Chronic motor performance following different traumatic brain injury severity-A systematic review

3,3'-Diindolylmethane improves pathology and neurological outcome following traumatic brain injury

3,3'-Diindolylmethane (DIM), a naturally occurring bis-indole found in cruciferous vegetables and produced in small amounts in the normal flora of the human gut, has demonstrated neuroprotective benefits in models of CNS hypoxia and stroke. In the CNS, DIM modulates the activation of the aryl hydrocarbon receptor (AhR) and inhibits its pro-inflammatory effects. Although capable of crossing the blood brain barrier, DIM's bioavailability is limited by its low solubility. Dispersed BR4044 provides a nanoscale high-solubility DIM suspension with the potential for treating traumatic brain injury (TBI). The present study aimed to determine whether BR4044 treatment could reduce pathology and improve behavioral recovery following moderate TBI. Male Sprague Dawley rats received moderate fluid percussion injury or sham surgery followed by vehicle or BR4044 treatment in the acute recovery period. TBI BR4044 animals showed significantly reduced cortical and hippocampal edema and lower levels of serum-derived extracellular vesicles compared to TBI Vehicle animals. BR4044 treatment of TBI animals preserved sensorimotor function and associative fear memory. Cortical contusion size and neuronal loss in the parietal cortex and CA3 region of the hippocampus were also significantly reduced with BR4044 treatment. BR4044 also decreased microbleeding and nuclear AhR at the contusion site. This translational study demonstrates that BR4044 ameliorates pathology and improves neurological outcomes following TBI by reducing brain edema, lowering acute extracellular vesicle release, modulating AhR, preserving cortical and hippocampal neurons, reducing red blood cell (RBC) extravasation into the injured brain, and promoting behavioral recovery.

Balance Performance After Mild Traumatic Brain Injury in Children and Adolescents: Instrumented BESS in the Acute Situation and Over Time

Background: Mild traumatic brain injury (mTBI) in the pediatric population is a significant public health concern, often associated with persistent post-concussion symptoms, including postural instability. Current tools for assessing postural control, such as the Balance Error Scoring System (BESS), lack integration with objective metrics. Incorporating force plate sensors into BESS assessments may enhance diagnostic accuracy and support return-to-play or sports decisions. This study evaluates postural performance in children with mTBI compared to controls using an instrumented BESS and examines recovery trajectories after mTBI. Methods: This prospective, longitudinal study included 31 children with mTBI (12.01 ± 3.28 years, 20 females) and 31 controls (12.31 ± 3.27 years, 18 females). Postural control was assessed using an instrumented BESS protocol during standing on a ground reaction force plate at three timepoints: within 72 h post injury (T1), at two weeks (T2), and three months after trauma (T3). Posturographic parameters derived from the displacement of the center of pressure included the ellipse area, path length, and mean velocity in the anterior-posterior and medio-lateral directions. Symptom burden was monitored using the Post-Concussion Symptom Inventory (PCSI). Results: The BESS total scores did not differ significantly between the groups at any timepoint. A significant reduction in BESS errors over time was observed exclusively in the two-legged stance on a soft surface (p = 0.047). The instrumented BESS revealed higher body swaying in the mTBI group compared to controls, particularly under demanding conditions. Significant between-group differences were most frequently observed in single-leg soft surface (38% of comparisons) and two-legged soft surface stances (29%). In those cases, path length and mean velocity differed between groups, respectively. Ellipse area did not show significant differences across conditions. Conclusions: An instrumented BESS has the potential to enhance the detection of subtle postural deficits in pediatric mTBI patients. Specifically, more demanding conditions with altered sensory-proprioceptive input and path length as an outcome measure should be focused on. This study underscores the need for tailored and age-appropriate objective and quantitative balance assessments to improve diagnostic precision in pediatric mTBI populations.

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.

Disparities between Native Americans and Whites in trajectories of functional independence and life satisfaction over the 5 years after traumatic brain injury

PURPOSE

Traumatic brain injury (TBI) can lead to impairments in motor and cognitive function and reduced life satisfaction. TBI is one of the leading causes of death and disability worldwide and disproportionately affects Native Americans, who have the highest rates of TBI among all races in the United States and elevated likelihood for fatality and severe complications. This study investigated whether disparities in functional and life satisfaction outcomes exist longitudinally over the 5 years after complicated mild, moderate, or severe TBI between Native Americans and White individuals; it further explored which demographic and injury-related covariates account for them.

