Mild traumatic brain injury recovery: a growth curve modelling analysis over 2 years

Moving forward on the road to recovery after concussion: participant experiences of interdisciplinary intervention for persisting post-concussion symptoms

PURPOSE

Many factors contribute to persisting post-concussion symptoms (PPCSs), necessitating multi-modal treatment. Quantitative investigations have shown the potential of interdisciplinary intervention to reduce the burden of PPCSs and facilitate return to activities. There are often varied responses to intervention, warranting further investigation of potential factors underlying treatment response. This study aimed to explore participant experiences of i-RECOveR, an interdisciplinary intervention for PPCSs and its impact on symptoms, daily function, and concussion beliefs.

MATERIALS AND METHOD

Semi-structured interviews were conducted 1-month post-treatment via videoconferencing with 13 individuals (61% female) with mild traumatic brain injury (Mage=39.77 years, SD = 16.27) who participated in i-RECOveR. Interview transcripts were analysed thematically.

RESULTS

Three themes reflected participants' treatment journeys from concussion to life after treatment: (1) Dissatisfaction with Previous Consultations, reflected personal experiences prior to commencing treatment; (2) Perceived Active Ingredients of Intervention, reflected participant experiences of i-RECOveR; and (3) Impact of Interdisciplinary Intervention, reflected a range of positive changes after completing i-RECOveR.

CONCLUSIONS

Findings highlight current gaps in the acute management of concussion and provide end-user insights into the facilitators and barriers of treatment engagement and response. Responses also highlight the potential positive impact of interdisciplinary treatments. Clinician perspectives should be explored in future research.

Time to resolution of symptoms and recovery after mild traumatic brain injury: protocol for a systematic review and meta-analysis

INTRODUCTION

Mild traumatic brain injury (mTBI) is a leading cause of morbidity and mortality, with approximately 1 out of 200 people each year sustaining an mTBI in Europe. There is a growing awareness that recovery may take months or years. However, the exact time frame of recovery remains ill-defined in the literature. This systematic review aims to record the range of outcome measures used for mTBI and understand the time to recovery for different outcomes.

METHODS AND ANALYSIS

This protocol complies with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guideline. A prespecified literature search for articles in the English language will be conducted from database inception to the date of searches using MEDLINE and EMBASE. A trial search was conducted on 5 October 2023 with refinement of the search criteria following this. For each study, screening of the title, abstract and full text, as well as data extraction, will be done by two reviewers, with an adjudicating third reviewer if required. The risk of bias will be assessed using the Cochrane risk of bias tool for clinical trials and the Newcastle Ottawa score for cohort studies. The primary outcome is the time to resolution of symptoms in mTBI patients who have a full recovery, using any validated outcome measure. Results will be categorised by symptom groups, including but not limited to post-concussive symptoms, mental health, functional recovery and health-related quality of life. For mTBI patients who do not recover, this review will also explore the time to the plateau of symptoms and the sequelae of these symptoms. Where possible, meta-analysis will be undertaken, with a narrative review undertaken when this is not possible. Subgroup analyses of patients aged over 64 years, and patients with repetitive head injury, are planned.

ETHICAL REVIEW AND DISSEMINATION

Ethical review is not required, as no original data will be collected. Results will be disseminated through peer-reviewed publications and academic conferences.

PROSPERO REGISTRATION NUMBER

CRD42023462797.

"I hope it'll get better… in the end, it didn't really get better": a qualitative study of access to specialized rehabilitation services as experienced by adults with persistent MTBI symptoms

PURPOSE

Persistent symptoms experienced by adults following mild traumatic brain injury (mTBI) can significantly impact their daily activities. It is often difficult for them to access specialized rehabilitation services. The aim of this study is to explore this population's experience surrounding access to specialized rehabilitation services, including waiting time.

MATERIALS AND METHODS

This study used a qualitative phenomenological approach and was conducted using semi-structured interviews. Twelve adults with mTBI who had received specialized interdisciplinary rehabilitation services were recruited. The interviews focused on participants' recollection of their patient journey after injury, their perception of waiting, barriers and facilitators to access, and the impacts of these experiences on their condition.

RESULTS

Participants reported experiencing symptoms such as anxiety, depression, worry, sadness, and discouragement before accessing specialized services. They all agreed that they did not receive clear information about their recovery process or the health services available to them, which exacerbated their mental health symptoms.

CONCLUSION

The findings show that participants experienced uncertainty because they lacked information regarding recovery and access to health services after their injury. Education about symptoms and recovery, as well as emotional support for people with mTBI should be made available during the waiting period.

