Pain
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Although classical trigeminal neuralgia (CTN) is frequently caused by neurovascular contact (NVC) at the trigeminal root entry zone (REZ), both anatomical and MRI studies have shown that NVC of the trigeminal nerve frequently occurs in individuals without CTN. To assess the accuracy of MRI in distinguishing symptomatic from asymptomatic trigeminal NVC, we submitted to high-definition MRI the series of CTN patients referred to our outpatient service between June 2011 and January 2013 (n=24), and a similar number of age-matched healthy controls. Two neuroradiologists, blinded to the clinical data, evaluated whether the trigeminal nerve displayed NVC in the REZ or non-REZ, whether it was dislocated by the vessel or displayed atrophy at the contact site, and whether the offending vessel was an artery or a vein. ⋯ When REZ contact and nerve atrophy coexisted, both specificity and positive predictive value rose to 100%. Meta-analysis showed that REZ NVC was detected in 76% of symptomatic and 17% of asymptomatic nerves (P<.0001), whereas anatomical changes were detected in 52% of symptomatic and 9% of asymptomatic nerves (P<.0001). In conclusion, trigeminal REZ NVC, as detected by MRI, is highly likely to be symptomatic when it is associated with anatomical nerve changes.
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The degree of variability in the patient baseline 7-day diary of pain ratings has been hypothesized to have a potential effect on the assay sensitivity of randomized clinical trials of pain therapies. To address this issue, we obtained clinical trial data from the Food and Drug Administration (FDA) through the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership, and harmonized patient level data from 12 clinical trials (4 gabapentin and 8 pregabalin) in postherpetic neuralgia (PHN) and painful diabetic peripheral neuropathy (DPN). Models were developed using exploratory logistic regression to examine the interaction between available baseline factors and treatment (placebo vs active medication) in predicting patient response to therapy (ie, >30% improvement). ⋯ In addition, there was a small but significant age-by-treatment interaction in the PHN model, and small weight-by-treatment interaction in the DPN model. The patient's sex, baseline pain level, and the study protocol had an effect only on the likelihood of response overall. Our results suggest the possibility that, at least in some disease processes, excluding patients with a highly variable baseline 7-day diary has the potential to improve the assay sensitivity of these analgesic clinical trials, although reductions of external validity must be considered when increasing the homogeneity of the investigated sample.
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Randomized Controlled Trial
Short-term Improvement in Insomnia Symptoms Predicts Long-term Improvements in Sleep, Pain, and Fatigue in Older Adults with Co-Morbid Osteoarthritis and Insomnia.
In a primary care population of 367 older adults (aged ⩾60 years) with osteoarthritis (OA) pain and insomnia, we examined the relationship between short-term improvement in sleep and long-term sleep, pain, and fatigue outcomes through secondary analyses of randomized controlled trial data. Study participants, regardless of experimental treatment received, were classified either as improvers (⩾30% baseline to 2-month reduction on the Insomnia Severity Index [ISI]) or as nonimprovers. After controlling for treatment arm and potential confounders, improvers showed significant, sustained improvements across 18 months compared with nonimprovers in pain severity (P<0.001, adjusted mean difference=-0.51 [95% CI: -0.80, -0.21), arthritis symptoms (P<0.001, 0.63 [0.26, 1.00]), and fear avoidance (P=0.009, -2.27 [-3.95, -0.58]) but not in catastrophizing or depression. Improvers also showed significant, sustained improvements in ISI (P<0.001, -3.03 [-3.74, -2.32]), Pittsburgh Sleep Quality Index Total (P<0.001, -1.45 [-1.97, -0.93]) and general sleep quality (P<0.001, -0.28 [-0.39, -0.16]) scores, Flinders Fatigue Scale (P<0.001, -1.99 [-3.01, -0.98]), and Dysfunctional Beliefs About Sleep Scale (P=0.037, -2.44 [-4.74, -0.15]), but no improvements on the Functional Outcomes of Sleep Questionnaire or the Epworth Sleepiness Scale. We conclude that short-term (2-month) improvements in sleep predicted long-term (9- and 18-month) improvements for multiple measures of sleep, chronic pain, and fatigue. These improvements were not attributable to nonspecific benefits for psychological well-being, such as reduced depression. These findings are consistent with benefits of improved sleep for chronic pain and fatigue among older persons with osteoarthritis pain and comorbid insomnia if robust improvements in sleep are achieved and sustained.
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Few studies have used prospective designs in large population surveys to assess the risk of developing chronic widespread pain (CWP). We wanted to examine 1) how many people without CWP developed it after 11years, and 2) how anxiety, depression, alcohol use, smoking, sleeping problems, and body mass index (BMI) were associated with this development. This study was based on a representative population-based Norwegian cohort attending both the second (1995 to 1997) and the third (2006 to 2008) wave of the Nord-Trøndelag Health Study (HUNT2 and HUNT3, respectively). ⋯ Anxiety and depression, former and current smoking status, BMI<18.5 kg/m(2), BMI⩾25 kg/m(2), and sleeping problems were all associated with an increased risk of CWP. High and moderate levels of alcohol use were associated with a reduced risk of CWP. In summary, this study indicates that CWP develops over a long-term period for a substantial group of healthy people, and that both psychosocial and lifestyle factors influence the risk of CWP onset.
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Randomized Controlled Trial
The effect of Cognitive Bias Modification for Interpretation (CBM-I) on avoidance of pain during an acute experimental pain task.
Research confirms that patients with chronic pain show a tendency to interpret ambiguous stimuli as pain related. However, whether modifying these interpretive pain biases impacts pain outcomes is unknown. This study aimed to demonstrate that interpretation biases towards pain can be modified, and that changing these biases influences pain outcomes in the cold pressor task. ⋯ The major finding was that interpretive bias mediated the relationship between bias condition and hesitance time, supporting the causal role of interpretive biases for avoidance behaviors in current chronic pain models. No differences were found on other pain outcomes regarding bias or threat, and the efficacy of the bias modification was not impacted by different levels of threat. These results suggest that cognitive bias modification should be further explored as a potential intervention in pain.