Subtle changes of gray matter volume in fibromyalgia reflect chronic musculoskeletal pain rather than disease-specific effects

Distinctive cortical morphological patterns in primary trigeminal neuralgia: a cross-sectional clinical study

PURPOSE

The characteristics of surface-based morphological patterns to primary trigeminal neuralgia (PTN) are still not well understood. This study aims to screen the useful cortical indices for the prediction of PTN and the quantification of pain severity.

METHODS

Fifty PTN patients and 48 matched healthy subjects enrolled in the study from March 2016 to August 2021. High-resolution T1 data were performed at 3.0 Tesla scanner and were analyzed with FreeSurfer software to detect the abnormalities of cortical mean curve (CMC), cortical thickness (CT), surface area (SA), and cortical volume (CV) in PTN patients compared to healthy controls. Logistic regression analysis was conducted to determine whether certain morphological patterns could predict PTN disorder. Then, the relationships of cortical indices to the pain characteristics in patient group were examined using linear regression model.

RESULTS

Distinctive cortical alterations were discovered through surface-based analysis, including increased temporal CMC, decreased insular CT and fusiform SA, along with decreased CV in several temporal and occipital areas. Moreover, the difference of temporal CMC was greater than other cortical parameters between the two groups, and the combination of certain morphological indices was of good value in the diagnosis for PTN. Besides, CT of left insula was negatively associated with the pain intensity in PTN patients.

CONCLUSION

The patients with PTN demonstrate distinctive morphological patterns in several cortical regions, which may contribute to the imaging diagnosis of this refractory disorder and be useful for the quantification of the orofacial pain.

CLINICAL TRIALS

The registry name of this study in https://clinicaltrials.gov/ : Magnetic Resonance Imaging Study on Patients with Trigeminal Neuralgia (MRI-TN) https://clinicaltrials.gov/ ID: NCT02713646 A link to the full application: https://clinicaltrials.gov/ct2/results?cond=&term=NCT02713646&cntry=&state=&city=&dist= The first patient with primary trigeminal neuralgia was recruited on November 28, 2016.

Association of APOE-ε4, Osteoarthritis, β-Amyloid, and Tau Accumulation in Primary Motor and Somatosensory Regions in Alzheimer Disease

BACKGROUND AND OBJECTIVES

One of the most prevalent chronic diseases, osteoarthritis (OA), may work in conjunction with APOE-ε4 to accelerate Alzheimer disease (AD) alterations, particularly in the primary motor (precentral) and somatosensory (postcentral) cortices. To understand the reasoning behind this, we investigated how OA and APOE-ε4 influence the accumulation of β-amyloid (Aβ) and tau accumulation in primary motor and somatosensory regions in Aβ-positive (Aβ+) older individuals.

METHODS

We selected Aβ+ Alzheimer Disease Neuroimaging Initiative participants, defined by baseline 18F-florbetapir (FBP) Aβ PET standardized uptake value ratio (SUVR) of AD summary cortical regions, who had longitudinal Aβ PET, the records of OA medical history, and APOE-ε4 genotyping. We examined how OA and APOE-ε4 relate to baseline and longitudinal Aβ accumulation and tau deposition measured at follow-up in precentral and postcentral cortical areas and how they modulate Aβ-associated future higher tau levels, adjusting for age, sex, and diagnosis and using multiple comparison corrections.

RESULTS

A total of 374 individuals (mean age 75 years, 49.2% female, 62.8% APOE-ε4 carriers) who underwent longitudinal FBP PET with a median follow-up of 3.3 years (interquartile range [IQR] 3.4, range 1.6-9.4) were analyzed, and 96 people had 18F-flortaucipir (FTP) tau PET measured at a median of 5.4 (IQR 1.9, range 4.0-9.3) years postbaseline FBP PET. Neither OA nor APOE-ε4 was related to baseline FBP SUVR in precentral and postcentral regions. At follow-up, OA rather than APOE-ε4 was associated with faster Aβ accumulation in postcentral region (β = 0.005, 95% CI 0.001-0.008) over time. In addition, OA but not the APOE-ε4 allele was strongly linked to higher follow-up FTP tau levels in precentral (β = 0.098, 95% CI 0.034-0.162) and postcentral (β = 0.105, 95% CI 0.040-0.169) cortices. OA and APOE-ε4 were also interactively associated with higher follow-up FTP tau deposition in precentral (β = 0.128, 95% CI 0.030-0.226) and postcentral (β = 0.124, 95% CI 0.027-0.223) regions.

DISCUSSION

This study suggests that OA was associated with faster Aβ accumulation and higher Aβ-dependent future tau deposition in primary motor and somatosensory regions, providing novel insights into how OA increases the risk of AD.

