Relationship between transdiagnostic dimensions of psychopathology and traumatic brain injury (TBI): A TRACK-TBI study

Value-consistent rehabilitation is associated with long-term psychological flexibility and quality of life after traumatic brain injury

Meaningful steps have been taken toward using holistic approaches in outpatient rehabilitation for traumatic brain injury (TBI) (i.e., treating the whole individual); however, research and practice continue to disproportionately focus on adapting to physical and cognitive changes. Research suggests treatment focusing on individual values may be important for psychological adjustment after TBI. The current study sought to explore individual values across multiple life domains in those with TBI as well as what values outpatient rehabilitation was helpful for, and to examine discrepancies between these factors (i.e., value-consistent rehabilitation) in relation to important long-term treatment outcomes. 215 adults with a history of TBI who had participated in outpatient rehabilitation completed online surveys assessing how consistent outpatient rehabilitation was with individual values, psychological flexibility, and quality of life. The life domains with the greatest discrepancies between individual importance and rehabilitation helpfulness were spirituality, intimate relations, and family relations. Greater value-consistent rehabilitation was associated with higher levels of psychological flexibility and quality of life beyond demographics and injury characteristics. Our findings provide further support in favour of holistic, client-centred approaches that are facilitated by neurological rehabilitation programs.

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.

Exploring emotional distress symptom clusters in young adults with childhood traumatic brain injury

BACKGROUND

Depression, anxiety, and stress are persistent and co-occurring symptoms in survivors of childhood traumatic brain injury (TBI), and often impact on health-related quality of life (HRQoL). This paper explored emotional distress symptom clusters and associated factors in young adults with childhood TBI.

METHODS

We included 54 young adults who sustained mild (n = 14), moderate (n = 27), and severe (n = 13) childhood TBI, at 20 years post-injury. The Depression Anxiety Stress Scale was administered. Cluster group membership was identified using two-step clustering and hierarchical clustering methods, and associated factors were assessed with multiple regression models.

RESULTS

Two symptom cluster groups were identified, including a No Distress (n = 66%) and an Elevated Distress (n = 33%) group, with the latter showing significantly higher symptoms of depression, anxiety, and stress (all p < .001). Elevated Distress group membership was linked to tobacco use and poor sleep quality, while poor HRQoL was associated with younger age at injury and Elevated Distress group membership.

CONCLUSIONS

Using cluster methodology, we showed that one-third of young adults with childhood TBI had elevated emotional distress symptoms. This underscores the complex emotional profile of this subgroup and the need for assessment, analysis, and treatment methods that target a range of symptoms rather than relying on single-diagnostic protocols.

ABBREVIATIONS

ANOVA: Analysis of Variance; CT: Computed Tomography; DASS: Depression Anxiety Stress Scale; GCS: Glasgow Coma Scale; HREC: Human Research Ethics Committee; HRQoL: Health-Related Quality of Life; IBM: International Business Machines Corporation; MRI: Magnetic Resonance Imaging; PTA: Post-Traumatic Amnesia; QoL: Quality of Life; QOLIBRI: Quality of Life after Brain Injury Scale; REDCap: Research Electronic Data Capture; SES: Socioeconomic Status; SPSS: Statistical Package for the Social Sciences; TBI: Traumatic Brain Injury.

Neurobehavioral Symptom Profiles for the Behavioral Assessment Screening Tool in Chronic Traumatic Brain Injury

OBJECTIVE

To identify neurobehavioral symptom profiles among persons with chronic traumatic brain injury (TBI) using the Behavioral Assessment Screening Tool (BAST) and to consider participant characteristics that differ between profile groups.

SETTING

Community.

PARTICIPANTS

Participants (n = 615) were English-speaking adults (≥18) and had a self-reported history of at least one TBI of any severity.

DESIGN

Secondary analysis of cross-sectional data.

MAIN MEASURES

The BAST measures neurobehavioral symptoms in the domains of Negative Affect, Fatigue, Executive Dysfunction, Impulsivity, and Substance Misuse.

