The journal of pain : official journal of the American Pain Society
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Vocalizing is a ubiquitous pain behavior. The present study investigated whether it helps alleviate pain and sought to discern potential underlying mechanisms. Participants were asked to immerse one hand in painfully cold water. On separate trials, they said "ow," heard a recording of them saying "ow," heard a recording of another person saying "ow," pressed a button, or sat passively. Compared to sitting passively, saying "ow" increased the duration of hand immersion. Although on average, participants predicted this effect, their expectations were uncorrelated with pain tolerance. Like vocalizing, button pressing increased the duration of hand immersion, and this increase was positively correlated with the vocalizing effect. Hearing one's own or another person's "ow" was not analgesic. Together, these results provide first evidence that vocalizing helps individuals cope with pain. Moreover, they suggest that motor more than other processes contribute to this effect. ⋯ Participants immersed their hand in painfully cold water longer when saying "ow" than when doing nothing. Whereas button pressing had a similar effect, hearing one's own or another person's "ow" did not. Thus, vocalizing in pain is not only communicative. Like other behaviors, it helps cope with pain.
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Randomized Controlled Trial
Can experimentally induced positive affect attenuate generalization of fear of movement-related pain?
Recent experimental data show that associative learning processes are involved not only in the acquisition but also in the spreading of pain-related fear. Clinical studies suggest involvement of positive affect in resilience against chronic pain. Surprisingly, the role of positive affect in associative learning in general, and in fear generalization in particular, has received scant attention. In a voluntary movement paradigm, in which one arm movement (reinforced conditioned stimulus [CS+]) was followed by a painful stimulus and another was not (unreinforced conditioned stimulus [CS-]), we tested generalization of fear inhibition in response to 5 novel but related generalization movements (GSs; within-subjects) after either a positive affect induction or a control exercise (Group = between-subjects) in healthy participants (N = 50). The GSs' similarity with the original CS+ movement and CS- movement varied. Fear learning was assessed via verbal ratings. Results indicated that there was an interaction between the increase in positive affect and the linear generalization gradient. Stronger increases in positive affect were associated with steeper generalization curves because of relatively lower pain-unconditioned stimulus expectancy and less fear of stimuli more similar to the CS-. There was no Group by Stimulus interaction. Results thus suggest that positive affect may enhance safety learning through promoting generalization from known safe movements to novel yet related movements. Improved safety learning may be a central mechanism underlying the association between positive affect and increased resilience against chronic pain. ⋯ We investigated the extent to which positive affect influences the generalization (ie, spreading) of pain-related fear inhibition in response to situations similar to the original, pain-eliciting situation. Results suggest that increasing positive affect in the acute pain stage may limit the spreading of pain-related fear, thereby potentially inhibiting transition to chronic pain conditions.
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Parental responses to their child's pain are associated with the young person's functioning. Psychological flexibility--defined as the capacity to persist with or change behavior, depending on one's values and the current situation, while recognizing cognitive and noncognitive influences on behavior--may provide a basis for further investigating the role of these responses. The Parent Psychological Flexibility Questionnaire (PPFQ) is a promising but preliminary measure of this construct. Parents of 332 young people with pain (301 mothers, 99 fathers, 68 dyads) completed the PPFQ during appointments in a pediatric pain clinic. Initial item screening eliminated 6 of the 31 items. Mothers' and fathers' data were then subjected to separate principal components analyses with oblique rotation, resulting in a 4-factor solution including 17 items, with subscales suggesting Values-Based Action, Pain Acceptance, Emotional Acceptance, and Pain Willingness. The PPFQ correlated significantly with adolescent-rated pain acceptance, functional disability, and depression. Differences were observed between mothers' and fathers' PPFQ scores, in particular, those related to school absence and fears of physical injury. The 17-item PPFQ appears reasonable for research and clinical use and may potentially identify areas for intervention with parents of young people with chronic pain. ⋯ Parent psychological flexibility, as measured by the PPFQ, appears relevant to functioning, depression, and pain acceptance in adolescents with chronic pain. This model may help tie parental responses to adolescent distress and disability and may help clarify the development and maintenance of disability within the context of chronic pain.
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Review
Reporting of sample size calculations in analgesic clinical trials: ACTTION systematic review.
Sample size calculations determine the number of participants required to have sufficiently high power to detect a given treatment effect. In this review, we examined the reporting quality of sample size calculations in 172 publications of double-blind randomized controlled trials of noninvasive pharmacologic or interventional (ie, invasive) pain treatments published in European Journal of Pain, Journal of Pain, and Pain from January 2006 through June 2013. Sixty-five percent of publications reported a sample size calculation but only 38% provided all elements required to replicate the calculated sample size. In publications reporting at least 1 element, 54% provided a justification for the treatment effect used to calculate sample size, and 24% of studies with continuous outcome variables justified the variability estimate. Publications of clinical pain condition trials reported a sample size calculation more frequently than experimental pain model trials (77% vs 33%, P < .001) but did not differ in the frequency of reporting all required elements. No significant differences in reporting of any or all elements were detected between publications of trials with industry and nonindustry sponsorship. Twenty-eight percent included a discrepancy between the reported number of planned and randomized participants. This study suggests that sample size calculation reporting in analgesic trial publications is usually incomplete. Investigators should provide detailed accounts of sample size calculations in publications of clinical trials of pain treatments, which is necessary for reporting transparency and communication of pre-trial design decisions. ⋯ In this systematic review of analgesic clinical trials, sample size calculations and the required elements (eg, treatment effect to be detected; power level) were incompletely reported. A lack of transparency regarding sample size calculations may raise questions about the appropriateness of the calculated sample size.