Browse by Audience
Persistent pain in breast cancer survivors is common. Psychological and sleep-related factors modulate perception, interpretation and coping with pain and may contribute to the clinical phenotype. The present analysis pursued the hypothesis that breast cancer survivors form subgroups, based on psychological and sleep-related parameters that are relevant to the impact of pain on the patients' life.
Learn More >The neuropeptide S/neuropeptide S receptor (NPS/NPSR) system is involved in the regulation of anxiety in rodents. Chronic inflammation can induce anxiety. Our lab has observed that electroacupuncture (EA) has a beneficial effect on chronic inflammatory pain and pain-related anxiety; however, the mechanism should be further clarified. In the present study, we used an inflammatory pain model to investigate the role of the NPS/NPSR system in the anterior cingulate cortex (ACC) in the analgesic and antianxiety effects of EA.
Learn More >Pain alters cognitive performance through centrally mediated effects in the brain. In this study, we hypothesized that persistent activation of peripheral nociceptors after injury would lead to the development of a chronic pain state that impairs attention-related behavior and results in changes in peripheral neuron phenotypes. Attentional performance was measured in rats using the 5-choice serial reaction time titration variant to determine the initial impact of partial L5 spinal nerve ligation and the effect of persistent nociceptor activation on the resolution of injury. The changes in peripheral neuronal sensibilities and phenotypes were determined in sensory afferents using electrophysiologic signatures and receptive field properties from dorsal root ganglion recordings. Partial spinal nerve injury impaired attentional performance, and this was further impaired in a graded fashion by nociceptive input through an engineered surface. Impairment in attention persisted for only up to 4 days initially, followed by a second phase 7 to 10 weeks after injury in animals exposed to nociceptive input. In animals with prolonged impairment in behavior, the mechanonociceptors displayed a persistent hypersensitivity marked by decreased threshold, increased activity to a given stimulus, and spontaneous activity. Nerve injury disrupts attentional performance acutely and is worsened with peripheral mechanonociceptor activation. Acute impairment resolves, but persistent nociceptive activation produces re-emergence of impairment in the attention-related task associated with electrophysiological abnormalities in peripheral nociceptors. This is consistent with the development of a chronic pain state marked by cognitive impairment and related to persistently abnormal peripheral input.
Learn More >Pain and hypersensitivity months after peripheral injury reflect abnormal input from peripheral afferents likely in conjunction with central sensitization. We hypothesize that peripheral changes occur in defined sensory afferents and resolve as behavioral response to injury resolves. Male Sprague-Dawley rats underwent sham or partial L5 spinal nerve ligation, and paw withdrawal threshold (PWT) was sequentially measured during recovery. At 2, 4, 8, and 12 weeks after injury, randomized animals underwent electrophysiologic assessment of L4 fast-conducting high- and low-threshold mechanoreceptors, and individual neuronal mechanical thresholds (MTs) were contrasted with PWTs in the same animals. Paw withdrawal thresholds decreased after injury and resolved over time (P < 0.001). Similarly, MTs of fast-conducting high-threshold mechanoreceptors decreased after injury and resolved over time (P < 0.001). By contrast, MTs of low-threshold mechanoreceptors increased after injury and resolved over time (P < 0.001). Distributions of recordings from each afferent subtype were perturbed after injury, and this too resolved over time. After resolution of behavioral changes, several electrical abnormalities persisted in both neuronal subtypes. These data extend previous findings that mechanically sensitive nociceptors are sensitized, whereas tactile, largely Aβ afferents are desensitized after nerve injury by showing that the time course of resolution of these changes mirrors that of behavioral hypersensitivity in a surgical injury including neural damage. These data support a role of abnormal peripheral input, from both nociceptor and tactile afferents, during recovery from peripheral injury and underscore the potential importance of both classes of afferents as potential targets for pain treatment.
Learn More >Epidemiological and cross-sectional studies have shown that post-traumatic stress disorder symptoms (PTSS) are common and impairing in youth with chronic pain. Yet, the co-occurrence of PTSS and pediatric chronic pain has not been examined longitudinally, which has limited understanding of theoretically proposed mechanisms (eg, sleep disturbance) underlying the PTSS-pain relationship over time. This longitudinal study aimed to fill this gap. Participants included 138 youth (Mage = 14.29, 75% girls) referred to a tertiary-level outpatient chronic pain program and one of their parents. At baseline, youth reported their pain intensity and interference, PTSS, and subjective sleep disturbances (ie, sleep quality and insomnia). Youth and parents completed semistructured diagnostic interviews to determine the child's post-traumatic stress disorder diagnostic status, and youth completed an objective assessment of sleep patterns for 7 days using actigraphy. At 3-month follow-up, youth once again completed the diagnostic interview and reported their pain intensity, pain interference, and PTSS. Partially latent cross-lagged structural equation panel models revealed that, controlling for pain intensity, pain interference and PTSS co-occurred at baseline, but not at follow-up (while controlling for baseline levels). Higher levels of baseline PTSS were predictive of increases in pain interference at follow-up. Furthermore, subjective sleep disturbances mediated the relationship between baseline PTSS and follow-up pain interference. These findings lend support to conceptual models of PTSS-pain co-occurrence and highlight a critical need to assess and address trauma and sleep disturbances in youth with chronic pain.
Learn More >The primary aim of this study was to better understand the role that social factors (i.e., social support, satisfaction in participation with social roles, social isolation, and self-perceived ability to perform social roles and activities) play in pain-related interference and depressive symptoms in adults with chronic pain. Moreover, this study also examined if sex exerts a moderating role in these associations.
Learn More >To explore naturally occurring clinical subgroups of post-traumatic headache.
Learn More >Recent work, both clinical and experimental, suggests that the hypothalamic hormone oxytocin (OT) and its receptor (OTR) may be involved in migraine pathophysiology. In order to better understand possible central actions of OT in migraine/headache pathogenesis, we mapped the distribution of OT and OTR in nerve cells and fibers in rat brain with a focus on areas related to migraine attacks and/or shown previously to contain calcitonin gene related peptide (CGRP), another neuropeptide involved in migraine.
Learn More >Movement representation techniques such as motor imagery (MI) and action observation (AO) could play an important role in the field of rehabilitation of patients with musculoskeletal pain; however, the effects of these tools on clinical pain remain unclear. Our objective is therefore to develop a systematic review and meta-analysis of the effects of MI and AO regarding pain intensity on patients with musculoskeletal pain. Databases and data treatment MEDLINE, EMBASE, CINAHL and Google Scholar were searched. Last search was run on July 2019. Meta-analysis was conducted to determine the effectiveness on pain intensity in patients with post-surgical pain or chronic pain, and GRADE was used to rate the quality, certainty, and applicability of the evidence.
Learn More >Although migraine is defined by the headache and headache associated symptoms, the true beginning of a migraine attack lies in the premonitory phase and to understand the generation of attacks one needs to investigate the phase before headache starts. The premonitory phase of migraine is characterized by a well described complex of symptoms. Its duration, however, is not clearly defined and there are to date no biomarkers to help defining when this phase starts.
Learn More >