RESULTS

Using latent profile analysis (LPA), we identified 3 different neurobehavioral profiles. Overall symptom frequency and differences in the pattern of symptom frequency across domains differentiated the profile groups. Average domain scores differed significantly across the profiles (P < .001) for all domains except Fatigue (P = .076). Those in profile 3 (High-Risk group) reported the most frequent symptoms across all domains (similar Negative Affect frequency as profile 1). Substance Misuse was especially high in this group. Compared to profile 2 (High Negative Affect group), participants in profile 1 (Moderate-Risk group) endorsed significantly more frequent (and more variable) symptoms across all BAST domains, particularly Impulsivity and Substance Misuse. Participants in profile 2 endorsed the least frequent symptoms across all domains. Demographic comparison showed that groups differed based on gender, age, and injury severity (mild vs moderate-severe), with profile 3 composed of the most men and the most persons in early adulthood, and profile 2 composed of the most women and those with mild TBI.

CONCLUSIONS

We differentiated 3 neurobehavioral symptom profiles among persons with chronic TBI and determined differences in sociodemographic factors between the groups. Future research should focus on validating these profiles in another sample of individuals with chronic TBI. Characterizing persons according to multidimensional symptom profiles could allow for more tailored approaches to predict and prevent long-term negative outcomes.

IMproving psYchosocial adjustment to Traumatic Brain Injury from acute to chronic injury through development and evaluation of the myTBI online psychoeducation platform: protocol for a mixed-methods study

INTRODUCTION

This protocol describes the myTBI study which aims to: (1) develop an online psychoeducation platform for people with traumatic brain injury (TBI), their family members/caregivers, and healthcare staff to improve psychosocial adjustment to TBI across different phases of injury (acute, postacute, and chronic), and (2) undertake an evaluation of efficacy, acceptability, and feasibility.

METHODS AND ANALYSIS

A three-stage mixed-methods research design will be used. The study will be undertaken across four postacute community-based neurorehabilitation and disability support services in Western Australia. Stage 1 (interviews and surveys) will use consumer-driven qualitative methodology to: (1) understand the recovery experiences and psychosocial challenges of people with TBI over key stages (acute, postacute, and chronic), and (2) identify required areas of psychosocial support to inform the psychoeducation platform development. Stage 2 (development) will use a Delphi expert consensus method to: (1) determine the final psychoeducation modules, and (2) perform acceptance testing of the myTBI platform. Finally, stage 3 (evaluation) will be a randomised stepped-wedge trial to evaluate efficacy, acceptability, and feasibility. Outcomes will be measured at baseline, postintervention, follow-up, and at final discharge from services. Change in outcomes will be analysed using multilevel mixed-effects modelling. Follow-up surveys will be conducted to evaluate acceptability and feasibility.

ETHICS AND DISSEMINATION

Ethics approval was granted by North Metropolitan Health Service Mental Health Research Ethics and Governance Office (RGS0000005877). Study findings will be relevant to clinicians, researchers, and organisations who are seeking a cost-effective solution to deliver ongoing psychoeducation and support to individuals with TBI across the recovery journey.

TRIAL REGISTRATION NUMBER

ACTRN12623000990628.

Emotional Resilience Predicts Preserved White Matter Microstructure Following Mild Traumatic Brain Injury

BACKGROUND

Adult patients with mild traumatic brain injury (mTBI) exhibit distinct phenotypes of emotional and cognitive functioning identified by latent profile analysis of clinical neuropsychological assessments. When discerned early after injury, these latent clinical profiles have been found to improve prediction of long-term outcomes from mTBI. The present study hypothesized that white matter (WM) microstructure is better preserved in an emotionally resilient mTBI phenotype compared with a neuropsychiatrically distressed mTBI phenotype.

METHODS

The present study used diffusion magnetic resonance imaging to investigate and compare WM microstructure in major association, projection, and commissural tracts between the two phenotypes and over time. Diffusion magnetic resonance images from 172 patients with mTBI were analyzed to compute individual diffusion tensor imaging maps at 2 weeks and 6 months after injury.

RESULTS

By comparing the diffusion tensor imaging parameters between the two phenotypes at global, regional, and voxel levels, emotionally resilient patients were shown to have higher axial diffusivity compared with neuropsychiatrically distressed patients early after mTBI. Longitudinal analysis revealed greater compromise of WM microstructure in neuropsychiatrically distressed patients, with greater decrease of global axial diffusivity and more widespread decrease of regional axial diffusivity during the first 6 months after injury compared with emotionally resilient patients.