RESEARCH METHOD

The current study used a subsample of the national TBI Model Systems Database of 80 demographically and injury-severity matched Native American and White pairs (total n = 160).

RESULTS

A series of longitudinal hierarchical linear models found that Native Americans experienced significantly lower Functional Independence Measure Cognitive and Motor trajectories than Whites; however, life satisfaction was comparable. Native Americans had declining cognitive function over time relative to a slight increase in White individuals. This differential movement dissipated with the addition of employment status at the time of injury and type of health insurance.

CONCLUSIONS

These results demonstrate a profound need to further investigate the cultural and contextual variables unique to Native Americans that underlie these differences and highlight the importance of culturally responsive treatment and rehabilitation in bridging the gap in recovery. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Neuroinflammatory Response in the Traumatic Brain Injury: An Update

The central nervous system (CNS) comprises membranes and barriers that are vital to brain homeostasis. Membranes form a robust shield around neural structures, ensuring protection and structural integrity. At the same time, barriers selectively regulate the exchange of substances between blood and brain tissue, which is essential for maintaining homeostasis. Another highlight is the glymphatic system, which cleans metabolites and waste from the brain. Traumatic brain injury (TBI) represents a significant cause of disability and mortality worldwide, resulting from the application of direct mechanical force to the head that results in a primary injury. Therefore, this review aims to elucidate the mechanisms associated with the secondary injury cascade, in which there is intense activation of glial cells, dysfunction of the glymphatic system, glutamatergic neurotoxicity, additional molecular and biochemical changes that lead to a neuroinflammatory process, and oxidative stress and in which way they can be associated with cognitive damage that is capable of lasting for an extended period.

Aerobic performance in rats subjected to incremental-speed running exercise: A multiple regression analysis study emphasizing thermoregulation-related variables

Single-variable analyses have limited ability to explain complex phenomena such as the regulation of prolonged physical (aerobic) performance. Our study aimed to identify predictors of performance in rats subjected to incremental-speed running exercise. Notably, most variables assessed were associated with rats' thermoregulation. We extracted data from 355 records obtained in 216 adult Wistar rats. Hierarchical multiple linear regression analyses were conducted to identify the predictive power of eight variables. The distance traveled, a performance index, was the dependent variable. The independent variables included body mass, biological sex, body core temperature (TCORE) measurement site, and the following thermoregulation-related variables: ambient temperature (TAMB), initial TCORE, exercise-induced change in TCORE (ΔTCORE), ΔTCORE from 0 to 10 min (ΔTCORE 0-10; when TCORE increase is fastest), and heat loss index (HLI). This analysis with eight variables revealed an adjusted R2 of 0.495; TAMB, ΔTCORE, body mass, and ΔTCORE 0-10 had the highest predictive powers (β values: -0.700, 0.463, -0.353, and -0.130, respectively). Additional analyses consisted of separate regressions for each TCORE index measured: abdominal (TABD), brain (TBRAIN), and colonic (TCOL) temperature. These analyses yielded adjusted R2 values of 0.608 (TABD), 0.550 (TBRAIN), and 0.437 (TCOL). Again, the distance traveled was primarily predicted by body mass and thermoregulation-related variables (TAMB, ΔTCORE, and ΔTCORE 0-10). Among these four variables, ΔTCORE was the only one with a positive β value (directly predicted performance), while the others had negative values. Collectively, these findings advance our understanding of performance regulation in rats, especially regarding the role of thermoregulation-related variables.

Lower extremity muscle activity during reactive balance differs between adults with chronic traumatic brain injury and controls

Background

Control of reactive balance is key to achieving safe independent walking and engagement in life activities. After traumatic brain injury (TBI), motor impairments and mobility challenges are persistent sequelae. To date, no studies have explored muscle activity of individuals with chronic TBI during a task that requires reactive control of balance.

Objective

To investigate lower extremity muscle activity during a reactive balance test performed by adults with chronic severe TBI and matched controls. We hypothesized that abnormal activity of lower extremity muscles would be related with poorer reactive balance performance. Also, we performed an exploratory analysis for those with TBI investigating the impact of unilateral versus bilateral lower extremity involvement in the control of reactive balance.

