The Mayo Classification System for Traumatic Brain Injury Severity

Disrupted flexible use of context-dependent relational memory in adults following moderate-severe traumatic brain injury

Learning associative information and extracting regularities from that remembered information to adaptively meet goals is a hallmark of navigating life. Adaptive goal-directive behavior has been historically attributed to prefrontal functions, and more recently to hippocampal relational memory. Disruptions in either of these systems, both frequently seen in Traumatic Brain Injury (TBI), have far reaching consequences in everyday life. In the current study, we investigate the impact of chronic, moderate-to-severe TBI on both relational memory processes as well as the ability to use regularities or rules extracted from that remembered information to guide behavior via both overt responses and eye-tracking. Individuals with and without TBI completed a context-dependent relational memory task designed to assess both 1) the formation and organization of overlapping relational associations (hippocampal-dependent); and 2) the acquisition and flexible use of learned, context-dependent rules (ventromedial prefrontal-dependent). Behavioral measures revealed that relative to neurotypical matched comparison participants, participants with TBI were significantly impaired on context-dependent relational memory measures, but showed spared memory guided rule-use. Eye-tracking data indicated largely intact information gathering at study for participants with TBI, but impaired flexibility at test leading to poor behavioral outcomes. Critically, these data suggest that relational memory impairment is a significant source of behavioral dysfunction in TBI, which likely contributes to poor outcomes in both laboratory testing and real-life, long-term trajectories following injury. Furthermore, this study highlights the feasibility and strength of incorporating eye-tracking into studies of TBI to gain novel insights into information gathering and use across time.

A meta-analytic review examining the validity of executive functioning tests to predict functional outcomes in individuals with a traumatic brain injury

OBJECTIVES

Deficits in executive functioning are a common consequence of Traumatic Brain Injury (TBI) and the severity of TBI is known to predict functional outcomes. In this review, the authors examine the ability of three commonly used tests of executive functioning [The Trail Making Test (TMT-B), The Wisconsin Card Sorting Test (WCST), and Verbal Fluency (VF)] to predict domains of function.

METHODS

Seven hundred and twenty articles were identified and twenty-four met inclusion criteria (original articles published in English examining an adult TBI population). Data were subject to a study quality analysis and then meta-analyzed to assess whether tests of executive functioning (TMT-B, WCST, and VF) can predict functional, employment, and driving outcomes following a TBI.

RESULTS

The TMT-B (r = 0.29; 95% CI 0.17-0.41) and the WCST (r = 0.20; 95% CI 0.02-0.37) were significantly associated with functional outcomes. The TMT-B was also associated with a person's ability to return to driving (r = 0.3890; 95% CI 0.2678-0.5103). No test of executive functioning was associated with employment outcomes following a TBI.

CONCLUSION

These findings are important to guide rehabilitation strategies and future planning. This review has also highlighted the scarcity of research on specific outcomes.

Lasting Impact: Exploring the Brain Mechanisms that Link Traumatic Brain Injury to Parkinson's Disease

Development of Parkinson's Disease (PD) is linked with a history of traumatic brain injury (TBI), although the mechanisms driving this remain unclear. Of note, many key parallels have been identified between the pathologies of PD and TBI; in particular, PD is characterised by loss of dopaminergic neurons from the substantia nigra (SN), accompanied by broader changes to dopaminergic signalling, disruption of the Locus Coeruleus (LC) and noradrenergic system, and accumulation of aggregated α-synuclein in Lewy Bodies, which spreads in a stereotypical pattern throughout the brain. Widespread disruptions to the dopaminergic and noradrenergic systems, including progressive neuronal loss from the SN and LC, have been observed acutely following injury, some of which have also been identified chronically in TBI patients and preclinical models. Furthermore, changes to α-synuclein expression are also seen both acutely and chronically following injury throughout the brain, although detailed characterisation of these changes and spread of pathology is limited. In this review, we detail the current literature regarding dopaminergic and noradrenergic disruption and α-synuclein pathology following injury, with particular focus on how these changes may predispose individuals to prolonged pathology and progressive neurodegeneration, particularly the development of PD. While it is increasingly clear that TBI is a key risk factor for the development of PD, significant gaps remain in current understanding of neurodegenerative pathology following TBI, particularly chronic manifestations of injury.

Prevalence and clinical significance of sensory changes after moderate-severe traumatic brain injury: A cross-sectional study

BACKGROUND

Sensory changes are commonly observed in individuals with moderate-severe traumatic brain injury (msTBI) but remain under-researched.

OBJECTIVES

This study examined the prevalence of sensory changes after msTBI and relationships with emotional distress, functional disability, and life satisfaction.

METHODS

A cross-sectional survey was conducted including 387 participants with msTBI (mean years post-injury, 12.8; range = 0.4-35.0 years) and 60 controls, not matched on age and sex but recruited in the same period. Self-reported sensory symptoms were assessed using a custom checklist and the Somatic Symptom Scale-8 (SSS-8). Emotional distress, functional disability, and life satisfaction were measured through the Hospital Anxiety and Depression Scale (HADS), 12-Item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0), and Satisfaction With Life Scale (SWLS). We compared the frequency of sensory symptoms between groups and examined associations with demographics, injury factors, and clinical outcomes within the msTBI sample.

RESULTS

70% with msTBI reported experiencing ≥1 sensory changes due to their brain injury, and 35% reported experiencing dizziness in the previous week, averaging 2.2 symptoms in total, which was significantly higher than controls after adjusting for age and sex. Sensory changes were more common in younger participants (light hypersensitivity), females (light and noise hypersensitivity), those with more severe TBI (overall sensory changes, affected vision, reduced smell), and those fewer years post-injury (overall sensory changes, noise hypersensitivity, reduced smell, altered taste, dizziness), though many of these associations did not survive multiple comparison correction. Sensory changes were clearly and consistently associated with worse clinical outcomes, with medium-large effect sizes for emotional distress and functional disability and smaller effects for life satisfaction.

CONCLUSIONS

Although causality cannot be established, these findings suggest that sensory changes are a clinically significant issue after msTBI, even among individuals more than a decade post-injury on average. This underscores the need for routine assessment and further research on underlying mechanisms and interventions.

Neuron-Derived Extracellular Vesicles: Emerging Regulators in Central Nervous System Disease Progression

The diagnosis and exploration of central nervous system (CNS) diseases remain challenging due to the blood-brain barrier (BBB), complex signaling pathways, and heterogeneous clinical manifestations. Neurons, as the core functional units of the CNS, play a pivotal role in CNS disease progression. Extracellular vesicles (EVs), capable of crossing the BBB, facilitate intercellular and cell-extracellular matrix (ECM) communication, making neuron-derived extracellular vesicles (NDEVs) a focal point of research. Recent studies reveal that NDEVs, carrying various bioactive substances, can exert either pathogenic or protective effects in numerous CNS diseases. Additionally, NDEVs show significant potential as biomarkers for CNS diseases. This review summarizes the emerging roles of NDEVs in CNS diseases, including Alzheimer's disease, depression, traumatic brain injury, schizophrenia, ischemic stroke, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. It aims to provide a novel perspective on developing therapeutic and diagnostic strategies for CNS diseases through the study of NDEVs.

Blood-Based Protein Biomarkers in the Chronic Phase of Traumatic Brain Injury: A Systematic Review

There has been limited exploration of blood-based biomarkers in the chronic period following traumatic brain injury (TBI). Our objective was to conduct a systematic review of studies examining blood-based protein biomarkers with at least one sample collected 12 months post-TBI in adults (≥16 years). Database searches were conducted in Embase, MEDLINE, and Science Citation Index-Expanded on July 24, 2023. Risk of bias was assessed using modified Joanna Briggs Institute critical appraisal tools. Only 30 of 12,523 articles met inclusion criteria, with samples drawn from 12 months to 48 years. Higher quality evidence (low risk of bias; large samples) identified promising inflammatory biomarkers at 12 months post-injury in both moderate-severe TBI (GFAP) and mild TBI (eotaxin-1, IFN-y, IL-8, IL-9, IL-17A, MCP-1, MIP-1β, FGF-basic, and TNF-α). Studies with low risk of bias but smaller samples also suggest NSE, MME, and CRP may be informative, alongside protein variants for α-syn (10H, D5), amyloid-β (A4, C6T), TDP-43 (AD-TDP 1;2;3;9;11), and tau (D11C). Findings for NfL were inconclusive. Longitudinal data were mostly available for acute samples followed until 12 months post-injury, with limited evaluation of changes beyond 12 months. Associations of some blood-based biomarkers with cognitive, sleep, and functional outcomes were reported. The overall strength of the evidence in this review was limited by the risk of bias and small sample sizes. Replication is required within prospective longitudinal studies that move beyond 12 months post-injury. Novel efforts should be guided by promising neurodegenerative-disease markers and use panels to model polypathology.

Exploring Demographic and Cognitive Predictors of Self-Management in Quasi-Randomized Fall Prevention Intervention for Older Adults With and Without Traumatic Brain Injury

OBJECTIVE

Changes in health behavior are key to maintaining health, safety, and independence of older adults. The purpose of this study was to explore factors impacting training in self-management and behavior change in older adults with and without traumatic brain injury (TBI), informing efforts to improve safety and independent function.

METHODS

Forty-one older adults, 19 with TBI, completed a self-regulation intervention (mental contrasting with implementation intentions; MCII) to promote fall prevention behavior change. Participant outcomes were related to single and recurring behavior changes; implementation outcomes were measured as modifications to treatment.

RESULTS

Although participants with TBI performed more poorly on tests of neurocognitive function, there were no differences in behavior change rates following MCII, suggesting the treatment worked similarly for participants with and without TBI. Across both groups, those with higher executive function scores were more likely to complete recurring behavior changes. Participants with higher stress, higher Fall Risk Scores, or history of TBI were more likely to need modifications to treatment.

CONCLUSIONS

This quasi-experimental pilot study describes cognitive and psychosocial predictors that may be critical for participation and success in health behavior change and self-management of fall prevention for older adults with and without TBI.

