Individually unique dynamics of cortical connectivity reflect the ongoing intensity of chronic pain
In this study, we investigated the cortical encoding of 20 patients with chronic back pain and 20 chronic migraineurs in 4 repeated fMRI sessions. A brain parcellation approach subdivided the whole brain into 408 regions. Linear mixed-effects models were fitted for each pair of brain regions to explore the relationship between the dynamic cortical connectivity and the observed trajectory of the patients' ratings of fluctuating endogenous pain. Overall, we found that periods of high and increasing pain were predominantly related to low cortical connectivity. The change of pain intensity in chronic back pain was subserved by...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Noninvasive vagus nerve stimulation modulates trigeminal but not extracephalic somatosensory perception: functional evidence for a trigemino-vagal system in humans
This study used a randomized, single-blind, sham-controlled, crossover design and comprised 3 projects with 3 independent cohorts of healthy participants. Project I (n = 15) was explorative. Six quantitative sensory test parameters, including mechanical pain threshold (MPT), were measured over the left V1 dermatome and forearm and compared before and after unilateral nVNS. Projects II (n = 20) and III (n = 21) were preregistered online (https://osf.io/r4jb9). Quantitative sensory test parameters were compared over the left (Project II) or bilateral V1 and V3 dermatomes (Project III), respectively, in addition to the left f...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
How do placebo effects contribute to mindfulness-based analgesia? Probing acute pain effects and interactions using a randomized balanced placebo design
This study aimed to characterize the role of mindfulness and placebo processes underlying mindfulness-based pain attenuation. Both treatment (focused attention mindfulness vs sham) and instruction (told mindfulness vs told sham) were manipulated in a balanced placebo design. Changes in acute heat pain were evaluated in 153 healthy adults randomized to receive 6 × 20 minutes of 1 of 4 treatment by instruction interventions or no treatment. Participants receiving any intervention demonstrated improved pain outcomes (unpleasantness, intensity, and tolerance) relative to those receiving no treatment. The instruction manipulat...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
A nigra–subthalamic circuit is involved in acute and chronic pain states
The basal ganglia modulate somatosensory pain pathways, but it is unclear whether a common circuit exists to mitigate hyperalgesia in pain states induced by peripheral nociceptive stimuli. As a key output nucleus of the basal ganglia, the substantia nigra pars reticulata (SNr) may be a candidate for this role. To test this possibility, we optogenetically modulated SNr GABAergic neurons and examined pain thresholds in freely behaving male mice in inflammatory and neuropathic pain states as well as comorbid depression in chronic pain. We observed that stimulation of either SNr GABAergic neurons or their projections to the su...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Preconditioning by voluntary wheel running attenuates later neuropathic pain via nuclear factor E2–related factor 2 antioxidant signaling in rats
This study provides insight into the mechanisms by which physical activity may prevent neuropathic pain. Preconditioning by voluntary wheel running, terminated prior to nerve injury, suppresses later neuropathic pain in both sexes, and it is modulated through the activation of Nrf2-antioxidant signaling. (Source: Pain)
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Reversal of neuropathic pain is associated with corticostriatal functional reorganization after nerve repair in the spared nerve injury model
Following surgical repair after peripheral nerve injury, neuropathic pain diminishes in most patients but can persist in a small proportion of cases, the mechanism of which remains poorly understood. Based on the spared nerve injury (SNI), we developed a rat nerve repair (NR) model, where a delayed reconstruction of the SNI-injured nerves resulted in alleviating chronic pain-like behavior only in a subpopulation of rats. Multiple behavioral measures were assayed over 11-week presurgery and postsurgery periods (tactile allodynia, pain prick responses, sucrose preference, motor coordination, and cold allodynia) in SNI (n = 1...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Pain response to cannabidiol in opioid-induced hyperalgesia, acute nociceptive pain, and allodynia using a model mimicking acute pain in healthy adults in a randomized trial (CANAB II)