CONCLUSIONS

These results provide neuroimaging evidence of WM microstructural differences underpinning mTBI phenotypes identified from neuropsychological assessments and show differing longitudinal trajectories of these biological effects. These findings suggest that diffusion magnetic resonance imaging can provide short- and long-term imaging biomarkers of resilience.

Bifactor analysis of the Hospital Anxiety and Depression Scale (HADS) in individuals with traumatic brain injury

Anxiety and depression symptoms are commonly experienced after traumatic brain injury (TBI). However, studies validating measures of anxiety and depression for this population are scarce. Using novel indices derived from symmetrical bifactor modeling, we evaluated whether the Hospital Anxiety and Depression Scale (HADS) reliably differentiated anxiety and depression in 874 adults with moderate-severe TBI. The results showed that there was a dominant general distress factor accounting for 84% of the systematic variance in HADS total scores. The specific anxiety and depression factors accounted for little residual variance in the respective subscale scores (12% and 20%, respectively), and overall, minimal bias was found in using the HADS as a unidimensional measure. Further, in a subsample of 184 participants, the HADS subscales did not clearly discriminate between formal anxiety and depressive disorders diagnosed via clinical interview. Results were consistent when accounting for degree of disability, non-English speaking background, and time post-injury. In conclusion, variance in HADS scores after TBI predominately reflects a single underlying latent variable. Clinicians and researchers should exercise caution in interpreting the individual HADS subscales and instead consider using the total score as a more valid, transdiagnostic measure of general distress in individuals with TBI.

Group-Based Patterns of Life Satisfaction and Functional Independence over the 10 Years after Traumatic Brain Injury in Older Adults: A Model Systems Study

BACKGROUND

Older adults who sustain a traumatic brain injury (TBI) have been shown to have reduced functional independence and life satisfaction relative to younger individuals with TBI. The purpose of this study was to examine the covarying patterns of functional independence and life satisfaction over the 10 years after TBI in adults who were 60 years of age or older upon injury.

METHOD

Participants were 1841 individuals aged 60 or older at the time of TBI, were enrolled in the longitudinal TBI Model Systems database, and had Functional Independence Measure and Satisfaction with Life Scale scores during at least one time point at 1, 2, 5, and 10 years after TBI.

RESULTS

A k-means cluster analysis identified four distinct group-based longitudinal patterns of these two variables. Three cluster groups suggested that functional independence and life satisfaction generally traveled together over time, with one group showing relatively high functional independence and life satisfaction over time (Cluster 2), one group showing relatively moderate functional independence and life satisfaction (Cluster 4), and one group showing relatively low functional independence and life satisfaction (Cluster 1). Cluster 3 had relatively high functional independence over time but, nonetheless, relatively low life satisfaction; they were also the youngest group upon injury. Participants in Cluster 2 generally had the highest number of weeks of paid competitive employment but lower percentages of underrepresented racial/ethnic minority participants, particularly Black and Hispanic individuals. Women were more likely to be in the cluster with the lowest life satisfaction and functional independence (Cluster 1).

CONCLUSION

Functional independence and life satisfaction generally accompany one another over time in older adults, although this does not always occur, as life satisfaction can still be low in a subgroup of older individuals after TBI with higher functioning. These findings contribute to a better understanding of post-TBI recovery patterns in older adults over time that may inform treatment considerations to improve age-related discrepancies in rehabilitation outcomes.

Functional Recovery, Symptoms, and Quality of Life 1 to 5 Years After Traumatic Brain Injury

Importance

Many level I trauma center patients experience clinical sequelae at 1 year following traumatic brain injury (TBI). Longer-term outcome data are needed to develop better monitoring and rehabilitation services.

Objective

To examine functional recovery, TBI-related symptoms, and quality of life from 1 to 5 years postinjury.

Design, Setting, and Participants

This cohort study enrolled trauma patients across 18 US level I trauma centers between 2014 and 2018. Eligible participants were enrolled within 24 hours of injury and followed up to 5 years postinjury. Data were analyzed January 2023.

Exposures

Mild TBI (mTBI), moderate-severe TBI (msTBI), or orthopedic traumatic controls (OTC).

