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Purpose: To investigate pain hypervigilance in individuals suffering from chronic neck and shoulder pain (CNSP) and its underlying brain mechanism., Methods: The evaluation of pain vigilance was conducted through the utilization of pain vigilance and awareness questionnaires. Voxel-wise regional homogeneity (ReHo) from 60 CNSP patients and 60 healthy controls (HCs) using resting-state fMRI data. Voxel-wise two-sample T-test was conducted to reveal the ReHo variations between CNSP and HC. Correlation analyses were utilized to reveal the connection between brain abnormalities and medical measurements. Furthermore, a mediation analysis was conducted to elucidate the pathway-linking changes in brain function with medical measurements., Results: Our present study revealed three main findings. Firstly, patients with CSNP demonstrated a heightened vigilance of pain in comparison to healthy adults, a common occurrence among individuals with chronic pain conditions. Secondly, we observed brain abnormalities in various brain regions in CSNP patients, and these alterations were associated with the extent of pain vigilance. Lastly, the pain hypervigilance impact on the severity of pain was found to be controlled by regional neural activity in the anterior cingulate cortex (ACC) in subjects with CSNP., Conclusion: Our findings suggested that long-term repetitive nociceptive input caused by chronic pain further aggravates the pain intensity by impairing the vigilance-related pain processing within the anterior cingulate cortex in CNSP patients., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Numerous neuroimaging techniques have been recently used to investigate central mechanisms involved in pain perception and to examine morphological and functional brain alterations associated with chronic pain. Compared to self-reporting approaches, objective imaging techniques are expected to potentially lead to better pain assessment and guide management. This comprehensive scoping review aims to identify recent magnetic resonance imaging (MRI) approaches that have been used to characterize the brain of chronic pain subjects, using structural, chemical and functional MRI techniques., Methods: A systematic search and review of the literature was conducted and the resultant studies were critically examined for relevance., Results: MRI neuroimaging of various chronic pain conditions were summarized. We classified the collected studies into: structural brain alterations, VBM (voxel based morphology) examination of structural changes, DTI, changes in brain chemistry, functional and blood flow brain alterations., Discussion: From our clinical experience, we have noted that most clinicians are not aware of the capabilities of advanced MRI methods in assessing cortical manifestations of chronic pain. In addition, many clinicians are not aware of the cortical alterations present in individuals with chronic pain. This comprehensive scoping review thus sets out to first summarize MRI neuroimaging techniques that are available in the current literature to examine chronic pain. We then identify cortical MR approaches that have been able to reliably predict transition from acute to chronic pain. Finally, we summarize MRI neuroimaging techniques that have been used to track treatment response of individuals with chronic pain.

Background: Ultrasonographic evaluation of trigger points detected by physical examination in patients with myofascial pain syndrome is being used more frequently in clinical care. However, the sonographic appearance of trigger points, in association with pain and disability, has not been adequately described., Objective: To reveal the presence of trigger points with ultrasonography in those with myofascial pain syndrome and to determine if ultrasound images can help discriminate between demographic and disease characteristics., Methods: Fifty-two participants with chronic neck pain (NP) were in this cross-sectional study. The pain intensity was evaluated using a 0-10 cm visual analog scale (VAS). The neck disability index measured the NP-induced disability status of the participants. Ultrasonography was used to measure the thicknesses of the paraspinal muscles and the presence of hypoechoic areas within these muscles., Results: There was a positive correlation between the VAS scores of the participants and the ultrasonographic detection of myofascial trigger points (MTPs) in the multifidus and middle trapezius muscles (right/left r = .30, p = .027; r = .29, p = .029; r = .32, p = .009, r = .30, p = .011, respectively). These features correlated with the disability levels of the participants and the MTPs on both the right and left sides of the splenius, multifidus, upper trapezius, and middle trapezius (r = .32, p = .028; r = .38, p = .013, r = .25, p = .027; r = .33, p = .016; r = .25, p = .025, r = .32, p = .018, r = .28, p = .013, r = .29, p = .016, respectively). A significant correlation was present between the detection of MTP at ultrasonography and decreased muscle thickness in the relevant muscles (between p = .001 and p = .034)., Conclusion: The detection of MTPs with ultrasonography is associated with the severity of pain and disability in those with chronic NP. Features on ultrasound include hypoechoic changes within muscle and reduced muscle thickness associated with MTPs., (© 2023 American Academy of Physical Medicine and Rehabilitation.)

