The journal of pain : official journal of the American Pain Society
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Contingency learning, in particular the formation of danger beliefs, underpins conditioned fear and avoidance behavior, yet equally important is the formation of safety beliefs. That is, when threat beliefs and accompanying fear/avoidance spread to technically safe cues, it might cause disability. Indeed, such over generalization has been advanced as a trans-diagnostic pathologic marker, but it has not been investigated in chronic pain. Using a novel hand pain scenario contingency learning task, we tested the hypotheses that chronic hand pain patients demonstrate less differential pain expectancy judgments because of poor safety learning and demonstrate broader generalization gradients than healthy controls. Participants viewed digitized 3-dimensional hands in different postures presented in random order (conditioned stimulus [CS]) and rated the likelihood that a fictive patient would feel pain when moving the hand into that posture. Subsequently, the outcome (pain/no pain) was presented on the screen. One hand posture was followed by pain (CS+), another was not (CS-). Generalization was tested using novel hand postures (generalization stimuli) that varied in how similar they were to the original conditioned stimuli. Patients, but not healthy controls, demonstrated a contingency learning deficit determined by impaired safety learning, but not by exaggerated pain expectancy toward the CS+. Patients showed flatter, asymmetric generalization gradients than the healthy controls did, with higher pain expectancy for novel postures that were more similar to the original CS-. The results clearly uphold our hypotheses and suggest that contingency learning deficits might be important in the development and maintenance of the chronic pain-related disability. ⋯ Chronic hand pain patients demonstrate 1) reduced differential contingency learning determined by a lack of safety belief formation, but not by exaggerated threat belief formation, and 2) flatter, asymmetric generalization gradients than the healthy controls.
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Published adult prevalence estimates of chronic pain in the United States vary significantly. A more consistent pain measure is needed to assess unmet need for pain management in the general population. In this study, secondary analyses of the 2010 Quality of Life Supplement of the National Health Interview Survey are used to calculate the point prevalence of "persistent pain," which we defined as constant or frequent pain persisting for at least 3 months. Rates of persistent pain are also calculated by risk group, chronic condition, and disability status. Findings show that about 19.0% of adults in the United States report persistent pain. Rates of persistent pain are higher among women, adults aged 60 to 69, adults who rate their health as fair or poor, adults who are overweight or obese, and those who were hospitalized 1 or more times in the preceding year. Most adults who report conditions such as arthritis, carpal tunnel syndrome, or back or joint pain do not describe their pain as "persistent." Of the estimated 39.4 million adults who report persistent pain, 67.2% say their pain is "constantly present," and 50.5% say their pain is sometimes "unbearable and excruciating." ⋯ Persistent pain, defined as self-reported pain "every day" or "most days" in the preceding 3 months, is a useful way to characterize health-related quality of life in the general population, and policy makers should consider including this core measure in ongoing health surveys like the National Health Interview Survey and the Medical Expenditure Panel Survey, the authors conclude.
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Survival outcomes in patients with squamous cell carcinoma of the head and neck (HNSCC) vary by extent of disease, behavioral factors, and socioeconomic factors. We assessed the extent to which pretreatment pain influences survival in 2,340 newly diagnosed patients with HNSCC, adjusting for disease stage, symptoms, pain medications, comorbidities, smoking, alcohol consumption, age, sex, and race/ethnicity. Patients rated their pain at presentation to the cancer center (0 = "no pain" and 10 = "pain as bad as you can imagine"). Survival time was calculated from the date of diagnosis to the date of death of any cause or last follow-up. Five-year overall survival was calculated for all the variables assessed in the study. Severe pain (≥7) was most prevalent among those with oral cancer (20.4%; pharynx = 18.8%; larynx = 16.1%) and significantly varied by tumor stage, fatigue severity, smoking status, comorbid lung disease, and race (all P < .05) across cancer diagnoses. Overall 5-year survival varied by pain for oral (severe pain = 31% vs nonsevere pain = 52%; P < .001) and pharyngeal cancer (severe pain = 33% vs nonsevere pain = 53%; P < .001). Multivariable analyses showed that pain persisted as an independent prognostic factor for survival. Pain reported prior to treatment should be considered in understanding survival outcomes in HNSCC patients. ⋯ Pretreatment pain was an independent predictor of survival in a large sample of HNSCC patients even after accounting for tumor node metastasis stage, fatigue, age, race/ethnicity, smoking, and alcohol intake. Therefore, symptoms at presentation and before cancer treatment are important factors to be considered in understanding survival outcomes in HNSCC patients.
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The oldest known method for relieving pain is music, and yet, to date, the underlying neural mechanisms have not been studied. Here, we investigate these neural mechanisms by applying a well-defined painful stimulus while participants listened to their favorite music or to no music. Neural responses in the brain, brain stem, and spinal cord were mapped with functional magnetic resonance imaging spanning the cortex, brain stem, and spinal cord. Subjective pain ratings were observed to be significantly lower when pain was administered with music than without music. The pain stimulus without music elicited neural activity in brain regions that are consistent with previous studies. Brain regions associated with pleasurable music listening included limbic, frontal, and auditory regions, when comparing music to non-music pain conditions. In addition, regions demonstrated activity indicative of descending pain modulation when contrasting the 2 conditions. These regions include the dorsolateral prefrontal cortex, periaqueductal gray matter, rostral ventromedial medulla, and dorsal gray matter of the spinal cord. This is the first imaging study to characterize the neural response of pain and how pain is mitigated by music, and it provides new insights into the neural mechanism of music-induced analgesia within the central nervous system. ⋯ This article presents the first investigation of neural processes underlying music analgesia in human participants. Music modulates pain responses in the brain, brain stem, and spinal cord, and neural activity changes are consistent with engagement of the descending analgesia system.