Profiles of Cognitive Functioning at 6 Months After Traumatic Brain Injury Among Patients in Level I Trauma Centers: A TRACK-TBI Study

Neuroinflammation: An Oligodendrocentric View

Chronic neuroinflammation, driven by central nervous system (CNS)-resident astrocytes and microglia, as well as infiltration of the peripheral immune system, is an important pathologic mechanism across a range of neurologic diseases. For decades, research focused almost exclusively on how neuroinflammation impacted neuronal function; however, there is accumulating evidence that injury to the oligodendrocyte lineage is an important component for both pathologic and clinical outcomes. While oligodendrocytes are able to undergo an endogenous repair process known as remyelination, this process becomes inefficient and usually fails in the presence of sustained inflammation. The present review focuses on our current knowledge regarding activation of the innate and adaptive immune systems in the chronic demyelinating disease, multiple sclerosis, and provides evidence that sustained neuroinflammation in other neurologic conditions, such as perinatal white matter injury, traumatic brain injury, and viral infections, converges on oligodendrocyte injury. Lastly, the therapeutic potential of targeting the impact of inflammation on the oligodendrocyte lineage in these diseases is discussed.

Chronic impairment of neurovascular coupling and cognitive decline in young survivors of severe traumatic brain injury

Severe traumatic brain injury (TBI) leads to chronic cognitive decline, imposing a significant societal burden. The regulation of cerebral blood flow (CBF) is critical for cognitive function, and acute disruptions in CBF regulation predict poor TBI outcomes. However, the long-term effects of TBI on CBF regulation and their association with cognitive function remain poorly understood. This study aimed to investigate whether severe TBI results in chronic CBF dysregulation and whether this contributes to long-term cognitive deficits. Additionally, we examined the role of TBI-induced insulin-like growth factor 1 (IGF-1) deficiency in cerebrovascular dysfunction. We assessed cognitive function, basal CBF (via phase contrast MRI), CBF autoregulation (via transcranial Doppler), and neurovascular coupling (NVC) in 33 TBI survivors (mean age 37.6 years, ~ 10 years post-injury) and 21 age-matched healthy controls. Serum IGF-1 levels were also measured. TBI survivors exhibited significant impairments in memory and executive function compared to controls. While basal CBF and autoregulation remained intact, NVC responses were chronically impaired and correlated with cognitive deficits. However, IGF-1 levels did not differ between groups and were not associated with NVC impairment or cognitive function. Our findings indicate that severe TBI results in chronic impairment of neurovascular coupling, which likely contributes to long-term cognitive deficits. These results highlight the need for further research to identify underlying neurovascular mechanisms and develop interventions to restore NVC and cognitive function in TBI survivors.

Clinical, Neuroimaging, and Genetic Markers Associated with Cognitive and Functional Outcomes After Traumatic Brain Injury

Background: Traumatic brain injury (TBI) is a major cause of long-term disability worldwide, often leading to progressive cognitive and functional impairments. This study aimed to investigate the underlying factors contributing to long-term deterioration in TBI patients. Methods: We conducted a comprehensive evaluation of 145 patients aged 18-66 years with a documented history of TBI and ongoing cognitive and behavioral deficits. Assessments included neuroimaging, laboratory tests, genetic analysis, and standardized tools such as the Montreal Cognitive Assessment (MoCA) and the Barthel Index. Results: Structural brain abnormalities, including ventricular enlargement and gliosis, were observed in a substantial portion of the cohort. Persistent neuroinflammatory markers were also identified. Genetic analysis revealed a significant association between cognitive decline and polymorphisms in the ACE and PON1 genes. Patients carrying these variants were more likely to exhibit reduced cognitive performance and greater functional limitations. Conclusion: These findings suggest that genetic predisposition, chronic neuroinflammation, and structural brain damage collectively contribute to long-term outcomes following TBI. This highlights the potential of genetic and imaging biomarkers in identifying high-risk individuals and supports the need for personalized approaches to diagnosis, monitoring, and treatment in chronic TBI management.

Sports-related concussion not associated with long-term cognitive or behavioural deficits: the PROTECT-TBI study

BACKGROUND

The cognitive effects of sports-related concussion (SRC) have been the subject of vigorous debate but there has been little research into long-term outcomes in non-athlete populations.