Main Outcomes and Measures

Functional independence (Glasgow Outcome Scale-Extended [GOSE] score 5 or higher), complete functional recovery (GOSE score, 8), better (ie, lower) TBI-related symptom burden (Rivermead Post Concussion Symptoms Questionnaire score of 15 or lower), and better (ie, higher) health-related quality of life (Quality of Life After Brain Injury Scale-Overall Scale score 52 or higher); mortality was analyzed as a secondary outcome.

Results

A total 1196 patients were included in analysis (mean [SD] age, 40.8 [16.9] years; 781 [65%] male; 158 [13%] Black, 965 [81%] White). mTBI and OTC groups demonstrated stable, high rates of functional independence (98% to 100% across time). While odds of independence were lower among msTBI survivors, the majority were independent at 1 year (72%), and this proportion increased over time (80% at 5 years; group × year, P = .005; independence per year: odds ratio [OR] for msTBI, 1.28; 95% CI, 1.03-1.58; OR for mTBI, 0.81; 95% CI, 0.64-1.03). For other outcomes, group differences at 1 year remained stable over time (group × year, P ≥ .44). Odds of complete functional recovery remained lower for persons with mTBI vs OTC (OR, 0.39; 95% CI, 0.28-0.56) and lower for msTBI vs mTBI (OR, 0.34; 95% CI, 0.24-0.48). Odds of better TBI-related symptom burden and quality of life were similar for both TBI subgroups and lower than OTCs. Mortality between 1 and 5 years was higher for msTBI (5.5%) than mTBI (1.5%) and OTC (0.7%; P = .02).

Conclusions and Relevance

In this cohort study, patients with previous msTBI displayed increased independence over 5 years; msTBI was also associated with increased mortality. These findings, in combination with the persistently elevated rates of unfavorable outcomes in mTBI vs controls imply that more monitoring and rehabilitation are needed for TBI.

Polygenic risk for mental disorders as predictors of posttraumatic stress disorder after mild traumatic brain injury

Many patients with mild traumatic brain injury (mTBI) are at risk for mental health problems such as posttraumatic stress disorder (PTSD). The objective of this study was to determine whether the polygenic risk for PTSD (or for related mental health disorders or traits including major depressive disorder [MDD] and neuroticism [NEU]) was associated with an increased likelihood of PTSD in the aftermath of mTBI. We used data from individuals of European ancestry with mTBI enrolled in TRACK-TBI (n = 714), a prospective longitudinal study of level 1 trauma center patients. One hundred and sixteen mTBI patients (16.3%) had probable PTSD (PCL-5 score ≥33) at 6 months post-injury. We used summary statistics from recent GWAS studies of PTSD, MDD, and NEU to generate polygenic risk scores (PRS) for individuals in our sample. A multivariable model that included age, sex, pre-injury history of mental disorder, and cause of injury explained 7% of the variance in the PTSD outcome; the addition of the PTSD-PRS (and five ancestral principal components) significantly increased the variance explained to 11%. The adjusted odds of PTSD in the uppermost PTSD-PRS quintile was nearly four times higher (aOR = 3.71, 95% CI 1.80-7.65) than in the lowest PTSD-PRS quintile. There was no evidence of a statistically significant interaction between PTSD-PRS and prior history of mental disorder, indicating that PTSD-PRS had similar predictive utility among those with and without pre-injury psychiatric illness. When added to the model, neither MDD-PRS nor NEU-PRS were significantly associated with the PTSD outcome. These findings show that the risk for PTSD in the context of mTBI is, in part, genetically influenced. They also raise the possibility that an individual's PRS could be clinically actionable if used-possibly with other non-genetic predictors-to signal the need for enhanced follow-up and early intervention; this precision medicine approach needs to be prospectively studied.

Empirical and Authoritative Classification of Neuropsychiatric Syndromes in Neurocognitive Disorders

