Pain
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Comparative Study
Neonatal pain facial expression: evaluating the primal face of pain.
The primal face of pain (PFP) is postulated to be a common and universal facial expression to pain, hardwired and present at birth. We evaluated its presence by applying a computer-based methodology consisting of "point-pair" comparisons captured from video to measure facial movement in the pain expression by way of change across two images: one image before and one image after a painful stimulus (heel-stick). ⋯ Although facial expression was not identical across or among groups, our analyses showed no particular clustering or unique display by sex, or ethnicity. The clinical significance of this commonality of pain display, and of the origin of its potential individual variation begs further evaluation.
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Comparative Study
Trends in use of opioids for non-cancer pain conditions 2000-2005 in commercial and Medicaid insurance plans: the TROUP study.
Opioids are widely prescribed for non-cancer pain conditions (NCPC), but there have been no large observational studies in actual clinical practice assessing patterns of opioid use over extended periods of time. The TROUP (Trends and Risks of Opioid Use for Pain) study reports on trends in opioid therapy for NCPC in two disparate populations, one national and commercially insured population (HealthCore plan data) and one state-based and publicly-insured (Arkansas Medicaid) population over a six year period (2000-2005). We track enrollees with the four most common NCPC conditions: arthritis/joint pain, back pain, neck pain, headaches, as well as HIV/AIDS. ⋯ Cumulative yearly opioid dose (in mg. morphine equivalents) received by NCPC patients treated with opioids increased (HealthCore 38%, Medicaid 37%) due to increases in number of days supplied rather than dose per day supplied. Use of short-acting Drug Enforcement Administration Schedule II opioids increased most rapidly, both in proportion of NCPC patients treated (HealthCore 54%, Medicaid 38%) and in cumulative yearly dose (HealthCore 95%, Medicaid 191%). These trends have occurred without any significant change in the underlying population prevalence of NCPC or new evidence of the efficacy of long-term opioid therapy and thus likely represent a broad-based shift in opioid treatment philosophy.
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Comparative Study
Combined effects of major depression, pain and somatic disorders on general functioning in the general adult population.
This study was carried out to assess the prevalence of major depressive disorder (MDD) in persons suffering from pain symptoms in various locations, both with and without comorbid somatic disorders and to analyze the single and combined effects of MDD, pain symptoms and somatic disorders on general functioning in the community. The 12-month prevalence of MDD, somatic disorders and pain symptoms, grouped according to location, were determined among 4181 participants from a community sample. Depression was assessed utilising the Composite International Diagnostic Interview. ⋯ The presence of pain increases risk of associated MDD. The number of pain locations experienced, rather than the specific location of pain, has the greatest impact on general functioning. Not only chronic pain, but pain of any type may be an indicator of MDD and decreased general functioning.
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Comparative Study
Effects of mood on pain responses and pain tolerance: an experimental study in chronic back pain patients.
Although chronic pain and depression commonly co-occur, causal relationships have yet to be established. A reciprocal relationship, with depression increasing pain and vice versa, is most frequently suggested, but experimental evidence is needed to validate such a view. The most straightforward approach would be a demonstration that increasing or decreasing depressed mood predictably modifies pain responses. ⋯ Results indicate that the induction of depressed mood resulted in significantly higher pain ratings at rest and lower pain tolerance, whilst induced happy mood resulted in significantly lower pain ratings at rest and greater pain tolerance. Correlations between changes in mood on the one hand and changes in pain response and pain tolerance on the other hand were consistent with these findings. It is concluded that, in chronic back pain patients, experimentally induced negative mood increases self-reported pain and decreases tolerance for a pain-relevant task, with positive mood having the opposite effect.
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Comparative Study
Touch or pain? Spatio-temporal patterns of cortical fMRI activity following brief mechanical stimuli.
Most imaging studies on the human pain system have concentrated so far on the spatial distribution of pain-related activity. In the present study, we investigated similarities and differences between the spatial and temporal patterns of brain activity related to touch vs. pain perception. To this end, we adopted an event-related functional magnetic resonance imaging (fMRI) paradigm allowing us to separately assess the activity related to stimulus anticipation, perception, and coding. ⋯ Significant decreases in fMRI signals following both tactile and painful stimuli were found in perigenual cingulate (pACC)/medial prefrontal cortex (MPF) and in the posterior cingulate/precuneus/paracentral lobule; more intense decreases were found in the pACC/MPF following painful stimuli. fMRI signal increases in the contralateral insula and in aMCC, but not in the parietal cortex, were more prolonged following painful than tactile stimuli. Moreover, a second peak of signal increases (albeit of lower intensity) was found in anterior insula and aMCC during pain intensity rating. These results show specific spatio-temporal patterns of cortical activity related to processing noxious vs. non-noxious mechanical stimuli.