalent studies in acute pain. In the past few years, this trend has begun to shift. This article discusses the novel approach of studying brain activity for spontaneous pain and its modulation by pharmacologic manipulation. We argue that the approach provides a solid methodology for studying clinical (especially neuropathic) pain and patient populations, and moreover, that the latest results using this approach imply that distinct clinical chronic pain conditions seem to involve specific brain circuitry, which is also distinct from the brain activity commonly observed in acute pain.
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Brain imaging studies have provided objective evidence of abnormal central regulation of pain in fibromyalgia (FM). Resting brain blood flow studies have reported mixed findings for several brain regions, whereas decreased thalamic blood flow has been noted by several investigators. ⋯ Data from other chronic conditions suggest that idiopathic pain may be maintained by similar central abnormalities as in FM, whereas chronic pain conditions with a known nociceptive source may not be. Future neuroimaging research in FM is clearly warranted and should continue to improve our understanding of factors involved in pain maintenance and symptom exacerbation.
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The application of functional imaging to study visceral sensation has generated considerable interest regarding insight into the function of the brain-gut axis. Brain activation in normal control subjects during visceral sensation includes the perigenual cingulate cortex, which is involved in affective processing and has direct connections to autonomic centers. In contrast, somatic pain rarely activates the perigenual cingulate. ⋯ Although this is partly because brain imaging is still a relatively new technique, it also reflects weaknesses inherent to the understanding of chronic visceral pain as a biopsychosocial phenomenon. The biopsychosocial concept is very broad and rarely provides for precise predictions or mechanisms that can be directly tested using brain imaging. Future use of brain imaging to examine chronic visceral pain and other pain disorders will be more likely to succeed by describing clear theoretical and clinical endpoints.