Mortality and morbidity 15 years after hospital admission with mild head injury: a prospective case-controlled population study

Neuroinflammation Plays a Potential Role in the Medulla Oblongata After Moderate Traumatic Brain Injury in Mice as Revealed by Nontargeted Metabonomics Analysis

Moderate traumatic brain injury (mTBI) involves a series of complex pathophysiological processes in not only the area in direct contact with mechanical violence but also in other brain regions far from the injury site, which may be important factors influencing subsequent neurological dysfunction or death. The medulla oblongata (MO) is a key area for the maintenance of basic respiratory and circulatory functions, whereas the pathophysiological processes after mTBI have rarely drawn the attention of researchers. In this study, we established a closed-head cortical contusion injury model, identified 6 different time points that covered the acute, subacute, and chronic phases, and then used nontargeted metabolomics to identify and analyze the changes in differential metabolites (DMs) and metabolic pathways in the MO region. Our results showed that the metabolic profile of the MO region underwent specific changes over time: harmaline, riboflavin, and dephospho-coenzyme A were identified as the key DMs and play important roles in reducing inflammation, enhancing antioxidation, and maintaining homeostasis. Choline and glycerophospholipid metabolism was identified as the key pathway related to the changes in MO metabolism at different phases. In addition, we confirmed increases in the levels of inflammatory factors and the activation of astrocytes and microglia by Western blot and immunofluorescence staining, and these findings were consistent with the nontargeted metabolomic results. These findings suggest that neuroinflammation plays a central role in MO neuropathology after mTBI and provide new insights into the complex pathophysiologic mechanisms involved after mTBI.

Risk Factors Analysis for 90-Day Mortality of Adult Patients with Mild Traumatic Brain Injury in an Italian Emergency Department

Purpose: The most prominent risk factors for mortality after mild traumatic brain injury (TBI) have not been established. This study aimed to establish risk factors related to 90-day mortality after a traumatic event. Methods: A retrospective cohort study on adult patients entering the Emergency Department of the University Hospital of Trieste for mild TBI from 1 January 2020 to 31 December 2020 was conducted. Results: The final population was 1221 patients (median age of 78 years). The 90-day mortality rate was 7% (90 patients). In the Cox regression model (likelihood ratio 110.9; p < 2 × 10-16), the variables that significantly correlated to 90-day mortality were age (less than 75 years old is a protective factor, HR 0.29 [95%CI 0.16-0.54]; p < 0.001); chronic liver disease (HR 4.59 [95%CI 2.56-8.24], p < 0.001); cognitive impairment (HR 2.76 [95%CI 1.78-4.27], p < 0.001); intracerebral haemorrhage (HR 15.38 [95%CI 6.13-38.63], p < 0.001); and hospitalization (HR 2.56 [95%CI 1.67-3.92], p < 0.001). Cardiovascular disease (47% vs. 11%; p < 0.001) and cognitive impairment (36% vs. 10%; p < 0.001) were more prevalent in patients over 75 years of age than the rest of the population. Conclusions: In our cohort of patients with mild TBI, 90-day mortality was low but not negligible. The risk factors associated with 90-day mortality included age, history of chronic liver disease, and cognitive impairment, as well as evidence of intracerebral hemorrhage and hospitalization. The mortality of the sub-population of older patients was likely to be linked to cardiovascular comorbidities and neurodegenerative diseases.

Diffusion Tensor Imaging Reveals Elevated Diffusivity of White Matter Microstructure that Is Independently Associated with Long-Term Outcome after Mild Traumatic Brain Injury: A TRACK-TBI Study

Diffusion tensor imaging (DTI) literature on single-center studies contains conflicting results regarding acute effects of mild traumatic brain injury (mTBI) on white matter (WM) microstructure and the prognostic significance. This larger-scale multi-center DTI study aimed to determine how acute mTBI affects WM microstructure over time and how early WM changes affect long-term outcome. From Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI), a cohort study at 11 United States level 1 trauma centers, a total of 391 patients with acute mTBI ages 17 to 60 years were included and studied at two weeks and six months post-injury. Demographically matched friends or family of the participants were the control group (n = 148). Axial diffusivity (AD), fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) were the measures of WM microstructure. The primary outcome was the Glasgow Outcome Scale Extended (GOSE) score of injury-related functional limitations across broad life domains at six months post-injury. The AD, MD, and RD were higher and FA was lower in mTBI versus friend control (FC) at both two weeks and six months post-injury throughout most major WM tracts of the cerebral hemispheres. In the mTBI group, AD and, to a lesser extent, MD decreased in WM from two weeks to six months post-injury. At two weeks post-injury, global WM AD and MD were both independently associated with six-month incomplete recovery (GOSE <8 vs = 8) even after accounting for demographic, clinical, and other imaging factors. DTI provides reliable imaging biomarkers of dynamic WM microstructural changes after mTBI that have utility for patient selection and treatment response in clinical trials. Continued technological advances in the sensitivity, specificity, and precision of diffusion magnetic resonance imaging hold promise for routine clinical application in mTBI.

