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The increased pain sensitivity following reduced sleep may be related to changes in cortical processing of nociceptive stimuli. Expectations shape pain perception and can inhibit (placebo) or enhance (nocebo) pain. Sleep restriction appears to enhance placebo responses; however, whether sleep restriction also affects nocebo responses remains unknown. The aim of the present study was to determine whether sleep restriction facilitates nocebo-induced changes in pain and pain-evoked cortical potentials.
Learn More >Opioids, which carry a high risk for addiction and overdose, are commonly prescribed after corneal surgery. Data are lacking describing opioid prescribing practices and opioid needs by patients after ophthalmic surgery.
Learn More >Exposure in vivo has been found successful in reducing pain-related fear, disability, and experienced pain in chronic pain patients. Despite the success of exposure treatment, experimental studies show that extinction learning is fragile, raising doubts whether extinction of pain-related fear generalizes to new threatening activities after treatment. This study examined whether a particular exposure treatment, in which patients are exposed to a variety of activities (Multiple Exposure condition), promotes generalization of extinction to new threatening situations, compared to an exposure treatment in which subjects are repeatedly exposed to the same set of activities (Repeated Exposure condition). Generalization tests were combined with randomized replicated single case experimental designs (N = 8). Included were patients with Complex Regional Pain Syndrome type I reporting elevated levels of pain-related fear. The Multiple Exposure treatment condition consisted of at least 15 activities to which patients were exposed once. The Repeated Exposure treatment condition exposed patients to only three activities during five sessions each. Generalization was tested by exposing patients to new fearful activities post-treatment and 6-months follow-up. Patients from both conditions performed equally well at both generalization tests. Daily measures showed that the Multiple Exposure condition is preferred to reduce fear of movement/(re)injury, pain catastrophizing and pain experience.
Learn More >The role of gonadal hormones in neural plasticity remains unclear. This study aimed to examine the effects of naturally fluctuating hormone levels over the menstrual cycle in healthy females. Gray matter, functional connectivity (FC) and white matter changes over the cycle were assessed by using functional magnetic resonance imaging (fMRI), resting state fMRI, and structural MRIs, respectively, and associated with serum gonadal hormone levels. Moreover, electrocutaneous sensitivity was evaluated in 14 women in four phases of their menstrual cycle (menstrual, follicular, ovulatory, and luteal). Electrocutaneous sensitivity was greater during follicular compared to menstrual phase. Additionally, pain unpleasantness was lower in follicular phase than other phases while pain intensity ratings did not change over the cycle. Significant variations in cycle phase effects on gray matter volume were found in the left inferior parietal lobule (IPL) using voxel-based morphometry. Subsequent Freesurfer analysis revealed greater thickness of left IPL during the menstrual phase when compared to other phases. Also, white matter volume fluctuated across phases in left IPL. Blood estradiol was positively correlated with white matter volume both in left parietal cortex and whole cortex. Seed-driven FC between left IPL and right secondary visual cortex was enhanced during ovulatory phase. A seed placed in right IPL revealed enhanced FC between left and right IPL during the ovulatory phase. Additionally, we found that somatosensory cortical gray matter was thinner during follicular compared to menstrual phase. We discuss these results in the context of likely evolutionary pressures selecting for enhanced perceptual sensitivity across modalities specifically during ovulation.
Learn More >Ankylosing spondylitis (AS) mainly affects the axial skeleton and is an important factor leading to chronic lower back pain in young individuals. However, few studies have explored alterations of brain gray matter volume in AS patients. The purpose of the present study was to describe brain gray matter abnormalities associated with AS pain. A total of 61 AS patients and 52 healthy controls (HCs) were included in this study. Using voxel-based morphometrics, we detected abnormal gray matter volume in AS patients. Based on the voxel-wise analysis, the gray matter volume in the left putamen of the AS group was increased significantly compared with that of the HC group. In addition, we found that the gray matter volume of the left putamen was positively correlated with the duration of AS and total back pain scores, whereas it was not significantly correlated with Bath Ankylosing Spondylitis Disease Activity Index scores, C-reactive protein, or erythrocyte sedimentation rate in AS patients. Taken together, our findings improve our understanding of the neural substrates of pain in AS and provide evidence of AS-related neurological impairment. Hence, further investigation of the pathophysiology of the left putamen in AS is warranted.
Learn More >Pain is a complex, multidimensional experience but often is measured as a unidimensional experience. This study aimed to separately assess the sensory and affective components of pain and identify their relations to important pain-related outcomes, particularly in terms of opioid misuse risk and emotion dysregulation among patients with chronic pain receiving treatment in Appalachia. Two hundred and twelve patients presenting to a multidisciplinary pain center completed the Difficulties in Emotion Regulation Scale (DERS-18), Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R), and short-form McGill Pain Questionnaire (SF-MPQ). The sensory experience of pain was unrelated to emotion dysregulation ( = 0.06, = 0.57) and weakly related to opioid misuse risk ( = 0.182, < 0.05). In contrast, the affective experience of pain was moderately related to emotion dysregulation ( = 0.217, < 0.05) and strongly related to opioid misuse risk ( = 0.37, < 0.01). In addition, emotion dysregulation predicted variance in opioid misuse risk above and beyond the affective and sensory experiences of pain (( = 0.693, < 0.001). The results suggest patients with a strong affective experience versus sensory experience of pain and challenges with emotion regulation may require a more comprehensive intervention to address these underlying components in order to reduce their risk of misusing opioid medications.
Learn More >Inflammation plays a significant role in the pathogenesis of knee osteoarthritis (KOA). Although both electro-acupuncture (EA) and manual acupuncture (MA) are known to influence systemic inflammation, little is known about the potential changes in inflammation as a working mechanism of EA and MA in KOA.
Learn More >Reduced pain tolerance may be one of the possible explanations for high prevalence of chronic pain among older people. We hypothesized that age-related alterations in pain tolerance are associated with functioning deterioration of the frontal cortex during normal aging. Twenty-one young and 41 elderly healthy participants underwent a tonic heat pain test, during which cerebral activity was recorded using electroencephalography (EEG). Elderly participants were divided into two subgroups according to their scores on executive tests, high performers (HPs; = 21) and low performers (LPs; = 20). Pain measures [exposure times (ETs) and perceived pain ratings] and cerebral activity were compared among the three groups. ETs were significantly lower in elderly LPs than in young participants and elderly HPs. Electroencephalographic analyses showed that gamma-band oscillations (GBOs) were significantly increased in pain state for all subjects, especially in the frontal sites. Source analysis showed that GBO increase in elderly LPs was contributed not only by frontal but also by central, parietal, and occipital regions. These findings suggest that better preservation of frontal functions may result in better pain tolerance by elderly subjects.
Learn More >To evaluate knowledge, practices, and beliefs of US patients receiving prescription opioids regarding opioid storage, disposal, and diversion.
Learn More >Physical dysfunction in chronic low back pain patients is influenced by psychological variables rather than by pain severity. Assessing personality traits may help clinicians address the complexity of patients' experiences and design treatments that target these vulnerabilities. This study aimed to identify the distinguishing personality traits of a cohort of patients with disabling chronic low back pain and to determine associations between those traits and fear-avoidance beliefs, depressive, and anxious moods.
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