White matter microstructural alterations in posttraumatic stress disorder: An ROI and whole-brain based meta-analysis

Childhood adversity is associated with longitudinal white matter changes after adulthood trauma

Background

Childhood adversity is associated with susceptibility to posttraumatic stress disorder (PTSD) in adulthood. Both PTSD and adverse experiences in childhood are linked to disrupted white matter microstructure, yet the role of white matter as a potential neural mechanism connecting childhood adversity to PTSD remains unclear. The present study investigated the potential moderating role of previous childhood adversity on longitudinal changes in white matter microstructures and posttraumatic stress symptoms following a recent traumatic event in adulthood.

Methods

As part of the AURORA Study, 114 recent trauma survivors completed diffusion weighted imaging at 2-weeks and 6-months after exposure. Participants reported on prior childhood adversity and PTSD symptoms at 2-weeks, 6-months, and 12-months post-trauma. We performed both region-of-interest (ROI) and whole-brain correlational tractography analyses to index associations between white matter microstructure changes and prior adversity.

Results

Whole-brain correlational tractography revealed that greater childhood adversity moderated the changes in quantitative anisotropy (QA) over time across threat and visual processing tracts including the cingulum bundle and inferior fronto-occipital fasciculus (IFOF). Further, QA changes within cingulum bundle, IFOF, and inferior longitudinal fasciculus were associated with changes in PTSD symptoms between 2-weeks and 6-months.

Conclusions

Our findings suggest temporal variability in threat and visual white matter tracts may be a potential neural pathway through which childhood adversity confers risk to PTSD symptoms after adulthood trauma. Future studies should take the temporal properties of white matter into consideration to better understand the neurobiology of childhood adversity and PTSD.

Cerebellar microstructural abnormalities in patients with somatic symptom disorders

BACKGROUND

Somatic Symptom Disorder (SSD) is a condition often linked to excessive health anxiety and somatic symptoms. In recent years, studies have found associations between the cerebellum and various mental illnesses, including SSD. However, the microstructure of cerebellar subregions in SSD using diffusion magnetic resonance imaging has not been fully defined.

METHODS

This is a cross-sectional study, that included 30 SSD patients and 30 age- and gender-matched healthy controls to investigate the microstructure of the cerebellum using diffusion magnetic resonance imaging. SSD diagnosis followed DSM-5 criteria, excluding major psychiatric comorbidities, while healthy controls underwent rigorous screening to exclude psychiatric or neurological histories. Clinical evaluations utilized standardized scales to assess depressive, anxiety, and cognitive symptoms. MRI data were acquired using a 3T Siemens Prisma scanner, including T1-weighted and diffusion-weighted imaging (30 directions, b = 1000/2000 s/mm²). Multi-compartment diffusion magnetic resonance imaging metrics from free water elimination diffusion tensor imaging and neurite orientation dispersion and density imaging were used to observe microstructural changes in the cerebellum's white matter and gray matter subregions in SSD patients.

RESULTS

Compared to the control group, patients with SSD exhibited significant alterations in white matter microstructure. These changes were characterized by increased free water-eliminated fractional anisotropy and neurite density index, as well as decreased free water-eliminated mean diffusivity and radial diffusivity. Furthermore, the cerebellum displayed varying microstructural changes across 26 gray matter subregions. These changes included reduced mean diffusivity, free water-eliminated axial diffusivity, and free water-eliminated radial diffusivity, alongside increased neurite density index and orientation dispersion index. Importantly, the study identified significant correlations between these microstructural changes and clinical symptoms. Specifically, Vermis X and the left lobule VIIb showed significant associations with both depression and anxiety scores.

CONCLUSIONS

The findings suggest greater neurite density and enhanced diffusion restriction in the cerebellum of patients with SSD, which may indicate possible adaptive changes associated with chronic stress.

The Spectrum of Cognitive Impairment in Atypical Parkinsonism Syndromes: A Comprehensive Review of Current Understanding and Research

Multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) are the most common atypical parkinsonism (AP) syndromes. They are clinically characterized by varying combinations of levodopa-poorly responsive parkinsonism, motor, cerebellar, and other signs. They are associated with a wide spectrum of non-motor symptoms, including prominent cognitive impairment such as global cognitive deficits, memory, executive, attentional, visuospatial, language, and non-verbal reasoning dysfunctions. Within the APs, their cognitive functioning is distributed along a continuum from MSA with the least impaired cognitive profile (similar to Parkinson's disease) to PSP and CBD with the greatest decline in global cognitive and executive domains. Although their pathological hallmarks are different-MSA α-synucleinopathy, CBD, and PSP 4-repeat tauopathies-cognitive dysfunctions in APs show both overlaps and dissimilarities. They are often preceding and anticipate motor dysfunctions, finally contributing to reduced quality of life of patients and caregivers. The present paper will review the current evidence of the prevalence and type of cognitive impairment in these AP syndromes, their neuroimaging, pathogenic backgrounds, and current management options based on extensive literature research. Cognitive dysfunctions in APs are due to disruption of prefronto-subcortical and striato-thalamo-cortical circuitries and multiple essential brain networks. This supports the concept that they are brain network disorders due to complex pathogenic mechanisms related to the basic proteinopathies that are still poorly understood. Therefore, the pathophysiology and pathogenesis of cognitive impairment in APs deserve further elucidation as a basis for early diagnosis and adequate treatment of these debilitating comorbidities.