Neuropsychiatric symptoms of neurocognitive disorders have been classified into higher-order constructs, often called neuropsychiatric syndromes. As with the general psychopathology literature, these classifications have been achieved through two approaches: empirical and authoritative. The authoritative approach relies on expert panels that condense the available evidence into operational criteria, whereas the empirical approach uses statistical methods to discover symptom patterns and possible hierarchies formed by them. In this article, the author reviews the strengths and weaknesses of both approaches using general psychopathology literature as a reference point. The authoritative approach, influenced by the DSM, has led to several sets of criteria, which could aid clinical trials, diagnostics, and communication. However, unknown reliability and the complex relationships between empirical evidence and published criteria may limit the utility of current criteria. The empirical approach has been used to explore syndrome structures on the basis of rating scales for neuropsychiatric symptoms. The structures suggested in these studies have not been replicated easily and have been limited by either small sample sizes, restricted breadth of neuropsychiatric assessment, or both. Suggestions for further development of both approaches are offered. First, neuropsychiatric symptoms and syndromes need to be studied with measures of broad scope and in large samples. These requirements are prerequisites not only for eliciting highly informative empirical classifications but also for understanding these symptoms at a more nuanced level. Second, both approaches could benefit from more transparency. Finally, the reliability of the available authoritative criteria should be examined.

Association of Traumatic Brain Injury Severity and Self-Reported Neuropsychiatric Symptoms in Wounded Military Service Members

The impact of traumatic brain injury (TBI) severity and loss of consciousness (LOC) on the development of neuropsychiatric symptoms was studied in injured service members (SMs; n = 1278) evacuated from combat settings between 2003 and 2012. TBI diagnoses of mild TBI (mTBI) or moderate-to-severe TBI (MS-TBI) along with LOC status were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes and the Defense and Veterans Brain Injury Center Standard Surveillance Case Definition for TBI. Self-reported psychiatric symptoms were evaluated for post-traumatic stress disorder (PTSD) with the PTSD Checklist, Civilian Version for PTSD, the Patient Health Questionnaire-9 for major depressive disorder (MDD), and the Patient Health Questionnaire-15 for somatic symptom disorder (SSD) in two time periods post-injury: Assessment Period 1 (AP1, 0.0-2.5 months) and Assessment Period 2 (AP2, 3-12 months). mTBI, but not MS-TBI, was associated with increased neuropsychiatric symptoms: PTSD in AP1 and AP2; MDD in AP1; and SSD in AP2. A subgroup analysis of mTBI with and without LOC revealed that mTBI with LOC, but not mTBI without LOC, was associated with increased symptoms as compared to non-TBI: PTSD in AP1 and AP2; MDD in AP1; and SSD in AP1 and AP2. Moreover, mTBI with LOC was associated with increased MDD symptoms in AP2, and SSD symptoms in AP1 and AP2, compared to mTBI without LOC. These findings reinforce the need for the accurate characterization of TBI severity and a multi-disciplinary approach to address the devastating impacts of TBI in injured SMs.

Neurostimulation for Functional Recovery After Traumatic Brain Injury: Current Evidence and Future Directions for Invasive Surgical Approaches

We aim to provide a comprehensive review of the current scientific evidence supporting the use of invasive neurostimulation in the treatment of deficits associated with traumatic brain injury (TBI), as well as to identify future directions for research and highlight important questions that remain unaddressed. Neurostimulation is a treatment modality with expanding applications in modern medical practice. Targeted electrical stimulation of specific brain regions has been shown to increase synaptogenesis and enhance structural reorganization of neuronal networks. This underlying therapeutic effect might be of high value for patients suffering from TBI because it could modulate neuronal connectivity and function of areas that are partially or completely spared after injury. The current published literature exploring the application of invasive neurostimulation for the treatment of functional deficits associated with TBI is scarce but promising. Rodent models have shown that targeted stimulation of the hippocampus or connecting structures can result in significant cognitive recovery, while stimulation of the motor cortex and deep cerebellar nuclei is associated with motor improvements. Data from clinical studies are extremely limited; single-patient reports and case series found neurostimulation to be effective in relieving motor symptoms, improving visuospatial memory, and supporting emotional adjustment. Looking forward, it will be important to identify stimulation targets and paradigms that can maximize improvement over multiple functional domains. It will also be important to corroborate the observed behavioral improvements with histological, electrophysiological, and radiological evidence. Finally, the impact of biological variables such as sex and age on the treatment outcomes needs to be explored.

