Long-term neurologic outcomes after traumatic brain injury

Subconcussive Blows to the Head: A Formative Review of Short-term Clinical Outcomes

BACKGROUND

Given questions about "lower thresholds" for concussion, as well as possible effects of repetitive concussion and chronic traumatic encephalopathy (CTE), and associated controversy, there is increasing interest in "subconcussive" blows and their potential significance.

OBJECTIVE

A formative review with critical examination of the developing literature on subconcussive blows in athletes with an emphasis on clinical outcomes.

METHODS

Studies of biomechanical, performance and/or symptom-based, and neuroimaging data were identified via PubMed search and critically reviewed. Five studies of symptom reporting/performance and 4 studies of neuroimaging were included.

RESULTS

The relation between biomechanical parameters and diagnosed concussion is not straightforward (ie, it is not the case that greater and more force leads to more severe injury or cognitive/behavioral sequelae). Neuropsychological studies of subconcussive blows within a single athletic season have failed to demonstrate any strong and consistent relations between number and severity of subconcussive events and cognitive change. Recent studies using neuroimaging have demonstrated a potential cumulative effect of subconcussive blows, at least in a subset of individuals.

CONCLUSION

Human studies of the neurological/neuropsychological impact of subconcussive blows are currently quite limited. Subconcussive blows, in the short-term, have not been shown to cause significant clinical effects. To date, findings suggest that any effect of subconcussive blows is likely to be small or nonexistent, perhaps evident in a subset of individuals on select measures, and maybe even beneficial in some cases. Longer-term prospective studies are needed to determine if there is a cumulative dose effect.

Progression of histopathological and behavioral abnormalities following mild traumatic brain injury in the male ferret

White matter damage is an important consequence of traumatic brain injury (TBI) in humans. Unlike rodents, ferrets have a substantial amount of white matter and a gyrencephalic brain; therefore, they may represent an ideal small mammal model to study human-pertinent consequences of TBI. Here we report immunohistochemical and behavioral results after a controlled cortical impact (CCI) injury to the sensorimotor cortex of adult male ferrets. We assessed inflammation in the neocortex and white matter, and behavior at 1 day post injury and 1, 4, and 16 weeks post injury (WPI). CCI in the ferret produced inflammation that originated in the neocortex near the site of the injury and progressed deep into the white matter with time. The density of microglia and astrocytes increased in the neocortex near the injury, peaking at 4WPI and remaining elevated at 16WPI. Microglial morphology in the neocortex was significantly altered in the first 4 weeks, but showed a return toward normal at 16 weeks. Clusters of microglial cells in the white matter persisted until 16WPI. We assessed motor and cognitive behavior using the open field, novel object recognition, T-maze, and gait tests. A transient deficit in memory occurred at 4WPI, with a reduction of rearing and motor ability at 12 and 16WPI. Behavioral impairments coincide with features of the inflammatory changes in the neocortex revealed by immunohistochemistry. The ferret represents an important animal model to explore ongoing damage in the white matter and cerebral cortex after TBI.

Pathologic Thr175 tau phosphorylation in CTE and CTE with ALS

Objective

To investigate whether chronic traumatic encephalopathy (CTE) and CTE with amyotrophic lateral sclerosis (CTE-ALS) exhibit features previously observed in other tauopathies of pathologic phosphorylation of microtubule-associated protein tau at Thr¹⁷⁵ (pThr¹⁷⁵ tau) and Thr²³¹ (pThr²³¹ tau), and glycogen synthase kinase–3β (GSK3β) activation, and whether these pathologic features are a consequence of traumatic brain injury (TBI).

Methods

Tau isoform expression was assayed by western blot in 6 stage III CTE cases. We also used immunohistochemistry to analyze 5 cases each of CTE, CTE-ALS, and 5 controls for expression of activated GSK3β, pThr¹⁷⁵ tau, pThr²³¹ tau, and oligomerized tau within spinal cord tissue and hippocampus. Using a rat model of moderate TBI, we assessed tau pathology and phospho-GSK3β expression at 3 months postinjury.

Results

CTE and CTE-ALS are characterized by the presence of all 6 tau isoforms in both soluble and insoluble tau isolates. Activated GSK3β, pThr¹⁷⁵ tau, pThr²³¹ tau, and oligomerized tau protein expression was observed in hippocampal neurons and spinal motor neurons. We observed tau neuronal pathology (fibrillar inclusions and axonal damage) and increased levels of pThr¹⁷⁵ tau and activated GSK3β in moderate TBI rats.

Conclusions

Pathologic phosphorylation of tau at Thr¹⁷⁵ and Thr²³¹ and activation of GSK3β are features of the tauopathy of CTE and CTE-ALS. These features can be replicated in an animal model of moderate TBI.