Neuropsychological review of records in forensic cases: An AACN best practices paper with international perspectives

Objective: The purpose of this American Academy of Clinical Neuropsychology (AACN) best practices paper is to provide the neuropsychological community with the fundamentals of a competent forensic review of records. Method: Narrative review addressing fundamental factors related to review of records. Examples highlighted information necessary for a forensic determination of traumatic brain injury (TBI), and the data from records that can be used to address questions regarding validity of presentation. International and intra-jurisdictional perspectives within the US were used to illustrate the necessity of adhering the review to the rules. Results: Factors identified involve ethical responsibilities, completeness in obtaining and reviewing relevant records, evaluation of credibility of the records, considerations regarding examinee self-reporting, grounding of opinions within peer-reviewed science, determination of causation in the context of litigation, and avoiding bias in reporting, as well as consideration of cultural and language factors. Different jurisdictional rules require close attention. Conclusions: Neuropsychologists need to be aware of the need for a competent review of records to obtain basic facts, maintain objectivity, and provide a context for conclusions in a neuropsychological examination report. In litigation cases, opinions based solely on review of records may be challenged for reasons that might include not having personally evaluated the plaintiff, and whether opinions meet Daubert criteria pertaining to sufficient scientific bases and facts. A thorough review in the context of examination helps deal with litigant/claimant subjectivity and malleability of self-report, and it can provide critical reasoning about other factors relevant to causation.

Retinal manifestations of traumatic brain injury

Retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) thinning occur weeks to months after traumatic brain injury (TBI), even without computed tomography (CT) findings. The patterns of RNFL and GCL loss and their relationship to TBI severity and CT findings have not been characterised. This observational study included consecutive patients assessed in hospital after TBI. All patients underwent OCT. A literature review was conducted to determine the test-retest variability of RNFL and GCL measurements. Of 135 included patients, 62 had follow up OCTs. The test-retest limit of agreement for global RNFL thickness was 4 µm. Two patients had symptomatic traumatic optic neuropathy, 17 had less severe RNFL thinning on follow up, six RNFL thickening and 31 no RNFL changes. Higher TBI severity, Marshall CT classification and lower time to first OCT after injury strongly associated with subsequent RNFL changes (p < 0.001 for all). Global RNFL thickness in patients with initial OCT < 42 days after injury declined by 1.74 µm/month with Marshall II CT findings, compared 0.05 µm/month with Marshall I, and 3.69 µm/month after severe TBI, versus 1.47 µm/month after mild. Subclinical OCT changes therefore occur after TBI, and may contribute to future multimodal TBI diagnostic and severity assessments.

Ageing with Traumatic Brain Injury: Long-Term Cognition and Wellbeing

Whether and how traumatic brain injury (TBI) impacts ageing in the decades post-injury remains a matter of debate, partly due to a lack of controlled studies. This study examined the long-term impact of TBI on cognition and wellbeing in middle-aged and older adults and explored the relationship between age, cognition, and wellbeing, compared with a non-TBI control group. Cross-sectional data from 143 participants aged ≥40 with moderate-severe TBI (6-33 years post-injury; mean age 59.64) were compared with 71 non-TBI controls (mean age 62.10) group matched on age, gender, and premorbid IQ. Individuals with significant confounding comorbidities were excluded. A battery of neuropsychological tests and wellbeing measures (emotional distress, sleep, health-related quality of life [HRQoL]) was administered. Older age and TBI were each independently associated with poorer cognition across multiple domains (p < 0.05). The relationship between verbal learning and memory impairment post-TBI differed between age groups: individuals with TBI in their 40s-60s performed significantly worse than same-aged controls on verbal story acquisition (B = 0.09, p = 0.040, 95% confidence interval [CI] [0.004, 0.17]) and recall (B = 0.12, p = 0.009, 95% CI [0.03, 0.21]), and verbal wordlist recall (B = 0.11, p = 0.007, 95% CI [0.03, 0.19]). In comparison, no significant group differences in verbal memory emerged for ages 70-90. The TBI group reported greater emotional distress (B = 3.55, p < 0.001, 95% CI [1.73, 5.37]), poorer sleep quality (B = 1.07, p = 0.016, 95% CI [0.20, 1.94]), and poorer physical HRQoL (B = -4.26, p = 0.003, 95% CI [-7.08, -1.43]) than controls at all ages. Poorer physical HRQoL was related to poorer cognition post-TBI (p < 0.05). Our results challenge the notion that TBI exacerbates ageing. Moderate-severe TBI resulted in significant long-term impairments in cognition and wellbeing, with verbal learning and memory more impaired during middle-adulthood but not older adulthood compared to controls. TBI was not associated with changes to wellbeing with ageing. Intervention for verbal memory deficits in middle-aged adults with TBI is important, along with wider long-term supports for cognition, wellbeing, and activity participation in all individuals with TBI.

Methylphenidate differentially alters corticostriatal connectivity after traumatic brain injury

Traumatic brain injury commonly impairs attention and executive function and disrupts the large-scale brain networks that support these cognitive functions. Abnormalities of functional connectivity are seen in corticostriatal networks, which are associated with executive dysfunction and damage to neuromodulatory catecholaminergic systems caused by head injury. Methylphenidate, a stimulant medication that increases extracellular dopamine and noradrenaline, can improve cognitive function following traumatic brain injury. In this experimental medicine add-on study to a randomized, double-blind, placebo-controlled clinical trial, we test whether administration of methylphenidate alters corticostriatal network function and influences drug response. Forty-three moderate-severe traumatic brain injury patients received 0.3 mg/kg of methylphenidate or placebo twice a day in 2-week blocks. Twenty-eight patients were included in the neuropsychological and functional imaging analysis (four females, mean age 40.9 ± 12.7 years, range 20-65 years) and underwent functional MRI and neuropsychological assessment after each block. 123I-Ioflupane single-photon emission computed tomography dopamine transporter scans were performed, and specific binding ratios were extracted from caudate subdivisions. Functional connectivity and the relationship to cognition were compared between drug and placebo conditions. Methylphenidate increased caudate to anterior cingulate cortex functional connectivity compared with placebo and decreased connectivity from the caudate to the default mode network. Connectivity within the default mode network was also decreased by methylphenidate administration, and there was a significant relationship between caudate functional connectivity and dopamine transporter binding during methylphenidate administration. Methylphenidate significantly improved executive function in traumatic brain injury patients, and this was associated with alterations in the relationship between executive function and right anterior caudate functional connectivity. Functional connectivity is strengthened to brain regions, including the anterior cingulate, that are activated when attention is focused externally. These results show that methylphenidate alters caudate interactions with cortical brain networks involved in executive control. In contrast, caudate functional connectivity reduces to default mode network regions involved in internally focused attention and that deactivate during tasks that require externally focused attention. These results suggest that the beneficial cognitive effects of methylphenidate might be mediated through its impact on the caudate. Methylphenidate differentially influences how the caudate interacts with large-scale functional brain networks that exhibit co-ordinated but distinct patterns of activity required for attentionally demanding tasks.

A Transdiagnostic, Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI)

Psychopathology, including depression, anxiety, and post-traumatic stress, is a significant yet inadequately addressed feature of moderate-severe traumatic brain injury (TBI). Progress in understanding and treating post-TBI psychopathology may be hindered by limitations associated with conventional diagnostic approaches, specifically the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD). The Hierarchical Taxonomy of Psychopathology (HiTOP) offers a promising, transdiagnostic alternative to psychiatric classification that may more effectively capture the experiences of individuals with TBI. However, HiTOP lacks validation in the TBI population. To address this gap, we administered a comprehensive questionnaire battery, including 56 scales assessing homogeneous symptom components and maladaptive traits within HiTOP, to 410 individuals with moderate-severe TBI. We evaluated the reliability and unidimensionality of each scale and revised those with psychometric problems. Using a top-down, exploratory latent variable approach (bass-ackwards modeling), we subsequently constructed a hierarchical model of psychopathological dimensions tailored to TBI. The results showed that, relative to norms, participants with moderate-severe TBI experienced greater problems in the established HiTOP internalizing and detachment spectra, but fewer problems with thought disorder and antagonism. Fourteen of the 56 scales demonstrated psychometric problems, which often appeared reflective of the TBI experience and associated disability. The Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI) model encompassed broad internalizing and externalizing spectra, splitting into seven narrower dimensions: Detachment, Dysregulated Negative Emotionality, Somatic Symptoms, Compensatory and Phobic Reactions, Self-Harm and Psychoticism, Rigid Constraint, and Harmful Substance Use. This study presents the most comprehensive empirical classification of psychopathology after TBI to date. It introduces a novel, TBI-specific transdiagnostic questionnaire battery and model, which addresses the limitations of conventional DSM and ICD diagnoses. The empirical structure of psychopathology after TBI largely aligned with the established HiTOP model (e.g., a detachment spectrum). However, these constructs need to be interpreted in relation to the unique experiences associated with TBI (e.g., considering the injury's impact on the person's social functioning). By overcoming the limitations of conventional diagnostic approaches, the HiTOP-TBI model has the potential to accelerate our understanding of the causes, correlates, consequences, and treatment of psychopathology after TBI.

Current and prospective roles of magnetic resonance imaging in mild traumatic brain injury

There is unmet clinical need for biomarkers to predict recovery or the development of long-term sequelae of mild traumatic brain injury, a highly prevalent condition causing a constellation of disabling symptoms. A substantial proportion of patients live with long-lasting sequelae affecting their quality of life and ability to work. At present, symptoms can be assessed through clinical tests; however, there are no imaging or laboratory tests fully reflective of pathophysiology routinely used by clinicians to characterize post-concussive symptoms. Magnetic resonance imaging has potential to link subtle pathophysiological alterations to clinical outcomes. Here, we review the state of the art of MRI research in adults with mild traumatic brain injury and provide recommendations to facilitate transition into clinical practice. Studies utilizing MRI can inform on pathophysiology of mild traumatic brain injury. They suggest presence of early cytotoxic and vasogenic oedema. They also show that mild traumatic brain injury results in cellular injury and microbleeds affecting the integrity of myelin and white matter tracts, all processes that appear to induce delayed vascular reactions and functional changes. Crucially, correlates between MRI parameters and post-concussive symptoms are emerging. Clinical sequences such as T1-weighted MRI, susceptibility-weighted MRI or fluid attenuation inversion recovery could be easily implementable in clinical practice, but are not sufficient, in isolation for prognostication. Diffusion sequences have shown promises and, although in need of analysis standardization, are a research priority. Lastly, arterial spin labelling is emerging as a high-utility research as it could become useful to assess delayed neurovascular response and possible long-term symptoms.

