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The effect of spinal cord stimulation (SCS) amplitude on the activation of dorsal column fibres has been widely studied through the recording of Evoked Compound Action Potentials (ECAPs), the sum of all action potentials elicited by an electrical stimulus applied to the fibres. ECAP amplitude grows linearly with stimulus current after a threshold, and a larger ECAP results in a stronger stimulus sensation for patients. This study investigates the effect of stimulus frequency on both the ECAP amplitude as well as the perceived stimulus sensation in patients undergoing SCS therapy for chronic back and/or leg pain.
Learn More >This study was conducted to characterize chronic low back pain (cLBP) and to identify treatment histories and preferences for cLBP management among Veterans and primary care providers within the Veterans Affairs (VA) healthcare system.
Learn More >Peripheral edema (i.e., lower limb swelling) can cause pain, weakness, and limited range of motion. However, few studies have examined its prevalence in the U.S. or its association with demographics, comorbidities, activity, or mobility. This study used data from the Health and Retirement Study, a nationally representative longitudinal survey of U.S. adults (age 51+/ N = 19,988 for 2016), to evaluate time trends and correlates of peripheral edema using weighted descriptive statistics and logistic regressions, respectively. Peripheral edema was assessed with the question "Have you had… // Persistent swelling in your feet or ankles?" The weighted prevalence of edema among older U.S. adults was 19% to 20% between 2000 and 2016. Peripheral edema was associated with older age, female sex, non-white race, low wealth, obesity, diabetes, hypertension, pain, low activity levels, and mobility limitations (odds ratios ranging from 1.2-5.6; p-values ≤0.001). This study provides the first estimates of national prevalence and correlates of peripheral edema among older Americans. Peripheral edema is common and strongly associated with comorbidities, pain, low activity levels, and mobility limitations, and disproportionately affects poorer and minority groups. Peripheral edema should be a focus of future research in order to develop novel and cost-effective interventions.
Learn More >Chronic plantar heel pain (CPHP) is associated with calcaneal bone spurs, but its associations with other calcaneal bone features are unknown. This study therefore aimed to determine associations between having CPHP and bone density and microarchitecture of the calcaneus. We assessed 220 participants with CPHP and 100 age- and sex-matched population-based controls. Trabecular bone density, thickness, separation and number, BV/TV, and cortical density, thickness and area were measured using a Scanco Xtreme1 HR-pQCT scanner at a plantar and mid-calcaneal site. Clinical, physical activity and disease history data were also collected. Associations with bone outcomes were assessed using multivariable linear regression adjusting for age, sex, physical activity, BMI and ankle plantarflexor strength. We assessed for potential effect modification of CPHP on these covariates using interaction terms. There were univariable associations at the plantar calcaneus where higher trabecular bone density, BV/TV and thickness and lower trabecular separation were associated with CPHP. In multivariable models, having CPHP was not independently associated with any bone outcome, but modified associations of BMI and ankle plantarflexor strength with mid-calcaneal and plantar bone outcomes respectively. Beneficial associations of BMI with mid-calcaneal trabecular density (BMI-case interaction standardised X/unstandardised Y beta -10.8(mgHA/cm3) (se 4.6), thickness -0.002(mm) (se 0.001) and BV/TV -0.009(%) (se 0.004) were reduced in people with CPHP. Beneficial associations of ankle plantarflexor strength with plantar trabecular density (ankle plantarflexor strength -case interaction -11.9(mgHA/cm3) (se 4.4)), thickness -0.003(mm) (se 0.001), separation -0.003(mm) (se 0.001) and BV/TV -0.010(%) (se 0.004) were also reduced. CPHP may have consequences for calcaneal bone density and microarchitecture by modifying associations of BMI and ankle plantarflexor strength with calcaneal bone outcomes. The reasons for these case-control differences are uncertain but could include a bone response to entheseal stress, altered loading habits and/or pain mechanisms. Confirmation with longitudinal study is required.
Learn More >Vestibular migraine (VM) is the most common neurological cause of vertigo in adults. Previous neuroimaging studies have reported structural alterations in areas associated with pain and vestibular processing. However, it is unclear whether altered resting-state functional connectivity (FC) exists in brain regions with structural abnormalities in patients with VM.
Learn More >Itch draws our attention to allow imposing action against bodily harm (e.g., remove insects). At the same time, itch is found to interfere with ongoing tasks and daily life goals. Despite the key role of attention in itch processing, interventions that train individuals to automatically disengage attention from itch cues are lacking. The present proof-of-principle attention bias modification (ABM) training study was aimed at investigating whether attention to itch as well as sensitivity to mild itch can be changed. Healthy volunteers were randomized over three ABM-training conditions. Training was done via a modified pictorial dot-probe task. In particular, participants were trained to look away from itch stimuli ( = 38), toward itch stimuli ( = 40) or not trained toward or away from itch at all (sham training, = 38). The effects of the ABM-training were tested primarily on attention to itch pictures. Secondarily, it was investigated whether training effects generalized to alterations in attention to itch words and mechanical itch sensitivity. The ABM-training did not alter attention toward the itch pictures, and there was no moderation by baseline levels of attention bias for itch. Also, attention bias to the itch words and itch sensitivity were not affected by the ABM-training. This study was a first step toward trainings to change attention toward itch. Further research is warranted to optimize ABM-training methodology, for example increasing motivation of participants. Eventually, an optimized training could be used in patient populations who suffer most from distraction by their symptoms of itch. Identifier: NL6134 (NTR6273). The website URL is: https://www.trialregister.nl/.
