Pain
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In this prospective cohort study we aimed to describe the natural course of acute neck and low back pain in a general population of Norway. We screened 9056 subjects aged 20-67 years who participated in a general health survey for a new episode of neck or low back pain the previous month. The screening identified 219 subjects who formed the cohort for this study. ⋯ Only 1 in 5 sought health care for their complaints. Still, the course of pain was comparable to effect sizes reported in interventional studies. This study thus contributes natural course reference data for comparisons of pain outcome in clinical trials and practice.
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A link between fibromyalgia syndrome (FMS) and posttraumatic stress disorder (PTSD) has been suggested because both conditions share some similar symptoms. The temporal relationships between traumatic experiences and the onset of PTSD and FMS symptoms have not been studied until now. All consecutive FMS patients in 8 study centres of different specialties were assessed from February 1 to July 31, 2012. ⋯ In 4.0% of patients' most burdensome traumatic experience, PTSD and FMS symptoms occurred in the same year. FMS and PTSD are linked in several ways: PTSD is a potential risk factor of FMS and vice versa. FMS and PTSD are comorbid conditions because they are associated with common antecedent traumatic experiences.
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Recent functional brain connectivity studies have contributed to our understanding of the neurocircuitry supporting pain perception. However, evoked-pain connectivity studies have employed cutaneous and/or brief stimuli, which induce sensations that differ appreciably from the clinical pain experience. Sustained myofascial pain evoked by pressure cuff affords an excellent opportunity to evaluate functional connectivity change to more clinically relevant sustained deep-tissue pain. ⋯ Moreover, greater connectivity during pain between contralateral S1/M1 and posterior insula, thalamus, putamen, and amygdala was associated with lower cuff pressures needed to reach the targeted pain sensation. These results demonstrate that sustained pain disrupts resting S1/M1 connectivity by shifting it to a network known to process stimulus salience. Furthermore, increased connectivity between S1/M1 and both sensory and affective processing areas may be an important contribution to interindividual differences in pain sensitivity.
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Conditioned pain modulation (CPM) (ie, diffuse noxious inhibitory controls) is characterized by reduced perception of pain caused by intense pain in a remote body area. The conditioning stimuli used to trigger CPM causes pain, but also important cardiovascular responses. Higher blood pressure has been associated with reduced pain sensitivity. ⋯ A significant positive association was observed between CPM magnitude and the increase in blood pressure during the CPT. These results show that resting blood pressure values are related to acute pain tolerance, while descending pain inhibition is associated with increases in blood pressure. The rise in blood pressure caused by the conditioning stimulus is an important factor predicting the extent of endogenous pain inhibition in healthy subjects.