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 Gut Microbiome: The Role of the Gut-Brain Axis in Neurodegenerative Processes

PURPOSE OF REVIEW

A deeper understanding of the communication network between the gut microbiome and the central nervous system, termed the gut-brain axis (GBA), has revealed new potential targets for intervention to prevent the development of neurodegenerative disease associated with tramatic brain injury (TBI). This review aims to comprehensively examine the role of GBA post-traumatic brain injury (TBI).

RECENT FINDINGS

The GBA functions through neural, metabolic, immune, and endocrine systems, creating bidirectional signaling pathways that modulate brain and gastrointestinal (GI) tract physiology. TBI perturbs these signaling pathways, producing pathophysiological feedback loops in the GBA leading to dysbiosis (i.e., a perturbed gut microbiome, impaired brain-blood barrier, impaired intestinal epithelial barrier (i.e., "leaky gut"), and a maladaptive, systemic inflammatory response. Damage to the CNS associated with TBI leads to GI dysmotility, which promotes small intestinal bacterial overgrowth (SIBO). SIBO has been associated with the early stages of neurodegenerative conditions such as Parkinson's and Alzheimer's disease. Many of the bacteria associated with this overgrowth promote inflammation and, in rodent models, have been shown to compromise the structural integrity of the intestinal mucosal barrier, causing malabsorption of essential nutrients and further exacerbating dysbiosis. TBI-induced pathophysiology is strongly associated with an increased risk of neurodegenerative diseases, including Parkinson's and Alzheimer's diseases, which represents a significant public health burden and challenge for patients and their families. A healthy gut microbiome has been shown to promote improved recovery from TBI and prevent the development of neurodegenerative disease, as well as other chronic complications. The role of the gut microbiome in brain health post-TBI demonstrates the potential for microbiome-targeted interventions to mitigate TBI-associated comorbidities. Promising new evidence on prebiotics, probiotics, diet, and fecal microbiota transplantation may lead to new therapeutic options for improving the quality of life for patients with TBI. Still, many of these preliminary findings must be explored further in clinical settings. This review covers the current understanding of the GBA in the setting of TBI and how the gut microbiome may provide a novel therapeutic target for treatment in this patient population.

High-dimensional proteomic analysis for pathophysiological classification of traumatic brain injury

Pathophysiology and outcomes after traumatic brain injury (TBI) are complex and heterogeneous. Current classifications are uninformative about pathophysiology. Proteomic approaches with fluid-based biomarkers are ideal for exploring complex disease mechanisms, because they enable sensitive assessment of an expansive range of processes potentially relevant to TBI pathophysiology. We used novel high-dimensional, multiplex proteomic assays to assess altered plasma protein expression in acute TBI. We analysed samples from 88 participants from the BIO-AX-TBI cohort [n = 38 moderate-severe TBI (Mayo Criteria), n = 22 non-TBI trauma and n = 28 non-injured controls] on two platforms: Alamar NULISA™ CNS Diseases and OLINK® Target 96 Inflammation. Patient participants were enrolled after hospital admission, and samples were taken at a single time point ≤10 days post-injury. Participants also had neurofilament light, GFAP, total tau, UCH-L1 (all Simoa®) and S100B (Millipore) data. The Alamar panel assesses 120 proteins, most of which were previously unexplored in TBI, plus proteins with known TBI specificity, such as GFAP. A subset (n = 29 TBI and n = 24 non-injured controls) also had subacute (10 days to 6 weeks post-injury) 3 T MRI measures of lesion volume and white matter injury (fractional anisotropy). Differential expression analysis identified 16 proteins with TBI-specific significantly different plasma expression. These were neuronal markers (calbindin 2, UCH-L1 and visinin-like protein 1), astroglial markers (S100B and GFAP), neurodegenerative disease proteins (total tau, pTau231, PSEN1, amyloid-beta-42 and 14-3-3γ), inflammatory cytokines (IL16, CCL2 and ficolin 2) and cell signalling- (SFRP1), cell metabolism- (MDH1) and autophagy-related (sequestome 1) proteins. Acute plasma levels of UCH-L1, PSEN1, total tau and pTau231 were correlated with subacute lesion volume. Sequestome 1 was positively correlated with white matter fractional anisotropy, whereas CCL2 was inversely correlated. Neuronal, astroglial, tau and neurodegenerative proteins were correlated with each other, IL16, MDH1 and sequestome 1. Exploratory clustering (k means) by acute protein expression identified three TBI subgroups that differed in injury patterns, but not in age or outcome. One TBI cluster had significantly lower white matter fractional anisotropy than control-predominant clusters but had significantly lower lesion subacute lesion volumes than another TBI cluster. Proteins that overlapped on two platforms had excellent (r > 0.8) correlations between values. We identified TBI-specific changes in acute plasma levels of proteins involved in neurodegenerative disease, inflammatory and cellular processes. These changes were related to patterns of injury, thus demonstrating that processes previously studied only in animal models are also relevant in human TBI pathophysiology. Our study highlights how proteomic approaches might improve classification and understanding of TBI pathophysiology, with implications for prognostication and treatment development.

Does Variation in Hospital Density and Social Deprivation Across Small Geographic Areas Play a Role in Perceived Barriers to Care Among People With Traumatic Brain Injury?

OBJECTIVE

To examine the role of area-level variables (hospital density and social deprivation) in the experience of health care access and quality among individuals with traumatic brain injury.

SETTING

Online questionnaire of community dwelling individuals Participants: 300 individuals with a history of traumatic brain injury with loss of consciousness.

DESIGN

Cross-sectional observational survey.

MAIN MEASURES

Barriers to Care Questionnaire, Social Deprivation Index, Hospital Density.

RESULTS

In an unadjusted regression model, less social deprivation and higher hospital density were associated with better perceived health care access and quality. After adjusting for personal factors of race, ethnicity, age, injury severity, food insecurity, and housing insecurity, the effect of social deprivation was fully attenuated whereas the effect of hospital density on health care access and quality remained significant. A model containing only the personal factors demonstrated reduced health care access and quality among individuals identifying as Hispanic. However, this effect was non-significant with the inclusion of the area-level contextual factors in a fully adjusted model.

CONCLUSIONS

Higher area-level hospital density is associated with a reduction in perceived barriers to care among individuals with TBI. In addition, contextual, area-level data accounted for the reduced health care access and quality among Hispanic participants. Area-level data can provide explanatory value in the study of health disparities for people with TBI from underrepresented racial and ethnic groups.

Precipitating Factors for Functional Cognitive Disorder

BACKGROUND

The underlying mechanisms of functional cognitive disorder (FCD) are still poorly understood. This hinders diagnostic identification and establishment of personalised and effective treatments. We aimed to describe the precipitating factors for new-onset FCD and explore differences between the acute and gradual onset FCD groups.

METHODS

Retrospective analysis of a consecutive sample of FCD patients seen in three dedicated clinics in the United Kingdom between September 2023 and March 2024. Only patients with at least one-year symptom duration were included. We extracted mode of onset and precipitating factors, demographics, comorbidities, family history of cognitive symptoms, personal exposure to dementia, symptom duration and trajectory, as well as cognitive testing when available.

RESULTS

Ninety-three patients were included, of which 45 had an acute onset of functional cognitive symptoms (48% of total). Of the acute onset group, 51% were female; mean age of symptom onset was 44 years (± 12). In the acute onset group, COVID-19 (n = 18, 40%), head injury (n = 16, 36%) and migraine (n = 16, 36%) were the most common precipitating factors for symptom onset, followed by cardiovascular/vasovagal events, dissociative episodes, panic, medication change, medical procedure under sedation and acute vertigo. The acute onset group was younger, most commonly had a fluctuating course of symptoms, and more headache and fatigue than the gradual onset group.

CONCLUSIONS

Functional cognitive disorder often begins acutely. The circumstances around onset may have treatment and prognostic implications. Similar to other functional disorders, the experience of abnormal cognition from an acute pathophysiological event can act as powerful precipitating factors for functional cognitive disorder.

Time restricted feeding alters the behavioural and physiological outcomes to repeated mild traumatic brain injury in male and female rats

Mild traumatic brain injury (mTBI) research has had limited success translating treatments from preclinical models to clinical application for concussion. One major factor that has been overlooked is the near 24-hour availability of food, both for experimental nocturnal rodents and patients suffering from mTBI. Here, we characterised the impact of food restriction limited to either the inactive (day) or the active phase (night), on repetitive mTBI (RmTBI) - induced outcomes in male and female rats. We found that active phase fed rats consumed more food, had increased body weight, and reduced brain weights. Behaviourally, active phase feeding increased motor coordination deficits and caused changes to thermal nociceptive processing following RmTBI. Hypothalamic transcriptomic analysis revealed minor changes in response to RmTBI, and genes associated with oxytocin-vasopressin regulation in response to inactive phase, but not active phase feeding. These transcript changes were absent in females, where the overall effect of RmTBI was minor. Prefrontal cortex lipidomics revealed an increase in sphingomyelin synthesis following injury and marked sex differences in response to feeding. Of the lipids that changed and overlapped between the prefrontal cortex and serum, dihydroceramides, sphingomyelins, and hexosylceramides, were higher in the serum but lower in the prefrontal cortex. Together, these results demonstrate that feeding time alters outcomes to RmTBI, independent of the hypothalamic transcriptome, and injury-specific lipids may serve as useful biomarkers in RmTBI diagnosis.