Prediction of cognitive outcome after mild traumatic brain injury from acute measures of communication within brain networks

A considerable but ill-defined proportion of patients with mild traumatic brain injury (mTBI) experience persistent cognitive sequelae; the ability to identify such individuals early can help their neurorehabilitation. Here we tested the hypothesis that acute measures of efficient communication within brain networks are associated with patients' risk for unfavorable cognitive outcome six months after mTBI. Diffusion and T1-weighted magnetic resonance imaging, alongside cognitive measures, were obtained to map connectomes both one week and six months post injury in 113 adult patients with mTBI (71 males). For task-related brain networks, communication measures (characteristic path length, global efficiency, navigation efficiency) were moderately correlated with changes in cognition. Taking into account the covariance of age and sex, more unfavorable communication within networks were associated with worse outcomes within cognitive domains frequently impacted by mTBI (episodic and working memory, verbal fluency, inductive reasoning, and processing speed). Individuals with more unfavorable outcomes had significantly longer and less efficient pathways within networks supporting verbal fluency (all t > 2.786, p < .006), highlighting the vulnerability of language to mTBI. Participants in whom a task-related network was relatively inefficient one week post injury were up to eight times more likely to have unfavorable cognitive outcome pertaining to that task. Our findings suggest that communication measures within task-related networks identify mTBI patients who are unlikely to develop persistent cognitive deficits after mTBI. Our approach and findings can help to stratify mTBI patients according to their expected need for follow-up and/or neurorehabilitation.

Studying missingness in spinal cord injury data: challenges and impact of data imputation

BACKGROUND

In the last decades, medical research fields studying rare conditions such as spinal cord injury (SCI) have made extensive efforts to collect large-scale data. However, most analysis methods rely on complete data. This is particularly troublesome when studying clinical data as they are prone to missingness. Often, researchers mitigate this problem by removing patients with missing data from the analyses. Less commonly, imputation methods to infer likely values are applied.

OBJECTIVE

Our objective was to study how handling missing data influences the results reported, taking the example of SCI registries. We aimed to raise awareness on the effects of missing data and provide guidelines to be applied for future research projects, in SCI research and beyond.

METHODS

Using the Sygen clinical trial data (n = 797), we analyzed the impact of the type of variable in which data is missing, the pattern according to which data is missing, and the imputation strategy (e.g. mean imputation, last observation carried forward, multiple imputation).

RESULTS

Our simulations show that mean imputation may lead to results strongly deviating from the underlying expected results. For repeated measures missing at late stages (> = 6 months after injury in this simulation study), carrying the last observation forward seems the preferable option for the imputation. This simulation study could show that a one-size-fit-all imputation strategy falls short in SCI data sets.

CONCLUSIONS

Data-tailored imputation strategies are required (e.g., characterisation of the missingness pattern, last observation carried forward for repeated measures evolving to a plateau over time). Therefore, systematically reporting the extent, kind and decisions made regarding missing data will be essential to improve the interpretation, transparency, and reproducibility of the research presented.

Does pain influence cognitive performance in patients with mild traumatic brain injury?

OBJECTIVES

Pain is still a neglected problem in mild traumatic brain injury (mTBI). In this cross-sectional study, we examined the frequency of musculoskeletal pain in a sample of adult patients with persistent cognitive symptoms after mTBI and whether pain level affected cognition.

METHODS

The participants were 23 adult patients aged 18-50 referred to brain injury rehabilitation clinics for neuropsychological assessment after having sustained an mTBI. A non-injured control group (n = 29) was recruited through advertisements. The patients were, on average, assessed 22 months after trauma. All participants completed a comprehensive neuropsychological test battery and completed the Örebro Musculoskeletal Pain Screening Questionnaire, The Rivermead Post-Concussion Symptoms Questionnaire, and the State-Trait Anxiety Inventory.

RESULTS

Patients reported high levels of current pain and significantly more frequent neck and shoulder pain than the non-injured controls. Patients also reported high post-concussive symptoms and anxiety levels and performed less well on several neuropsychological tests. Pain level was associated with slower processing speed among the controls but not related to performance in the mTBI group.

CONCLUSION

We conclude that musculoskeletal pain is frequent in mTBI patients referred to rehabilitation settings. Furthermore, the results indicate that the interaction between pain and cognitive functioning differs in mTBI compared to controls. Our results implicate that pain screening should be an integrated part of neuropsychological rehabilitation after mTBI to identify conditions that run the risk of becoming chronic. The study was approved by the Regional Ethical Board in Stockholm, Sweden (04-415/2).

Interdisciplinary rehabilitation for persisting post-concussion symptoms after mTBI: N=15 single case experimental design

BACKGROUND

Despite clinical guidelines recommending an interdisciplinary approach to persisting post-concussion symptom (PPCS) management, evaluations of interdisciplinary interventions remain scant.

OBJECTIVES

This pilot study aimed to explore the feasibility and preliminary efficacy of an interdisciplinary intervention for PPCSs.

METHOD

A single-case experimental design with randomisation to multiple baselines (2, 4, or 6 weeks) was repeated across 15 participants (53% female) with mild traumatic brain injury (mean age 38.3 years, SD 15.7). The 12-week treatment incorporated psychology, physiotherapy, and medical interventions. Feasibility outcomes included recruitment and retention rates, adverse events, treatment adherence and fidelity. Patient-centred secondary outcomes included the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), assessed 3 times per week during the baseline and treatment phases, and at the 1- and 3-month follow-ups. Other secondary outcomes included measures of mood, sleep and fatigue, physical functioning, health-related quality of life, illness perceptions, and goal attainment. Changes in PPCSs were evaluated using systematic visual analysis and Tau-U. Clinically significant changes in secondary outcomes were explored descriptively.