Risk of Dementia After Hospitalization Due to Traumatic Brain Injury: A Longitudinal Population-Based Study

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) is considered a potential modifiable dementia risk factor. We aimed to determine whether TBI actually increases the risk of dementia when adjusting for other relevant dementia risk factors.

METHODS

This was a national prospective longitudinal cohort study that included random and representative population samples from different parts of Finland of patients 25 through 64 years of age from 1992 to 2012. Major TBI was defined as a diagnosis of traumatic intracranial hemorrhage and hospital length of stay (LOS) ≥3 days and minor TBI was defined as a diagnosis of concussion and hospital LOS ≤1 day. Dementia was defined as any first hospital contact with a diagnosis of dementia, first use of an antidementia drug, or dementia as an underlying or contributing cause of death. Follow-up was until death or end of 2017.

RESULTS

Of 31,909 participants, 288 were hospitalized due to a major TBI and 406 were hospitalized due to a minor TBI. There was a total of 976 incident dementia cases during a median follow-up of 15.8 years. After adjusting for age and sex, hospitalization due to major TBI (hazard ratio [HR] 1.51, 95% CI 1.03-2.22), but not minor TBI, increased the risk of dementia. After additional adjustment for educational status, smoking status, alcohol consumption, physical activity, and hypertension, the association between major TBI and dementia weakened (HR 1.30, 95% CI 0.86-1.97). The risk factors most strongly attenuating the association between major TBI and dementia were alcohol consumption and physical activity.

DISCUSSION

There was an association between hospitalized major TBI and incident dementia. The association was diluted after adjusting for confounders, especially alcohol consumption and physical activity. Hospitalization due to minor TBI was not associated with an increased risk of dementia.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that major TBI is associated with incident dementia.

Patients with Prior Craniectomy or Craniotomy Have No Increased Risk of Acute Hemorrhage after Mild Traumatic Brain Injury

The aim of this study was to retrospectively evaluate the risk of acute hemorrhagic complications in patients after either a decompressive craniectomy or a craniotomy sustaining a recurrent mild traumatic brain injury. Furthermore, we analyze whether there is a higher risk for acute hemorrhagic complications considering patients with anticoagulation compared with patients without anticoagulation in both groups. All patients with mild traumatic brain injuries after either decompressive craniectomy or craniotomy, treated between January 2005 and December 2020 at a single level 1 trauma center, were included in this retrospective analysis. Patients were screened for intracranial bleeding after mild traumatic brain injury with computed tomography. Additionally, the type of anticoagulation and its relationship concerning the clinical outcome were assessed. A total of 188 patients who had sustained a mild traumatic brain injury were included in the study. Overall, 22 patients (11.7%) presented intracranial lesions. A bony defect (decompressive craniectomy) was present in 31 patients (16.5%). In 157 patients (83.5%) who underwent decompressive craniectomy, the bony defect was closed during a second operation. There was no significant correlation between both groups on the occurrence of intracranial bleeding (p = 0.216). Furthermore, no difference was present between patients with and without anticoagulation (p = 0.794) concerning acute hemorrhagic complications after recurrent traumatic brain injury. Pre-existing bony defects after decompressive craniectomy showed no higher risk for acute hemorrhagic complications after recurrent mild traumatic brain injury compared with patients who primarily underwent craniotomy. Anticoagulation did not influence the occurrence of intracranial bleeding after mild traumatic brain injury in patients with decompressive craniectomy.

Do state supports for persons with brain injury affect outcomes in the 5 Years following acute rehabilitation?

While a substantial literature has examined the effects of individual and family-level factors on outcomes following traumatic brain injury (TBI), minimal attention has been directed to the potential influence of the larger environmental context on outcomes. The purpose of the current study was to investigate the effects of state-level resources and supports as an environmental factor influencing long-term outcomes from TBI using data from the TBI Model Systems. We examined the effects of U.S. state supports that specifically target people with TBI (federal funding for state brain injury programs, per capita revenue generated by brain injury trust funds, and expenditures for brain injury specific Medicaid waivers) and one measure of the relative quality of a state's Long-Term Services and Supports (LTSS) for all people with disabilities. The primary hypothesis was that community participation, global functioning, and life satisfaction will be higher on average among people with TBI living in states with more brain injury specific programs and resources and better LTSS. The results of multilevel and fixed-effects modeling indicated that state supports have a small but significant impact on participation and life satisfaction. The most consistent finding indicated that states with better LTSS had higher levels of community participation and life satisfaction on average for people with TBI over and above individual-level differences and fluctuations in these outcomes over time. There was some indication that more brain injury specific supports also result in better participation in the community. These findings deserve replication and extension to include other environmental factors, particularly community level characteristics, that might affect outcomes from TBI.