Background: Ultrasonographic evaluation of trigger points detected by physical examination in patients with myofascial pain syndrome is being used more frequently in clinical care. However, the sonographic appearance of trigger points, in association with pain and disability, has not been adequately described. Objective: To reveal the presence of trigger points with ultrasonography in those with myofascial pain syndrome and to determine if ultrasound images can help discriminate between demographic and disease characteristics. Methods: Fifty‐two participants with chronic neck pain (NP) were in this cross‐sectional study. The pain intensity was evaluated using a 0–10 cm visual analog scale (VAS). The neck disability index measured the NP‐induced disability status of the participants. Ultrasonography was used to measure the thicknesses of the paraspinal muscles and the presence of hypoechoic areas within these muscles. Results: There was a positive correlation between the VAS scores of the participants and the ultrasonographic detection of myofascial trigger points (MTPs) in the multifidus and middle trapezius muscles (right/left r =.30, p =.027; r =.29, p =.029; r =.32, p =.009, r =.30, p =.011, respectively). These features correlated with the disability levels of the participants and the MTPs on both the right and left sides of the splenius, multifidus, upper trapezius, and middle trapezius (r =.32, p =.028; r =.38, p =.013, r =.25, p =.027; r =.33, p =.016; r =.25, p =.025, r =.32, p =.018, r =.28, p =.013, r =.29, p =.016, respectively). A significant correlation was present between the detection of MTP at ultrasonography and decreased muscle thickness in the relevant muscles (between p =.001 and p =.034). Conclusion: The detection of MTPs with ultrasonography is associated with the severity of pain and disability in those with chronic NP. Features on ultrasound include hypoechoic changes within muscle and reduced muscle thickness associated with MTPs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recent evidence has suggested that reversal of gray or white matter abnormalities could be a criterion of recovery in patients with chronic pain. OBJECTIVE: To determine the effectiveness of exercise-based interventions in reversing gray and white matter abnormalities in patients with chronic musculoskeletal pain. METHODS: An electronic search was performed in the MEDLINE (Via PubMed), EMBASE, Web of Science, LILACS, SPORTDiscus, CINAHL, PEDro, and CENTRAL databases. Randomized clinical trials (RCTs) including patients with chronic musculoskeletal pain, which assessed the change in gray and white matter abnormalities after exercise-based interventions were selected. The risk of bias was assessed using the Risk of Bias II tool. RESULTS: Four RCTs were included (n = 386). Three studies showed reversal of abnormalities with exercise-based interventions compared to control groups. The reversal was observed in the gray matter volume in the medial orbital prefrontal cortex and in the supplementary motor area of patients with osteoarthritis, in the hippocampus, insula, amygdala and thalamus in fibromyalgia patients. Furthermore, in patients with chronic spinal pain, reversal was observed in the gray matter thickness of the frontal middle caudal cortex and in the caudate, putamen and thalamus gray matter volume. CONCLUSIONS: There is insufficient evidence to determine the effectiveness of exercise-based interventions for reversing gray and white matter abnormalities in patients with chronic pain. Further studies are still needed in this field. [ABSTRACT FROM AUTHOR]

Chronic pain represents one of the most serious worldwide medical problems, in terms of both social and economic costs, often causing severe and intractable physical and psychological suffering. The lack of biological markers for pain, which could assist in forming clearer diagnoses and prognoses, makes chronic pain therapy particularly arduous and sometimes harmful. Opioids are used worldwide to treat chronic pain conditions, but there is still an ambiguous and inadequate understanding about their therapeutic use, mostly because of their dual effect in acutely reducing pain and inducing, at the same time, tolerance, dependence, and a risk for opioid use disorder. In addition, clinical studies suggest that opioid treatment can be associated with a high risk of immune suppression and the development of inflammatory events, worsening the chronic pain status itself. While opioid peptides and receptors are expressed in both central and peripheral nervous cells, immune cells, and tissues, the role of opioids and their receptors, when and why they are activated endogenously and what their exact role is in chronic pain pathways is still poorly understood. Thus, in this review we aim to highlight the interplay between pain and immune system, focusing on opioids and their receptors. [ABSTRACT FROM AUTHOR]