Neuroimaging of posttraumatic stress disorder in adults and youth: progress over the last decade on three leading questions of the field

Almost three decades have passed since the first posttraumatic stress disorder (PTSD) neuroimaging study was published. Since then, the field of clinical neuroscience has made advancements in understanding the neural correlates of PTSD to create more efficacious treatment strategies. While gold-standard psychotherapy options are available, many patients do not respond to them, prematurely drop out, or never initiate treatment. Therefore, elucidating the neurobiological mechanisms that define the disorder can help guide clinician decision-making and develop individualized mechanisms-based treatment options. To this end, this narrative review highlights progress made in the last decade in adult and youth samples on three outstanding questions in PTSD research: (1) Which neural alterations serve as predisposing (pre-exposure) risk factors for PTSD development, and which are acquired (post-exposure) alterations? (2) Which neural alterations can predict treatment outcomes and define clinical improvement? and (3) Can neuroimaging measures be used to define brain-based biotypes of PTSD? While the studies highlighted in this review have made progress in answering the three questions, the field still has much to do before implementing these findings into clinical practice. Overall, to better answer these questions, we suggest that future neuroimaging studies of PTSD should (A) utilize prospective longitudinal designs, collecting brain measures before experiencing trauma and at multiple follow-up time points post-trauma, taking advantage of multi-site collaborations/consortiums; (B) collect two scans to explore changes in brain alterations from pre-to-post treatment and compare changes in neural activation between treatment groups, including longitudinal follow up assessments; and (C) replicate brain-based biotypes of PTSD. By synthesizing recent findings, this narrative review will pave the way for personalized treatment approaches grounded in neurobiological evidence.

Distinct Longitudinal Brain White Matter Microstructure Changes and Associated Polygenic Risk of Common Psychiatric Disorders and Alzheimer's Disease in the UK Biobank

Background

During the course of adulthood and aging, white matter (WM) structure and organization are characterized by slow degradation processes such as demyelination and shrinkage. An acceleration of such aging processes has been linked to the development of a range of diseases. Thus, an accurate description of healthy brain maturation, particularly in terms of WM features, is fundamental to the understanding of aging.

Methods

We used longitudinal diffusion magnetic resonance imaging to provide an overview of WM changes at different spatial and temporal scales in the UK Biobank (UKB) (n = 2678; agescan 1 = 62.38 ± 7.23 years; agescan 2 = 64.81 ± 7.1 years). To examine the genetic overlap between WM structure and common clinical conditions, we tested the associations between WM structure and polygenic risk scores for the most common neurodegenerative disorder, Alzheimer's disease, and common psychiatric disorders (unipolar and bipolar depression, anxiety, obsessive-compulsive disorder, autism, schizophrenia, attention-deficit/hyperactivity disorder) in longitudinal (n = 2329) and cross-sectional (n = 31,056) UKB validation data.

Results

Our findings indicate spatially distributed WM changes across the brain, as well as distributed associations of polygenic risk scores with WM. Importantly, brain longitudinal changes reflected genetic risk for disorder development better than the utilized cross-sectional measures, with regional differences giving more specific insights into gene-brain change associations than global averages.

Conclusions

We extend recent findings by providing a detailed overview of WM microstructure degeneration on different spatial levels, helping to understand fundamental brain aging processes. Further longitudinal research is warranted to examine aging-related gene-brain associations.

Brain morphological changes and functional neuroanatomy related to cognitive and emotional distractors during working memory maintenance in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is associated with abnormalities in the processing and regulation of emotion as well as cognitive deficits. This study evaluated the differential brain activation patterns associated with cognitive and emotional distractors during working memory (WM) maintenance for human faces between patients with PTSD and healthy controls (HCs) and assessed the relationship between changes in the activation patterns by the opposing effects of distraction types and gray matter volume (GMV). Twenty-two patients with PTSD and twenty-two HCs underwent T1-weighted magnetic resonance imaging (MRI) and event-related functional MRI (fMRI), respectively. Event-related fMRI data were recorded while subjects performed a delayed-response WM task with human face and trauma-related distractors. Compared to the HCs, the patients with PTSD showed significantly reduced GMV of the inferior frontal gyrus (IFG) (p < 0.05, FWE-corrected). For the human face distractor trial, the patients showed significantly decreased activities in the superior frontal gyrus and IFG compared with HCs (p < 0.05, FWE-corrected). The patients showed lower accuracy scores and slower reaction times for the face recognition task with trauma-related distractors compared with HCs as well as significantly increased brain activity in the STG during the trauma-related distractor trial was observed (p < 0.05, FWE-corrected). Such differential brain activation patterns associated with the effects of distraction in PTSD patients may be linked to neural mechanisms associated with impairments in both cognitive control for confusable distractors and the ability to control emotional distraction.

Integration of graph network with kernel SVM and logistic regression for identification of biomarkers in SCA12 and its diagnosis

Spinocerebellar ataxia type 12 is a hereditary and neurodegenerative illness commonly found in India. However, there is no established noninvasive automatic diagnostic system for its diagnosis and identification of imaging biomarkers. This work proposes a novel four-phase machine learning-based diagnostic framework to find spinocerebellar ataxia type 12 disease-specific atrophic-brain regions and distinguish spinocerebellar ataxia type 12 from healthy using a real structural magnetic resonance imaging dataset. Firstly, each brain region is represented in terms of statistics of coefficients obtained using 3D-discrete wavelet transform. Secondly, a set of relevant regions are selected using a graph network-based method. Thirdly, a kernel support vector machine is used to capture nonlinear relationships among the voxels of a brain region. Finally, the linear relationship among the brain regions is captured to build a decision model to distinguish spinocerebellar ataxia type 12 from healthy by using the regularized logistic regression method. A classification accuracy of 95% and a harmonic mean of precision and recall, i.e. F1-score of 94.92%, is achieved. The proposed framework provides relevant regions responsible for the atrophy. The importance of each region is captured using Shapley Additive exPlanations values. We also performed a statistical analysis to find volumetric changes in spinocerebellar ataxia type 12 group compared to healthy. The promising result of the proposed framework shows that clinicians can use it for early and timely diagnosis of spinocerebellar ataxia type 12.

Aberrant white matter microstructure detected by automatic fiber quantification in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease

BACKGROUND AND OBJECTIVES

Myelin oligodendrocyte glycoprotein antibody-associated diseases (MOGAD) is an idiopathic inflammatory demyelinating disorder in children, for which the precise damage patterns of the white matter (WM) fibers remain unclear. Herein, we utilized diffusion tensor imaging (DTI)-based automated fiber quantification (AFQ) to identify patterns of fiber damage and to investigate the clinical significance of MOGAD-affected fiber tracts.