What are the views of those participating in a trial investigating acute post-traumatic benign paroxysmal positional vertigo? A qualitative study

OBJECTIVE

The purpose of this study was to explore the experiences of patients and healthcare professionals participating in a randomized feasibility trial exploring the management of acute post-traumatic benign paroxysmal positional vertigo (BPPV), and to establish the acceptability and tolerability of BPPV assessment and treatment procedures.

METHODS

This was a multi-center qualitative study nested within a wider randomized feasibility trial. Purposive sampling was used to gather a cohort of healthcare professionals and patients from three major trauma centres in London, UK. Data were gathered using semi-structured interviews and were analyzed using Framework analysis.

RESULTS

Fifteen healthcare professionals and 26 patients participated. Patients and healthcare professionals reported acute BPPV diagnosis was acceptable and practicable. However, divergence was noted regarding views of randomization. Participants proposed several research delivery and protocol modifications for a future trial, including changes to study design and outcome measures.

CONCLUSIONS

Healthcare professionals and patients participating in a multi-center qualitative study felt post-traumatic BPPV was feasible and acceptable to diagnose and treat acutely. Findings from this study will enhance the content and delivery of a future trial and may assist in influencing the development of clinical practice guidelines.

Traumatic Brain Injury and Risk of Incident Dementia: Forensic Applications of Current Research

OBJECTIVE

Traumatic Brain Injury (TBI) has been identified as a risk factor for later developing neurodegenerative disorders, and there has been significant attention on this association in forensic settings. As a result, forensic neuropsychologists are frequently asked to comment on risk for dementia after an alleged TBI in litigation and criminal cases. This article provides an evidence-based foundation to aid forensic practice by synthesizing comprehensive information pertaining to: (i) the role of the neuropsychologist in TBI-related litigation, (ii) the complexities associated with identifying TBIs in forensic cases, (iii) the science of TBI in relation to incident dementia, and (iv) current scientific evidence for chronic traumatic encephalopathy.

RESULTS

Developing a neurodegenerative disorder after TBI is the exception rather than the rule. Prevalence rates suggest that only a small subset (< 5%) of individuals with moderate-to-severe TBI, and even fewer (< 1%) with mild TBI (mTBI), appear to develop certain neurodegenerative diseases, and the characteristics that place some at risk remain unclear. The literature is mixed in terms of identifying a relationship between mTBI and later-in-life dementia risk. Also, the quality of positive evidence for risk of dementia after mTBI is weak and mostly consists of observational studies characterized by methodological limitations.

CONCLUSIONS

Methods used to establish the likely occurrence of a TBI in a forensic context are typically more extensive than those used in a routine clinical evaluation. Research methodology to define TBI is often even more rudimentary and inconsistent. Applying clinical research results of TBI and dementia outcomes to forensic cases at an individual level carries significant limitations. Estimating the contribution of remote head hits or concussion in a causal manner to dementia is a challenge forensic experts sometimes face, yet at present, the task is impossible beyond correlations and speculation.

Poor long-term outcomes and abnormal neurodegeneration biomarkers after military traumatic brain injury: the ADVANCE study

BACKGROUND

Traumatic brain injury (TBI) is common in military campaigns and is a risk factor for dementia. ArmeD SerVices TrAuma and RehabilitatioN OutComE-TBI (ADVANCE-TBI) aims to ascertain neurological outcomes in UK military personnel with major battlefield trauma, leveraging advances in quantification of axonal breakdown markers like neurofilament light (NfL), and astroglial marker glial fibrillar acidic protein (GFAP) in blood. We aimed to describe the causes, prevalence and consequences of TBI, and its fluid biomarker associations.

METHODS

TBI history was ascertained in 1145 servicemen and veterans, of whom 579 had been exposed to major trauma. Functional and mental health assessments were administered, and blood samples were collected approximately 8 years postinjury, with plasma biomarkers quantified (n=1125) for NfL, GFAP, total tau, phospho-tau181, amyloid-β 42 and 40. Outcomes were related to neurotrauma exposure.

RESULTS

TBI was present in 16.9% (n=98) of exposed participants, with 46.9% classified as mild-probable and 53.1% classified as moderate to severe. Depression (β=1.65, 95% CI (1.33 to 2.03)), anxiety (β=1.65 (1.34 to 2.03)) and post-traumatic stress disorder (β=1.30 (1.19 to 1.41)) symptoms were more common after TBI, alongside poorer 6 minute walk distance (β=0.79 (0.74 to 0.84)) and quality of life (β=1.27 (1.19 to 1.36), all p<0.001). Plasma GFAP was 11% (95% CI 2 to 21) higher post-TBI (p=0.013), with greater concentrations in moderate-to-severe injuries (47% higher than mild-probable (95% CI 20% to 82%, p<0.001). Unemployment was more common among those with elevated GFAP levels post-TBI, showing a 1.14-fold increase (95% CI 1.03 to 1.27, p<0.001) for every doubling in GFAP concentration.

CONCLUSIONS

TBI affected nearly a fifth of trauma-exposed personnel, related to worse mental health, motor and functional outcomes, as well as elevated plasma GFAP levels 8 years post-injury. This was absent after extracranial trauma, and showed a dose-response relationship with the severity of the injury.

Balance recovery and its link to vestibular agnosia in traumatic brain injury: a longitudinal behavioural and neuro-imaging study

BACKGROUND

Vestibular dysfunction causing imbalance affects c. 80% of acute hospitalized traumatic brain injury (TBI) cases. Poor balance recovery is linked to worse return-to-work rates and reduced longevity. We previously showed that white matter network disruption, particularly of right inferior longitudinal fasciculus, mediates the overlap between imbalance and impaired vestibular perception of self-motion (i.e., vestibular agnosia) in acute hospitalized TBI. However, there are no prior reports tracking the acute-longitudinal trajectory of objectively measured vestibular function for hospitalized TBI patients. We hypothesized that recovery of vestibular agnosia and imbalance is linked and mediated by overlapping brain networks.

METHODS

We screened 918 acute major trauma in-patients, assessed 146, recruited 39 acutely, and retested 34 at 6 months. Inclusion criteria were 18-65-year-old adults hospitalized for TBI with laboratory-confirmed preserved peripheral vestibular function. Benign paroxysmal positional vertigo and migraine were treated prior to testing. Vestibular agnosia was quantified by participants' ability to perceive whole-body yaw plane rotations via an automated rotating-chair algorithm. Subjective symptoms of imbalance (via questionnaires) and objective imbalance (via posturography) were also assessed.

RESULTS

Acute vestibular agnosia predicted poor balance recovery at 6 months. Recovery of vestibular agnosia and linked imbalance was mediated by bihemispheric fronto-posterior cortical circuits. Recovery of subjective symptoms of imbalance and objective imbalance were not correlated.

CONCLUSION

Vestibular agnosia mediates balance recovery post-TBI. The link between subjective dizziness and brain injury recovery, although important, is unclear. Therapeutic trials of vestibular recovery post-TBI should target enhancing bi-hemispheric connectivity and linked objective clinical measures (e.g., posturography).

Naming Ability in the Chronic Phase of Moderate-Severe Traumatic Brain Injury

INTRODUCTION

Naming difficulties are commonly reported in the acute and subacute stages of recovery of traumatic brain injury (TBI) and across severity levels. Previous studies, however, have used samples of mixed chronicity (acute and chronic) and severity (mild and severe) and then aggregated data across individuals from these distinct groups. Thus, we have little knowledge about the persistence of naming difficulties into the chronic stage of recovery in individuals with moderate-severe TBI.

PURPOSE

To increase the rigor and reproducibility of naming research in TBI, the present study sought to determine the presence and profile of naming disruptions into the chronic stage of moderate-severe TBI using a confrontation naming assessment.

METHOD

Thirty-three individuals aged 24-55 years in the chronic epoch of moderate-severe TBI and 33 demographically matched noninjured comparison (NC) participants completed the Philadelphia Naming Test (PNT). A mixed-effects logistic regression model predicting the probability of a correct response as a function of group was fit to the data.

RESULTS

Participants with TBI performed well on the PNT (all participants with TBI had over 90% accuracy). However, participants with TBI were statistically less likely to correctly name an item relative to demographically matched NC participants.

CONCLUSIONS

This study provides empirical evidence that naming difficulties persist into the chronic epoch of moderate-severe TBI. Despite high accuracy on the PNT, nearly 60% of these individuals with TBI reported continued difficulty with word finding in their daily lives. This discrepancy leaves open the possibility that, at this stage of injury, word-finding issues may be more reliably evoked and studied when the assessment is embedded within cognitively demanding and ecologically valid contexts (i.e., discourse, conversation). Further investigation of naming deficits in chronic moderate-severe TBI using a more naturalistic assessment is warranted.

Impact of early swallowing rehabilitation on oral feeding in patients with dysphagia following traumatic brain injury

OBJECTIVE

This study aimed to evaluate the effects of early swallowing rehabilitation on safe oral feeding in dysphagia patients following traumatic brain injury.

METHODS

Sixty-nine patients were divided into intervention and control groups, with the intervention group receiving swallowing rehabilitation therapy. The severity of swallowing disorders, cognitive function, and level of consciousness were assessed using the Mann Assessment of Swallowing Ability (MASA), Rancho Los Amigos (RLA), and Glasgow Coma Scale (GCS) before and after the intervention. Additionally, data on ventilator use duration and hospital stay length were collected.

RESULT

The intervention group exhibited a significant improvement in MASA scores (68.58) compared to the control group (38.10). No significant differences were observed in GCS and RLA scores post-intervention, indicating similar levels of consciousness and cognitive function between groups. While the duration of ventilator use was comparable, the intervention group achieved safe oral swallowing 12.12 days earlier than the control group.

DISCUSSION

The findings demonstrate that early swallowing rehabilitation significantly enhances recovery dysphagia post-brain injury, as evidenced by improved MASA scores and earlier achievement of safe oral feeding, despite no notable changes in cognition or consciousness. This underscores the importance of implementing early rehabilitation strategies in clinical practice.