Brain morphometric changes in fibromyalgia and the impact of psychometric and clinical factors: a volumetric and diffusion-tensor imaging study

BACKGROUND

Previous studies have repeatedly found distinct brain morphometric changes in patients with fibromyalgia (FM), mainly affecting gray and white matter abnormalities in areas related to sensory and affective pain processing. However, few studies have thus far linked different types of structural changes and not much is known about behavioral and clinical determinants that might influence the emergence and progression of such changes.

METHODS

We used voxel-based morphometry (VBM) and diffusion-tensor imaging (DTI) to detect regional patterns of (micro)structural gray (GM) and white matter (WM) alterations in 23 patients with FM compared to 21 healthy controls (HC), while considering the influence of demographic, psychometric, and clinical variables (age, symptom severity, pain duration, heat pain threshold, depression scores).

RESULTS

VBM and DTI revealed striking patterns of brain morphometric changes in FM patients. Bilateral middle temporal gyrus (MTG), parahippocampal gyrus, left dorsal anterior cingulate cortex (dACC), right putamen, right caudate nucleus, and left dorsolateral prefrontal cortex (DLPFC) showed significantly decreased GM volumes. In contrast, increased GM volume was observed in bilateral cerebellum and left thalamus. Beyond that, patients displayed microstructural changes of WM connectivity within the medial lemniscus, corpus callosum, and tracts surrounding and connecting the thalamus. Sensory-discriminative aspects of pain (pain severity, pain thresholds) primarily showed negative correlations with GM within bilateral putamen, pallidum, right midcingulate cortex (MCC), and multiple thalamic substructures, whereas the chronicity of pain was negatively correlated with GM volumes within right insular cortex and left rolandic operculum. Affective-motivational aspects of pain (depressive mood, general activity) were related to GM and FA values within bilateral putamen and thalamus.

CONCLUSIONS

Our results suggest a variety of distinct structural brain changes in FM, particularly affecting areas involved in pain and emotion processing such as the thalamus, putamen, and insula.

A systematic review and meta-analysis of voxel-based morphometric studies of fibromyalgia

Objective

Although neuroimaging investigations have revealed significant changes in brain structure in fibromyalgia (FM) patients, these findings are inconsistent. The current study conducted a systematic review and meta-analysis of voxel-based morphometric studies in order to comprehend those alterations in brain structure in FM patients.

Methods

Voxel-based morphometric (VBM) studies published up to January 17, 2023 were searched in the Web of Science, PubMed, EMBASE, Cochrane Library (CENTRAL), China National Knowledge Infrastructure (CNKI), Chongqing VIP, Wanfang Database. Two independent researchers carried out study screening, quality assessment, clinical data and neuroimaging data extraction. The whole-brain voxel-based gray matter (GM) data of FM patients were collected from eligible studies, and meta-analyzed using anisotropic effect size-signed differential mapping (AES-SDM).

Results

Twelve researches were included in this study, including 289 FM patients (mean age: 47.36 years) and 272 HS (mean age: 47.34 years). According to the meta-analysis, FM patients had increased GM in the right postcentral gyrus and left angular gyrus, and decreased GM in the right cingulate gyrus, right paracingulate gyrus, left cerebellum, and left gyrus rectus.

Conclusion

Our study suggests that fibromyalgia patients have altered gray matter in several brain regions that are involved in affective, cognitive functions, and in motor adaptations to pain processing.

From Low-Grade Inflammation in Osteoarthritis to Neuropsychiatric Sequelae: A Narrative Review

Nowadays, osteoarthritis (OA), a common, multifactorial musculoskeletal disease, is considered to have a low-grade inflammatory pathogenetic component. Lately, neuropsychiatric sequelae of the disease have gained recognition. However, a link between the peripheral inflammatory process of OA and the development of neuropsychiatric pathology is not completely understood. In this review, we provide a narrative that explores the development of neuropsychiatric disease in the presence of chronic peripheral low-grade inflammation with a focus on its signaling to the brain. We describe the development of a pro-inflammatory environment in the OA-affected joint. We discuss inflammation-signaling pathways that link the affected joint to the central nervous system, mainly using primary sensory afferents and blood circulation via circumventricular organs and cerebral endothelium. The review describes molecular and cellular changes in the brain, recognized in the presence of chronic peripheral inflammation. In addition, changes in the volume of gray matter and alterations of connectivity important for the assessment of the efficacy of treatment in OA are discussed in the given review. Finally, the narrative considers the importance of the use of neuropsychiatric diagnostic tools for a disease with an inflammatory component in the clinical setting.