RESULTS

16/26 individuals assessed for eligibility were enroled (61% recruitment rate); 15 completed the post-treatment follow-ups, and 13 completed the 1- and 3-month follow-up assessments (81% retention rate). High treatment adherence and competence in delivering treatments was observed. Moderate-large effect sizes for reducing PPCSs were observed in 12/15 cases, with 7/15 reaching statistical significance. Improvements were maintained at the 1- and 3-month follow-ups and were accompanied by reductions in fatigue, sleep difficulties, and mood symptoms, and changes in illness perceptions. All participants had clinically significant improvements in at least 1 outcome, with 81% of individual therapy goals achieved.

CONCLUSIONS

This pilot study provided preliminary support for a subsequent randomised controlled trial (RCT), with satisfactory recruitment, retention, treatment compliance, and treatment fidelity. Improvement was evident on participant outcomes including symptom reduction and goal attainment, suggesting that progressing to a phase-II RCT is worthwhile. Findings highlight the potential benefit of individualized interdisciplinary treatments.

MicroRNA biomarkers for diagnosis of mild traumatic brain injury and prediction of persistent symptoms: A prospective cohort study

The diagnosis of mild traumatic brain injury (mTBI) and early identification of patients who have persistent symptoms remains challenging. Symptoms are variably reported, and tests for cognitive impairment require specific expertise. The aim of this study was to assess the ability of plasma micro-ribonucleic acid (miRNA) biomarkers to distinguish between patients with mTBI and healthy controls. A secondary aim was to assess whether miRNA biomarker levels on the day of injury could predict persistent symptoms on day 7. Injured patients presented to an adult, tertiary referral hospital emergency department and were diagnosed with isolated mTBI (n = 75). Venous blood samples were collected within 6 h of injury. Symptom severity was assessed using the Rivermead Post-Concussion Symptom Questionnaire (RPQ) on the day of injury and at 7 days post-injury. The comparator group (n = 44) were healthy controls without any injury, who had bloods sampled and symptom severity assessed at the same time-point. Patients after mTBI reported higher symptom severity and had worse cognitive performance than the control group. Plasma miR423-3p levels were significantly higher among mTBI patients acutely post-injury compared to healthy controls and provided moderate discriminative ability (AUROC 0.67; 95 %CI: 0.57-0.77). None of the assessed miRNA biomarkers predicted persistent symptoms at 7 days. Plasma miR423-3p levels measured within 6 h of injury can discriminate for mTBI compared to healthy controls, with potential utility for screening after head injury or as an adjunct to the diagnosis of mTBI. Acute plasma miRNA levels did not predict patients who reported persistent symptoms at 7 days.

Use of Support Vector Machines Approach via ComBat Harmonized Diffusion Tensor Imaging for the Diagnosis and Prognosis of Mild Traumatic Brain Injury: A CENTER-TBI Study

The prediction of functional outcome after mild traumatic brain injury (mTBI) is challenging. Conventional magnetic resonance imaging (MRI) does not do a good job of explaining the variance in outcome, as many patients with incomplete recovery will have normal-appearing clinical neuroimaging. More advanced quantitative techniques such as diffusion MRI (dMRI), can detect microstructural changes not otherwise visible, and so may offer a way to improve outcome prediction. In this study, we explore the potential of linear support vector classifiers (linearSVCs) to identify dMRI biomarkers that can predict recovery after mTBI. Simultaneously, the harmonization of fractional anisotropy (FA) and mean diffusivity (MD) via ComBat was evaluated and compared for the classification performances of the linearSVCs. We included dMRI scans of 179 mTBI patients and 85 controls from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI), a multi-center prospective cohort study, up to 21 days post-injury. Patients were dichotomized according to their Extended Glasgow Outcome Scale (GOSE) scores at 6 months into complete (n = 92; GOSE = 8) and incomplete (n = 87; GOSE <8) recovery. FA and MD maps were registered to a common space and harmonized via the ComBat algorithm. LinearSVCs were applied to distinguish: (1) mTBI patients from controls and (2) mTBI patients with complete from those with incomplete recovery. The linearSVCs were trained on (1) age and sex only, (2) non-harmonized, (3) two-category-harmonized ComBat, and (4) three-category-harmonized ComBat FA and MD images combined with age and sex. White matter FA and MD voxels and regions of interest (ROIs) within the John Hopkins University (JHU) atlas were examined. Recursive feature elimination was used to identify the 10% most discriminative voxels or the 10 most discriminative ROIs for each implementation. mTBI patients displayed significantly higher MD and lower FA values than controls for the discriminative voxels and ROIs. For the analysis between mTBI patients and controls, the three-category-harmonized ComBat FA and MD voxel-wise linearSVC provided significantly higher classification scores (81.4% accuracy, 93.3% sensitivity, 80.3% F1-score, and 0.88 area under the curve [AUC], p < 0.05) compared with the classification based on age and sex only and the ROI approaches (accuracies: 59.8% and 64.8%, respectively). Similar to the analysis between mTBI patients and controls, the three-category-harmonized ComBat FA and MD maps voxelwise approach yields statistically significant prediction scores between mTBI patients with complete and those with incomplete recovery (71.8% specificity, 66.2% F1-score and 0.71 AUC, p < 0.05), which provided a modest increase in the classification score (accuracy: 66.4%) compared with the classification based on age and sex only and ROI-wise approaches (accuracy: 61.4% and 64.7%, respectively). This study showed that ComBat harmonized FA and MD may provide additional information for diagnosis and prognosis of mTBI in a multi-modal machine learning approach. These findings demonstrate that dMRI may assist in the early detection of patients at risk of incomplete recovery from mTBI.