METHODS

This cohort study of UK community-dwelling adults (aged 50-90 years) was conducted between November 2015 and November 2020, with up to 4 years annual follow-up (n=15 214). Lifetime history of concussions was collected at baseline using the Brain Injury Screening Questionnaire. The first analysis grouped participants by type of concussion (no concussion, only SRC, only non-SRC (nSRC), mixed concussions (both SRC and nSRC)) and the second grouped the participants by number (0, 1, 2 or 3+ SRC or nSRC). Mixed models were used to assess the effect of concussion on outcomes including four cognitive domains and one behavioural measure (Mild Behavioural Impairment-C).

RESULTS

Analysis of the included participants (24% male, mean age=64) at baseline found that the SRC group had significantly better working memory (B=0.113, 95% CI 0.038, 0.188) and verbal reasoning (B=0.199, 95% CI 0.092, 0.306) compared with those without concussion. Those who had suffered one SRC had significantly better verbal reasoning (B=0.111, 95% CI 0.031, 0.19) and attention (B=0.115, 95% CI 0.028, 0.203) compared with those with no SRC at baseline. Those with 3+ nSRCs had significantly worse processing speed (B=-0.082, 95% CI -0.144 to -0.019) and attention (B=-0.156, 95% CI -0.248 to -0.063). Those with 3+ nSRCs had a significantly worse trajectory of verbal reasoning with increasing age (B=-0.088, 95% CI -0.149 to -0.026).

CONCLUSIONS

Compared with those reporting no previous concussions, those with SRC had no cognitive or behavioural deficits and seemed to perform better in some tasks. As indicated by previous studies, sports participation may confer long-term cognitive benefits.

Traumatic Brain Injury and Artificial Intelligence: Shaping the Future of Neurorehabilitation-A Review

Traumatic brain injury (TBI) is a leading cause of disability and death globally, presenting significant challenges for diagnosis, prognosis, and treatment. As healthcare technology advances, artificial intelligence (AI) has emerged as a promising tool in enhancing TBI rehabilitation outcomes. This literature review explores the current and potential applications of AI in TBI management, focusing on AI's role in diagnostic tools, neuroimaging, prognostic modeling, and rehabilitation programs. AI-driven algorithms have demonstrated high accuracy in predicting mortality, functional outcomes, and personalized rehabilitation strategies based on patient data. AI models have been developed to predict in-hospital mortality of TBI patients up to an accuracy of 95.6%. Furthermore, AI enhances neuroimaging by detecting subtle abnormalities that may be missed by human radiologists, expediting diagnosis and treatment decisions. Despite these advances, ethical considerations, including biases in AI algorithms and data generalizability, pose challenges that must be addressed to optimize AI's implementation in clinical settings. This review highlights key clinical trials and future research directions, emphasizing AI's transformative potential in improving patient care, rehabilitation, and long-term outcomes for TBI patients.

Development and validation of a model to predict cognitive impairment in traumatic brain injury patients: a prospective observational study

Background

Traumatic brain injury (TBI) is a significant public health issue worldwide that affects millions of people every year. Cognitive impairment is one of the most common long-term consequences of TBI, seriously affect the quality of life. We aimed to develop and validate a predictive model for cognitive impairment in TBI patients, with the goal of early identification and support for those at risk of developing cognitive impairment at the time of hospital admission.

Methods

The training cohort included 234 TBI patients, all of whom were admitted to the Department of Neurosurgery at the Third Affiliated Hospital of Soochow University from May 2017 to April 2020. These patients were selected from our previously published studies. Baseline characteristics, medical history, clinical TBI characteristics, treatment details, and vital signs during hospitalization were screened via least absolute shrinkage and selection operator (LASSO) and logistic regression to construct a predictive net risk score. The derived score represents an estimate of the risk of developing cognitive impairment in patients with TBI. A nomogram was constructed, and its accuracy and predictive performance were evaluated with the area under the receiver operating characteristic curve (AUC), calibration curves, and clinical decision curves. For the validation cohort, data were prospectively collected from TBI patients admitted to the Department of Neurosurgery at the Third Affiliated Hospital of Soochow University from March 1, 2024 to August 30, 2024, according to the inclusion and exclusion criteria. This study is registered with the Chinese Clinical Trial Registry (ChiCTR) at http://www.chictr.org.cn/ (registration number: ChiCTR2400083495).