Traumatic brain injury and forensic evaluations: Three case studies of U.S. asylum-seekers

Traumatic brain injuries are common among refugees and asylum-seekers and can result from a range of etiologies, including intimate partner violence, gang violence, war-related trauma, and torture. Regardless of the cause, these injuries often result in a host of neuropsychiatric and other symptoms that may complicate individuals' subsequent health outcomes. For asylum-seekers, documenting prior head trauma is essential to the legal process, since traumatic brain injuries and their subsequent effects on memory and cognition may affect the ability to provide thorough testimony. Using three case vignettes, we explore how to approach the forensic evaluation of asylum-seekers with a history of traumatic brain injury, illustrating the range of etiologies and sequelae of traumatic brain injury in this complex population.

Diffuse axonal injury predicts neurodegeneration after moderate-severe traumatic brain injury

Traumatic brain injury is associated with elevated rates of neurodegenerative diseases such as Alzheimer's disease and chronic traumatic encephalopathy. In experimental models, diffuse axonal injury triggers post-traumatic neurodegeneration, with axonal damage leading to Wallerian degeneration and toxic proteinopathies of amyloid and hyperphosphorylated tau. However, in humans the link between diffuse axonal injury and subsequent neurodegeneration has yet to be established. Here we test the hypothesis that the severity and location of diffuse axonal injury predicts the degree of progressive post-traumatic neurodegeneration. We investigated longitudinal changes in 55 patients in the chronic phase after moderate-severe traumatic brain injury and 19 healthy control subjects. Fractional anisotropy was calculated from diffusion tensor imaging as a measure of diffuse axonal injury. Jacobian determinant atrophy rates were calculated from serial volumetric T1 scans as a measure of measure post-traumatic neurodegeneration. We explored a range of potential predictors of longitudinal post-traumatic neurodegeneration and compared the variance in brain atrophy that they explained. Patients showed widespread evidence of diffuse axonal injury, with reductions of fractional anisotropy at baseline and follow-up in large parts of the white matter. No significant changes in fractional anisotropy over time were observed. In contrast, abnormally high rates of brain atrophy were seen in both the grey and white matter. The location and extent of diffuse axonal injury predicted the degree of brain atrophy: fractional anisotropy predicted progressive atrophy in both whole-brain and voxelwise analyses. The strongest relationships were seen in central white matter tracts, including the body of the corpus callosum, which are most commonly affected by diffuse axonal injury. Diffuse axonal injury predicted substantially more variability in white matter atrophy than other putative clinical or imaging measures, including baseline brain volume, age, clinical measures of injury severity and microbleeds (>50% for fractional anisotropy versus <5% for other measures). Grey matter atrophy was not predicted by diffuse axonal injury at baseline. In summary, diffusion MRI measures of diffuse axonal injury are a strong predictor of post-traumatic neurodegeneration. This supports a causal link between axonal injury and the progressive neurodegeneration that is commonly seen after moderate/severe traumatic brain injury but has been of uncertain aetiology. The assessment of diffuse axonal injury with diffusion MRI is likely to improve prognostic accuracy and help identify those at greatest neurodegenerative risk for inclusion in clinical treatment trials.

The utility of heart rate variability as a prognostic factor in children with traumatic brain injury

OBJECTIVE

This study aimed to do a literature review to prove the hypothesis that a change in autonomous nervous system regulation, more precisely a decrease in heart rate variability (HRV), is associated with a worse outcome and could be used as a prognostic factor in children with TBI.

METHODS

Databases (Pubmed, World of Science and Scopus) studies were conducted from 1996 to 2017, considering HRV in children with TBI. Seven studies were analyzed.

RESULTS

Patients that became brain dead had a markedly lower LF/HF ratio, with a significant decrease after the first few hours of hospitalization. Patients with a more favorable prognosis had significantly higher LF/HF ratios.

DISCUSSION

The HRV can be useful when determining the severity of neurological damage and a prognostic factor in the evaluation of its recovery. However, to assess the true value of HRV monitoring in children with TBI, a prospective study with identified thresholds for HRV, comparison to the standard methods of assessment and predictions should be made blinded to outcome at admission and then through the clinical course including the post-acute phase of rehabilitation. In the absence of this, any recommendation for its use as a prognostic tool may be premature.

Does Mild Traumatic Brain Injury Increase the Risk for Dementia? A Systematic Review and Meta-Analysis

Background: Mild traumatic brain injury (mTBI) is a putative risk factor for dementia; however, despite having apparent face validity, the evidence supporting this hypothesis remains inconclusive. Understanding the role of mTBI as a risk factor is becoming increasingly important given the high prevalence of mTBI, and the increasing societal burden of dementia. Objective: Our objective was to use the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) format to determine if an association exists between mTBI and dementia and related factors, and to quantify the degree of risk. Methods: In this format, two authors conducted independent database searches of PubMed, PsycInfo, and CINAHL using three search blocks to find relevant papers published between 2000 and 2020. Relevant studies were selected using pre-defined inclusion/exclusion criteria, and bias scoring was performed independently by the two authors before a subset of studies was selected for meta-analysis. Twenty-one studies met the inclusion criteria for this systematic review. Results: The meta-analysis yielded a pooled odds ratio of 1.96 (95% CI 1.698–2.263), meaning individuals were 1.96 times more likely to be diagnosed with dementia if they had a prior mTBI. Most studies examining neuropsychiatric and neuroimaging correlates of dementia found subtle, persistent changes after mTBI. Conclusion: These results indicate that mTBI is a risk factor for the development of dementia and causes subtle changes in performance on neuropsychiatric testing and brain structure in some patients.