Methods

Ten adults with chronic severe TBI who were independent community ambulators and ten matched controls performed the computerized reactive balance test (Propriotest®) while lower extremity muscle activity was recorded. Electromyographic (EMG) activity was contrasted (Mann-Whitney U Test) between groups across each 10 s epoch of the 120 s test. Additionally, test scores were correlated (Spearman) with lower extremity composite EMG activity to distinguish muscle activity patterns related with reactive balance performance. Lastly, reactive balance test scores were correlated with reactive balance test scores and clinical functional measures only for the TBI group.

Results

Although the TBI group exhibited greater EMG activity across the entire test compared with the control group, significant differences were not observed. Greater composite EMG activity correlated significantly with poorer reactive balance performance across most of the 10 s windows of the test.

Conclusion

Greater muscle activity exhibited during the reactive balance test by individuals with chronic severe TBI compared to those without disabilities, particularly at small unexpected perturbations, highlights the greater physiologic effort required to control reactive balance even after independent ambulation is achieved.

Longitudinal Assessment of Selective Motor Dysfunction in Service Members With Combat-Related Mild TBI

INTRODUCTION

Evaluations of clinical outcomes in service members with mild traumatic brain injury (TBI) sustained in combat have largely focused on neurobehavioral and somatic symptoms, neurocognitive functioning, and psychological/psychiatric health. Questions remain regarding other domains, such as gross or fine motor abilities, that could be impacted and are mission-critical to functional warfighters.

MATERIALS AND METHODS

The objective of the current study was to evaluate longitudinal motor function in U.S. Military personnel with and without mild TBI sustained in combat to assess the possible long-term impact. Data from the EValuation Of Longitudinal outcomes in mild TBI active duty military and VEterans (EVOLVE) study were leveraged for analysis. The EVOLVE study has evaluated and followed service members from combat and following medical evacuation with and without blast-related mild TBI, as well as blunt impact mild TBI, and noninjured combat-deployed service members, tracking 1-, 5-, and 10-year outcomes. Longitudinal demographic, neuropsychological, and motor data were leveraged. Cross-sectional differences in outcomes at each year among the 4 injury groups were assessed using rank regression, adjusting for age, education, sex, branch of service (Army vs. other), subsequent head injury exposure, and separation from service. To understand the possible performance impact of time on all the measures, mixed-effects rank regression was employed, assessing time with adjustments for group, age, education, subsequent head injury exposure, and service separation status, followed by Benjamini-Hochberg correction for multiple comparisons.

RESULTS

Evaluation for cognitive performance across 19 primary measures of interest at 1, 5, and 10 years did not identify any significant differences; however, gross motor function was found to be significantly different across groups at all time points (adjusted P < .001 at 1 year, P = .004 at 5 years, and P < .001 at 10 years) with both TBI groups consistently performing slower on the 25-Foot Walk and Grooved Pegboard than the nonblast control groups. While there were no cross-sectional differences across groups, many cognitive and motor measures were found to have significant changes over time, though not always in the direction of worse performance. Selective motor impairment in both TBI groups was identified compared to nonblast controls, but all groups were also found to exhibit a level of motor slowing when comparing performance at 1- to 10-year follow-ups.

CONCLUSIONS

Assessment of gross motor function reflected a consistent pattern of significantly slower performances for blast and nonblast TBI groups compared to controls, over all follow-up intervals. Fine motor function performance reflected a similar significant difference pattern at 1- and 5-year follow-up intervals, with a reduced difference from control groups at the 10-year follow-up. Maintenance of high-level motor functions, including overall motor speed, coordination, and reaction time, is a primary component for active warfighters, and any motor-related deficits could create an increased risk for the service member or unit. While the service members in this longitudinal study did not meet criteria for any specific clinical motor-related diagnoses or movement disorders, the finding of motor slowing may reflect a subclinical but significant change that could be a focus for intervention to return to preinjury levels.