METHODS

A total of 28 children with MOGAD and 31 healthy controls were included in this study. The AFQ approach was employed to track WM fiber with 100 equidistant nodes defined along each tract for statistical analysis of DTI metrics in both the entire and nodal manner. The feature selection method was used to further screen significantly aberrant DTI metrics of the affected fiber tracts or segments for eight common machine learning (ML) to evaluate their potential in identifying MOGAD. These metrics were then correlated with clinical scales to assess their potential as imaging biomarkers.

RESULTS

In the entire manner, significantly reduced fractional anisotropy (FA) was shown in the left anterior thalamic radiation, arcuate fasciculus, and the posterior and anterior forceps of corpus callosum in MOGAD (all p < 0.05). In the nodal manner, significant DTI metrics alterations were widely observed across 37 segments in 10 fiber tracts (all p < 0.05), mainly characterized by decreased FA and increased radial diffusivity (RD). Among them, 14 DTI metrics in seven fiber tracts were selected as important features to establish ML models, and satisfactory discrimination of MOGAD was obtained in all models (all AUC > 0.85), with the best performance in the logistic regression model (AUC = 0.952). For those features, the FA of left cingulum cingulate and the RD of right inferior frontal-occipital fasciculus were negatively and positively correlated with the expanded disability status scale (r = -0.54, p = 0.014; r = 0.43, p = 0.03), respectively.

CONCLUSION

Pediatric MOGAD exhibits extensive WM fiber tract aberration detected by AFQ. Certain fiber tracts exhibit specific patterns of DTI metrics that hold promising potential as biomarkers.

Federated Domain Adaptation via Transformer for Multi-Site Alzheimer's Disease Diagnosis

In multi-site studies of Alzheimer's disease (AD), the difference of data in multi-site datasets leads to the degraded performance of models in the target sites. The traditional domain adaptation method requires sharing data from both source and target domains, which will lead to data privacy issue. To solve it, federated learning is adopted as it can allow models to be trained with multi-site data in a privacy-protected manner. In this paper, we propose a multi-site federated domain adaptation framework via Transformer (FedDAvT), which not only protects data privacy, but also eliminates data heterogeneity. The Transformer network is used as the backbone network to extract the correlation between the multi-template region of interest features, which can capture the brain abundant information. The self-attention maps in the source and target domains are aligned by applying mean squared error for subdomain adaptation. Finally, we evaluate our method on the multi-site databases based on three AD datasets. The experimental results show that the proposed FedDAvT is quite effective, achieving accuracy rates of 88.75%, 69.51%, and 69.88% on the AD vs. NC, MCI vs. NC, and AD vs. MCI two-way classification tasks, respectively.

White matter predictors of PTSD: Testing different machine learning models in a sample of Black American women

BACKGROUND

Machine learning neuroimaging studies of posttraumatic stress disorder (PTSD) show promise for identifying neurobiological signatures of PTSD. However, studies to date, have largely evaluated a single machine learning approach, and few studies have examined white matter microstructure as a predictor of PTSD. Further, individuals from minoritized racial groups, specifically, Black individuals, who experience disproportionate trauma frequency, and have relatively higher rates of PTSD, have been underrepresented in these studies. We used four different machine learning models to test white matter microstructure classifiers of PTSD in a sample of trauma-exposed Black American women with and without PTSD.

METHOD

Participants included 45 Black women with PTSD and 89 trauma-exposed controls recruited from an ongoing trauma study. Current PTSD presence was estimated using the Clinician-Administered PTSD Scale. Average fractional anisotropy of 53 white matter tracts served as input features. Additional exploratory analysis incorporated estimates of interpersonal and structural racism exposure. Classification models included linear support vector machine, radial basis function support vector machine, multilayer perceptron, and random forest.

RESULTS

Performance varied notably between models. With white matter features along, linear support vector machine demonstrated the best model fit and reached an average AUC = 0.643. Inclusion of estimates of exposure to racism increased linear support vector machine performance (AUC = 0.808).

CONCLUSIONS

White matter microstructure had limited ability to predict PTSD presence in this sample. These results may indicate that the relationship between white matter microstructure and PTSD may be nuanced across race and gender spectrums.

Neuroimaging-based classification of PTSD using data-driven computational approaches: A multisite big data study from the ENIGMA-PGC PTSD consortium

BACKGROUND

Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group.

METHODS

We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality.

RESULTS

We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60 % test AUC for s-MRI, 59 % for rs-fMRI and 56 % for d-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75 % AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance.

CONCLUSION

These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable.

Neural correlates of pronoun processing: An activation likelihood estimation meta-analysis

Pronouns are unique linguistic devices that allow for the expression of referential relationships. Despite their communicative utility, the neural correlates of the operations involved in reference assignment and/or resolution, are not well-understood. The present study synthesized the neuroimaging literature on pronoun processing to test extant theories of pronoun comprehension. Following the PRISMA guidelines and thebest-practice recommendations for neuroimaging meta-analyses, a systematic literature search and record assessment were performed. As a result, 16 fMRI studies were included in the meta-analysis, and were coded in Scribe 3.6 for inclusion in the BrainMap database. The activation coordinates for the contrasts of interest were transformed into Talairach space and submitted to an Activation Likelihood Estimation (ALE) meta-analysis in GingerALE 3.0.1. The results indicated that pronoun processing had functional convergence in the left posterior middle and superior temporal gyri, potentially reflecting the retrieval, prediction and integration roles of these areas for pronoun processing.