The role of mood, post-traumatic stress, post-concussive symptoms and coping on outcome after MTBI in elderly patients

Elderly patients are at increased risk for persistent complaints after mild traumatic brain injury (MTBI). This study aimed to investigate the role of post-concussive symptoms, mood, post-traumatic stress, and coping on functional outcome in elderly with MTBI. Information on mood, post-concussive symptoms, post-traumatic stress, and coping was collected 2 weeks post-injury. Six months post-injury functional outcome was assessed with the Glasgow Outcome Scale Extended. One hundred and sixty-two patients aged ≥ 60 years were included, 55% male, mean age = 71 (±6.2) years. The most frequent cause of injury was falls from standing height (75%). Two weeks post-injury anxiety, depression, and post-traumatic stress were present in 15%, 12%, and 38% of patients, respectively, with 73% reporting post-concussive symptoms. Avoidant coping was the most frequently used coping style. Six months post-injury, 44% showed incomplete recovery. Higher depression scores (OR = 0.87, p = 0.005) and number of post-concussive symptoms (OR = 0.91, p = 0.03) were associated with incomplete recovery. Half of the elderly showed incomplete recovery 6 months after MTBI, with early depression or post-concussive symptoms as important factors. Coping style was not related to outcome. These results underline the need for a different approach in elderly patients, focusing on other predicting factors and fall prevention strategies.

Current health status and history of traumatic brain injury among Ohio adults

INTRODUCTION

Lifetime history of traumatic brain injury (TBI) with loss of consciousness (LOC) is prevalent in 21% of adult, non-institutionalised residents of Ohio. Prior history has been associated with lower incomes, inability to work and disability. The current study sought to evaluate the relationship between lifetime history and adverse health conditions.

METHODS

Data came from the 2014 Ohio Behavioral Risk Factors Surveillance System, which included a state-specific module eliciting lifetime history of TBI.

RESULTS

Non-institutionalised adults living in Ohio who have had at least one TBI with LOC were more likely to report fair or poor health, more days of poor health, more days when poor health limited activities, being diagnosed with a chronic condition and having less than 7 hours of sleep per night. The relationship with increasing number of TBIs was monotonic, with the likelihood of adverse health increasing as the number increased. A similar relationship was observed for increasing severity of the worst lifetime TBI. Experiencing a first TBI before age 15 was associated with poorer health but was not statistically different than incurring a first after age 15.

CONCLUSIONS

Adults who have experienced TBI with LOC in their lifetime are two to three times more likely to experience adverse health conditions when compared with same age-matched, sex-matched and race-matched adults without such history. These findings support re-examining the public health burden of TBI in light of lifetime exposure and not just the consequences of an index injury.

Long-term survival and five year hospital resource usage following traumatic brain injury in Scotland from 1997 to 2015: A population-based retrospective cohort study

BACKGROUND

It is unclear if traumatic brain injury (TBI) results in excess mortality compared with head injury without injury to neural structures (HI). Because TBI populations exhibit significant demographic differences from uninjured populations, to determine the effect of TBI on survival, it is essential that a similarly injured control population be used. We aimed to determine if survival and hospital resource usage differ following TBI compared with HI.

METHODS

This retrospective population-based cohort study included all 25 319 patients admitted to a Scottish NHS hospital from 1997 to 2015 with TBI. Participants were identified using previously validated ICD-10 based definitions. For comparison, a control group of all 194 049 HI cases was also identified. Our main outcome measures were hazards of all-cause mortality for patients with TBI, compared with those with HI, over the 18-year follow-up period; and odds of mortality at one month post-injury. Number of days spent as inpatients and number of outpatient attendances per surviving month post-injury were used as measures of resource utilisation.

RESULTS

The adjusted odds ratio for mortality in the first month post-injury for TBI, compared with HI, was 7.12 (95% confidence interval [CI] 6.73-7.52; p < 0.001). For the remaining 18-year study period, the hazards of morality after TBI were 0.93 (CI 0.90-0.96; p < 0.001). During the five-year post-injury period, brain injury was associated with 2.15 (CI 2.10-2.20; p < 0.001) more days spent as inpatient and 1.09 times more outpatient attendances (CI 1.07-1.11; p < 0.001) compared with HI.

CONCLUSIONS

Although initial mortality following TBI is high, survivors of the first month post-injury can achieve comparable long-term survival to HI. However, this is associated with, and may require, increased utilisation of hospital services in the TBI group.

