Pain
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Pain modulation by placebo mechanisms is one of the most robust and best-studied phenomena, yet almost all research investigating the mechanisms and implications of the placebo analgesia are based on adult research. After highlighting crucial aspects that need to be considered in studying pain modulation in children, this comprehensive review examines studies related to pain modulation with an emphasis on factors such as age, neural development and pain measures. ⋯ Taken together, research suggests that placebo mechanisms can affect therapeutic outcomes and potentially be exploited clinically to improve clinical outcomes in pediatric population. Recommendations for further investigating the mechanistic bases and harnessing placebo effects for supportive therapeutic applications are given.
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Chronic pain after laparoscopic cholecystectomy is related to postoperative pain during the first postoperative week, but it is unknown which components of the early pain response is important. In this prospective study, 100 consecutive patients were examined preoperatively, 1 week postoperatively, and 3, 6, and 12 months postoperatively for pain, psychological factors, and signs of hypersensitivity. Overall pain, incisional pain (somatic pain component), deep abdominal pain (visceral pain component), and shoulder pain (referred pain component) were registered on a 100-mm visual analogue scale during the first postoperative week. ⋯ There were no consistent signs of hypersensitivity in the referred pain area either pre- or postoperatively. There were no significant associations to any other variables examined. The risk of chronic pain after laparoscopic cholecystectomy is relatively low, but significantly related to the visceral pain response during the first postoperative week.
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The current study aimed to validate the child and parent pain catastrophizing scale in a large chronic pain sample and to identify child pain catastrophizing clinical reference points. Patients and parents (n=697) evaluated at a pediatric pain program completed the Pain Catastrophizing Scale, child (PCS-C) and parent (PCS-P) reports, along with additional measures of psychological functioning. The measure's psychometric properties were examined, as were relations across demographic, pain, and psychological characteristics and pain catastrophizing. ⋯ When comparing PCS-C scores based on child outcomes, significant differences emerged for low, moderate, and high catastrophizing levels. It appears that the influence of parent catastrophizing on outcomes can be explained through its impact on child catastrophizing levels. PCS-C reference points derived from this large sample can aid clinicians in assessment and treatment planning, in turn increasing the utility of the PCS-C for both clinical and research purposes.
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Abnormalities in the enzymatic activity of catechol-O-methyltransferase (COMT) contribute to chronic pain conditions, such as temporomandibular disorders (TMD). Thus, we sought to determine the effects of polymorphisms in COMT and functionally related pain genes in the COMT pathway (estrogen receptor 1 [ESR1], guanosine-5-triphosphate cyclohydrolase 1 [GCH1], methylenetetrahydrofolate reductase [MTHFR]) on COMT enzymatic activity, musculoskeletal pain, and pain-related intermediate phenotypes among TMD cases and healthy control subjects. Results show that the COMT rs4680 (val(158)met) polymorphism is most strongly associated with outcome measures, such that individuals with the minor A allele (met) exhibit reduced COMT activity, increased TMD risk, and increased musculoskeletal pain. ⋯ Among individuals with the COMT val allele, those with 2 copies of the ESR1 rs3020377 minor A allele exhibit reduced COMT activity, increased bodily pain, and poorer self-reported health. These data reveal that the GCH1 minor G allele confers a protective advantage among met carriers, whereas the ESR1 minor A allele is disadvantageous among val carriers. Furthermore, these data suggest that the ability to predict the downstream effects of genetic variation on COMT activity is critically important to understanding the molecular basis of chronic pain conditions.
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Pain can be communicated nonverbally through facial expressions, vocalisations, and bodily movements. Most studies have focussed on the facial display of pain, whereas there is little research on postural display. Stimulus sets for facial and vocal expressions of pain have been developed, but there is no equivalent for body-based expressions. ⋯ In addition, pain was rated as the most unpleasant (negative valence) of the expressions, and was associated with a high level of arousal. For the first time, specific postures communicating pain are described. The stimulus set is provided as a tool to facilitate the study of nonverbal pain communication, and its possible uses are discussed.