Opioids in general and remifentanil in particular can induce hyperalgesia. Preclinical data suggest that cannabidiol might have the capacity to reduce opioid-induced hyperalgesia (OIH). Thus, we investigated the effect of oral cannabidiol on OIH in healthy volunteers using an established pain model. Twenty-four healthy participants were included in this randomized, double-blinded, crossover study and received either a 1600-mg single-dose oral cannabidiol or placebo. Hyperalgesia, allodynia, and pain were induced by intracutaneous electrical stimulation. To provoke OIH, participants recieved an infusion of 0.1 µg/kg/min re...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Effects of hypnosis vs mindfulness meditation vs education on chronic pain intensity and secondary outcomes in veterans: a randomized clinical trial
This study compared the effectiveness of training in hypnosis (HYP) and mindfulness meditation (MM) with an active education control (ED). Veterans (N = 328) were randomly assigned to 8 manualized, group-based, in-person sessions of HYP (n = 110), MM (n = 108), or ED (n = 110). Primary (average pain intensity [API]) and secondary outcomes were assessed at pretreatment, posttreatment, and 3 and 6 months posttreatment. Treatment effects were evaluated using linear regression, a generalized estimating equation approach, or a Fisher exact test, depending on the variable. There were no significant omnibus between-group differen...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Joint effects of back pain and mental health conditions on healthcare utilization and costs in Ontario, Canada: a population-based cohort study
We assessed the joint effects of back pain and mental health conditions on healthcare utilization and costs in a population-based sample of adults in Ontario. We included Ontario adult respondents of the Canadian Community Health Survey between 2003 and 2012, followed up to 2018 by linking survey data to administrative databases. Joint exposures were self-reported back pain and mental health conditions (fair/poor mental health, mood, and anxiety disorder). We built negative binomial, modified Poisson and linear (log-transformed) models to assess joint effects (effects of 2 exposures in combination) of comorbid back pain an...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Resistance training protects against muscle pain through activation of androgen receptors in male and female mice
Resistance training–based exercise is commonly prescribed in the clinic for the treatment of chronic pain. Mechanisms of aerobic exercise for analgesia are frequently studied, while little is known regarding resistance training mechanisms. We developed a resistance training model in mice and hypothesized resistance training would protect against development of muscle pain, mediated through the activation of androgen receptors. Activity-induced muscle hyperalgesia was produced by 2 injections of pH 5.0 stimuli with fatiguing muscle contractions. Resistance training was performed by having mice climb a ladder with attached...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Research Paper Source Type: research
Visually evoked pain and its extinction using virtual reality in a patient with complex regional pain syndrome type II
In this case report, we used virtual reality (VR) to explore pain evoked by only the appearance of being touched (rather than actually being touched) in a person with complex regional pain syndrome type II. Furthermore, we explored the degree to which this visually evoked pain could be extinguished by applying exposure principles in VR. In stage 1, we identified 4 specific scenarios where pain was triggered by visually simulated touch (without physical stimulation) and used these scenarios to quantify baseline sensitivity to visuotactile stimulation. In stage 2, the patient undertook a 12-week virtual exposure program, and...
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Clinical Note Source Type: research
Partnering with patients in clinical trials of pain treatments: a narrative review
We described how regulatory and funding agencies have developed approaches to incorporate input from patients and patient partners in their decision-making processes. We provided an overview on key practices of patient recruitment and engagement as partners in clinical research and highlighted the perceived benefits and challenges of such partnerships. We summarized factors that can facilitate or hinder meaningful patient engagement in clinical trials of pain treatments and outlined gaps that future research should address to optimize patient-centered clinical research. (Source: Pain)
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Narrative Review Source Type: research
Socioeconomic position and pain: a topical review
No abstract available (Source: Pain)
Source: Pain - September 20, 2022 Category: Anesthesiology Tags: Topical Review Source Type: research
Erratum
No abstract available (Source: Pain)
Source: Pain - August 27, 2022 Category: Anesthesiology Tags: Erratum Source Type: research
Reply to Vlaeyen et al.
No abstract available (Source: Pain)
Source: Pain - August 27, 2022 Category: Anesthesiology Tags: Correspondence Source Type: research