Impact of age on acute post-TBI neuropathology in mice expressing humanized tau: a Chronic Effects of Neurotrauma Consortium Study

OBJECTIVES

We hypothesized that polypathology is more severe in older than younger mice during the acute phase following repetitive mild traumatic brain injury (r-mTBI).

METHODS

Young and aged male and female mice transgenic for human tau (hTau) were exposed to r-mTBI or a sham procedure. Twenty-four hours post-last injury, mouse brain tissue was immunostained for alterations in astrogliosis, microgliosis, tau pathology, and axonal injury.

RESULTS

Quantitative analysis revealed a greater percent distribution of glial fibrillary acid protein and Iba-1 reactivity in the brains of all mice exposed to r-mTBI compared to sham controls. With respect to axonal injury, the number of amyloid precursor protein-positive profiles was increased in young vs aged mice post r-mTBI. An increase in tau immunoreactivity was found in young and aged injured male hTau mice.

CONCLUSIONS

We report the first evidence in our model that r-mTBI precipitates a complex sequelae of events in aged vs young hTau mice at an acute time point, typified by an increase in phosphorylated tau and astroglisosis, and a diminished microgliosis response and axonal injury in aged mice. These findings suggest differential age-dependent effects in TBI pathobiology.

Eyeball pressure stimulation induces subtle sympathetic activation in patients with a history of moderate or severe traumatic brain injury

OBJECTIVE

After traumatic brain injury (TBI), there may be persistent central-autonomic-network (CAN) dysfunction causing cardiovascular-autonomic dysregulation. Eyeball-pressure-stimulation (EPS) normally induces cardiovagal activation. In patients with a history of moderate or severe TBI (post-moderate-severe-TBI), we determined whether EPS unveils cardiovascular-autonomic dysregulation.

METHODS

In 51 post-moderate-severe-TBI patients (32.7 ± 10.5 years old, 43.1 ± 33.4 months post-injury), and 30 controls (29.1 ± 9.8 years), we recorded respiration, RR-intervals (RRI), systolic and diastolic blood-pressure (BPsys, BPdia), before and during EPS (120 sec; 30 mmHg), using an ocular-pressure-device (Okulopressor®). We calculated spectral-powers of mainly sympathetic low (LF: 0.04-0.15 Hz) and parasympathetic high (HF: 0.15-0.5 Hz) frequency RRI-fluctuations, sympathetically mediated LF-powers of BPsys, and calculated normalized (nu) LF- and HF-powers of RRI. We compared parameters between groups before and during EPS by repeated-measurement-analysis-of-variance with post-hoc analysis (significance: p < 0.05).

RESULTS

At rest, sympathetically mediated LF-BPsys-powers were significantly lower in the patients than the controls. During EPS, only controls significantly increased RRIs and parasympathetically mediated HFnu-RRI-powers, but decreased LF-RRI-powers, LFnu-RRI-powers, and LF-BPsys-powers; in contrast, the patients slightly though significantly increased BPsys upon EPS, without changing any other parameter.

CONCLUSIONS

In post-moderate-severe-TBI patients, autonomic BP-modulation was already compromised at rest. During EPS, our patients failed to activate cardiovagal modulation but slightly increased BPsys, indicating persistent CAN dysregulation.

SIGNIFICANCE

Our findings unveil persistence of subtle cardiovascular-autonomic dysregulation even years after TBI.

Geriatric Traumatic Brain Injury: Epidemiology, Outcomes, Knowledge Gaps, and Future Directions

This review of the literature on traumatic brain injury (TBI) in older adults focuses on incident TBI sustained in older adulthood ("geriatric TBI") rather than on the separate, but related, topic of older adults with a history of earlier-life TBI. We describe the epidemiology of geriatric TBI, the impact of comorbidities and pre-injury function on TBI risk and outcomes, diagnostic testing, management issues, outcomes, and critical directions for future research. The highest incidence of TBI-related emergency department visits, hospitalizations, and deaths occur in older adults. Higher morbidity and mortality rates among older versus younger individuals with TBI may contribute to an assumption of futility about aggressive management of geriatric TBI. However, many older adults with TBI respond well to aggressive management and rehabilitation, suggesting that chronological age and TBI severity alone are inadequate prognostic markers. Yet there are few geriatric-specific TBI guidelines to assist with complex management decisions, and TBI prognostic models do not perform optimally in this population. Major barriers in management of geriatric TBI include under-representation of older adults in TBI research, lack of systematic measurement of pre-injury health that may be a better predictor of outcome and response to treatment than age and TBI severity alone, and lack of geriatric-specific TBI common data elements (CDEs). This review highlights the urgent need to develop more age-inclusive TBI research protocols, geriatric TBI CDEs, geriatric TBI prognostic models, and evidence-based geriatric TBI consensus management guidelines aimed at improving short- and long-term outcomes for the large and growing geriatric TBI population.

Epidemiology of recurrent traumatic brain injury in the general population: A systematic review

OBJECTIVE

To comprehensively assess recurrent traumatic brain injury (rTBI) risk and risk factors in the general population.