Reactive gliosis in traumatic brain injury: a comprehensive review

Traumatic brain injury (TBI) is one of the most common pathological conditions impacting the central nervous system (CNS). A neurological deficit associated with TBI results from a complex of pathogenetic mechanisms including glutamate excitotoxicity, inflammation, demyelination, programmed cell death, or the development of edema. The critical components contributing to CNS response, damage control, and regeneration after TBI are glial cells-in reaction to tissue damage, their activation, hypertrophy, and proliferation occur, followed by the formation of a glial scar. The glial scar creates a barrier in damaged tissue and helps protect the CNS in the acute phase post-injury. However, this process prevents complete tissue recovery in the late/chronic phase by producing permanent scarring, which significantly impacts brain function. Various glial cell types participate in the scar formation, but this process is mostly attributed to reactive astrocytes and microglia, which play important roles in several brain pathologies. Novel technologies including whole-genome transcriptomic and epigenomic analyses, and unbiased proteomics, show that both astrocytes and microglia represent groups of heterogenic cell subpopulations with different genomic and functional characteristics, that are responsible for their role in neurodegeneration, neuroprotection and regeneration. Depending on the representation of distinct glia subpopulations, the tissue damage as well as the regenerative processes or delayed neurodegeneration after TBI may thus differ in nearby or remote areas or in different brain structures. This review summarizes TBI as a complex process, where the resultant effect is severity-, region- and time-dependent and determined by the model of the CNS injury and the distance of the explored area from the lesion site. Here, we also discuss findings concerning intercellular signaling, long-term impacts of TBI and the possibilities of novel therapeutical approaches. We believe that a comprehensive study with an emphasis on glial cells, involved in tissue post-injury processes, may be helpful for further research of TBI and be the decisive factor when choosing a TBI model.

Long Noncoding RNA VLDLR-AS1 Levels in Serum Correlate with Combat-Related Chronic Mild Traumatic Brain Injury and Depression Symptoms in US Veterans

More than 75% of traumatic brain injuries (TBIs) are mild (mTBI) and military service members often experience repeated combat-related mTBI. The chronic comorbidities concomitant with repetitive mTBI (rmTBI) include depression, post-traumatic stress disorder or neurological dysfunction. This study sought to determine a long noncoding RNA (lncRNA) expression signature in serum samples that correlated with rmTBI years after the incidences. Serum samples were obtained from Long-Term Impact of Military-Relevant Brain-Injury Consortium Chronic Effects of Neurotrauma Consortium (LIMBIC CENC) repository, from participants unexposed to TBI or who had rmTBI. Four lncRNAs were identified as consistently present in all samples, as detected via droplet digital PCR and packaged in exosomes enriched for CNS origin. The results, using qPCR, demonstrated that the lncRNA VLDLR-AS1 levels were significantly lower among individuals with rmTBI compared to those with no lifetime TBI. ROC analysis determined an AUC of 0.74 (95% CI: 0.6124 to 0.8741; p = 0.0012). The optimal cutoff for VLDLR-AS1 was ≤153.8 ng. A secondary analysis of clinical data from LIMBIC CENC was conducted to evaluate the psychological symptom burden, and the results show that lncRNAs VLDLR-AS1 and MALAT1 are correlated with symptoms of depression. In conclusion, lncRNA VLDLR-AS1 may serve as a blood biomarker for identifying chronic rmTBI and depression in patients.

A pre-existing Toxoplasma gondii infection exacerbates the pathophysiological response and extent of brain damage after traumatic brain injury in mice

Traumatic brain injury (TBI) is a key contributor to global morbidity that lacks effective treatments. Microbial infections are common in TBI patients, and their presence could modify the physiological response to TBI. It is estimated that one-third of the human population is incurably infected with the feline-borne parasite, Toxoplasma gondii, which can invade the central nervous system and result in chronic low-grade neuroinflammation, oxidative stress, and excitotoxicity-all of which are also important pathophysiological processes in TBI. Considering the large number of TBI patients that have a pre-existing T. gondii infection prior to injury, and the potential mechanistic synergies between the conditions, this study investigated how a pre-existing T. gondii infection modified TBI outcomes across acute, sub-acute and chronic recovery in male and female mice. Gene expression analysis of brain tissue found that neuroinflammation and immune cell markers were amplified in the combined T. gondii + TBI setting in both males and females as early as 2-h post-injury. Glutamatergic, neurotoxic, and oxidative stress markers were altered in a sex-specific manner in T. gondii + TBI mice. Structural MRI found that male, but not female, T. gondii + TBI mice had a significantly larger lesion size compared to their uninfected counterparts at 18-weeks post-injury. Similarly, diffusion MRI revealed that T. gondii + TBI mice had exacerbated white matter tract abnormalities, particularly in male mice. These novel findings indicate that a pre-existing T. gondii infection affects the pathophysiological aftermath of TBI in a sex-dependent manner, and may be an important modifier to consider in the care and prognostication of TBI patients.