Unraveling the complexity of microglial responses in traumatic brain and spinal cord injury

Microglia, the resident innate immune cells of the central nervous system (CNS), play an important role in neuroimmune signaling, neuroprotection, and neuroinflammation. In the healthy CNS, microglia adopt a surveillant and antiinflammatory phenotype characterized by a ramified scanning morphology that maintains CNS homeostasis. In response to acquired insults, such as traumatic brain injury (TBI) or spinal cord injury (SCI), microglia undergo a dramatic morphologic and functional switch to that of a reactive state. This microglial switch is initially protective and supports the return of the injured tissue to a physiologic homeostatic state. However, there is now a significant body of evidence that both TBI and SCI can result in a chronic state of microglial activation, which contributes to neurodegeneration and impairments in long-term neurologic outcomes in humans and animal models. In this review, we discuss the complex role of microglia in the pathophysiology of TBI and SCI, and recent advancements in knowledge of microglial phenotypic states in the injured CNS. Furthermore, we highlight novel therapeutic strategies targeting chronic microglial responses in experimental models and discuss how they may ultimately be translated to the clinic for human brain and SCI.

Evidence of Peripheral Vestibular Impairment Among Adults With Chronic Moderate-Severe Traumatic Brain Injury

PURPOSE

Traumatic brain injury (TBI) is a leading cause of death and disability among adults in the United States. There is evidence to suggest the peripheral vestibular system is vulnerable to damage in individuals with TBI. However, there are limited prospective studies that describe the type and frequency of vestibular impairment in individuals with chronic moderate-severe TBI (> 6 months postinjury).

METHOD

Cervical and ocular vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) were used to assess the function of otolith organ and horizontal semicircular canal (hSCC) pathways in adults with chronic moderate-severe TBI and in noninjured comparison (NC) participants. Self-report questionnaires were administered to participants with TBI to determine prevalence of vestibular symptoms and quality of life associated with those symptoms.

RESULTS

Chronic moderate-severe TBI was associated with a greater degree of impairment in otolith organ, rather than hSCC, pathways. About 63% of participants with TBI had abnormal VEMP responses, compared to only ~10% with abnormal vHIT responses. The NC group had significantly less abnormal VEMP responses (~7%), while none of the NC participants had abnormal vHIT responses. As many as 80% of participants with TBI reported vestibular symptoms, and up to 36% reported that these symptoms negatively affected their quality of life.

CONCLUSIONS

Adults with TBI reported vestibular symptoms and decreased quality of life related to those symptoms and had objective evidence of peripheral vestibular impairment. Vestibular testing for adults with chronic TBI who report persistent dizziness and imbalance may serve as a guide for treatment and rehabilitation in these individuals.

SIFT IT: A feasibility and preliminary efficacy randomized controlled trial of a social cognition group treatment programme for people with acquired brain injury

Making sense of social situations requires social cognitive skills, which can be impaired after acquired brain injury (ABI), yet few evidence-based treatment options are available. This study aimed to evaluate the feasibility of a multi-faceted social cognition group treatment programme, SIFT IT, for people after ABI using an RCT design. Twenty-eight participants were recruited, and 23 were randomized into either Treatment or Waitlist. SIFT IT consisted of 14 weekly 90-minute small group sessions facilitated by a Clinical Psychologist. Topics included: emotion self-awareness, emotion perception, perspective taking, and choosing adaptive social responses. Preliminary efficacy outcomes were assessed at baseline, post-treatment, and three-month follow-up. Demand for treatment was evident with 61% recruitment and 91% post-treatment retention rates, with 63% attending at least 13/14 sessions. Large between-group treatment effects (with non-zero 95% confidence intervals) were observed for emotion perception, detecting hints, and informant ratings of social cognitive deficits. Implementation challenges recruiting to groups and maintaining group allocation fidelity, with a small sample size does, however, raise questions about the appropriateness of an RCT design in a future efficacy trial. Overall, this study showed there is demand for social cognitive interventions after ABI and the SIFT IT programme was practicable and acceptable to participants.Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12617000405314.

An Ecological Momentary Assessment and Intervention Tool for Memory in Chronic Traumatic Brain Injury: Development and Usability of Memory Ecological Momentary Intervention

Background

Memory and learning deficits are among the most impactful and longest-lasting symptoms experienced by people with chronic traumatic brain injury (TBI). Despite the persistence of post-TBI memory deficits and their implications for community reintegration, memory rehabilitation is restricted to short-term care within structured therapy sessions. Technology shows promise to extend memory rehabilitation into daily life and to increase the number and contextual diversity of learning opportunities. Ecological momentary assessment and intervention frameworks leverage mobile phone technology to assess and support individuals' behaviors across contexts and have shown benefits in other chronic conditions. However, few studies have used regular outreach via text messaging for adults with chronic TBI, and none have done so to assess and support memory.

Objective

This study aimed to develop and test the usability of memory ecological momentary intervention (MEMI), a text message-based assessment and intervention tool for memory in daily life. MEMI is designed to introduce new information, cue retrieval of the information, and assess learning across time and contexts. We tested MEMI via an iterative, user-centered design process to ready it for a future trial.

Methods

We developed MEMI by leveraging automated text messages for prompts using a REDCap (Research Electronic Data Capture)/Twilio interface linking to the Gorilla web-based behavioral experimental platform. We recruited 14 adults with chronic, moderate-severe TBI from the Vanderbilt Brain Injury Patient Registry to participate in 3 rounds of usability testing: one round of ThinkAloud sessions using the platform and providing real-time feedback to an experimenter (n=4) and 2 rounds of real-world usability testing in which participants used MEMI in their daily lives for a week and provided feedback (n=5/round). We analyzed engagement and quantitative and qualitative user feedback to assess MEMI's usability and acceptability.

Results

Participants were highly engaged with MEMI, completing an average of 11.8 out of 12 (98%) possible sessions. They rated MEMI as highly usable, with scores on the System Usability Scale across all rounds equivalent to an A+ on a standardized scale. In semistructured interviews, they stated that MEMI was simple and easy to use, that daily retrieval sessions were not burdensome, and that they perceived MEMI as helpful for memory. We identified a few small issues (eg, instruction wording) and made improvements between usability testing rounds.

Conclusions

Testing MEMI with adults with chronic TBI revealed that this technology is highly usable and favorably rated for this population. We incorporated feedback regarding users' preferences and plan to test the efficacy of this tool in a future clinical trial.

Brain-based correlates of depression and traumatic brain injury: a systematic review of structural and functional magnetic resonance imaging studies

Introduction

Depression is prevalent after traumatic brain injury (TBI). However, there is a lack of understanding of the brain-based correlates of depression post-TBI. This systematic review aimed to synthesize findings of structural and functional magnetic resonance imaging (MRI) studies to identify consistently reported neural correlates of depression post-TBI.

Methods

A search for relevant published studies was conducted through OVID (MEDLINE, APA PsycINFO, and Embase), with an end date of August 3rd, 2023. Fourteen published studies were included in this review.

Results

TBI patients with depression exhibited distinct changes in diffusion- based white matter fractional anisotropy, with the direction of change depending on the acuteness or chronicity of TBI. Decreased functional connectivity (FC) of the salience and default mode networks was prominent alongside the decreased volume of gray matter within the insular, dorsomedial prefrontal, and ventromedial prefrontal cortices. Seven studies reported the correlation between observed neuroimaging and depression outcomes. Of these studies, 42% indicated that FC of the bilateral medial temporal lobe subregions was correlated with depression outcomes in TBI.

Discussion

This systematic review summarizes existing neuroimaging evidence and reports brain regions that can be leveraged as potential treatment targets in future studies examining depression post-TBI.

Plasma biomarkers in chronic single moderate-severe traumatic brain injury

Blood biomarkers are an emerging diagnostic and prognostic tool that reflect a range of neuropathological processes following traumatic brain injury (TBI). Their effectiveness in identifying long-term neuropathological processes after TBI is unclear. Studying biomarkers in the chronic phase is vital because elevated levels in TBI might result from distinct neuropathological mechanisms during acute and chronic phases. Here, we examine plasma biomarkers in the chronic period following TBI and their association with amyloid and tau PET, white matter microarchitecture, brain age and cognition. We recruited participants ≥40 years of age who had suffered a single moderate-severe TBI ≥10 years previously between January 2018 and March 2021. We measured plasma biomarkers using single molecule array technology [ubiquitin C-terminal hydrolase L1 (UCH-L1), neurofilament light (NfL), tau, glial fibrillary acidic protein (GFAP) and phosphorylated tau (P-tau181)]; PET tracers to measure amyloid-β (18F-NAV4694) and tau neurofibrillary tangles (18F-MK6240); MRI to assess white matter microstructure and brain age; and the Rey Auditory Verbal Learning Test to measure verbal-episodic memory. A total of 90 post-TBI participants (73% male; mean = 58.2 years) were recruited on average 22 years (range = 10-33 years) post-injury, and 32 non-TBI control participants (66% male; mean = 57.9 years) were recruited. Plasma UCH-L1 levels were 67% higher {exp(b) = 1.67, P = 0.018, adjusted P = 0.044, 95% confidence interval (CI) [10% to 155%], area under the curve = 0.616} and P-tau181 were 27% higher {exp(b) = 1.24, P = 0.011, adjusted P = 0.044, 95% CI [5% to 46%], area under the curve = 0.632} in TBI participants compared with controls. Amyloid and tau PET were not elevated in TBI participants. Higher concentrations of plasma P-tau181, UCH-L1, GFAP and NfL were significantly associated with worse white matter microstructure but not brain age in TBI participants. For TBI participants, poorer verbal-episodic memory was associated with higher concentration of P-tau181 {short delay: b = -2.17, SE = 1.06, P = 0.043, 95% CI [-4.28, -0.07]; long delay: bP-tau = -2.56, SE = 1.08, P = 0.020, 95% CI [-4.71, -0.41]}, tau {immediate memory: bTau = -6.22, SE = 2.47, P = 0.014, 95% CI [-11.14, -1.30]} and UCH-L1 {immediate memory: bUCH-L1 = -2.14, SE = 1.07, P = 0.048, 95% CI [-4.26, -0.01]}, but was not associated with functional outcome. Elevated plasma markers related to neuronal damage and accumulation of phosphorylated tau suggest the presence of ongoing neuropathology in the chronic phase following a single moderate-severe TBI. Plasma biomarkers were associated with measures of microstructural brain disruption on MRI and disordered cognition, further highlighting their utility as potential objective tools to monitor evolving neuropathology post-TBI.