Mild cognitive impairment in multiple system atrophy: a brain network disorder

Cognitive impairment (CI), previously considered as a non-supporting feature of multiple system atrophy (MSA), according to the second consensus criteria, is not uncommon in this neurodegenerative disorder that is clinically characterized by a variable combination of autonomic failure, levodopa-unresponsive parkinsonism, motor and cerebellar signs. Mild cognitive impairment (MCI), a risk factor for dementia, has been reported in up to 44% of MSA patients, with predominant impairment of executive functions/attention, visuospatial and verbal deficits, and a variety of non-cognitive and neuropsychiatric symptoms. Despite changing concept of CI in this synucleinopathy, the underlying pathophysiological mechanisms remain controversial. Recent neuroimaging studies revealed volume reduction in the left temporal gyrus, and in the dopaminergic nucleus accumbens, while other morphometric studies did not find any gray matter atrophy, in particular in the frontal cortex. Functional analyses detected decreased functional connectivity in the left parietal lobe, bilateral cuneus, left precuneus, limbic structures, and cerebello-cerebral circuit, suggesting that structural and functional changes in the subcortical limbic structures and disrupted cerebello-cerebral networks may be associated with early cognitive decline in MSA. Whereas moderate to severe CI in MSA in addition to prefrontal-striatal degeneration is frequently associated with cortical Alzheimer and Lewy co-pathologies, neuropathological studies of the MCI stage of MSA are unfortunately not available. In view of the limited structural and functional findings in MSA cases with MCI, further neuroimaging and neuropathological studies are warranted in order to better elucidate its pathophysiological mechanisms and to develop validated biomarkers as basis for early diagnosis and future adequate treatment modalities in order to prevent progression of this debilitating disorder.

Persistence of post-traumatic stress disorder in Chinese Shidu parents is associated with combined gray and white matter abnormalities

Post-traumatic stress disorder (PTSD) is one of the most common mental health disorders among Shidu parents. Identification of gray and white matter differences between persistence of PTSD (P-PTSD) and remission of PTSD (R-PTSD) is crucial to determine their prognosis. A total of 37 Shidu parents with PTSD were followed for five years. Surface-based morphometry and diffusion tensor imaging were carried out to analyze the differences in gray and white matter between P-PTSD and R-PTSD. Finally, 30 patients with PTSD were enrolled, including 12 with P-PTSD and 18 with R-PTSD. Compared with patients with R-PTSD, patients with P-PTSD exhibited lower fractional anisotropy (FA) in Cluster 1 (including body of the corpus callosum, superior longitudinal fasciculus, corticospinal tract) and Cluster 2 (including inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, splenium of the corpus callosum) in the left cerebral hemisphere and higher cortical thickness in the right lateral occipital cortex (LOC). In patients with P-PTSD, FA values of Cluster 2 were negatively correlated with cortical thickness of the right LOC. These results suggest that among Shidu parents, differences were observed in gray and white matter between P-PTSD and R-PTSD. Moreover, some certain gray and white matter abnormalities were often present simultaneously in P-PTSD.

Neuro-psychiatric symptoms in directly and indirectly blast exposed civilian survivors of urban missile attacks

BACKGROUND

Blast-explosion may cause traumatic brain injury (TBI), leading to post-concussion syndrome (PCS). In studies on military personnel, PCS symptoms are highly similar to those occurring in post-traumatic stress disorder (PTSD), questioning the overlap between these syndromes. In the current study we assessed PCS and PTSD in civilians following exposure to rocket attacks. We hypothesized that PCS symptomatology and brain connectivity will be associated with the objective physical exposure, while PTSD symptomatology will be associated with the subjective mental experience.

METHODS

Two hundred eighty nine residents of explosion sites have participated in the current study. Participants completed self-report of PCS and PTSD. The association between objective and subjective factors of blast and clinical outcomes was assessed using multivariate analysis. White-matter (WM) alterations and cognitive abilities were assessed in a sub-group of participants (n = 46) and non-exposed controls (n = 16). Non-parametric analysis was used to compare connectivity and cognition between the groups.

RESULTS

Blast-exposed individuals reported higher PTSD and PCS symptomatology. Among exposed individuals, those who were directly exposed to blast, reported higher levels of subjective feeling of danger and presented WM hypoconnectivity. Cognitive abilities did not differ between groups. Several risk factors for the development of PCS and PTSD were identified.

CONCLUSIONS

Civilians exposed to blast present higher PCS/PTSD symptomatology as well as WM hypoconnectivity. Although symptoms are sub-clinical, they might lead to the future development of a full-blown syndrome and should be considered carefully. The similarities between PCS and PTSD suggest that despite the different etiology, namely, the physical trauma in PCS and the emotional trauma in PTSD, these are not distinct syndromes, but rather represent a combined biopsychological disorder with a wide spectrum of behavioral, emotional, cognitive and neurological symptoms.

Characterizing White Matter Changes along Fibers in Treatment-Naive Pediatric Posttraumatic Stress Disorder

Children and adolescents are more susceptible than adults to developing posttraumatic stress disorder (PTSD). Pediatric PTSD is characterized by functional alterations in brain fear circuitry, but little is known about the underlying microstructural changes; previous work has mainly focused on the corpus callosum. This study is aimed at investigating brain-wide microstructural abnormalities in pediatric PTSD, their relationship to age and sex, and their potential diagnostic value. The microstructure of major white matter tracts was assessed from diffusion tensor images acquired from 24 treatment-naive non-comorbid PTSD patients <18 years and 24 trauma-exposed non-PTSD controls (TENP) matched for age, sex, and years of education. Statistical analyses included pointwise comparisons, correlations with symptom severity, and diagnosis-by-age/sex interactions; support vector machine analyses were conducted to determine whether microstructure distinguishes PTSD from TENP. Compared with TENP, pediatric PTSD patients showed higher fractional anisotropy and lower radial diffusivity in right superior longitudinal fasciculus and lower axial diffusivity in right uncinate fasciculus. These white matter microstructural abnormalities were highly correlated with PTSD symptom severity. No significant diagnosis by age or sex interaction was observed. The pointwise axial diffusivity measurements presented the best PTSD vs. TENP classification performance. In summary, pediatric PTSD patients showed clinically relevant microstructural abnormalities in uncinate and superior longitudinal fasciculus, which extend understanding of pediatric PTSD neurobiology beyond the corpus callosum and have diagnostic potential in distinguishing stressed individuals with and without PTSD.

