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Racial and ethnic minorities in the United States report higher levels of both clinical and experimental pain, yet frequently receive inadequate pain treatment. Although these disparities are well documented, their underlying causes remain largely unknown. Evidence from social psychological and health disparities research suggests that clinician-patient racial/ethnic concordance may improve minority patient health outcomes. Yet whether clinician-patient racial/ethnic concordance influences pain remains poorly understood.
Learn More >The neuroimaging community has shown tremendous interest in exploring the brain's spontaneous activity using functional magnetic resonance imaging (fMRI). On the contrary, the spinal cord has been largely overlooked despite its pivotal role in processing sensorimotor signals. Only a handful of studies have probed the organization of spinal resting-state fluctuations, always using static measures of connectivity. Many innovative approaches have emerged for analyzing dynamics of brain fMRI, but they have not yet been applied to the spinal cord, although they could help disentangle its functional architecture. Here, we leverage a dynamic connectivity method based on the clustering of hemodynamic-informed transients to unravel the rich dynamic organization of spinal resting-state signals. We test this approach in 19 healthy subjects, uncovering fine-grained spinal components and highlighting their neuroanatomical and physiological nature. We provide a versatile tool, the spinal innovation-driven co-activation patterns (SpiCiCAP) framework, to characterize spinal circuits during rest and task, as well as their disruption in neurological disorders.
Learn More >Migraine treatment may mitigate migraine and associated pain in the perioperative period.
Learn More >The characteristics of the hypersensitivity to auditory stimuli during the interictal period in episodic migraine are discussed. The combined use of event-related potentials, time-frequency power and phase-synchronization can provide relevant information about the time-course of sensory-attentional processing in migraine and its underlying mechanisms.
Learn More >A literature review was conducted to compare placebo responses in a recent trial-which implemented an Accurate Pain Reporting (APR) and Placebo Response Reduction (PRR) training program-to placebo responses in similar previous trials in chronic lower back pain (CLBP) which did not use such training.
Learn More >The aim of the current study was to identify typical alterations in resting state connectivity within different stages of the migraine cycle and to thus explore task-free mechanisms of headache attack generation in migraineurs.
Learn More >The incidence of herpes zoster (HZ) has been increasing in recent decades. Although two vaccines for HZ are available, there have been few studies on the incidence rates of HZ and post-herpetic neuralgia (PHN) since their introduction. This study examined the incidence rates of HZ and PHN from 1994-2018 in the United States to determine if they have continued to increase since introduction of the herpes zoster vaccines.
Learn More >Transient receptor potential vanilloid type 1 (TRPV1) receptors activated by heat and capsaicin are expressed in trigeminal nociceptive neurons and implicated in the generation of migraine pain. Genetic studies suggested that single-nucleotide polymorphism (SNP) 1911A>G (rs8065080), leading to amino acid substitution Ile585Val, in the TRPV1 gene affects functional activity of TRPV1 receptors and is involved in different pain conditions. However, this polymorphism has not been tested in migraine patients. The objective of this pilot study was to investigate genetic factors of migraine susceptibility. We evaluated frequency distribution of AA, AG, and GG variants of SNP 1911A>G in the TRPV1 gene in patients with episodic and chronic migraine compared with healthy individuals. The study included 46 patients diagnosed with migraine (27 episodic and 19 chronic) and 50 healthy individuals as a control group. DNA from peripheral blood was used to test TRPV1 SNP using allele-specific PCR combined with gel electrophoresis. The genotype frequency distribution in episodic migraine was comparable with that in controls (AA 33%, AG 56%, GG 11% and AA 34%, AG 46%, GG 20%, respectively). On the contrary, in chronic migraine, the distribution differed significantly (p < 0.05) (AA 68%, AG 32%, GG 0%). This are first indications for a distinctive genotype frequency distribution of TRPV1 1911A>G in chronic migraine patients compared with episodic migraine patients and controls. Our data confirm a different predisposition to chronic pain in migraine and give a prerequisite for a new look at the nature of chronification of migraine, proposing that the absence of GG genotype may be considered as possible risk biomarker of episodic migraine evolution to chronic form.
Learn More >Visceral pain can be disabling for patients and challenging to treat in the clinic. Spinal cord stimulation is a NICE approved treatment for chronic neuropathic pain, presenting potential advantages over conventional therapies for managing chronic visceral pain. A retrospective study revealed that a specific type of spinal cord stimulation, BurstDR (Abbott, TX, USA), was effective at improving pain and quality of life in patients with chronic visceral pain. Baseline pain scores significantly correlated with change at follow-up, suggesting it may be possible to identify potential responders from the outset. BurstDR was safe: rates of revision, explantation and complications were low. Clinical trials exploring the long-term effects of BurstDR including a control arm are needed. Findings could have the potential to inform best practice and improve outcomes for individuals with chronic visceral pain.
Learn More >Diabetic polyneuropathy (DPN) is a common complication to diabetes and is often associated with neuropathic pain. The mechanisms underlying development and maintenance of painful DPN are largely unknown and quantification of intraepidermal nerve fiber density (IENFD) from skin biopsy, one of the neuropathological gold standard when diagnosing DPN, does not differentiate between patients with and without pain. Identification of possible pain pathophysiological biomarkers in patients with painful DPN may increase our knowledge of mechanisms behind neuropathic pain. Animal models of painful DPN have been shown to have an increased density of peptidergic nerve fibers (Substance P (SP) and Calcitonin-gene related peptide (CGRP)). In this study we performed a detailed skin biopsy analysis in a well-characterized group of DPN patients with primarily small fiber involvement, with and without pain and in healthy controls and test for correlation between skin biopsy findings and pain intensity and quantitative sensory testing (QST). We found that while there was no difference in IENFD using PGP 9.5 between patients with and without pain, patients with pain had increased density of dermal peptidergic fibers containing SP and CGRP compared to patients with painless DPN and healthy controls. Peptidergic nerve fiber density correlated with pain ratings in patients with pain (R=0.33; p=0.019) but not with QST results. Here we show, for the first time in humans, an increased density of dermal peptidergic fibers in painful DPN. These findings provide new insight in the pathophysiological mechanisms of pain in diabetes and opens the research towards new therapeutic targets.
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