Findings

The training cohort included 234 patients. The mean (standard deviation, SD) age of the patients in the cohort was 47.74 (17.89) years, and 184 patients (78.63%) were men. The validation cohort included 84 patients with a mean (SD) age of 48.44 (14.42) years, and 68 patients (80.95%) were men. Among the 48 potential predictors, the following 6 variables were significant independent predictive factors and were included in the net risk score: age (odds ratio (OR) = 1.06, 95% confidence interval (CI): 1.03-1.08, P = 0.00), years of education (OR = 0.80, 95% CI: 0.70-0.93, P = 0.00), pulmonary infection status (OR = 4.64, 95% CI: 1.41-15.27, P = 0.01), epilepsy status (OR = 4.79, 95% CI: 1.09-21.13, P = 0.04), cerebrospinal fluid leakage status (OR = 5.57, 95% CI: 1.08-28.75, P = 0.04), and the Helsinki score (OR = 1.53, 95% CI: 1.28-1.83, P = 0.00). The AUC in the training cohort was 0.90, and the cut-off value was 0.71. The AUC in the validation cohort was 0.87, and the cut-off value was 0.63. The score was translated into an online risk calculator that is freely available to the public (https://yuanxiaofang.shinyapps.io/Predict_cognitive_impairment_in_TBI/).

Interpretation

This model for predicting post-TBI cognitive impairment has potential value for facilitating early predictions by clinicians, aiding the early initiation of preventative interventions for cognitive impairment.

Funding

This research was supported by Science and Technology Development Plan Project of ChangZhou (CJ20229036); Science and Technology Project of Changzhou Health Commission (QN202113).

Cortical lesions and focal white matter injury are associated with attentional performance in chronic traumatic brain injury

Cognitive impairment, often due to attentional deficits, is a primary driver of disability after traumatic brain injury. It remains unclear whether attentional deficits are caused by injury to specific brain structures or the total burden of injury. In this cross-sectional, multicentre cohort study, we tested whether the association between brain injury and attentional performance varies by neuroanatomic location. Participants in the late effects of traumatic brain injury study were at least 18 years old and at least 1 year after a mild, moderate or severe traumatic brain injury. They underwent MRI and neuropsychological assessment at one of two sites. The primary and secondary outcomes, each measuring aspects of attentional performance, were the Trails A t-score and the standardized score on California Verbal Learning Test 2 Immediate Recall Trial 1. Imaging variables included the size and location (seven regions and seven networks) of encephalomalacic brain lesions and regional white matter fractional anisotropy measured with diffusion MRI (14 regions). We used ANOVA to test whether attentional performance differed by lesion location and linear mixed models to test whether attentional performance differed based on regional fractional anisotropy. One hundred eighty-eight participants met inclusion criteria (mean age 57, 69% male, 88% White). Participants with encephalomalacic brain lesions [N = 73 (39%)] had worse Trails A [mean (95% confidence interval) difference: 4.7 (0.3, 9.1); P = 0.036] but not secondary outcome performance [-0.3 (-0.1, 0.7); P = 0.17]. Among participants with lesions, Trails A performance did not differ by lesion size (P = 0.07) or location (P = 0.41 by region; P = 0.78 by network). We identified a significant interaction between regional fractional anisotropy and attentional performance on both primary (P = 0.001) and secondary (P = 0.001) outcome measures. Post hoc testing identified the strongest associations with Trails A performance in the sagittal stratum [1 SD decrement in Trails A: -0.2 (-0.3, -0.1) SD change in fractional anisotropy; P Bonferroni = 0.0057] and external capsule [-0.1 (-0.2, -0.1); P Bonferroni = 0.042] and the strongest association with secondary attentional scores in the corpus callosum [0.2 (0.1, 0.3); P Bonferroni = 0.014]. In a multivariate model, white matter integrity in the sagittal stratum (P = 0.008), but not encephalomalacic lesions (P = 0.3), was independently associated with Trails A performance. Diminished white matter integrity and cortical injury were each associated with attentional test performance, but only white matter injury demonstrated independent and region-specific effects. The peak statistical association with attentional test performance was in the sagittal stratum, a widely connected white matter region. Further investigation into the connections spanning this and nearby regions may reveal therapeutic targets for neuromodulation.

White matter damage and degeneration in traumatic brain injury

Traumatic brain injury (TBI) is a complex condition that can resolve over time but all too often leads to persistent symptoms, and the risk of poor patient outcomes increases with aging. TBI damages neurons and long axons within white matter tracts that are critical for communication between brain regions; this causes slowed information processing and neuronal circuit dysfunction. This review focuses on white matter injury after TBI and the multifactorial processes that underlie white matter damage, potential for recovery, and progression of degeneration. A multiscale perspective across clinical and preclinical advances is presented to encourage interdisciplinary insights from whole-brain neuroimaging of white matter tracts down to cellular and molecular responses of axons, myelin, and glial cells within white matter tissue.