Identification of Resting-State Network Functional Connectivity and Brain Structural Signatures in Fibromyalgia Using a Machine Learning Approach

Abnormal resting-state functional connectivity (rs-FC) and brain structure have emerged as pathological hallmarks of fibromyalgia (FM). This study investigated and compared the accuracy of network rs-FC and brain structural features in identifying FM with a machine learning (ML) approach. Twenty-six FM patients and thirty healthy controls were recruited. Clinical presentation was measured by questionnaires. After MRI acquisitions, network rs-FC z-score and network-based gray matter volume matrices were exacted and preprocessed. The performance of feature selection and classification methods was measured. Correlation analyses between predictive features in final models and clinical data were performed. The combination of the recursive feature elimination (RFE) selection method and support vector machine (rs-FC data) or logistic regression (structural data), after permutation importance feature selection, showed high performance in distinguishing FM patients from pain-free controls, in which the rs-FC ML model outperformed the structural ML model (accuracy: 0.91 vs. 0.86, AUC: 0.93 vs. 0.88). The combined rs-FC and structural ML model showed the best performance (accuracy: 0.95, AUC: 0.95). Additionally, several rs-FC features in the final ML model correlated with FM's clinical data. In conclusion, ML models based on rs-FC and brain structural MRI features could effectively differentiate FM patients from pain-free subjects.

Increased gray matter following mindfulness-based stress reduction in breast cancer survivors with chronic neuropathic pain: preliminary evidence using voxel-based morphometry

PURPOSE

To investigate the impact of Mindfulness-Based Stress Reduction (MBSR) on gray matter volume (GMV) in female breast cancer survivors who suffer from chronic neuropathic pain (CNP).

METHODS

Voxel-based morphometry (VBM) was used to explore differences in GMV in 13 MBSR trainees and 10 waitlisted controls, with MRI scans and self-report measures completed pre- and post-8 weeks of training.

RESULTS

Compared to controls, the MBSR group had greater GMV in the angular gyrus and middle frontal gyrus post-training. The MBSR group's right parahippocampal gyrus GMV increased from pre- to post-training, whereas the control group's left parahippocampal gyrus, precuneus, middle temporal gyrus, and right cuneus GMV decreased over the same time period. Pain interference was significantly reduced and mindfulness was significantly increased following MBSR for the intervention group only.

CONCLUSIONS

MBSR was associated with increased GMV in regions where GMV is known to (1) increase with mindfulness and reorientation of attention and (2) decrease with the experience of chronic neuropathic pain. By contrast, the control group's decreases in GMV may be due to the negative effects of CNP which potentially may be reduced with MBSR, though further research is needed.

IMPLICATIONS FOR CANCER SURVIVORS

Given the poor efficiency of pharmacotherapies in a high percentage of women with neuropathic pain following breast cancer treatment, adjunct methods are required. MBSR may affect the brain to help alter attention and perception of pain, thus playing a potentially important role in the path to wellness for breast cancer survivors.

Altered Pain in the Brainstem and Spinal Cord of Fibromyalgia Patients During the Anticipation and Experience of Experimental Pain

Chronic pain associated with fibromyalgia (FM) affects a large portion of the population but the underlying mechanisms leading to this altered pain are still poorly understood. Evidence suggests that FM involves altered neural processes in the central nervous system and neuroimaging methods such as functional magnetic resonance imaging (fMRI) are used to reveal these underlying alterations. While many fMRI studies of FM have been conducted in the brain, recent evidence shows that the changes in pain processing in FM may be linked to autonomic and homeostatic dysregulation, thus requiring further investigation in the brainstem and spinal cord. Functional magnetic resonance imaging data from 15 women with FM and 15 healthy controls were obtained in the cervical spinal cord and brainstem at 3 tesla using previously established methods. In order to investigate differences in pain processing in these groups, participants underwent trials in which they anticipated and received a predictable painful stimulus, randomly interleaved with trials with no stimulus. Differences in functional connectivity between the groups were investigated by means of structural equation modeling. The results demonstrate significant differences in brainstem/spinal cord network connectivity between the FM and control groups which also correlated with individual differences in pain responses. The regions involved in these differences in connectivity included the LC, hypothalamus, PAG, and PBN, which are known to be associated with autonomic homeostatic regulation, including fight or flight responses. This study extends our understanding of altered neural processes associated with FM and the important link between sensory and autonomic regulation systems in this disorder.

Alterations of the White Matter in Patients With Knee Osteoarthritis: A Diffusion Tensor Imaging Study With Tract-Based Spatial Statistics

Background

Functional and structural alterations in the gray matter have been observed in patients with knee osteoarthritis (KOA). However, little is known about white matter changes in KOA. Here, we evaluated fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) to investigate potential alterations in the white matter of patients with KOA.