METHODS

We systematically searched MEDLINE, EMBASE, and the references of included studies until January 16, 2017, for general population observational studies reporting rTBI risk or risk factors. Estimates were not meta-analyzed due to significant methodologic heterogeneity between studies, which was evaluated using meta-regression.

RESULTS

Twenty-two studies reported recurrence risk and 11 reported on 27 potential risk factors. rTBI risk was heterogeneous and varied from 0.43% (95% confidence interval [CI] 0.19%-0.67%) to 41.92% (95% CI 34.43%-49.40%), with varying follow-up periods (3 days-55 years). Median time to recurrence ranged from 0.5 to 3.8 years. In studies where cases were ascertained from multiple points of care, at least 5.50% (95% CI 4.80%-6.30%) of patients experienced a recurrence after a 1-year follow-up. Studies that used administrative data/self-report surveys to ascertain cases tended to report higher risk. Risk factors measured at time of index traumatic brain injury (TBI) that were significantly associated with rTBI in more than one study were male sex, prior TBI before index case, moderate or severe TBI, and alcohol intoxication. Risk factors reported in a single study that were significantly associated with rTBI were epilepsy, not seeking medical care, and multiple factors indicative of low socioeconomic status.

CONCLUSIONS

rTBI is an important contributor to the general population TBI burden. Certain risk factors can help identify individuals at higher risk of these repeated injuries. However, higher quality research that improves on rTBI surveillance methodology is needed.

The chronic and evolving neurological consequences of traumatic brain injury

Traumatic brain injury (TBI) can have lifelong and dynamic effects on health and wellbeing. Research on the long-term consequences emphasises that, for many patients, TBI should be conceptualised as a chronic health condition. Evidence suggests that functional outcomes after TBI can show improvement or deterioration up to two decades after injury, and rates of all-cause mortality remain elevated for many years. Furthermore, TBI represents a risk factor for a variety of neurological illnesses, including epilepsy, stroke, and neurodegenerative disease. With respect to neurodegeneration after TBI, post-mortem studies on the long-term neuropathology after injury have identified complex persisting and evolving abnormalities best described as polypathology, which includes chronic traumatic encephalopathy. Despite growing awareness of the lifelong consequences of TBI, substantial gaps in research exist. Improvements are therefore needed in understanding chronic pathologies and their implications for survivors of TBI, which could inform long-term health management in this sizeable patient population.

Severity of traumatic brain injury correlates with long-term cardiovascular autonomic dysfunction

After traumatic brain injury (TBI), central autonomic dysfunction might contribute to long-term increased mortality rates. Central autonomic dysfunction might depend on initial trauma severity. This study was performed to evaluate differences in autonomic modulation at rest and upon standing between patients with a history of mild TBI (post-mild-TBI patients), moderate or severe TBI (post-moderate–severe-TBI patients), and healthy controls. In 20 post-mild-TBI patients (6–78 months after TBI), age-matched 20 post-moderate–severe-TBI patients (6–94 months after TBI) and 20 controls, we monitored respiration, RR intervals (RRI) and systolic blood pressure (BPsys) at supine rest and upon standing. We determined mainly sympathetic low (LF) and parasympathetic high (HF) frequency powers of RRI fluctuations, sympathetically mediated LF-BPsys powers, LF/HF-RRI ratios, normalized (nu) LF-RRI and HF-RRI powers, and compared data between groups, at rest and upon standing (ANOVA with post hoc testing). We correlated autonomic parameters with initial Glasgow Coma Scale (GCS) scores (Spearman test; significance: p < 0.05). Supine BPsys and LFnu-RRI powers were higher while HFnu-RRI powers were lower in post-moderate–severe-TBI patients than post-mild-TBI patients and controls. LFnu-RRI powers were higher and HFnu-RRI powers were lower in post-mild-TBI patients than controls. Upon standing, only post-mild-TBI patients and controls increased LF-BPsys powers and BPsys and decreased HF-RRI powers. GCS scores correlated positively with LFnu-RRI powers, LF/HF-RRI ratios, and inversely with HFnu-RRI powers, at standing position. More than 6 months after TBI, there is autonomic dysfunction at rest and upon standing which is more pronounced after moderate–severe than mild TBI and in part correlates with initial trauma severity.

Long-term health outcomes after exposure to repeated concussion in elite level: rugby union players

BACKGROUND

There is continuing concern about effects of concussion in athletes, including risk of the neurodegenerative disease chronic traumatic encephalopathy. However, information on long-term health and wellbeing in former athletes is limited.

METHOD

Outcome after exposure to repeated brain injury was investigated in 52 retired male Scottish international rugby players (RIRP) and 29 male controls who were similar in age and social deprivation. Assessment included history of playing rugby and traumatic brain injury, general and mental health, life stress, concussion symptoms, cognitive function, disability and markers of chronic stress (allostatic load).