Heart Rate Variability and Cerebral Autoregulation in Patients with Traumatic Brain Injury with Paroxysmal Sympathetic Hyperactivity Syndrome

BACKGROUND

Severe traumatic brain injury (TBI) can lead to transient changes in autonomic nervous system (ANS) functioning and development of paroxysmal sympathetic hyperactivity (PSH) syndrome. Clinical manifestation of ANS disorders may be obscured by therapeutic interventions in TBI. This study aims to analyze ANS metrics and cerebral autoregulation in patients with PSH syndrome to determine their significance in early prognostication.

METHODS

This single-center retrospective study investigated the relationship between changes in ANS metrics, cerebral autoregulation, and PSH syndrome. Arterial blood pressure and intracranial pressure signals were monitored for 5 days post TBI. ANS metrics included time and frequency domain heart rate variability (HRV) metrics. Cerebral autoregulation was assessed using the pressure reactivity index.

RESULTS

Sixty-six patients with severe TBI (median age 33 [interquartile range 26-50] years) were analyzed, and PSH was confirmed in nine cases. Impairment of cerebral autoregulation was observed in 67% of patients with PSH and 72% without the syndrome. Patients with PSH had higher HRV in the low-frequency range (LF; 253 ± 178 vs. 176 ± 227 ms2; p = 0.035) and lower heart rates (HRs; 70 ± 7 vs. 78 ± 19 bpm; p = 0.027) compared to those without PSH. A receiver operating characteristic curve analysis indicated that HR (area under the curve (AUC) = 0.73, p = 0.006) and HRV in the LF (AUC = 0.70, p = 0.009) are moderate predictors of PSH. In the multiple logistic regression model for PSH, diffuse axonal trauma (odds ratio (OR) = 10.82, 95% confidence interval (CI) = 1.70-68.98, p = 0.012) and HR (OR = 0.91, 95%  CI 0.84-0.98, p = 0.021) were significant factors.

CONCLUSIONS

Elevated HRV in the LF and decreased HR may serve as early predictors of PSH syndrome development, particularly in patients with diffuse axonal trauma. Further research is needed to investigate the utility of the cerebral autoregulation-ANS relationship in PSH prognostication.

Reduced on-line speech gesture integration during multimodal language processing in adults with moderate-severe traumatic brain injury: Evidence from eye-tracking

BACKGROUND

Language is multimodal and situated in rich visual contexts. Language is also incremental, unfolding moment-to-moment in real time, yet few studies have examined how spoken language interacts with gesture and visual context during multimodal language processing. Gesture is a rich communication cue that is integrally related to speech and often depicts concrete referents from the visual world. Using eye-tracking in an adapted visual world paradigm, we examined how participants with and without moderate-severe traumatic brain injury (TBI) use gesture to resolve temporary referential ambiguity.

METHODS

Participants viewed a screen with four objects and one video. The speaker in the video produced sentences (e.g., "The girl will eat the very good sandwich"), paired with either a meaningful gesture (e.g., sandwich-holding gesture) or a meaningless grooming movement (e.g., arm scratch) at the verb "will eat." We measured participants' gaze to the target object (e.g., sandwich), a semantic competitor (e.g., apple), and two unrelated distractors (e.g., piano, guitar) during the critical window between movement onset in the gesture modality and onset of the spoken referent in speech.

RESULTS

Both participants with and without TBI were more likely to fixate the target when the speaker produced a gesture compared to a grooming movement; however, relative to non-injured participants, the effect was significantly attenuated in the TBI group.

DISCUSSION

We demonstrated evidence of reduced speech-gesture integration in participants with TBI relative to non-injured peers. This study advances our understanding of the communicative abilities of adults with TBI and could lead to a more mechanistic account of the communication difficulties adults with TBI experience in rich communication contexts that require the processing and integration of multiple co-occurring cues. This work has the potential to increase the ecological validity of language assessment and provide insights into the cognitive and neural mechanisms that support multimodal language processing.

Temporary ambiguity and memory for the context of spoken language in adults with moderate-severe traumatic brain injury

Language is processed incrementally, with addressees considering multiple candidate interpretations as speech unfolds, supporting the retention of these candidate interpretations in memory. For example, after interpreting the utterance, "Click on the striped bag", listeners exhibit better memory for non-mentioned items in the context that were temporarily consistent with what was said (e.g., dotted bag), vs. not consistent (e.g., dotted tie), reflecting the encoding of linguistic context in memory. Here, we examine the impact of moderate-severe traumatic brain injury (TBI) on memory for the contexts of language use. Participants with moderate-severe TBI (N=71) and non-injured comparison participants (NC, N=85) interpreted temporarily ambiguous utterances in rich contexts. A subsequent memory test demonstrated that participants with TBI exhibited impaired memory for context items and an attenuated memory advantage for mentioned items compared to NC participants. Nonetheless, participants with TBI showed similar, although attenuated, patterns in memory for temporarily-activated items as NC participants.

Cardiorespiratory fitness and working memory in persons with traumatic brain injury: a cross-sectional analysis

INTRODUCTION

Cognitive impairment is a highly impactful consequence of traumatic brain injury (TBI) and there are limited evidence-based treatment practices to combat these impairments. Evidence from other populations suggest that aerobic exercise training (AET) is beneficial for a variety of cognitive deficits, but the research in persons with TBI to date is equivocal. One potential reason is the heterogeneity of exercise prescriptions and outcome measures. This stems from the fact that studies have not been designed based on previous data supporting a specific AET prescription to target a cognitive domain. The primary purpose of this cross-sectional analysis was to examine the relationship between cardiorespiratory fitness (CRF), as a cross-sectional surrogate of AET, and cognition in persons with TBI to inform future research.

METHODS

Cross-sectional analysis was conducted on baseline data of persons with TBI who completed neuropsychological assessments to evaluate several cognitive domains and a cardiopulmonary exercise test (CPET) to measure CRF. Based on the normal distribution of an outcome, Pearson's r or Spearman's ρ was calculated to measure the relationship between CRF and cognition.

RESULTS

Data were analyzed for all participants who demonstrated valid CPETs (n = 21 of 29). Based on the cycle ergometer-based norms of CRF, males in this sample were in the 69th percentile and females in this sample were in the 56th percentile, with high variability across individuals. Higher CRF, as measured by peak power output (Wpeak), was significantly associated with greater working memory (ρ = 0.465, p = 0.017), even after post-hoc corrections.

CONCLUSIONS

These data suggest average and highly variable CRF in persons with TBI of all severity and support cycle ergometry-based CPET testing in this population. Further, these data provide support for future research applying AET to target working memory and possibly other executive functions in persons with TBI. This research is a small step toward large-scale randomized controlled trials that can directly impact clinical care to treat cognitive symptoms post-TBI.

Health literacy after traumatic brain injury: characterisation and control comparison

Background Little is known about health literacy in traumatic brain injury (TBI) survivors. The aims of this study were to compare health literacy in individuals with TBI with that of a control group; to examine the association between health literacy in individuals with TBI and demographic, injury, and cognitive factors; and compare the relationship between health literacy and physical and mental health outcomes. Methods A cross-sectional observational study design was used. Adults (≥18years) were recruited from an outpatient research centre in Victoria, Australia. There were 209 participants with a complicated mild to severe TBI at least 1year previously (up to 30years 6months) and 206 control participants. Results Individuals with TBI did not have poorer health literacy than controls (IRR=1.31, P =0.102, CI95% [0.947, 1.812]). Further analysis could not be completed due to the highly skewed Health Literacy Assessment Using Talking Touchscreen Technology - Short Form (Health LiTT-SF) data. Conclusion Health literacy performance in individuals with TBI was not significantly different to controls. Premorbid education may provide a critical cognitive reserve upon which TBI survivors can draw to aid their health literacy. These findings are specific to the Health LiTT-SF measure only and require replication using more comprehensive health literacy measures in culturally diverse samples.

Experiences with home monitoring technology in older adults with traumatic brain injury: a qualitative study

BACKGROUND

Home monitoring systems utilising artificial intelligence hold promise for digitally enhanced healthcare in older adults. Their real-world use will depend on acceptability to the end user i.e. older adults and caregivers. We explored the experiences of adults over the age of 60 and their social and care networks with a home monitoring system installed on hospital discharge after sustaining a moderate/severe Traumatic Brain Injury (TBI), a growing public health concern.

METHODS

A qualitative descriptive approach was taken to explore experiential data from older adults and their caregivers as part of a feasibility study. Semi-structured interviews were conducted with 6 patients and 6 caregivers (N = 12) at 6-month study exit. Data were analysed using Framework analysis. Potential factors affecting acceptability and barriers and facilitators to the use of home monitoring in clinical care and research were examined.

RESULTS

Home monitoring was acceptable to older adults with TBI and their caregivers. Facilitators to the use of home monitoring were perceived need for greater support after hospital discharge, the absence of sound and video recording, and the peace of mind provided to care providers. Potential barriers to adoption were reliability, lack of confidence in technology and uncertainty at how data would be acted upon to improve safety at home.

CONCLUSIONS

Remote monitoring approaches are likely to be acceptable, especially if patients and caregivers see direct benefit to their care. We identified key barriers and facilitators to the use of home monitoring in older adults who had sustained TBI, which can inform the development of home monitoring for research and clinical use. For sustained use in this demographic the technology should be developed in conjunction with older adults and their social and care networks.