Gender Differences in Adolescents' Affective Symptoms and Behavioral Disorders After Mild Traumatic Brain Injury

OBJECTIVE

Mild traumatic brain injuries (mTBI) are considered self-limiting and full recovery is expected. Recent studies identify deficits persisting years after mTBI. Large-scale prospective data permit testing the hypothesis that mTBI increases incidence of affective and behavioral symptoms after new, past , or new and past mTBI.

SETTING

The study involved secondary analyses of survey responses from the Adolescent Brain Cognitive Development (ABCD) Study.

PARTICIPANTS

Adolescents in the ABCD Study ( n = 11 869; Wave 1, aged 9-10 years; Wave 2, aged 11-12 years) whose parents reported a new ( n = 157), past ( n = 1318), or new and past ( n = 50) mTBI on the Ohio State University Traumatic Brain Injury Identification Method short form were compared with controls who had no history of mTBI ( n = 9,667).

DESIGN

Multivariable binary logistic regression models examined associations between a new, past, or new and past mTBI and current affective (aggression, depression, anxiety) and behavioral (somatic, thought, social, attention, attention deficit hyperactivity disorder, conduct) disorders while controlling for demographic factors and baseline symptoms.

MAIN MEASURES

The primary measure was parental reports of psychiatric and behavioral symptoms on the Child Behavior Checklist.

RESULTS

Girls exhibited no significant effects after a new mTBI, although a past mTBI increased anxiety (adjusted odds ratios [aOR] = 1.83, 95% confidence interval [CI: 1.15-2.90]) and attention (1.89 [1.09-3.28]) problems. Girls with new and past mTBIs reported elevated anxiety (17.90 [4.67-68.7]), aggression (7.37 [1.49-36.3]), social (9.07 [2.47-33.30]), thought (7.58 [2.24-25.60]), and conduct (6.39 [1.25-32.50]) disorders. In boys, new mTBI increased aggression (aOR = 3.83, 95% CI [1.42-10.30]), whereas past mTBI heightened anxiety (1.91 [1.42-2.95]), but new and past mTBIs had no significant effects.

CONCLUSION

Adolescents are at greater risk of affective and behavioral symptoms after an mTBI. These effects differ as a function of gender and time of injury. Extended screening for mTBI history and monitoring of affective and behavioral disorders after mTBI in adolescents are warranted.

Structural-functional connectivity bandwidth predicts processing speed in mild traumatic brain Injury: A multiplex network analysis

An emerging body of work has revealed alterations in structural (SC) and functional (FC) brain connectivity following mild TBI (mTBI), with mixed findings. However, these studies seldom integrate complimentary neuroimaging modalities within a unified framework. Multilayer network analysis is an emerging technique to uncover how white matter organization enables functional communication. Using our novel graph metric (SC-FC Bandwidth), we quantified the information capacity of synchronous brain regions in 53 mild TBI patients (46 females; age mean = 40.2 years (y), σ = 16.7 (y), range: 18-79 (y). Diffusion MRI and resting state fMRI were administered at the acute and chronic post-injury intervals. Moreover, participants completed a cognitive task to measure processing speed (30 Seconds and Counting Task; 30-SACT). Processing speed was significantly increased at the chronic, relative to the acute post-injury intervals (p = <0.001). Nonlinear principal components of direct (t = -1.84, p = 0.06) and indirect SC-FC Bandwidth (t = 3.86, p = <0.001) predicted processing speed with a moderate effect size (R2 = 0.43, p < 0.001), while controlling for age. A subnetwork of interhemispheric edges with increased SC-FC Bandwidth was identified at the chronic, relative to the acute mTBI post-injury interval (pFDR = 0.05). Increased interhemispheric SC-FC Bandwidth of this network corresponded with improved processing speed at the chronic post-injury interval (partial r = 0.32, p = 0.02). Our findings revealed that mild TBI results in complex reorganization of brain connectivity optimized for maximum information flow, supporting improved cognitive performance as a compensatory mechanism. Moving forward, this measurement may complement clinical assessment as an objective marker of mTBI recovery.