RESULTS

The estimated number of concussions in RIRP averaged 14 (median=7; IQR 5-40). Performance was poorer in RIRP than controls on a test of verbal learning (p=0.022) and of fine co-ordination of the dominant hand (p=0.038) and not significantly different on other cognitive tests (p>0.05). There were no significant associations between number of concussions and performance on cognitive tests. Other than a higher incidence of cardiovascular disease in controls, no group differences were detected in general or mental health or estimates of allostatic load. In RIRP, persisting symptoms attributed to concussion were more common if reporting more than nine concussions (p=0.028), although these symptoms were not perceived to affect social or work functioning.

CONCLUSIONS

Despite a high number of concussions in RIRP, differences in mental health, social or work functioning were not found late after injury. Subtle group differences were detected on two cognitive tests, the cause of which is uncertain. Prospective group comparison studies on representative cohorts are required.

Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury

Background

Patients with a history of mild TBI (post-mTBI-patients) have an unexplained increase in long-term mortality which might be related to central autonomic dysregulation (CAD). We investigated whether standardized baroreflex-loading, induced by a Valsalva maneuver (VM), unveils CAD in otherwise healthy post-mTBI-patients.

Methods

In 29 healthy persons (31.3 ± 12.2 years; 9 women) and 25 post-mTBI-patients (35.0 ± 13.2 years, 7 women, 4–98 months post-injury), we monitored respiration (RESP), RR-intervals (RRI) and systolic blood pressure (BP) at rest and during three VMs. At rest, we calculated parameters of total autonomic modulation [RRI-coefficient-of-variation (CV), RRI-standard-deviation (RRI-SD), RRI-total-powers], of sympathetic [RRI-low-frequency-powers (LF), BP-LF-powers] and parasympathetic modulation [square-root-of-mean-squared-differences-of-successive-RRIs (RMSSD), RRI-high-frequency-powers (HF)], the index of sympatho-vagal balance (RRI LF/HF-ratios), and baroreflex sensitivity (BRS). We calculated Valsalva-ratios (VR) and times from lowest to highest RRIs after strain (VR-time) as indices of parasympathetic activation, intervals from highest systolic BP-values after strain-release to the time when systolic BP had fallen by 90 % of the differences between peak-phase-IV-BP and baseline-BP (90 %-BP-normalization-times), and velocities of BP-normalization (90 %-BP-normalization-velocities) as indices of sympathetic withdrawal.

We compared patient- and control-parameters before and during VM (Mann-Whitney-U-tests or t-tests; significance: P < 0.05).

Results

At rest, RRI-CVs, RRI-SDs, RRI-total-powers, RRI-LF-powers, BP-LF-powers, RRI-RMSSDs, RRI-HF-powers, and BRS were lower in patients than controls. During VMs, 90 %-BP-normalization-times were longer, and 90 %-BP-normalization-velocities were lower in patients than controls (P < 0.05).

Conclusions

Reduced autonomic modulation at rest and delayed BP-decrease after VM-induced baroreflex-loading indicate subtle CAD with altered baroreflex adjustment to challenge. More severe autonomic challenge might trigger more prominent cardiovascular dysregulation and thus contribute to increased mortality risk in post-mTBI-patients.

Health Problems Precede Traumatic Brain Injury in Older Adults

OBJECTIVES

To evaluate whether indices of preinjury health and functioning are associated with risk of incident traumatic brain injury (TBI) with loss of consciousness (LOC) and to evaluate health-related factors associated with mortality in individuals with incident TBI.

DESIGN

Prospective community cohort study.

SETTING

Group Health, Seattle, Washington.

PARTICIPANTS

Individuals aged 65 and older with no self-reported prior TBI with LOC (N = 3,363) were enrolled and followed every 2 years for an average of 7.5 years (range 0-18 years).

MEASUREMENTS

Weibull survival models were used to evaluate baseline and time-varying predictors of incident TBI with LOC, including measures of depression, activities of daily living (ADLs), cerebrovascular disease, and disease comorbidity.

RESULTS

In an adjusted multivariate model, baseline depression symptoms as measured according to Center for Epidemiologic Studies Depression Scale (CES-D) score (hazard ratio (HR) for 4 points = 1.23, 95% confidence interval (CI) = 1.02-1.49, P = .03) and baseline activity of daily living (ADL) impairment (HR = 2.37, 95% CI = 1.24-4.53, P = .009) were associated with incident TBI. In a model that included time-dependent covariates, cerebrovascular disease at the previous visit (HR = 2.28, 95% CI = 1.37-3.78, P < .001), CES-D score the previous visit (HR for 4 points = 1.23, 95% CI = 1.02-1.49, P < .04) and baseline ADL impairment (HR 2.14, 95% CI = 1.11-4.13, P = .02) predicted incident TBI. Of factors considered, cerebrovascular disease and ADL impairment were associated with earlier mortality in participants with incident TBI with LOC.

CONCLUSION

Indices of health, mood, and functional status predict incident TBI with LOC in older adults. These findings may have implications for injury prevention and postinjury clinical management.