Neuroimaging and Clinical Findings in Healthy Middle-Aged Adults With Mild Traumatic Brain Injury in the PREVENT Dementia Study

Importance

Traumatic brain injuries (TBI) represent an important, potentially modifiable risk factor for dementia. Despite frequently observed vascular imaging changes in individuals with TBI, the relationships between TBI-associated changes in brain imaging and clinical outcomes have largely been overlooked in community cases of TBI.

Objective

To assess whether TBI are associated with and interact with midlife changes in neuroimaging and clinical features in otherwise healthy individuals.

Design, Setting, and Participants

This cross-sectional analysis used baseline data from the PREVENT Dementia program collected across 5 sites in the UK and Ireland between 2014 and 2020. Eligible participants were cognitively healthy midlife adults aged between 40 and 59 years. Data were analyzed between January 2023 and April 2024.

Exposure

Lifetime TBI history was assessed using the Brain Injury Screening Questionnaire.

Main Outcomes and Measures

Cerebral microbleeds and other markers of cerebral small vessel disease (white matter hyperintensities [WMH], lacunes, perivascular spaces) were assessed on 3T magnetic resonance imaging. Clinical measures were cognition, sleep, depression, gait, and cardiovascular disease (CVD) risk, assessed using Computerized Assessment of Information Processing (COGNITO), Pittsburgh Sleep Quality Index, Center for Epidemiologic Studies Depression Scale, clinical interviews, and the Framingham Risk Score, respectively.

Results

Of 617 participants (median [IQR] age, 52 [47-56] years; 380 female [61.6%]), 223 (36.1%) had a history of TBI. TBI was associated with higher microbleed count (β = 0.10; 95% CI, 0.01-0.18; P = .03), with a dose-response association observed with increasing number of TBI events (β = 0.05; 95% CI, 0.01-0.09; P = .03). Conversely, TBI was not associated with other measures of small vessel disease, including WMH. Furthermore, TBI moderated microbleed associations with vascular risk factors and clinical outcomes, such that associations were present only in the absence of TBI. Importantly, observations held when analyses were restricted to individuals reporting only mild TBI.

Conclusions and Relevance

In this cross-sectional study of healthy middle-aged adults, detectable changes in brain imaging and clinical features were associated with remote, even mild, TBI in the general population. The potential contribution of vascular injury to TBI-related neurodegeneration presents promising avenues to identify potential targets, with findings highlighting the need to reduce TBI through early intervention and prevention in both clinical care and policymaking.

New insights into metabolism dysregulation after TBI

Traumatic brain injury (TBI) remains a leading cause of death and disability that places a great physical, social, and financial burden on individuals and the health system. In this review, we summarize new research into the metabolic changes described in clinical TBI trials, some of which have already shown promise for informing injury classification and staging. We focus our discussion on derangements in glucose metabolism, cell respiration/mitochondrial function and changes to ketone and lipid metabolism/oxidation to emphasize potentially novel biomarkers for clinical outcome prediction and intervention and offer new insights into possible underlying mechanisms from preclinical research of TBI pathology. Finally, we discuss nutrition supplementation studies that aim to harness the gut/microbiome-brain connection and manipulate systemic/cellular metabolism to improve post-TBI recovery. Taken together, this narrative review summarizes published TBI-associated changes in glucose and lipid metabolism, highlighting potential metabolite biomarkers for clinical use, the cellular processes linking these markers to TBI pathology as well as the limitations and future considerations for TBI "omics" work.

Recall and recognition of similarities items in neuropsychological assessment: Memory, validity, and meaning

The current study examined whether the Memory Similarities Extended Test (M-SET), a memory test based on the Similarities subtest of the Wechsler Abbreviated Scale of Intelligence, Second Edition (WASI-II), has value in neuropsychological testing. The relationship of M-SET measures of cued recall (CR) and recognition memory (REC) to brain injury severity and memory scores from the Wechsler Memory Scale, Fourth Edition (WMS-IV) was analyzed in examinees with traumatic brain injuries ranging from mild to severe. Examinees who passed standard validity tests were divided into groups with intracranial injury (CT + ve, n = 18) and without intracranial injury (CT-ve, n = 50). In CT + ve only, CR was significantly correlated with Logical Memory I (LMI: rs = .62) and Logical Memory II (LMII: rs = .65). In both groups, there were smaller correlations with delayed visual memory (VRII: rs = .38; rs = .44) and psychomotor speed (Coding: rs = .29; rs = .29). The REC score was neither an indicator of memory ability nor an internal indicator of performance validity. There were no differences in M-SET or WMS-IV scores for CT-ve and CT + ve, and reasons for this are discussed. It is concluded that M-SET has utility as an incidental cued recall measure.