Sleep Quality Disturbances Are Associated with White Matter Alterations in Veterans with Post-Traumatic Stress Disorder and Mild Traumatic Brain Injury

Sleep disturbances are strongly associated with mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD). PTSD and mTBI have been linked to alterations in white matter (WM) microstructure, but whether poor sleep quality has a compounding effect on WM remains largely unknown. We evaluated sleep and diffusion magnetic resonance imaging (dMRI) data from 180 male post-9/11 veterans diagnosed with (1) PTSD (n = 38), (2) mTBI (n = 25), (3) comorbid PTSD+mTBI (n = 94), and (4) a control group with neither PTSD nor mTBI (n = 23). We compared sleep quality (Pittsburgh Sleep Quality Index, PSQI) between groups using ANCOVAs and calculated regression and mediation models to assess associations between PTSD, mTBI, sleep quality, and WM. Veterans with PTSD and comorbid PTSD+mTBI reported poorer sleep quality than those with mTBI or no history of PTSD or mTBI (p = 0.012 to <0.001). Poor sleep quality was associated with abnormal WM microstructure in veterans with comorbid PTSD+mTBI (p < 0.001). Most importantly, poor sleep quality fully mediated the association between greater PTSD symptom severity and impaired WM microstructure (p < 0.001). Our findings highlight the significant impact of sleep disturbances on brain health in veterans with PTSD+mTBI, calling for sleep-targeted interventions.

Posttraumatic Stress and Traumatic Brain Injury: Cognition, Behavior, and Neuroimaging Markers in Vietnam Veterans

BACKGROUND

Posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) are common in Veterans and linked to behavioral disturbances, increased risk of cognitive decline, and Alzheimer's disease.

OBJECTIVE

We studied the synergistic effects of PTSD and TBI on behavioral, cognitive, and neuroimaging measures in Vietnam war Veterans.

METHODS

Data were acquired at baseline and after about one-year from male Veterans categorized into: PTSD, TBI, PTSD+TBI, and Veteran controls without PTSD or TBI. We applied manual tractography to examine white matter microstructure of three fiber tracts: uncinate fasciculus (N = 91), cingulum (N = 87), and inferior longitudinal fasciculus (N = 95). ANCOVAs were used to compare Veterans' baseline behavioral and cognitive functioning (N = 285), white matter microstructure, amyloid-β (N = 230), and tau PET (N = 120). Additional ANCOVAs examined scores' differences from baseline to follow-up.

RESULTS

Veterans with PTSD and PTSD+TBI, but not Veterans with TBI only, exhibited poorer behavioral and cognitive functioning at baseline than controls. The groups did not differ in baseline white matter, amyloid-β, or tau, nor in behavioral and cognitive functioning, and tau accumulation change. Progression of white matter abnormalities of the uncinate fasciculus in Veterans with PTSD compared to controls was observed; analyses in TBI and PTSD+TBI were not run due to insufficient sample size.

CONCLUSIONS

PTSD and PTSD+TBI negatively affect behavioral and cognitive functioning, while TBI does not contribute independently. Whether progressive decline in uncinate fasciculus microstructure in Veterans with PTSD might account for cognitive decline should be further studied. Findings did not support an association between PTSD, TBI, and Alzheimer's disease pathology based on amyloid and tau PET.

Aberrant white matter microstructure evaluation by automated fiber quantification in typhoon-related post-traumatic stress disorder

Super typhoons can lead to post-traumatic stress disorder (PTSD), which can adversely affect a person's mental health after a disaster. Neuroimaging studies suggest that patients with PTSD may have post-exposure abnormalities of the white matter. However, little is known about these defects, if they are localized to specific regions of the white matter fibers, or whether they may be potential biomarkers for PTSD. Typhoon survivors with PTSD (n = 27), trauma-exposed controls (TEC) (n = 33), and healthy controls (HCs) (n = 30) were enrolled. We used automated fiber quantification (AFQ) to process the participants' DTI and compared diffusion metrics among the three groups. To evaluate diagnostic value, we used support vector machine (SVM) and a random forest (RF) classifier to build a machine learning model. White matter fiber segmentation between the three groups was found to be statistically significant for the fractional anisotropy (FA) value of the right anterior thalamic radiation (ATR) (26-50 nodes) and right uncinate fasciculus (UF) (60-72 nodes) (FDR correction, p < 0.05). By analyzing the characteristics of the machine learning model, the two most important variables were the right ATR and right UF for differentiating PTSD and trauma-exposed controls (TEC) from the healthy controls (HC). In addition, the left cingulum cingulate and left UF were the most critical variables in the differentiation of PTSD and TEC. AFQ with machine learning can localize abnormalities in specific regions of white matter fibers. These regions may be used as a diagnostic biomarker for PTSD.

White matter abnormalities in first-episode patients with depersonalization/derealization disorder: A tract-based spatial statistics study

BACKGROUND

Neuroimaging studies on depersonalization / derealization disorder (DPD) have revealed that there are structural and functional alterations across numerous brain regions. However, to date, the exact white matter abnormalities that are associated with different clinical symptoms and cognitive impairments in first-episode, drug-naïve patients with DPD remain unclear.

METHODS

Overall, 25 first-episode, drug-naïve patients with DPD and 23 healthy controls were recruited and underwent DTI scans. The tract-based spatial statistics analysis was conducted in order to determine white matter microstructural changes between the two groups. Correlation analysis was conducted between the fractional anisotropy (FA) of abnormal WM fibers and the total score of the 30-item Cambridge Depersonalization Scale (CDS-30), cognitive assessments.

RESULTS

Patients with DPD demonstrated higher FA in the right corpus callosum (CC), and posterior corona radiate (CR), compared to healthy controls. The FA in the right CC demonstrated a positive correlation with total score of CDS-30, numbing, unreality of self, perceptual alterations, and temporal disintegration, respectively. FA in the right CR region indicated a positive correlation with the total score of CDS-30, unreality of self, perceptual alterations, and temporal disintegration, respectively. Furthermore, FA in the right CR region was found to be negatively correlated with the Continuous Performance Test and the Stroop color-word test.