Identifying prioritization criteria for patients with mtbi waiting for multidisciplinary rehabilitation services: A Delphi study

INTRODUCTION

Rehabilitation service providers must take into account prognostic factors when making clinical decisions, which includes using these factors as prioritization criteria. The goal of this study was to establish consensus on patient prioritization criteria based on prognostic factors related to persistent symptoms for patients with mild traumatic brain injury (mTBI) waiting for outpatient specialized rehabilitation services.

MATERIALS AND METHODS

We conducted a Delphi survey involving clinicians, researchers, decision makers, and patients. Before the survey, we presented the results of an overview of systematic reviews summarizing the evidence on prognostic factors related to post-concussion symptoms.

RESULTS

After two rounds, the 17 experts reached consensus on the inclusion of 12 prioritization criteria: acute stress disorder, anxiety and depression, baseline mental and physical health, functional impacts and difficulties in performing daily habits after the trauma, motivation to receive services, multiple concussions, prior neurological problems, PTSD, quality of sleep, return to work failures, somatic complaints, suicidal ideation.

CONCLUSION

Healthcare stakeholders must consider a wide range of factors to guide clinical decision-making, including about access to care and patient prioritization. This study shows that the Delphi technique can be used to reach consensus on such decisions regarding patients with mTBI who are waiting for outpatient specialized rehabilitation services.

Research on the Potential Biomarkers of Mild Traumatic Brain Injury: a Systematic Review and Bibliometric Analysis

Reliable diagnostic methods for mild traumatic brain injury (mTBI) are lacking, and many researchers continue to search for objective biomarkers that can both define and detect mTBI. Although much research has been conducted in this field, there have not been many bibliometric studies. In this study, we aim to analyze the development over the last two decades in scientific output relating to the diagnosis of mTBI. To do this, we extracted documents from Web of Science, PubMed, and Embase and performed descriptive analysis (number of publications, primary journals, authors, and countries/regions), trend topics analysis, and citation analysis for papers across the globe, with a particular focus on molecular markers. One thousand twenty-three publications spanning 390 journals were identified on Web of Science, PubMed, and Embase for the period from 2000 to 2022. The number of publications increased every year (from 2 in 2000 to 137 in 2022). Of all the publications we analyzed, 58.7% had authors from the USA. Our analysis shows that molecular markers are the most studied markers in the field of mTBI diagnostics, accounting for 28.4% of all publications, and that the number of studies focused on this specific aspect has increased sharply in the past 5 years, indicating that molecular markers may become a research trend in the future.

Temporal changes in the microglial proteome of male and female mice after a diffuse brain injury using label-free quantitative proteomics

Traumatic brain injury (TBI) triggers neuroinflammatory cascades mediated by microglia, which promotes tissue repair in the short-term. These cascades may exacerbate TBI-induced tissue damage and symptoms in the months to years post-injury. However, the progression of the microglial function across time post-injury and whether this differs between biological sexes is not well understood. In this study, we examined the microglial proteome at 3-, 7-, or 28-days after a midline fluid percussion injury (mFPI) in male and female mice using label-free quantitative proteomics. Data are available via ProteomeXchange with identifier PXD033628. We identified a reduction in microglial proteins involved with clearance of neuronal debris via phagocytosis at 3- and 7-days post-injury. At 28 days post-injury, pro-inflammatory proteins were decreased and anti-inflammatory proteins were increased in microglia. These results indicate a reduction in microglial clearance of neuronal debris in the days post-injury with a shift to anti-inflammatory function by 28 days following TBI. The changes in the microglial proteome that occurred across time post-injury did not differ between biological sexes. However, we did identify an increase in microglial proteins related to pro-inflammation and phagocytosis as well as insulin and estrogen signaling in males compared with female mice that occurred with or without a brain injury. Although the microglial response was similar between males and females up to 28 days following TBI, biological sex differences in the microglial proteome, regardless of TBI, has implications for the efficacy of treatment strategies targeting the microglial response post-injury.

The influence of psychological flexibility on persistent post concussion symptoms and functional status after mild traumatic brain injury

PURPOSE

This study investigated the predictive role of psychological flexibility on long-term mTBI outcomes.

METHOD

Adults with mTBI (N = 147) completed a context specific measure of psychological flexibility, (AAQ-ABI), psychological distress, and mTBI outcomes at less than three months post injury (M = 6.02 weeks after injury) and 6 months later (N = 102). Structural equation modelling examined the mediating effects of psychological flexibility on psychological distress and mTBI outcomes at six months. The direct effect of psychological flexibility at less than three months on mTBI outcomes at six months was entered into the model, plus pre-injury and injury risk factors.

RESULTS

The theoretically derived model had good overall fit (χ2 = 1.42; p = 0.09; NFI = 0.95; TLI = 0.95; CFI = 0.98 and RMSEA = 0.06). Psychological flexibility at less than 3 months was directly significantly related to psychological distress and post-concussion symptoms at six months. Psychological flexibility at 6 months significantly mediated the relationship between psychological distress and functional disability but not post-concussion symptoms at six months post injury.

