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
The effects of parental presence upon the facial expression of pain: the moderating role of child pain catastrophizing.
This experiment investigated the effects of child catastrophic thinking and parental presence on the facial expressions of children when experiencing pain. School children experienced pressure pain in either one of two conditions: (1) when observed by a parent (n=53 children and their parent), or (2) when observed by an adult stranger (n=31 children). ⋯ Children who have frequent catastrophic thoughts expressed high pain regardless of who they believed was observing them. Results are discussed in terms of the social consequences of pain catastrophizing, and the variables contributing to the expression or suppression of pain display in children and its impact upon others.
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Comparative Study
Principle components analysis of pain thresholds to thermal, electrical, and mechanical stimuli suggests a predominant common source of variance.
We addressed the question whether pain thresholds to different stimuli measure independent aspects of pain or one common phenomenon. In the first case, different stimuli are required to completely characterize a subject's pain sensitivity. In the second case, different stimuli are redundant and can be used to calculate composite scores across pain modalities. ⋯ Only minor variance components, each explaining <14% of the total variance, indicated a distinction of pain stimuli. There, a pattern of similarities and dissimilarities emerged agreeing with known distinct mechanisms of nociceptive responses to different stimuli. We conclude that characterizing a person as being generally stoical or complaining to any painful stimulus appears to be justified at least at pain threshold level.
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This study examined the effects of anxiety and depression on pain in women with rheumatoid arthritis (RA; n=82) or osteoarthritis (OA; n=88). Anxiety and depression symptoms were assessed at the beginning of the study. Arthritis pain, interpersonal stress, negative affect, and positive affect were assessed weekly for 11 consecutive weeks. ⋯ When entered together into the prediction equations, anxiety alone was still related to elevations in current and next week pain. In addition, anxiety alone was indirectly related to current pain through negative affect and depression alone was indirectly related to current pain through positive affect. These results highlight the need for careful study of the differential effects of anxiety and depression and treatments that target their unique mechanisms.