CONCLUSION

The altered white matter microstructure and cognitive impairments of medication naïve DPD patients were observed. Abnormalities in the integrity of CC and CR were associated with severity of symptoms and cognitive impairments, which may provide a potential biomarker for clinical studies on DPD.

Scene Construction and Spatial Processing in Post-traumatic Stress Disorder

Introduction

Post-traumatic stress disorder (PTSD) is associated with hippocampal system structural and functional impairments. Neurobiological models of PTSD posit that contextual memory for traumatic events is impaired due to hippocampal system dysfunction whilst memory of sensory details is enhanced due to amygdalar impact on sensory cortices. If hippocampal system dysfunction is a core feature of PTSD, then non-traumatic hippocampal-dependent cognitive functions such as scene construction, spatial processing, and memory should also be impaired in individuals with PTSD.

Methods

Forty-six trauma survivors, half diagnosed with PTSD, performed two tasks that involved spatial processing. The first was a scene construction task which requires conjuring-up spatially coherent multimodal scenarios, completed by all participants. Twenty-six participants (PTSD: n = 13) also completed a navigation task in a virtual environment, and underwent structural T1, T2 and diffusion-tensor MRI to quantify gray and white matter integrity. We examined the relationship between spatial processing, neural integrity, and symptom severity in a multiple factor analysis.

Results

Overall, patients with PTSD showed impaired performance in both tasks compared to controls. Scenes imagined by patients were less vivid, less detailed, and generated less sense of presence; importantly they had disproportionally reduced spatial coherence between details. Patients also made more errors during virtual navigation. Two components of the multiple factor analysis captured group differences. The first component explained 25% of the shared variance: participants that constructed less spatially coherent scenes also made more navigation errors and had reduced white matter integrity to long association tracts and tracts connecting the hippocampus, thalamus, and cingulate. The second component explained 20% of the variance: participants who generated fewer scene details, with less spatial coherence between them, had smaller hippocampal, parahippocampal and isthmus cingulate volumes. These participants also had increased white matter integrity to the right hippocampal cingulum bundle.

Conclusion

Our results suggest that patients with PTSD are impaired at imagining even neutral spatially coherent scenes and navigating through a complex spatial environment. Patients that showed reduced spatial processing more broadly had reduced hippocampal systems volumes and abnormal white matter integrity to tracts implicated in multisensory integration.

Neurobiological Changes in Posttraumatic Stress Disorder and Their Reversibility by Psychotherapy

Abstract. Background: Posttraumatic stress disorder (PTSD) is a debilitating illness associated with distressing symptoms and a high societal burden. Objective: To investigate the neurobiological underpinnings of PTSD to improve our understanding of this disorder and its treatment. Methods: This article reviews currently researched mechanisms that can explain the development of PTSD symptoms. It presents key findings on neural (i. e., brain functioning and brain structure), neuroendocrine (i. e., noradrenergic and hypothalamic-pituitary-adrenal axis activity), and related (epi)‌genetic changes in individuals with PTSD. Furthermore, it presents preliminary research examining the reversibility of these alterations during psychotherapeutic treatment. Results: PTSD is characterized by specific neurobiological alterations, with preliminary findings indicating that at least some of these may normalize during psychotherapy. Discussion: A multidimensional perspective on the development, maintenance, and treatment of PTSD has the potential to improve our understanding of the causal processes underlying the disorder and may ultimately inform the conception of novel treatments.

Emotion Dysregulation Following Trauma: Shared Neurocircuitry of Traumatic Brain Injury and Trauma-Related Psychiatric Disorders

The psychological trauma associated with events resulting in traumatic brain injury (TBI) is an important and frequently overlooked factor that may impede brain recovery and worsen mental health following TBI. Indeed, individuals with comorbid posttraumatic stress disorder (PTSD) and TBI have significantly poorer clinical outcomes than individuals with a sole diagnosis. Emotion dysregulation is a common factor leading to poor cognitive and affective outcomes following TBI. Here, we synthesize how acute postinjury molecular processes stemming from either physical or emotional trauma may adversely impact circuitry subserving emotion regulation and ultimately yield long-term system-level functional and structural changes that are common to TBI and PTSD. In the immediate aftermath of traumatic injury, glucocorticoids stimulate excess glutamatergic activity, particularly in prefrontal cortex-subcortical circuitry implicated in emotion regulation. In human neuroimaging work, assessing this same circuitry well after the acute injury, TBI and PTSD show similar impacts on prefrontal and subcortical connectivity and activation. These neural profiles indicate that emotion regulation may be a useful target for treatment and early intervention to prevent the adverse sequelae of TBI. Ultimately, the success of future TBI and PTSD early interventions depends on the fields' ability to address both the physical and emotional impact of physical injury.

Psychoradiological abnormalities in treatment-naive noncomorbid patients with posttraumatic stress disorder

BACKGROUND

Neuroimaging studies in posttraumatic stress disorder (PTSD) have identified various alterations in white matter (WM) microstructural organization. However, it remains unclear whether these are localized to specific regions of fiber tracts, and what diagnostic value they might have. This study set out to explore the spatial profile of WM abnormalities along defined fiber tracts in PTSD.

METHODS

Diffusion tensor images were obtained from 77 treatment-naive noncomorbid patients with PTSD and 76 demographically matched trauma-exposed non-PTSD (TENP) controls. Using automated fiber quantification, tract profiles of fractional anisotropy, axial diffusivity, mean diffusivity, and radial diffusivity were calculated to evaluate WM microstructural organization. Results were analyzed by pointwise comparisons, by correlation with symptom severity, and for diagnosis-by-sex interactions. Support vector machine analyses assessed the ability of tract profiles to discriminate PTSD from TENP.