CONCLUSION

The exploratory findings suggest that a context specific measure of psychological flexibility assessed acutely and in the chronic phase of recovery may predict longer-term mTBI outcomes.Implications for RehabilitationPersistent post-concussion symptoms (PPCS) after mild traumatic brain injury (mTBI) can have a significant impact on wellbeing, functional status, and quality of life.In this study, psychological flexibility early in recovery, was associated with higher levels of psychological distress and more severe post-concussion symptoms six months later.Psychological flexibility at six months post-injury also mediated the relationship between psychological distress and functional disability.A context specific measure of psychological flexibility may predict poorer long-term outcomes following mTBI.

Functional-structural large-scale brain networks are correlated with neurocognitive impairment in acute mild traumatic brain injury

Background

This study was conducted to investigate topological changes in large-scale functional connectivity (FC) and structural connectivity (SC) networks in acute mild traumatic brain injury (mTBI) and determine their potential relevance to cognitive impairment.

Methods

Seventy-one patients with acute mTBI (29 males, 42 females, mean age 43.54 years) from Nanjing First Hospital and 57 matched healthy controls (HC) (33 males, 24 females, mean age 46.16 years) from the local community were recruited in this prospective study. Resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) were acquired within 14 days (mean 3.29 days) after the onset of mTBI. Then, large-scale FC and SC networks with 116 regions from the automated anatomical labeling (AAL) brain atlas were constructed. Graph theory analysis was used to analyze global and nodal metrics. Finally, correlations were assessed between topological properties and neurocognitive performances evaluated by the Montreal Cognitive Assessment (MoCA). Bonferroni correction was performed out for multiple comparisons in all involved analyses.

Results

Compared with HC, acute mTBI patients had a higher normalized clustering coefficient (γ) for FC (Cohen's d=4.076), and higher γ and small worldness (σ) for SC (Cohen's d=0.390 and Cohen's d=0.395). The mTBI group showed aberrant nodal degree (Dc), nodal efficiency (Ne), and nodal local efficiency (Nloc) for FC and aberrant Dc, nodal betweenness (Bc), nodal clustering coefficient (NCp) and Ne for SC mainly in the frontal and temporal, cerebellum, and subcortical areas. Acute mTBI patients also had higher functional-structural coupling strength at both the group and individual levels (Cohen's d=0.415). These aberrant global and nodal topological properties at functional and structural levels were associated with attention, orientation, memory, and naming performances (all P<0.05).

Conclusions

Our findings suggested that large-scale FC and SC network changes, higher correlation between FC and SC and cognitive impairment can be detected in the acute stage of mTBI. These network aberrances may be a compensatory mechanism for cognitive impairment in acute mTBI patients.

Surface-fill H2S-releasing silk fibroin hydrogel for brain repair through the repression of neuronal pyroptosis

Traumatic brain injury (TBI) remains the major cause of disability and mortality worldwide due to the persistent neuroinflammation and neuronal death induced by TBI. Among them, pyroptosis, a specific type of programmed cell death (PCD) triggered by inflammatory signals, plays a significant part in the pathological process after TBI. Inhibition of neuroinflammation and pyroptosis is considered a possible strategy for the treatment of TBI. In our previous study, exogenous hydrogen sulfide(H₂S) exerted a neuroprotective effect after TBI. Here, we developed a surface-fill H₂S-releasing silk fibroin (SF) hydrogel (H₂S@SF hydrogel) to achieve small-dose local administration and avoid volatile and toxic side effects. We used a controlled cortical impact (CCI) to establish a mild TBI model in mice to examine the effect of H₂S@SF hydrogel on TBI-induced pyroptosis. We found that H₂S@SF hydrogel inhibited the expression of H₂S synthase in neurons after TBI and significantly inhibited TBI-induced neuronal pyroptosis. In addition, immunofluorescence staining results showed that the necroptosis protein receptor-interacting serine/threonine-protein kinase 1 (RIPK1) partially colocalized with the pyroptosis protein Gasdermin D (GSDMD) in the same cells. H₂S@SF hydrogel can also inhibit the expression of the necroptosis protein. Moreover, H₂S@SF hydrogel also alleviates brain edema and the degree of neurodegeneration in the acute phase of TBI. The neuroprotective effect of H₂S@SF hydrogel was further confirmed by wire-grip test, open field test, Morris water maze, beam balance test, radial arm maze, tail suspension, and forced swimming test. Lastly, we also measured spared tissue volume, reactive astrocytes and activated microglia to demonstrate H₂S@SF hydrogel impacts on long-term prognosis in TBI. Our study provides a new theoretical basis for the treatment of H₂S after TBI and the clinical application of H₂S@SF hydrogel. STATEMENT OF SIGNIFICANCE: Silk fibroin (SF) hydrogel controls the release of hydrogen sulfide (H₂S) to inhibit neuronal pyroptosis and neuroinflammation in injured brain tissue. In this study, we synthesized a surface-fill H₂S-releasing silk fibroin hydrogel, which could slowly release H₂S to reshape the homeostasis of endogenous H₂S in injured neurons and inhibit neuronal pyroptosis in a mouse model of traumatic brain injury. Meanwhile, H₂S@SF hydrogel could alleviate brain edema and the degree of neurodegeneration, improve motor dysfunction, anxious behavior and memory impairment caused by TBI, reduce tissue loss and ameliorate neuroinflammation. Our study provides a new theoretical basis for the treatment of H₂S after TBI and the clinical application of H₂S@SF hydrogel.