Concussion is confusing us all

It is time to stop using the term concussion as it has no clear definition and no pathological meaning. This confusion is increasingly problematic as the management of ‘concussed’ individuals is a pressing concern. Historically, it has been used to describe patients briefly disabled following a head injury, with the assumption that this was due to a transient disorder of brain function without long-term sequelae. However, the symptoms of concussion are highly variable in duration, and can persist for many years with no reliable early predictors of outcome. Using vague terminology for post-traumatic problems leads to misconceptions and biases in the diagnostic process, producing uninterpretable science, poor clinical guidelines and confused policy. We propose that the term concussion should be avoided. Instead neurologists and other healthcare professionals should classify the severity of traumatic brain injury and then attempt to precisely diagnose the underlying cause of post-traumatic symptoms.

Head Trauma with or without Mild Brain Injury Increases the Risk of Future Traumatic Death: A Controlled Prospective 15-Year Follow-Up Study

Patients who have recovered from traumatic brain injury (TBI) show an increased risk of premature death. To investigate long-term mortality rates in a population admitted to the hospital for head injury (HI), we conducted a population-based prospective case-control, record-linkage study, All subjects who were living in Northern Ostrobothnia, and who were admitted to Oulu University Hospital in 1999 because of HI (n=737), and 2196 controls matched by age, gender, and residence randomly drawn from the population of Northern Ostrobothnia were included. Death rate and causes of death in HI subjects during 15 years of follow-up was compared with the general population controls. The crude mortality rates were 56.9, 18.6, and 23.8% for subjects having moderate-to-severe traumatic brain injury (TBI), mild TBI, and head injury without TBI, respectively. The corresponding approximate annual mortality rates were 6.7%, 1.4%, and 1.9%. All types of index HI predicted a significant risk of traumatic death in the future. Subjects who had HI without TBI had an increased risk of both death from all causes (hazard ratio 2.00; 95% confidence interval 1.57-2.55) and intentional or unintentional traumatic death (4.01, 2.20-7.30), compared with controls. The main founding was that even HI without TBI carries an increased risk of future traumatic death. The reason for this remains unknown and further studies are needed. To prevent such premature deaths, post-traumatic therapy should include an interview focusing on lifestyle factors.

Mortality following Traumatic Brain Injury Inpatient Rehabilitation

The aim of this study was to examine the rate and causes of mortality following mild to severe traumatic brain injury (TBI) rehabilitation and to develop a multivariate prognostic model of mortality. We conducted a cohort study of 3341 individuals with mild to severe TBI followed-up from a post-acute inpatient rehabilitation center. Rate of death and survival between one and 26 years following injury were examined using standardized mortality ratios (SMRs) and prognostic models developed using Cox regression. A mortality rate of 9.3% was observed and an overall SMR of 1.04 (95% confidence interval [CI]=1.04-1.05). A statistically significant elevated SMR of 1.20 (95% CI=1.06-1.37) was observed for males, and both males and females had an elevated risk of death from external causes. Females also were found to have a significantly elevated SMR of 5.02 (95% CI=1.36-12.80) for intentional self-harm. Individuals ages 15-44 had a two-fold increase in mortality, compared with the general population. The multivariate Cox model indicated that increased risk of mortality was associated with older age, being male, being unemployed prior to injury, having a history of stroke, alcohol use, mental health issues, and back injury sustained in the accident. Premorbid lifestyle factors exerted a greater influence on mortality following TBI, compared with injury-related factors. This risk was especially prominent for younger individuals, who died primarily due to external causes. These findings highlight the need for interventions that address premorbid issues, such as substance abuse and mental health issues.

Head injury and mortality in the homeless

Risk factors for head injury are also risk factors for becoming homeless but there is little research on this vulnerable group, who can be neglected by health services that specialize in acquired brain injury. This study investigates the prevalence of admissions to hospital with a head injury in the homeless and associations with later mortality. It compares homeless people with and without a record of hospitalized head injury (HHI) and the Glasgow population. Data were obtained from a U.K. National Health Service strategy to enhance care of the homeless. This included development and production of local registers of homeless people. In Glasgow, the initiative took place over a seven-year period (2004-2010) and comprised 40 general practitioner (family practice) services in the locality of 55 homeless hostels. The register was linked to hospital admissions with head injury recorded in Scottish Medical Records and to the General Register of Scotland, which records deaths. A total of 1590 homeless people was registered in general practitioner (family doctor) returns. The prevalence of admission to hospital with head injury in the homeless over a 30-year period (13.5%) was 5.4 times higher than in the Glasgow population. In the homeless with HHI, 33.6% died in the seven-year census period, compared with 13.9% in the homeless with no hospitalized HI (NHHI). The standardized mortality ratio for HHI (4.51) was more than twice that for NHHI (2.08). The standardized mortality ratio for HHI aged 15-34 (17.54) was particularly high. These findings suggest that HHI is common in the homeless relative to the general population and is a risk factor for late mortality in the homeless population.