RESULTS

Compared to TENP, PTSD showed lower fractional anisotropy accompanied by higher radial diffusivity and mean diffusivity in the left uncinate fasciculus, and lower fractional anisotropy accompanied by higher radial diffusivity in the right anterior thalamic radiation. Tract profile alterations were correlated with symptom severity, suggesting a pathophysiological relevance. There were no significant differences in diagnosis-by-sex interaction. Tract profiles allowed individual classification of PTSD versus TENP with significant accuracy, of potential diagnostic utility.

CONCLUSIONS

These findings add to the knowledge of the neuropathological basis of PTSD. WM alterations based on a tract-profile quantification approach are a potential biomarker for PTSD.

Brain correlates of depression, post-traumatic distress, and inflammatory biomarkers in COVID-19 survivors: A multimodal magnetic resonance imaging study

Psychiatric sequelae substantially contribute to the post-acute burden of disease associated with COVID-19, persisting months after clearance of the virus. Brain imaging shows white matter (WM) hypodensities/hyperintensities, and the involvement of grey matter (GM) in prefrontal, anterior cingulate (ACC) and insular cortex after COVID, but little is known about brain correlates of persistent psychopathology. With a multimodal approach, we studied whole brain voxel-based morphometry, diffusion-tensor imaging, and resting-state connectivity, to correlate MRI measures with depression and post-traumatic distress (PTSD) in 42 COVID-19 survivors without brain lesions, at 90.59 ​± ​54.66 days after COVID. Systemic immune-inflammation index (SII) measured in the emergency department, which reflects the immune response and systemic inflammation based on peripheral lymphocyte, neutrophil, and platelet counts, predicted worse self-rated depression and PTSD, widespread lower diffusivity along the main axis of WM tracts, and abnormal functional connectivity (FC) among resting state networks. Self-rated depression and PTSD inversely correlated with GM volumes in ACC and insula, axial diffusivity, and associated with FC. We observed overlapping associations between severity of inflammation during acute COVID-19, brain structure and function, and severity of depression and post-traumatic distress in survivors, thus warranting interest for further study of brain correlates of the post-acute COVID-19 syndrome. Beyond COVID-19, these findings support the hypothesis that regional GM, WM microstructure, and FC could mediate the relationship between a medical illness and its psychopathological sequelae, and are in agreement with current perspectives on the brain structural and functional underpinnings of depressive psychopathology.

Pediatric PTSD is characterized by age- and sex-related abnormalities in structural connectivity

Pediatric post-traumatic stress disorder (pPTSD) is a prevalent and pervasive form of mental illness comprising a disparate constellation of psychiatric symptoms. Emerging evidence suggests that pPTSD may be characterized by alterations in functional networks traversing the brain. Yet, little is known about pathological changes in the structural tracts underlying functional connectivity. In adults, PTSD is linked to widespread change in white matter integrity throughout the brain, yet similar studies with youth populations have yet to be conducted. Current understanding of the nature and treatment of pPTSD may be enhanced by examining alterations in white matter, while further untangling effects of age and sex. Here, we assess the microstructure of 12 major white matter tracts in a sample of well-phenotyped youth with PTSD. Measures of fractional anisotropy were derived from diffusion tensor images acquired from 82 unmediated youth (ages 8-18), of whom 39 met criteria for pPTSD. Diagnosis of pPTSD was linked to remarkable age- and sex-linked differences in the microstructure of major white matter tracts including the uncinate fasciculus, cingulum bundle, and inferior longitudinal fasciculus. In each case, youth with PTSD show an absence of increased white matter integrity with age, suggesting an altered pattern of neurodevelopment that may contribute to persistence or worsening of illness. Broadly, our results suggest abnormal white matter development in pediatric PTSD, a finding which may contribute to illness persistence, comorbidity with other disorders, and poorer prognosis across time. Critically, these findings further speak to the nature of pPTSD as a 'whole-brain' disorder.

White Matter Abnormalities in Patients With Typhoon-Related Posttraumatic Stress Disorder

Patients with posttraumatic stress disorder (PTSD) might have white matter abnormalities. However, less is known about white matter changes after exposing a specific traumatic event. The purpose of this study was to explore the abnormalities of diffusion in cerebral white matter and its relationship with the clinical symptoms in patients with PTSD by using diffusion tensor imaging (DTI). Diffusion-weighted imaging of the cerebrum was performed in typhoon survivors with (n = 27) and without PTSD (n = 33) and healthy controls (HCs) (n = 30). Differences in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated among groups using voxel-based analysis of the DTI data. Correlations between diffusion indices and clinical symptoms in patients with PTSD were also assessed. Both patients with PTSD and trauma-exposed control (TEC) group showed increased FA in the anterior limb of the internal capsule, forceps of the corpus callosum, and corona radiata relative to the HC group. Additionally, there was a negative correlation between FA values in the white matter and the clinical symptoms. Trauma exposure may result in disruption of cerebral white matter in individuals with or without PTSD, particularly in the frontal fibers. Aberrant white matter alterations may be associated with the severity of PTSD symptoms.

Acute White Matter Integrity Post-trauma and Prospective Posttraumatic Stress Disorder Symptoms

Background: Little is known about what distinguishes those who are resilient after trauma from those at risk for developing posttraumatic stress disorder (PTSD). Previous work indicates white matter integrity may be a useful biomarker in predicting PTSD. Research has shown changes in the integrity of three white matter tracts-the cingulum bundle, corpus callosum (CC), and uncinate fasciculus (UNC)-in the aftermath of trauma relate to PTSD symptoms. However, few have examined the predictive utility of white matter integrity in the acute aftermath of trauma to predict prospective PTSD symptom severity in a mixed traumatic injury sample. Method: Thus, the current study investigated acute brain structural integrity in 148 individuals being treated for traumatic injuries in the Emergency Department of a Level 1 trauma center. Participants underwent diffusion-weighted magnetic resonance imaging 2 weeks post-trauma and completed several self-report measures at 2-weeks (T1) and 6 months (T2), including the Clinician Administered PTSD Scale for DSM-V (CAPS-5), post-injury. Results: Consistent with previous work, T1 lesser anterior cingulum fractional anisotropy (FA) was marginally related to greater T2 total PTSD symptoms. No other white matter tracts were related to PTSD symptoms. Conclusions: Results demonstrate that in a traumatically injured sample with predominantly subclinical PTSD symptoms at T2, acute white matter integrity after trauma is not robustly related to the development of chronic PTSD symptoms. These findings suggest the timing of evaluating white matter integrity and PTSD is important as white matter differences may not be apparent in the acute period after injury.