Disinhibition, rather than moderate-to-severe traumatic brain injury, moderates the impact of anger provocation on subjective emotional experience

OBJECTIVE

Altered reactivity to emotional stimuli is common after traumatic brain injury (TBI), which is suggested to reflect difficulties with emotion regulation. While disinhibition is common after moderate-to-severe TBI, limited research has investigated the link between disinhibition and emotional reactivity in this clinical group. The aim of this research, therefore, was to investigate the relationship between disinhibition and TBI to anger provocation.

METHOD

Thirty-five individuals with moderate-to-severe TBI and thirty-one controls completed an anger induction task. Participants rated their experience of emotions and subjective arousal before and after the induction. Heart rate, respiration and skin conductance were also measured. Disinhibition was measured using the Frontal Systems Behavior Scale.

RESULTS

In the full sample, the mood induction led to increased skin conductance, respiration, and self-reported anger, tension, arousal and negative mood. There were no differences between those with TBI and controls. Disinhibition interacted with the impact of anger provocation on subjective, but not objective, outcomes such that those elevated in disinhibition reported increased feelings of anger and tension in response to the mood induction. Disinhibition did not interact with TBI across any subjective and objective emotional measures examined in response to mood induction.

CONCLUSIONS

While anger causes emotional changes for all individuals, these changes are particularly pronounced among those who are disinhibited, irrespective of whether an individual has sustained a TBI. This is an important consideration when examining emotional regulation post-TBI as the degree of disinhibition appears to alter subjective interpretations of emotional events, which could lead to emotion dysregulation.

Exposure to Adverse Childhood Experiences Predicts Increased Neurobehavioral Symptom Reporting in Adults with Mild Traumatic Brain Injury

The objective of this study was to understand whether exposure to adverse childhood experiences (ACEs) before 18 years of age predicts increased neurobehavioral symptom reporting in adults presenting for treatment secondary to persistent symptoms after mild traumatic brain injury (mTBI). This cross-sectional study identified 78 individuals with mTBI from 2014 to 2018 presenting for treatment to an outpatient multidisciplinary rehabilitation clinic. Neurobehavioral symptom inventory (NSI-22) scores were collected on admission, and ACEs for each patient were abstracted by medical record review. A linear regression model was used to assess if an individual who experienced at least one ACE before age 18 resulted in significantly different neurobehavioral scores compared with those not reporting any history of an ACE before age 18. Participants who reported at least one ACE before age 18 had significantly increased NSI-22 scores on admission to the rehabilitation clinic compared with patients without history of ACEs (mean difference 10.1, p = 0.011), adjusted for age and gender. For individuals presenting for treatment after mTBI, a history of ACEs before age 18 was associated with increased neurobehavioral symptoms.

Comprehension of Miranda warnings in adults with chronic, moderate-severe traumatic brain injury

INTRODUCTION

To compare comprehension of Miranda rights in adults with traumatic brain injury (TBI) versus adults without TBI as measured by response accuracy on the Miranda Right Comprehension Instruments.

METHODS

Data were collected virtually via teleconferencing from July 2022 to February 2023. Participants included 25 adults with moderate-severe TBI (12 females, 13 males) and 25 adults without TBI (12 females, 13 males), ages 20-55 years. In this observational study, both groups (with and without TBI) completed the Miranda Right Comprehension Instruments (MRCI), which includes four instruments including Comprehension of Miranda Rights, Comprehension of Miranda Rights-Recognition, Function of Rights in Interrogation, Comprehension of Miranda Vocabulary instruments. Response accuracy on the MRCI was compared across groups.

RESULTS

The TBI group was significantly less accurate when responding to questions on the MRCI compared to the NC group.

CONCLUSION

Individuals with chronic moderate-severe TBI underperform their non-injured peers on the Miranda Rights Comprehension Instruments, a tool used in legal settings when there is doubt about an individual's understanding of their Miranda rights. TBI is a risk factor for disruptions in comprehension of language in legal contexts that may, in part, contribute to the increased interaction with the criminal justice system and incarceration for individuals with TBI. Implications for policy, advocating, and intervention are discussed.

Simultaneous arterial spin labeling functional MRI and fluorodeoxyglucose PET in mild chronic traumatic brain injury

BACKGROUND AND PURPOSE

To determine the effect of mild chronic traumatic brain injury (cTBI) on cerebral blood flow and metabolism.

METHODS

62 cTBI and 40 healthy controls (HCs) with no prior history of cTBI underwent both pulsed arterial spin labeling functional magnetic resonance imaging (PASL-fMRI) and fluorodeoxyglucose positron emission tomography (FDG-PET) scanning via a Siemens mMR (simultaneous PET/MRI) scanner. 30 participants also took part in a series of neuropsychological clinical measures (NCMs). Images were processed using statistical parametric mapping software relevant to each modality to generate relative cerebral blood flow (rCBF) and glucose metabolic standardized uptake value ratio (gSUVR) grey matter maps. A voxel-wise two-sample T-test and two-tailed gaussian random field correction for multiple comparisons was performed.

RESULTS

cTBI patients showed a significant increase in rCBF and gSUVR in the right thalamus as well as a decrease in bilateral occipital lobes and calcarine sulci. An inverse relationship between rCBF and gSUVR was found in the left frontal lobe, the left precuneus and regions in the right temporal lobe. Within those regions rCBF values correlated with 9 distinct NCMs and gSUVR with 3.

CONCLUSION

Simultaneous PASL-fMRI and FDG-PET can identify functional changes in a mild cTBI population. Within this population FDG-PET identified more regions of functional disturbance than ASL fMRI and NCMs are shown to correlate with rCBF and glucose metabolism (gSUVR) in various brain regions. As a result, both imaging modalities contribute to understanding the underlying pathophysiology and clinical course of mild chronic traumatic brain injury.

A Pilot Study of Saliva MicroRNA Signatures in Children with Moderate-to-Severe Traumatic Brain Injury

Background/Objectives: Traumatic brain injury (TBI) is a leading cause of death and disability in children. Currently, no biological test can predict outcomes in pediatric TBI, complicating medical management. This study sought to identify brain-related micro-ribosomal nucleic acids (miRNAs) in saliva associated with moderate-to-severe TBI in children, offering a potential non-invasive, prognostic tool. Methods: A case-control design was used, enrolling participants ≤ 18 years old from three pediatric trauma centers. Participants were divided into moderate-to-severe TBI and non-TBI trauma control groups. Saliva samples were collected within 24 h of injury, with additional samples at 24-48 h and >48 h post-injury from the TBI group. miRNA profiles were visualized with partial least squares discriminant analysis (PLSDA) and hierarchical clustering. Mann-Whitney testing was used to compare miRNAs between groups, and mixed models were used to assess longitudinal expression patterns. DIANA miRPath v3.0 was used to interrogate the physiological functions of miRNAs. Results: Twenty-three participants were enrolled (14 TBI, nine controls). TBI and control groups displayed complete separation of miRNA profiles on PLSDA. Three miRNAs were elevated (adj. p < 0.05) in TBI (miR-1255b-5p, miR-3142, and miR-4320), and two were lower (miR-326 and miR-4646-5p). Three miRNAs (miR-3907, miR-4254, and miR-1273g-5p) showed temporal changes post-injury. Brain-related targets of these miRNAs included the glutamatergic synapse and GRIN2B. Conclusions: This study shows that saliva miRNA profiles in children with moderate-to-severe TBI may differ from those with non-TBI trauma and exhibit temporal changes post-injury. These miRNAs could serve as non-invasive biomarkers for prognosticating pediatric TBI outcomes. Further studies are needed to confirm these findings.

Association of early dexmedetomidine exposure with brain injury biomarker levels following moderate - Severe traumatic brain injury: A TRACK-TBI study

BACKGROUND

Traumatic brain injury (TBI) triggers autonomic dysfunction and inflammatory response that can result in secondary brain injuries. Dexmedetomidine is an alpha-2 agonist that may modulate autonomic function and inflammation and has been increasingly used as a sedative agent for critically ill TBI patients. We aimed to investigate the association between early dexmedetomidine exposure and blood-based biomarker levels in moderate-to-severe TBI (msTBI).

METHODS

We conducted a retrospective cohort study using data from the Transforming Clinical Research and Knowledge in Traumatic Brain Injury Study (TRACK-TBI), which enrolled acute TBI patients prospectively across 18 United States Level 1 trauma centers between 2014-2018. Our study population focused on adults with msTBI defined by Glasgow Coma Scale score 3-12 after resuscitation, who required mechanical ventilation and sedation within the first 48 h of ICU admission. The study's exposure was early dexmedetomidine utilization (within the first 48 h of admission). Primary outcome included brain injury biomarker levels measured from circulating blood on day 3 following injury, including glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neuron-specific enolase (NSE), S100 calcium-binding protein B (S100B) and the inflammatory biomarker C-reactive protein (CRP). Secondary outcomes assessed biomarker levels on days 5 and 14. Linear mixed-effects regression modelling of the log-transformed response variable was used to analyze the association of early dexmedetomidine exposure with brain injury biomarker levels.

RESULTS

Among the 352 TRACK-TBI subjects that met inclusion criteria, 50 (14.2 %) were exposed to early dexmedetomidine, predominantly male (78 %), white (81 %), and non-Hispanic (81 %), with mean age of 39.8 years. Motor vehicle collisions (27 %) and falls (22 %) were common causes of injury. No significant associations were found between early dexmedetomidine exposure with day 3 brain injury biomarker levels (GFAP, ratio = 1.46, 95 % confidence interval [0.90, 2.34], P = 0.12; UCH-L1; ratio = 1.17 [0.89, 1.53], P = 0.26; NSE, ratio = 1.19 [0.92, 1.53], P = 0.19; S100B, ratio = 1.01 [0.95, 1.06], P = 0.82; hs-CRP, ratio = 1.29 [0.91, 1.83], P = 0.15). The hs-CRP level at day 14 in the dexmedetomidine group was higher than that of the non-exposure group (ratio = 1.62 [1.12, 2.35], P = 0.012).

