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Despite well-documented pain disparities among adults from non-White and Hispanic groups, less is known about pain disparities in non-White and Hispanic pediatric populations.
Learn More >Altered pain facilitatory and inhibitory mechanisms have been recognized as an important manifestation in patients with chronic pain, and quantitative sensory testing (QST) can act as a proxy for this process. We have recently developed a simple bedside QST tool kit () for more clinical use. The purpose of this study was to investigate its test-retest reliability and to evaluate its validity compared with the laboratory-based QST protocols in patients with knee osteoarthritis (OA).
Learn More >Oxytocin has been shown to increase trust, decrease anxiety and affect learning as has been observed in conditioning paradigms. Trust, anxiety and learning are important factors that influence placebo effects. In this study we investigated whether oxytocin can increase placebo analgesia, decrease nocebo hyperalgesia, and influence extinction processes of both. Eighty male volunteers were assigned to a 40 IU of oxytocin nasal spray group, or to a placebo control group. Placebo analgesia and nocebo hyperalgesia were induced by a conditioning procedure in combination with verbal suggestions. The results demonstrate that the conditioning procedure successfully elicited significant placebo analgesia and nocebo hyperalgesia responses (p < .001). Furthermore, extinction was observed (p < .001), although placebo and nocebo responses did not return to baseline and remained significant. Oxytocin did not influence placebo analgesia or nocebo hyperalgesia and had no effect on extinction. This study provides support against the placebo-boosting effects of oxytocin and was the first one to demonstrate that it also did not influence nocebo effects or extinction processes, however, these results pertain to only a male sample. As managing placebo and nocebo effects has widespread clinical implications, further research should investigate other neurobiological or behavioral pathways to boost placebo and decrease nocebo effects. Trial registration: The study protocol was preregistered on the website www.trialregister.nl under the number NTR6506. Perspective: The present study demonstrated that placebo analgesia and nocebo hyperalgesia can be successfully induced by conditioning and verbal suggestions. We could not confirm the hypothesis that oxytocin affects either of these phenomena. Other pharmacological agents and behavioral manipulations for increasing placebo and decreasing nocebo effects should be investigated.
Learn More >The brainstem has been discussed as the main player in the pathogenesis of migraine. Dysfunctional brainstem nuclei and their abnormal connections to other key brain centers may contribute to headache and other symptoms of migraine. In the present study, 32 patients with migraine without aura (MWoA) and 32 age- and sex-matched healthy controls (HCs) underwent resting-state fMRI scans. We used masked independent analysis (mICA) to investigate whether patients with MWoA exhibited abnormal brainstem nuclei-cortical functional connectivity (FC). The mICA can suppress adjacent physiological noise and prevent results from being driven by the much stronger signals of the surrounding structures. Regional homogeneity (ReHo) was used to investigate whether the brainstem regions with abnormal FC to other brain areas exhibited abnormal regional neuronal activity. Patients with MWoA showed significantly weaker FC between the posterior pons and the left superior parietal lobule, the left middle temporal gyrus and the left middle frontal gyrus. Furthermore, patients with MWoA exhibited significantly decreased ReHo values in the posterior pons compared with HCs, and the posterior pons ReHo value was significantly negatively correlated with HIT-6 scores in the MWoA group. Patients with MWoA exhibited functional abnormalities in the posterior pons and weakened connections between the posterior pons and several key cortical brain areas involved in pain processing during the resting state. Perspective: This study provided increased evidence that the pons is involved in pathophysiological mechanism of migraine, and weakened connections suggest that the touch and pain sensation of migraine sufferers may not be properly relayed to cortical processing areas, which may be associated with the pathogenesis of MWoA.
Learn More >Chronic pain affects 1-3 million Canadian children and adolescents and their families. The primary objective of the Partnering For Pain project was to collaboratively identify the top 10 research priorities in pediatric chronic pain.
Learn More >To compare the prevalence of facial pain and headache across various regions in Sweden.
Learn More >Knee pain in osteoarthritis is complex and complicated by the fact that osteoarthritis is considered to be a disorder of multiple phenotypes. This complexity challenges our understanding as to why some people remain relatively symptom-free, while others progress to persistent pain. One approach to understanding the mechanisms underlying the transition to persistent pain is by identifying pain susceptibility phenotypes in people with or at risk of knee osteoarthritis. Using variables representative of the multidimensional nature of pain in people who were free of persistent pain, we identified four phenotypes characterised by low pressure pain thresholds and temporal summation and not psychosocial factors in those who developed persistent pain two years later. The group with the highest proportion of low pressure pain thresholds and a moderate proportion with facilitated temporal summation had twice the odds of developing persistent knee pain. This work provides preliminary insights into the critical importance of altered neurobiological mechanisms of pain signalling that contributes to development of chronic, persistent pain in knee osteoarthritis.
Learn More >Opioid-related deaths continue to increase in North America, an epidemic that was initiated by high rates of opioid prescribing. We designed a multifaceted, theory-informed Opioid Self-Assessment (OSA) package, to increase adherence to the Canadian Opioid Guideline among family physicians. This study aimed to assess changes in Canadian family physicians' knowledge and practices after completing the OSA package.
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