Brainstem damage is associated with poorer sleep quality and increased pain in gulf war illness veterans

AIMS

Gulf War Illness (GWI) is manifested as multiple chronic symptoms, including chronic pain, chronic fatigue, sleep problems, neuropsychiatric disorders, respiratory, gastrointestinal, and skin problems. No single target tissue or unifying pathogenic process has been identified that accounts for this variety of symptoms. The brainstem has been suspected to contribute to this multiple symptomatology. The aim of this study was to assess the role of the brainstem in chronic sleep problems and pain in GWI veterans.

MATERIALS AND METHODS

We enrolled 90 veterans (Age = 50 ± 5, 87% Male) who were deployed to the 1990-91 Gulf War and presented with GWI symptoms. Sleep quality was evaluated using the global Pittsburgh Sleep Quality Index. Pain intensities were obtained with the Brief Pain Inventory sum score. Volumes in cortical, subcortical, brainstem, and brainstem subregions and diffusion tensor metrics in 10 bilateral brainstem tracts were tested for correlations with symptom measures.

KEY FINDINGS

Poorer sleep quality was significantly correlated with atrophy of the whole brainstem and brainstem subregions (including midbrain, pons, medulla). Poorer sleep quality also significantly correlated with lower fractional anisotropy in the nigrostriatal tract, medial forebrain tract, and the dorsal longitudinal fasciculus. There was a significant correlation between increased pain intensity and decreased fractional anisotropy in the dorsal longitudinal fasciculus. These correlations were not altered after controlling for age, sex, total intracranial volumes, or additional factors, e.g., depression and neurological conditions.

SIGNIFICANCE

These findings suggest that the brainstem plays an important role in the aberrant neuromodulation of sleep and pain symptoms in GWI.

Treatment outcome of posttraumatic stress disorder: A white matter tract analysis

Despite the development of empirically supported treatments for posttraumatic stress disorder (PTSD), many individuals remain symptomatic following therapy or dropout prematurely. Neuroimaging studies examining PTSD treatment outcome may offer valuable insights into possible mechanisms that may impact treatment efficacy. To date, few studies of PTSD have used neuroimaging to examine symptom change following completed treatment, and most have focused on gray matter. Studies of white matter are equally important, as changes in white matter integrity (WMI) are connected to a host of detrimental outcomes. The current study examined symptom change of 21 women with PTSD as a result of interpersonal violence who received baseline diffusion tensor imaging (DTI) scans and completed 12 weeks of Cognitive Processing Therapy (CPT). After controlling for baseline PTSD severity, fractional anisotropy (FA) in the left internal capsule, posterior limb of the internal capsule, left cingulate gyrus, superior longitudinal fasciculus, and splenium of the corpus callosum was predicted by PTSD symptom change. Results contribute to understanding neural changes within therapy and may assist in predicting individual treatment response. Namely, by identifying areas potentially impacted by PTSD treatment, future studies may be able to connect the function of these white matter areas to better predict patient PTSD treatment outcome.

Diffusion Tensor Imaging Reveals White Matter Differences in Military Personnel Exposed to Trauma with and without Post-traumatic Stress Disorder

BACKGROUND

Post-traumatic stress disorder (PTSD) is a debilitating mental health condition that develops in response to exposure to a traumatic event. The purpose of this study was to investigate white matter differences using diffusion tensor imaging (DTI) in trauma exposed military personnel with and without PTSD.

METHODS

Data were acquired in compliance with the Hospital for Sick Children and Canadian Armed Forces Research Ethics Boards for the following groups: military personnel with PTSD (PTSD, n = 23), trauma exposed military personnel with no PTSD diagnosis (TE, n = 25) and civilian controls (CC, n =13) . All participants were male. DTI was acquired on a Siemens Trio 3T MRI. Maps of Fractional Anisotropy (FA), Mean Diffusivity (MD), Axial Diffusivity (AD), and Radial Diffusivity (RD) were analyzed using Tract-Based Spatial Statistics (TBSS).

RESULTS

In the PTSD and TE groups, FA was significantly greater within the hippocampus, corpus callosum, cingulum, and several associated white matter tracts. Elevated FA was shown to be largely due to reduced RD suggesting a possible structural substrate that underscores neurophysiological connectivity.

CONCLUSIONS

This study reinforces previous findings showing differences in DTI metrics within the limbic system in military personnel exposed to trauma with and without PTSD.

Morphological Changes in Cortical and Subcortical Structures in Multiple System Atrophy Patients With Mild Cognitive Impairment

Objective

This study aimed to investigate the morphometric alterations in the cortical and subcortical structures in multiple system atrophy (MSA) patients with mild cognitive impairment (MCI), and to explore the association with cognitive deficits.

Methods

A total of 45 MSA patients (25 MSA-only, 20 MSA-MCI) and 29 healthy controls were recruited. FreeSurfer software was used to analyze cortical thickness, and voxel-based morphometry was used to analyze the gray matter volumes. Cortical thickness and gray matter volume changes were correlated with cognitive scores.

Results

Compared to healthy controls, both MSA subgroups exhibited widespread morphology alterations of brain structures in the fronto-temporal regions. Direct comparison of MSA-MCI and MSA-only patients showed volume reduction in the left superior and middle temporal gyrus, while cortical thinning was found in the left middle and inferior temporal gyrus in MSA-MCI patients. Cortical thinning in the left middle temporal gyrus correlated with cognitive assessment and disease duration.

Conclusion

Structural changes in the brain occur in MSA-MCI patients. The alteration of brain structure in the left temporal regions might be a biomarker of cognitive decline in MSA-MCI patients.