CONCLUSIONS

There were no significant associations between early dexmedetomidine exposure and day 3 brain injury biomarkers in msTBI. Our findings suggest that early dexmedetomidine use is not correlated with either decrease or increase in brain injury biomarkers following msTBI. Further research is necessary to confirm these findings.

Traumatic optic neuropathy management: a systematic review

BACKGROUND

Traumatic optic neuropathy is classically described in up to 8% of patients with traumatic brain injury (TBI), but subclinical or undiagnosed optic nerve damage is much more common. When more sensitive testing is performed, at least half of patients with moderate to severe TBI demonstrate visual field defects or optic atrophy on examination with optical coherence tomography. Acute optic nerve compression and ischaemia in orbital compartment syndrome require urgent surgical and medical intervention to lower the intraocular pressure and diminish the risk of permanent optic nerve dysfunction. Other manifestations of traumatic optic neuropathy have more variable treatments in international practice.

METHODS

We conducted a systematic review of traumatic optic neuropathy treatments in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement.

RESULTS

We included three randomised controlled trials of intravenous methylprednisolone (IVMP), erythropoietin, and levodopa-carbidopa combination, with no evidence of benefit for any treatment. In addition, large studies in TBI have found strong evidence of increased mortality in patients treated with megadose IVMP.

CONCLUSIONS

There is therefore no evidence of benefit for any medical treatment and strong evidence of harm from IVMP. There is also no evidence of benefit for optic canal decompression for traumatic optic neuropathy. Orbital compartment syndrome is a separate entity that requires both medical and surgical interventions to prevent visual loss.

Memory for Conversation in Traumatic Brain Injury: A Feasibility Study and Preliminary Findings

PURPOSE

Despite common clinical complaints about memory for conversation after traumatic brain injury (TBI), the nature and severity of this deficit are unknown. In this research note, we report feasibility and preliminary data from a new conversation memory study protocol.

METHOD

Participants in this feasibility study were 10 pairs, each including an adult with chronic, moderate-to-severe TBI and their chosen familiar conversation partner. The experiment began with a naturalistic conversation between participants with TBI and their conversation partners. After a filled delay, participants next completed verbal recall for the conversation, which we transcribed and coded for their accuracy relative to the original conversation. Participants also read chosen statements from their original conversation and predicted what each partner would remember in a week. One week later, participants completed a posttest about who said each of the chosen statements, allowing direct comparison to their predictions.

RESULTS

We successfully collected conversation memory data from all 10 pairs, suggesting that this protocol is feasible for future study. In this preliminary sample, people with TBI and their conversation partners did not differ in the accuracy of their recall for the conversation about 20 min after it occurred. When asked to predict their partner's delayed memory, conversation partners were less accurate than participants with TBI because they underestimated how much their partners with TBI would remember.

CONCLUSION

Measuring memory for conversation in TBI is feasible and may advance the characterization of cognitive-communication impairment in TBI, and its heterogeneity, in everyday contexts.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25927513.

Traumatic brain injuries in paediatric patients: individual vs. team sports-related hospitalizations

Paediatric sport participation continues to increase in the United States, with a corresponding increase in sports-related concussions or traumatic brain injuries (TBIs). It is important to recognize which sports are at elevated risk and identify risk factors for hospital admission and length of stay (LOS). Paediatric patients (ages 5-18) from 2008 to 2014 were identified from the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS). Eight hundred and ninety-four patients included those who were hospitalized with a TBI resulting from participation in an individual (451 patients) or team (443 patients) sport. We evaluated the differences in LOS and total charges between individual and team sports and found that compared to team sports, TBI patients in individual sports had significantly longer hospital stays compared to team sports (1.75 days versus 1.34 days, p < 0.001) and costlier ($27,333 versus $19,069, p < 0.001) hospital stays. This may be due to reduced awareness and reduced compliance with return-to-play protocols in individual sports. Safety education information at a young age, increased awareness of TBIs, and additional medical support for individual sports as well as team sports may help mitigate these findings.

Mental and Physical Health Comorbidities in Traumatic Brain Injury: A Non-TBI Controls Comparison

OBJECTIVE

To examine whether aging with a TBI was associated with a greater burden of health-related comorbidities compared with a non-TBI control cohort and examine the associations between comorbidity burden, emotional outcomes, and health-related quality of life (HRQoL) after TBI across ages.

DESIGN

Cross-sectional.

SETTING

Research center or telephone.

PARTICIPANTS

The study included 559 participants (NTBI=291, NControls=268). Participants with TBI were recruited during inpatient rehabilitation and had sustained a moderate-severe TBI 1-33 years previously. Non-TBI controls were a convenience sample recruited through advertisements in the community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The number of cardiovascular, general physical health, and mental health comorbidities was compared between cohorts and age strata using Poisson regression. The relationships between comorbidities, age, emotional outcomes (Generalized Anxiety Disorder Scale-7, Patient Health Questionnaire-9), and HRQoL (PROMIS Global Health Measure) were examined with linear regression. Distinct subgroups of comorbidities were identified using latent class analysis. Associations between comorbidity classes with demographic and outcome variables were evaluated using multinomial logistic and linear regressions, respectively.

RESULTS

TBI participants had a significantly higher comorbidity burden than controls, primarily driven by elevated rates of mental health disorders (RR=2.71, 95% confidence interval [1.37, 5.35]). Cardiovascular and physical health comorbidities were not elevated in the TBI group compared with controls. Both cohorts had 3 similar comorbidity subgroups, suggesting consistent patterns of co-occurring health conditions regardless of TBI exposure. Physical and mental health comorbidities were associated with elevated depression and anxiety symptoms and diminished HRQoL after TBI compared with controls.

CONCLUSION

TBI was associated with greater mental, but not physical, health comorbidities in the decades after injury. However, physical and mental health comorbidities significantly affected emotional and HRQoL status after TBI, underscoring a greater need for long-term support for individuals with TBI coping with both physical and mental health comorbidities.

Can Long-Term Outcomes of Posttraumatic Headache be Predicted?

PURPOSE OF REVIEW

Headache is one of the most common symptoms of traumatic brain injury, and it is more common in patients with mild, rather than moderate or severe, traumatic brain injury. Posttraumatic headache can be the most persistent symptom of traumatic brain injury. In this article, we review the current understanding of posttraumatic headache, summarize the current knowledge of its pathophysiology and treatment, and review the research regarding predictors of long-term outcomes.

RECENT FINDINGS

To date, posttraumatic headache has been treated based on the semiology of the primary headache disorder that it most resembles, but the pathophysiology is likely to be different, and the long-term prognosis differs as well. No models exist to predict long-term outcomes, and few studies have highlighted risk factors for the development of acute and persistent posttraumatic headaches. Further research is needed to elucidate the pathophysiology and identify specific treatments for posttraumatic headache to be able to predict long-term outcomes. In addition, the effect of managing comorbid traumatic brain injury symptoms on posttraumatic headache management should be further studied. Posttraumatic headache can be a persistent symptom of traumatic brain injury, especially mild traumatic brain injury. It has traditionally been treated based on the semiology of the primary headache disorder it most closely resembles, but further research is needed to elucidate the pathophysiology of posttraumatic headache and determine risk factors to better predict long-term outcomes.

Attentional Orienting and Disfluency-Related Memory Boost Are Intact in Adults With Moderate-Severe Traumatic Brain Injury

PURPOSE

Traumatic brain injury (TBI) is associated with a range of cognitive-communicative deficits that interfere with everyday communication and social interaction. Considerable effort has been directed at characterizing the nature and scope of cognitive-communication disorders in TBI, yet the underlying mechanisms of impairment are largely unspecified. The present research examines sensitivity to a common communicative cue, disfluency, and its impact on memory for spoken language in TBI.

METHOD

Fifty-three participants with moderate-severe TBI and 53 noninjured comparison participants listened to a series of sentences, some of which contained disfluencies. A subsequent memory test probed memory for critical words in the sentences.

RESULTS

Participants with TBI successfully remembered the spoken words (b = 1.57, p < .0001) at a similar level to noninjured comparison participants. Critically, participants with TBI also exhibited better recognition memory for words preceded by disfluency compared to words from fluent sentences (b = 0.57, p = .02).

CONCLUSIONS

These findings advance mechanistic accounts of cognitive-communication disorder by revealing that, when isolated for experimental study, individuals with moderate-severe TBI are sensitive to attentional orienting cues in speech and exhibit enhanced recognition of individual words preceded by disfluency. These results suggest that some aspects of cognitive-communication disorders may not emerge from an inability to perceive and use individual communication cues, but rather from disruptions in managing (i.e., attending, weighting, integrating) multiple cognitive, communicative, and social cues in complex and dynamic interactions. This hypothesis warrants further investigation.

Factors related to social inferencing performance in moderate-severe, chronic TBI

OBJECTIVE

Following traumatic brain injury (TBI), deficits in social cognition are common. Social inferencing is a crucial component of social cognition that enables an individual to understand the thoughts, feelings, and intentions of a communication partner when this information is not explicitly stated. Existing literature suggests a variety of factors contribute to social inferencing success (e.g. biological sex, executive functioning), yet findings are not conclusive, largely because these factors have been examined in isolation.

METHOD

In this cross-sectional study, stepwise regression with cross validation was used to examine the extent that several theoretically motivated factors were associated with social inferencing (measured by performance on The Awareness of Social Inference Test [TASIT]) in adult participants with TBI (n = 105). Demographic information, executive functioning, aggression, emotional functioning measures, and participation in society were all examined in relation to social inferencing performance.

RESULTS

The findings confirm the importance of higher-level cognitive skills (i.e. executive functioning) in social inferencing, and advance the literature by underlining the potential importance of productive participation in social inferencing performance.

CONCLUSION

This study innovatively highlights factors linked with social inferencing skills and, in doing so, how deficits in social inferencing might manifest in the lives of individuals with TBI.