The journal of pain : official journal of the American Pain Society
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Comparative Study
Observational learning and pain-related fear: an experimental study with colored cold pressor tasks.
The primary aim of the current study was to experimentally test whether pain-related fear can be acquired through observational learning, whether extinction occurs after actual exposure to the aversive stimulus, and whether pain-related fear was associated with increased pain ratings. During an observation phase, female volunteers watched a video showing models performing cold pressor tasks (CPT), of which the color served as a conditioned stimulus (CS). In a differential fear conditioning paradigm, each of 2 colors were either paired with models' painful (CS+) or neutral (CS-) facial expressions. Exposure consisted of participants performing CPTs of both colors (10°C). Self-reported fear of pain and expected pain ratings were obtained after the observation period, while actual pain and avoidance measures were obtained during and after exposure. Results show that after observing another person performing the CPT associated with the painful faces, subjects report more fear of pain and expect more intense and unpleasant pain as compared with the CPT associated with the neutral faces. This effect of observational learning on pain-related fear persisted until after exposure. During and after exposure no stimulus-type effect for pain ratings was found. This study provides preliminary evidence for observational learning of pain-related fear in humans. ⋯ Fear of pain can be more disabling than pain itself, and is a risk factor for chronic pain. Knowledge about the acquisition of pain-related fear may help to develop novel pain management programs. This study is one of the first to demonstrate the effects of observational learning on pain-related fear.
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Previously we showed that swearing produces a pain lessening (hypoalgesic) effect for many people.(20) This paper assesses whether habituation to swearing occurs such that people who swear more frequently in daily life show a lesser pain tolerance effect of swearing, compared with people who swear less frequently. Pain outcomes were assessed in participants asked to repeat a swear word versus a nonswear word. Additionally, sex differences and the roles of pain catastrophizing, fear of pain, and daily swearing frequency were explored. Swearing increased pain tolerance and heart rate compared with not swearing. Moreover, the higher the daily swearing frequency, the less was the benefit for pain tolerance when swearing, compared with when not swearing. This paper shows apparent habituation related to daily swearing frequency, consistent with our theory that the underlying mechanism by which swearing increases pain tolerance is the provocation of an emotional response. ⋯ This article presents further evidence that, for many people, swearing (cursing) provides readily available and effective relief from pain. However, overuse of swearing in everyday situations lessens its effectiveness as a short-term intervention to reduce pain.
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The primary symptom of fibromyalgia (FM) is chronic, widespread pain; however, patients report additional symptoms including decreased concentration and memory. Performance-based deficits are seen mainly in tests of working memory and executive function. Neural correlates of executive function were investigated in 18 FM patients and 14 age-matched healthy controls during a simple Go/No-Go task (response inhibition) while they underwent functional magnetic resonance imaging (fMRI). Performance was not different between FM and healthy control, in either reaction time or accuracy. However, fMRI revealed that FM patients had lower activation in the right premotor cortex, supplementary motor area, midcingulate cortex, putamen and, after controlling for anxiety, in the right insular cortex and right inferior frontal gyrus. A hyperactivation in FM patients was seen in the right inferior temporal gyrus/fusiform gyrus. Despite the same reaction times and accuracy, FM patients show less brain activation in cortical structures in the inhibition network (specifically in areas involved in response selection/motor preparation) and the attention network along with increased activation in brain areas not normally part of the inhibition network. We hypothesize that response inhibition and pain perception may rely on partially overlapping networks, and that in chronic pain patients, resources taken up by pain processing may not be available for executive functioning tasks such as response inhibition. Compensatory cortical plasticity may be required to achieve performance on a par with control groups. ⋯ Neural activation (fMRI) during response inhibition was measured in fibromyalgia patients and controls. FM patients show lower activation in the inhibition and attention networks and increased activation in other areas. Inhibition and pain perception may use overlapping networks: resources taken up by pain processing may be unavailable for other processes.
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The present study investigated the effects of social threat to physical integrity on reported pain and facial pain expression. Predictions of a cognitive appraisal model and a communicative perspective on pain expression were compared. Participants (N = 67) received 5 electric pain stimuli administered by a confederate. They were led to believe that 5 pain stimuli were the minimum, a fixed amount, or the maximum number of pain stimuli allowed, thereby varying the social threat posed by the confederate. Reported pain and facial pain expression were recorded during the delivery of pain stimuli. Increased perceived social threat led to an increase of reported pain, specifically for high pain catastrophizing participants, while it led to a reduction of facial pain expression. This is the first study to demonstrate that a social threat manipulation has opposite effects on reported pain and facial expression, suggesting differences in adaptive function for both forms of pain expression. ⋯ This is the first demonstration showing an increase in verbal pain report and a decrease in nonverbal pain expression at the same time during social threat. This knowledge may contribute to improving pain assessment in different contexts.
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For 2 weeks following surgery, 55 patients with preexisting chronic pain (CP) reported daily postoperative pain with movement and at rest. Of these, 30 CP patients used opioid pharmacotherapy for CP management and 25 did not. We modeled pain resolution in each patient using a linear fit so that each patient yielded 2 scores for each pain rating: 1) an intercept, or initial level of pain, immediately after surgery; and 2) a slope, or rate of pain resolution. The patients not using opioid pharmacotherapy had a mean pain with movement intercept of 5.4 and a slope of -.20, while the patients using opioid pharmacotherapy had a significantly higher mean intercept of 7.68 (P = .001) and a slope of -.21, sustaining higher pain levels over days. The opioid pharmacotherapy patients had the same rate of pain resolution as the other CP patients, and both groups resolved their pain more slowly than normal surgery patients. Preexisting CP may predispose a patient undergoing surgery to a slower rate of postoperative pain resolution. Chronic pain patients who use opioids share this predisposition but in addition, they are at risk for markedly higher postoperative pain across the entire pain resolution trajectory. ⋯ This is an observational rather than a randomized controlled study, and as such is less definitive. Nonetheless, these findings are consistent with those of animal studies showing that prolonged exposure to opioids can produce opioid-induced hyperalgesia. Patients with opioid pharmacotherapy for chronic pain who undergo surgery merit special attention for acute pain management.