Uncharted territory: The feasibility of serial computerised cognitive assessment the first week post-stroke

BACKGROUND

Cognitive impairment is common and problematic post-stroke, yet vital information to understand early cognitive recovery is lacking. To examine early cognitive recovery, it is first necessary to establish the feasibility of repeat cognitive assessment during the acute post-stroke phase.

OBJECTIVE

To determine if serial computerised testing is feasible for cognitive assessment in an acute post-stroke phase, measured by assessment completion rates.

METHOD

An observational cohort study recruited consecutive stroke patients admitted to an acute stroke unit within 48 hours of onset. Daily assessment with the Cambridge Neuropsychological Test Automated Battery (CANTAB) was performed for seven days, and single Montreal Cognitive Assessment (MoCA).

RESULTS

Seventy-one participants were recruited, mean age 74 years, with 67 completing daily testing. Participants had predominantly mild (85%; NIHSS ≤6), ischemic (90%) stroke, 32% demonstrated clinical delirium. The first day of testing, 76% of participants completed CANTAB batteries. Eighty-seven percent of participants completed MoCA a mean of 3.4 days post-stroke. The proportion of CANTAB batteries completed improved significantly from day 2 to day 3 post-stroke with test completion rates stabilizing ≥ 92% by day 4. Participants with incomplete CANTAB were older, with persisting delirium, and longer stay in acute care.

CONCLUSION

Serial computerised cognitive assessments are feasible the first week post-stroke and provide a novel approach to measuring cognitive change for both clinical and research purposes. Maximum completion rates by day four have clinical implications for optimal timing of cognitive testing.

Neuropathological Mechanisms of Mild Traumatic Brain Injury: A Perspective From Multimodal Magnetic Resonance Imaging

Mild traumatic brain injury (mTBI) accounts for more than 80% of the total number of TBI cases. The mechanism of injury for patients with mTBI has a variety of neuropathological processes. However, the underlying neurophysiological mechanism of the mTBI is unclear, which affects the early diagnosis, treatment decision-making, and prognosis evaluation. More and more multimodal magnetic resonance imaging (MRI) techniques have been applied for the diagnosis of mTBI, such as functional magnetic resonance imaging (fMRI), arterial spin labeling (ASL) perfusion imaging, susceptibility-weighted imaging (SWI), and diffusion MRI (dMRI). Various imaging techniques require to be used in combination with neuroimaging examinations for patients with mTBI. The understanding of the neuropathological mechanism of mTBI has been improved based on different angles. In this review, we have summarized the application of these aforementioned multimodal MRI techniques in mTBI and evaluated its benefits and drawbacks.

Blood-based biomarkers and traumatic brain injury-A clinical perspective

Blood-based biomarkers are promising tools to complement clinical variables and imaging findings in the diagnosis, monitoring and outcome prediction of traumatic brain injury (TBI). Several promising biomarker candidates have been found for various clinical questions, but the translation of TBI biomarkers into clinical applications has been negligible. Measured biomarker levels are influenced by patient-related variables such as age, blood-brain barrier integrity and renal and liver function. It is not yet fully understood how biomarkers enter the bloodstream from the interstitial fluid of the brain. In addition, the diagnostic performance of TBI biomarkers is affected by sampling timing and analytical methods. In this focused review, the clinical aspects of glial fibrillary acidic protein, neurofilament light, S100 calcium-binding protein B, tau and ubiquitin C-terminal hydrolase-L1 are examined. Current findings and clinical caveats are addressed.

Cognitive profile of mild traumatic brain injury patients requiring acute hospitalization - A UC davis cognitive screener (UCD-Cog) study

OBJECTIVE

Identification of patients with mTBI at risk for developing persistent-post concussive syndromes should begin during the ED/inpatient evaluation due to frequent lack of post-discharge follow-up. The best method for evaluating cognitive deficits in these acute settings and how to utilize this information to optimize follow-up care is a matter of ongoing research. In this descriptive study, we present the cognitive profile of 214 hospitalized patients with mTBI using a novel cognitive and behavioral screener, the UCD-Cog.

METHOD

A retrospective review of patients with mTBI requiring hospitalization who were enrolled in the UC Davis TBI Registry over the course of 1 year.

RESULTS

Reasoning, executive function, and delayed recall were the most frequently impaired cognitive domains. GCS 13-14 was associated with higher numbers of impaired cognitive domains and frequencies of impairments in domains traditionally associated with post-concussive symptoms. Patients with abnormal UCD-Cog results, regardless of GCS, were recommended higher levels of post-discharge care and supervision.

CONCLUSION

Inpatient cognitive profiles using the UCD-Cog were consistent with evaluations during the subacute/chronic phase of mTBI and supports the clinical utility of acute cognitive screeners for mTBI management. Future studies will determine how the acute cognitive assessments correlate with long-term mTBI outcomes.