Traumatic brain injury: progress and challenges in prevention, clinical care, and research

Traumatic brain injury (TBI) has the highest incidence of all common neurological disorders, and poses a substantial public health burden. TBI is increasingly documented not only as an acute condition but also as a chronic disease with long-term consequences, including an increased risk of late-onset neurodegeneration. The first Lancet Neurology Commission on TBI, published in 2017, called for a concerted effort to tackle the global health problem posed by TBI. Since then, funding agencies have supported research both in high-income countries (HICs) and in low-income and middle-income countries (LMICs). In November 2020, the World Health Assembly, the decision-making body of WHO, passed resolution WHA73.10 for global actions on epilepsy and other neurological disorders, and WHO launched the Decade for Action on Road Safety plan in 2021. New knowledge has been generated by large observational studies, including those conducted under the umbrella of the International Traumatic Brain Injury Research (InTBIR) initiative, established as a collaboration of funding agencies in 2011. InTBIR has also provided a huge stimulus to collaborative research in TBI and has facilitated participation of global partners. The return on investment has been high, but many needs of patients with TBI remain unaddressed. This update to the 2017 Commission presents advances and discusses persisting and new challenges in prevention, clinical care, and research.

In LMICs, the occurrence of TBI is driven by road traffic incidents, often involving vulnerable road users such as motorcyclists and pedestrians. In HICs, most TBI is caused by falls, particularly in older people (aged ≥65 years), who often have comorbidities. Risk factors such as frailty and alcohol misuse provide opportunities for targeted prevention actions. Little evidence exists to inform treatment of older patients, who have been commonly excluded from past clinical trials—consequently, appropriate evidence is urgently required. Although increasing age is associated with worse outcomes from TBI, age should not dictate limitations in therapy. However, patients injured by low-energy falls (who are mostly older people) are about 50% less likely to receive critical care or emergency interventions, compared with those injured by high-energy mechanisms, such as road traffic incidents.

Mild TBI, defined as a Glasgow Coma sum score of 13–15, comprises most of the TBI cases (over 90%) presenting to hospital. Around 50% of adult patients with mild TBI presenting to hospital do not recover to pre-TBI levels of health by 6 months after their injury. Fewer than 10% of patients discharged after presenting to an emergency department for TBI in Europe currently receive follow-up. Structured follow-up after mild TBI should be considered good practice, and urgent research is needed to identify which patients with mild TBI are at risk for incomplete recovery.

The selection of patients for CT is an important triage decision in mild TBI since it allows early identification of lesions that can trigger hospital admission or life-saving surgery. Current decision making for deciding on CT is inefficient, with 90–95% of scanned patients showing no intracranial injury but being subjected to radiation risks. InTBIR studies have shown that measurement of blood-based biomarkers adds value to previously proposed clinical decision rules, holding the potential to improve efficiency while reducing radiation exposure. Increased concentrations of biomarkers in the blood of patients with a normal presentation CT scan suggest structural brain damage, which is seen on MR scanning in up to 30% of patients with mild TBI. Advanced MRI, including diffusion tensor imaging and volumetric analyses, can identify additional injuries not detectable by visual inspection of standard clinical MR images. Thus, the absence of CT abnormalities does not exclude structural damage—an observation relevant to litigation procedures, to management of mild TBI, and when CT scans are insufficient to explain the severity of the clinical condition.

Although blood-based protein biomarkers have been shown to have important roles in the evaluation of TBI, most available assays are for research use only. To date, there is only one vendor of such assays with regulatory clearance in Europe and the USA with an indication to rule out the need for CT imaging for patients with suspected TBI. Regulatory clearance is provided for a combination of biomarkers, although evidence is accumulating that a single biomarker can perform as well as a combination. Additional biomarkers and more clinical-use platforms are on the horizon, but cross-platform harmonisation of results is needed. Health-care efficiency would benefit from diversity in providers.

In the intensive care setting, automated analysis of blood pressure and intracranial pressure with calculation of derived parameters can help individualise management of TBI. Interest in the identification of subgroups of patients who might benefit more from some specific therapeutic approaches than others represents a welcome shift towards precision medicine. Comparative-effectiveness research to identify best practice has delivered on expectations for providing evidence in support of best practices, both in adult and paediatric patients with TBI.