Learn More >The negative effects of chronic pain and obesity are compounded in those with both conditions. Despite this, little research has focused on the pathophysiology in pediatric samples.
Learn More >In some patients, migraine attacks are associated with symptoms of allodynia which can be localized (cephalic) or generalized (extracephalic). Using functional neuroimaging and cutaneous thermal stimulation, we aimed to investigate the differences in brain activation of patients with episodic migraine (n = 19) based on their allodynic status defined by changes between ictal and interictal pain tolerance threshold for each subject at the time of imaging. In this prospective imaging study, differences were found in brain activity between the ictal and interictal visits in the brainstem/pons, thalamus, insula, cerebellum and cingulate cortex. Significant differences were also observed in the pattern of activation along the trigeminal pathway to noxious heat stimuli in no allodynia vs. generalized allodynia in the thalamus and the trigeminal nucleus but there were no activation differences in the trigeminal ganglion. The functional magnetic resonance imaging (fMRI) findings provide direct evidence for the view that in migraine patients who are allodynic during the ictal phase of their attacks, the spinal trigeminal nucleus and posterior thalamus become hyper-responsive (sensitized)-to the extent that they mediate cephalic and extracephalic allodynia, respectively. In addition, descending analgesic systems seem as "switched off" in generalized allodynia.
Learn More >Parental Catastrophizing and Goal Pursuit in the Context of Child Chronic Pain: A Daily Diary Study.
Despite daily variability in children's chronic pain experiences, little is known about how parents' emotions and goals toward their child's pain are influenced by these daily changes. This diary study examined how daily child pain intensity (as perceived by parents) moderates the associations between parental catastrophic thoughts about child pain on the one hand, and daily parental distress and parents' goals with regard to their child's pain (pain control vs. activity engagement) on the other hand. Participants were 25 parents of 20 different children = 18; 90% girls). Children, aged 8-14 years ( = 9.5, = 2.09), experienced either chronic headache or functional abdominal pain with an average pain duration of 22.5 months ( = 24.5 months). Daily parental responses (i.e., perceived child pain intensity, distress and goal endorsement) were collected through a 3-week daily diary (resulting in 413 valid diary reports). Parents completed the Pain Catastrophizing Scale for Parents prior to starting the diary (PCS-P general) and a daily measure (PCS-P daily) included in the diary. To account for the interdependence of the data, the data were analyzed using multilevel modeling. Perceived daily child pain intensity moderated the impact of parental general and daily catastrophic thoughts on parents' daily distress. Only for parents experiencing low general catastrophic thoughts an increase in distress was observed on days when they perceived their child's pain intensity as high. For all parents, high levels of perceived child pain intensity were related to more distress on days where parents reported high levels of catastrophic thinking (i.e., PCS-P daily). Perceived daily child pain intensity also moderated the impact of parental general catastrophic thinking on parents' daily endorsement of goals. Parents with high levels of general catastrophic thinking reported a lower focus on child pain control on days when child pain intensity was perceived to be low. Parents with low general catastrophic thinking reported lower endorsement of the activity engagement goal on days where the child's pain intensity was perceived to be low. These findings highlight the complexity of daily fluctuations in parental distress and goals regarding their child's pain. Clinical implications and future directions are critically assessed.
Learn More >: The COVID-19 pandemic presents one of the greatest threats to pediatric pain care seen in generations. Due to public health restrictions, many pediatric pain clinics halted in-person appointments, delaying and disrupting access to care. There is no existing research on the impacts of COVID-19 on pediatric chronic pain care in Canada or the challenges experienced by health care professionals and pain clinics. : The aim of this study was to evaluate the impact of COVID-19 on Canadian pediatric chronic pain care by documenting how health care professionals provided care during the first six months of the pandemic. : Two Canadian online cross-sectional surveys were conducted: one among Canadian pediatric pain clinic directors (Study 1) and another among multidisciplinary pediatric pain health care professionals (Study 2). : Responses from 13/13 Canadian pediatric pain clinics/rehabilitation programs indicated that all clinics provided virtual care during the pandemic. No significant changes were reported on the frequency of appointment requests. Most clinics reported no perceived change in patient pain levels ( = 9/13, 69%) or occurrence of pain flares ( = 10/13, 77%). Results from 151 individual health care professionals indicated that the majority (90%) of non-emergency department respondents were providing virtual care. The main challenges of virtual care included technological barriers, financial concerns, infrastructure and logistics, privacy, and clinical challenges. : This study documented the impact of the COVID-19 pandemic on pediatric chronic pain care in Canada and highlighted the rapid shift to using virtual solutions. Simultaneously, respondents outlined current challenges and potential solutions to consider in the development of virtual care guidelines and policy in Canada.
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