Developing Biomarkers of Mild Traumatic Brain Injury: Promise and Progress of CNS-Derived Exosomes

Mild traumatic brain injuries (mTBI) are common injuries across civilian and military populations. Although most individuals recover after mTBI, some individuals continue to show long-term symptoms as well as increased risk for neurodegenerative and neuropsychiatric disorders. Currently, diagnosing TBI severity relies primarily on self-report and subjective symptoms, with limited tools for diagnosis or prognosis. Brain-derived exosomes, a form of extracellular vesicle, may offer a solution for interpreting injury states by aiding in diagnosis as well as outcome prediction with relatively low patient burden. Exosomes, which are released into circulation, contain both protein and RNA cargo that can be isolated and quantified, providing a molecular window into molecular status of the exosome source. Here we examined the current literature studying the utility of exosomes, in particular neuronal- and astrocyte-derived exosomes, to identify protein and miRNA biomarkers of injury severity, trajectory, and functional outcome. Current evidence supports the potential for these emerging new tools to capture an accessible molecular window into the brain as it responds to a traumatic injury, however a number of limitations must be addressed in future studies. Most current studies are relatively small and cross sectional; prospective, longitudinal studies across injury severity, and populations are needed to track exosome cargo changes after injury. Standardized exosome isolation as well as advancement in identifying/isolating exosomes from CNS-specific tissue sources will improve mechanistic understanding of cargo changes as well as reliability of findings. Exosomes are also just beginning to be used in model systems to understand functional effects of TBI-associated cargo such as toxicity. Finally linking exosome cargo changes to objective markers of neuronal pathology and cognitive changes will be critical in validating these tools to provide insights into injury and recovery states after TBI.

Age-at-Injury Determines the Extent of Long-Term Neuropathology and Microgliosis After a Diffuse Brain Injury in Male Rats

Traumatic brain injury (TBI) can occur at any age, from youth to the elderly, and its contribution to age-related neuropathology remains unknown. Few studies have investigated the relationship between age-at-injury and pathophysiology at a discrete biological age. In this study, we report the immunohistochemical analysis of naïve rat brains compared to those subjected to diffuse TBI by midline fluid percussion injury (mFPI) at post-natal day (PND) 17, PND35, 2-, 4-, or 6-months of age. All brains were collected when rats were 10-months of age (n = 6–7/group). Generalized linear mixed models were fitted to analyze binomial proportion and count data with R Studio. Amyloid precursor protein (APP) and neurofilament (SMI34, SMI32) neuronal pathology were counted in the corpus callosum (CC) and primary sensory barrel field (S1BF). Phosphorylated TAR DNA-binding protein 43 (pTDP-43) neuropathology was counted in the S1BF and hippocampus. There was a significantly greater extent of APP and SMI34 axonal pathology and pTDP-43 neuropathology following a TBI compared with naïves regardless of brain region or age-at-injury. However, age-at-injury did determine the extent of dendritic neurofilament (SMI32) pathology in the CC and S1BF where all brain-injured rats exhibited a greater extent of pathology compared with naïve. No significant differences were detected in the extent of astrocyte activation between brain-injured and naïve rats. Microglia counts were conducted in the S1BF, hippocampus, ventral posteromedial (VPM) nucleus, zona incerta, and posterior hypothalamic nucleus. There was a significantly greater proportion of deramified microglia, regardless of whether the TBI was recent or remote, but this only occurred in the S1BF and hippocampus. The proportion of microglia with colocalized CD68 and TREM2 in the S1BF was greater in all brain-injured rats compared with naïve, regardless of whether the TBI was recent or remote. Only rats with recent TBI exhibited a greater proportion of CD68-positive microglia compared with naive in the hippocampus and posterior hypothalamic nucleus. Whilst, only rats with a remote brain-injury displayed a greater proportion of microglia colocalized with TREM2 in the hippocampus. Thus, chronic alterations in neuronal and microglial characteristics are evident in the injured brain despite the recency of a diffuse brain injury.

Brain-gut axis dysfunction in the pathogenesis of traumatic brain injury

Traumatic brain injury (TBI) is a chronic and progressive disease, and management requires an understanding of both the primary neurological injury and the secondary sequelae that affect peripheral organs, including the gastrointestinal (GI) tract. The brain-gut axis is composed of bidirectional pathways through which TBI-induced neuroinflammation and neurodegeneration impact gut function. The resulting TBI-induced dysautonomia and systemic inflammation contribute to the secondary GI events, including dysmotility and increased mucosal permeability. These effects shape, and are shaped by, changes in microbiota composition and activation of resident and recruited immune cells. Microbial products and immune cell mediators in turn modulate brain-gut activity. Importantly, secondary enteric inflammatory challenges prolong systemic inflammation and worsen TBI-induced neuropathology and neurobehavioral deficits. The importance of brain-gut communication in maintaining GI homeostasis highlights it as a viable therapeutic target for TBI. Currently, treatments directed toward dysautonomia, dysbiosis, and/or systemic inflammation offer the most promise.