Progress has also been made in improving outcome assessment after TBI. Key instruments have been translated into up to 20 languages and linguistically validated, and are now internationally available for clinical and research use. TBI affects multiple domains of functioning, and outcomes are affected by personal characteristics and life-course events, consistent with a multifactorial bio-psycho-socio-ecological model of TBI, as presented in the US National Academies of Sciences, Engineering, and Medicine (NASEM) 2022 report. Multidimensional assessment is desirable and might be best based on measurement of global functional impairment. More work is required to develop and implement recommendations for multidimensional assessment. Prediction of outcome is relevant to patients and their families, and can facilitate the benchmarking of quality of care. InTBIR studies have identified new building blocks (eg, blood biomarkers and quantitative CT analysis) to refine existing prognostic models. Further improvement in prognostication could come from MRI, genetics, and the integration of dynamic changes in patient status after presentation.

Neurotrauma researchers traditionally seek translation of their research findings through publications, clinical guidelines, and industry collaborations. However, to effectively impact clinical care and outcome, interactions are also needed with research funders, regulators, and policy makers, and partnership with patient organisations. Such interactions are increasingly taking place, with exemplars including interactions with the All Party Parliamentary Group on Acquired Brain Injury in the UK, the production of the NASEM report in the USA, and interactions with the US Food and Drug Administration. More interactions should be encouraged, and future discussions with regulators should include debates around consent from patients with acute mental incapacity and data sharing. Data sharing is strongly advocated by funding agencies. From January 2023, the US National Institutes of Health will require upload of research data into public repositories, but the EU requires data controllers to safeguard data security and privacy regulation. The tension between open data-sharing and adherence to privacy regulation could be resolved by cross-dataset analyses on federated platforms, with the data remaining at their original safe location. Tools already exist for conventional statistical analyses on federated platforms, however federated machine learning requires further development. Support for further development of federated platforms, and neuroinformatics more generally, should be a priority.

This update to the 2017 Commission presents new insights and challenges across a range of topics around TBI: epidemiology and prevention (section 1 ); system of care (section 2 ); clinical management (section 3 ); characterisation of TBI (section 4 ); outcome assessment (section 5 ); prognosis (Section 6 ); and new directions for acquiring and implementing evidence (section 7 ). Table 1 summarises key messages from this Commission and proposes recommendations for the way forward to advance research and clinical management of TBI.

Differing associations between measures of somatic symptom reporting, personality, and mild traumatic brain injury (mTBI)

Objective: Somatic complaints are known to complicate recovery after mild traumatic brain injury (mTBI), but the construct is poorly understood due to evolving definitions of associated disorders and uncertainty related to its position within the broader construct network of psychopathology. Methods: To better understand measures of somatic symptom reporting widely used with mTBI patients, we examined relationships between the Brief Symptom Inventory-18 Somatization (SOM) scale, the Minnesota Multiple Personality Inventory-2-Restructured Form Somatic Complaints (RC1) scale, other measures of psychological and personality functioning, and mTBI in both athlete concussion (n = 100) and civilian trauma (n = 75 mTBI, n = 79 orthopedic injury) samples. Results: The association between post-injury SOM and RC1 was moderate (r=.37-.46) and similar to associations between these inventories and depression and anxiety symptoms. In civilians with mTBI, RC1 was more strongly associated with diverse personality dimensions than SOM. mTBI athletes reported increases in somatic symptoms from pre- to post-injury, with larger group effect sizes on SOM (ηp2 = 0.34, p < .001) than RC1 (ηp2 = 0.09, p = .003). Civilian mTBI patients showed a trend for somewhat higher post-injury RC1 scores than orthopedic trauma controls (ηp2 = 0.02, p = .068). Conclusions: Findings add to the current knowledge of the influence of somatic complaints in mTBI. BSI-18 SOM and MMPI-2-RF RC1 are not interchangeable, as they are only modestly correlated and demonstrate differing associations with other clinical outcomes and mTBI.

Tailoring multidimensional outcomes to level of functional recovery after traumatic brain injury