Methods

A total of 166 patients with KOA, along with 88 age- and sex-matched healthy controls were recruited and underwent brain magnetic resonance imaging (MRI). Diffusion tensor imaging (DTI) data were collected and analyzed using tract-based spatial statistics (TBSS). Statistical significances were determined at p < 0.05 and were corrected by the threshold-free cluster enhancement (TFCE) method. Then, we evaluated potential correlations between FA, MD, AD, RD values and disease duration, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and visual analog scale (VAS) scores.

Results

FA values for the body of corpus callosum, splenium of corpus callosum, bilateral superior longitudinal fasciculus, cingulum, bilateral superior corona radiata, and right posterior corona radiata were significantly higher in patients with KOA than in healthy controls (p < 0.05, TFCE corrected). Compared with healthy controls, patients with KOA also had significantly lower MD, AD, and RD values of the genu of corpus callosum, body of corpus callosum, splenium of corpus callosum, corona radiata, right posterior thalamic radiation, superior longitudinal fasciculus, and middle cerebellar peduncle (p < 0.05, TFCE corrected). Negative correlations were detected between WOMAC scores and AD values for the body of the corpus callosum and the splenium of the corpus callosum (p < 0.05, FDR corrected).

Conclusion

Patients with KOA exhibited extensive white matter alterations in sensorimotor and pain-related regions. Longitudinal observation studies on the causation between abnormalities in the white matter tracts and KOA is needed in the future.

The puzzle of fibromyalgia between central sensitization syndrome and small fiber neuropathy: a narrative review on neurophysiological and morphological evidence

Fibromyalgia (FM) is a condition characterized by chronic widespread pain whose pathogenesis is still not fully defined. Evidence based on structural and functional neuroimaging methods, electrophysiological, and morphological - skin biopsy - features demonstrated a central and peripheral nervous system involvement. A dysfunction in nociceptive inputs processing at the central level was highlighted as the primary cause of FM, but other data coming from different laboratories contributed to emphasize again the peripheral origin of FM. In fact, small fibers neuropathy (SFN) was observed in a large number of patients submitted to skin biopsy. The complex interaction between central and peripheral factors is opening a new scenario about the management of this neurological disorder. Whether proximal SFN is an initiating event leading to FM or is the consequence of stress-related insular hyper excitability remains unclear. Mild sufferance of peripheral afferents could function as a trigger for an exaggerated response of the so-called "salience matrix" in predisposed individuals. On the other side, the intriguing hypothesis rising from animal models could indicate that the cortical hyper function could cause peripheral small afferent damage. The research should go on the genetic origin of such peripheral and central abnormalities, the acquired facilitating factors, and the presence of different phenotypes in order to search for efficacious treatments, which are still lacking.

Correlating cognition and cortical excitability with pain in fibromyalgia: a case control study

BACKGROUND

Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal symptoms, primarily attributed to sensitization of somatosensory system carrying pain. Few reports have investigated the impact of fibromyalgia symptoms on cognition, corticomotor excitability, sleepiness, and the sleep quality - all of which can deteriorate the quality of life in fibromyalgia. However, the existing reports are underpowered and have conflicting directions of findings, limiting their generalizability. Therefore, the present study was designed to compare measures of cognition, corticomotor excitability, sleepiness, and sleep quality using standardized instruments in the recruited patients of fibromyalgia with pain-free controls.

METHODS

Diagnosed cases of fibromyalgia were recruited from the Rheumatology department for the cross-sectional, case-control study. Cognition (Mini-Mental State Examination, Stroop color-word task), corticomotor excitability (Resting motor threshold, Motor evoked potential amplitude), daytime sleepiness (Epworth sleepiness scale), and sleep quality (Pittsburgh sleep quality index) were studied according to the standard procedure.

RESULTS

Thirty-four patients of fibromyalgia and 30 pain-free controls were recruited for the study. Patients of fibromyalgia showed decreased cognitive scores (p = 0.05), lowered accuracy in Stroop color-word task (for color: 0.02, for word: 0.01), and prolonged reaction time (< 0.01, < 0.01). Excessive daytime sleepiness in patients were found (< 0.01) and worsened sleep quality (< 0.01) were found. Parameters of corticomotor excitability were comparable between patients of fibromyalgia and pain-free controls.

CONCLUSIONS

Patients of fibromyalgia made more errors, had significantly increased reaction time for cognitive tasks, marked daytime sleepiness, and impaired quality of sleep. Future treatment strategies may include cognitive deficits and sleep disturbances as an integral part of fibromyalgia management.