Objective: Acupuncture has been shown to be effective in the treatment of chronic pain. However, their neural mechanism underlying the effective acupuncture response to chronic pain is still unclear. We investigated whether metabolic patterns in the pain matrix network might predict acupuncture therapy responses in patients with primary dysmenorrhea (PDM) using a machine-learning-based multivariate pattern analysis (MVPA) on positron emission tomography data (PET). Methods: Forty-two patients with PDM were selected and randomized into two groups: real acupuncture and sham acupuncture (three menstrual cycles). Brain metabolic data from the three special brain networks (the sensorimotor network (SMN), default mode network (DMN), and salience network (SN)) were extracted at the individual level by using PETSurfer in fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) data. MVPA analysis based on metabolic network features was employed to predict the pain relief after treatment in the pooled group and real acupuncture treatment, separately. Results: Paired t -tests revealed significant alterations in pain intensity after real but not sham acupuncture treatment. Traditional mass-univariate correlations between brain metabolic and alterations in pain intensity were not significant. The MVPA results showed that the brain metabolic pattern in the DMN and SMN did predict the pain relief in the pooled group of patients with PDM (R 2 = 0.25, p = 0.005). In addition, the metabolic pattern in the DMN could predict the pain relief after treatment in the real acupuncture treatment group (R 2 = 0.40, p = 0.01). Conclusion: This study indicates that the individual-level metabolic patterns in DMN is associated with real acupuncture treatment response in chronic pain. The present findings advanced the knowledge of the brain mechanism of the acupuncture treatment in chronic pain. [ABSTRACT FROM AUTHOR]

The most common cause of chronic musculoskeletal pain is chronic myofascial pain syndrome (MPS). MPS often presents with increased muscle stiffness, and the myofascial trigger point (MTrP). Imaging modalities have been used to identify the MTrP, but their role in the detection and diagnosis of MPS remains unclear. The purpose of this review was to identify evidence in literature for the use of imaging in the role of classifying and explaining the physiology of MTrPs. Since few imaging techniques have been performed on MTrPs, we explored the imaging techniques that can effectively image complex skeletal muscle microstructure, and how they could be used. As part of a scoping review, we conducted a systematic search from three medical databases (CINAHL, EMBASE and MEDLINE) from year to year to analyze past MTrP imaging, as well as analyzing imaging techniques performed on the microstructure of muscle. Previously, ultrasound has been used to differentiate active, latent MTrPs, but these studies do not adequately address their underlying anatomical structure. MRI remains the standard method of imaging skeletal muscle. The existing MRI literature suggests that the DTI technique can quantify muscle injury, strain, and structure. However, theoretically, HARDI and DKI techniques seem to provide more information for complex structural areas, although these modalities have a disadvantage of longer scan times and have not been widely used on skeletal muscle. Our review suggests that DTI is the most effective imaging modality that has been used to define the microstructure of muscle and hence, could be optimal to image the MTrP. HARDI and DKI are techniques with theoretical potential for analysis of muscle, which may provide more detailed information representative of finer muscle structural features. Future research utilizing MRI techniques to image muscle are necessary to provide a more robust means of imaging skeletal muscle and the MTrP. [ABSTRACT FROM AUTHOR]

This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception–emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes. [ABSTRACT FROM AUTHOR]

Objectives: Investigate the relation of chronic pain interference to functional connectivity (FC) of brain regions and to cortical thickness in post-911 Veterans and Service Members (SMs) who sustained a mild traumatic brain injury (mTBI). Methods: This is an observational study with cross-sectional analyses. A sample of 65 enrollees completing initial evaluation at a single site of the Chronic Effects of Neurotrauma Consortium (CENC) reported pain interference ratings on the TBI QOL. Functional connectivity and cortical thickness were measured. Results: Severity of pain interference was negatively related to FC of the default mode network (DMN), i.e., participants who reported more severe pain interference had less FC between mesial prefrontal cortex and posterior regions of the DMN including posterior cingulate cortex and precuneus. Cortical thickness of specific regions was positively related to severity of pain interference. Conclusion: The more that pain was perceived to interfere with daily life, the less the FC between regions in a network associated with self-referential thought and mind wandering. Although cortical thickness in specific brain regions was positively related to severity of pain interference, follow-up longitudinal data, control group data, and study of individual differences in this cohort will expand this initial report and replicate these findings. [ABSTRACT FROM AUTHOR]