There is increasing emphasis on multi-dimensional outcomes in traumatic brain injury (TBI), but achieving this aim is hampered by a plethora of overlapping assessment tools. There is a clear need for advice on the choice of outcomes and we examine level of functional recovery as a framework to guide selection of assessments. In this cohort study we analysed cross-sectional data from 2604 patients enrolled in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) project. Patients were followed up 6 months after injury and assessed on the Glasgow Outcome Scale-Extended (GOSE), cognitive tests, and patient-reported outcomes. We describe assessment completeness and prevalence of impairment. Relationships between outcomes were visualized using UpSet plots and hierarchical cluster analysis. GOSE categories varied markedly for both completion rates, 34-91% for patient reported outcomes and 9-81% for cognitive tests, and prevalence of impairment, 3-82% for patient reported outcomes and 9-59% for cognitive tests. In complete case samples, the GOSE identified impairment in 59-61%, while the most impaired patient reported outcome was the Short-Form 12 Physical Component Summary (28% overall), and the most impaired cognitive test was Trail Making Test Part A (19% overall). The findings show that degree of disability is a key context of use for cognitive tests and patient reported outcomes. Level of functional recovery provides a guide to the feasibility of different types of assessment and the likelihood of impairment, and can help tailor suitable assessment approaches to individuals and groups.

Mental Health Consequences of Traumatic Brain Injury

Traumatic brain injury (TBI) is associated with a host of psychiatric and neurobehavioral problems. As mortality rates have declined for severe TBI, attention has turned to the cognitive, affective, and behavioral sequelae of injuries across the severity spectrum, which are often more disabling than residual physical effects. Moderate and severe TBI can cause personality changes including impulsivity, severe irritability, affective instability, and apathy. Mild TBI, once considered a largely benign phenomenon, is now known to be associated with a range of affective symptoms, with suicidality, and with worsening or new onset of several psychiatric disorders including posttraumatic stress disorder and major depressive disorder. Repetitive head impacts, often in athletic contexts, are now believed to be associated with a number of emotional and behavioral sequelae. The nature and etiology of mental health manifestations of TBI (including a combination of brain dysfunction and psychological trauma and interrelationships between cognitive, affective, and physical symptoms) are complex and have been a focus of recent epidemiological and mechanistic studies. This paper will review the epidemiology of psychiatric and neurobehavioral problems after TBI in military, civilian, and athletic contexts.

Pediatric traumatic brain injury and a subsequent transient immune challenge independently influenced chronic outcomes in male mice

Traumatic brain injury (TBI) is a major contributor to death and disability worldwide. Children are at particularly high risk of both sustaining a TBI and experiencing serious long-term consequences, such as cognitive deficits, mental health problems and post-traumatic epilepsy. Severe TBI patients are highly susceptible to nosocomial infections, which are mostly acquired within the first week of hospitalization post-TBI. Yet the potential chronic impact of such acute infections following pediatric TBI remains unclear. In this study, we hypothesized that a peripheral immune challenge, such as lipopolysaccharide (LPS)-mimicking a hospital-acquired infection-would worsen inflammatory, neurobehavioral, and seizure outcomes after experimental pediatric TBI. To test this, three-week old male C57Bl/6J mice received a moderate controlled cortical impact or sham surgery, followed by 1 mg/kg i.p. LPS (or 0.9% saline vehicle) at 4 days TBI. Mice were randomized to four groups; sham-saline, sham-LPS, TBI-saline or TBI-LPS (n = 15/group). Reduced general activity and increased anxiety-like behavior were observed within 24 h in LPS-treated mice, indicating a transient sickness response. LPS-treated mice also exhibited a reduction in body weights, which persisted chronically. From 2 months post-injury, mice underwent a battery of tests for sensorimotor, cognitive, and psychosocial behaviors. TBI resulted in hyperactivity and spatial memory deficits, independent of LPS; whereas LPS resulted in subtle deficits in spatial memory retention. At 5 months post-injury, video-electroencephalographic recordings were obtained to evaluate both spontaneous seizure activity as well as the evoked seizure response to pentylenetetrazol (PTZ). TBI increased susceptibility to PTZ-evoked seizures; whereas LPS appeared to increase the incidence of spontaneous seizures. Post-mortem analyses found that TBI, but not LPS, resulted in robust glial reactivity and loss of cortical volume. A TBI × LPS interaction in hippocampal volume suggested that TBI-LPS mice had a subtle increase in ipsilateral hippocampus tissue loss; however, this was not reflected in neuronal cell counts. Both TBI and LPS independently had modest effects on chronic hippocampal gene expression. Together, contrary to our hypothesis, we observed minimal synergy between TBI and LPS. Instead, pediatric TBI and a subsequent transient immune challenge independently influenced chronic outcomes. These findings have implications for future preclinical modeling as well as acute post-injury patient management.