Investigating structural and perfusion deficits due to repeated head trauma in active professional fighters

Repeated head trauma experienced by active professional fighters results in various structural, functional and perfusion damage. However, whether there are common regions of structural and perfusion damage due to fighting and whether these structural and perfusion differences are associated with neuropsychological measurements in active professional fighters is still unknown. To that end, T1-weighted and pseudocontinuous arterial spin labeling MRI on a group of healthy controls and active professional fighters were acquired. Voxelwise group comparisons, in a univariate and multivariate sense, were performed to investigate differences in gray and white matter density (GMD, WMD) and cerebral blood flow (CBF) between the two groups. A significantly positive association between global GMD and WMD was obtained with psychomotor speed and reaction time, respectively, in our cohort of active professional fighters. In addition, regional WMD deficit was observed in a cluster encompassing bilateral pons, hippocampus, and thalamus in fighters (0.49 ± 0.04 arbitrary units (a.u.)) as compared to controls (0.51 ± 0.05a.u.). WMD in the cluster of active fighters was also significantly associated with reaction time. Significantly lower CBF was observed in right inferior temporal lobe with both partial volume corrected (46.9 ± 14.93 ml/100 g/min) and non-partial volume corrected CBF maps (25.91 ± 7.99 ml/100 g/min) in professional fighters, as compared to controls (65.45 ± 22.24 ml/100 g/min and 35.22 ± 12.18 ml/100 g/min respectively). A paradoxical increase in CBF accompanying right cerebellum and fusiform gyrus in the active professional fighters (29.52 ± 13.03 ml/100 g/min) as compared to controls (19.43 ± 12.56 ml/100 g/min) was observed with non-partial volume corrected CBF maps. Multivariate analysis with both structural and perfusion measurements found the same clusters as univariate analysis in addition to a cluster in right precuneus. Both partial volume corrected and non-partial volume corrected CBF of the cluster in the thalamus had a significantly positive association with the number of fights. In addition, GMD of the cluster in right precuneus was significantly associated with psychomotor speed in our cohort of active professional fighters. Our results suggest a heterogeneous pattern of structural and CBF deficits due to repeated head trauma in active professional fighters. This finding indicates that investigating both structural and CBF changes in the same set of participants may help to understand the pathophysiology and progression of cognitive decline due to repeated head trauma.

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Repetitive head trauma revealed no global structural or global perfusion deficits.

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Cluster of significantly lower WMD was associated with reaction time in fighters.

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Fighters had lower CBF in right inferior temporal lobe.

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Multivariate analysis revealed a cluster associated with number of fights.

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Combined analysis of structural and perfusion measurements is recommended.

Acute Traumatic Coagulopathy Accompanying Isolated Traumatic Brain Injury is Associated with Worse Long-Term Functional and Cognitive Outcomes

BACKGROUND

Approximately one-third of patients with isolated traumatic brain injury (iTBI) present with acute traumatic coagulopathy (ATC). ATC is associated with increased morbidity and mortality. Its effects on long-term functional and cognitive outcomes are not as well characterized.

METHODS

Data from the Citicoline Brain Injury Treatment Trial (COBRIT) were analyzed retrospectively. Exclusion criteria were renal failure or malignancy, and any extracranial injury severity score >3. ATC was defined as INR > 1.3, PTT > 38 s, or platelets < 100 K, determined at baseline, and during the first 7 days of hospitalization.

RESULTS

Six hundred forty-seven patients were included; 21 % were found to have ATC. Highest incidence occurred at baseline, and Day Two. Forty-two percent of ATC patients had a GCS < 8, compared with 11.3 % of non-ATC patients (p < 0.001). A significantly higher proportion of ATC patients was transfused blood products, required greater than 4L of fluids, demonstrated hyperthermia and hypothermia, were hypotensive and demonstrated elevated lactate when compared to non-ATC patients. In-hospital mortality, mean hospital length of stay, incidence of DVT and seizures were also significantly higher in ATC patients. A significantly lower portion of ATC patients had good outcomes on the GOS-E (i.e., score > 6), and the DRS (i.e., score < 2) at 180 days, for which ATC was found to be an independent predictor with binary logistic regression. ATC patients also performed significantly worse on several components of the CVLT-II at 180 days.

CONCLUSIONS

ATC accompanying iTBI is associated with worse functional and cognitive outcomes at 180 days.

Neuroinflammation in traumatic brain injury: A chronic response to an acute injury

Every year, approximately 1.4 million US citizens visit emergency rooms for traumatic brain injuries. Formerly known as an acute injury, chronic neurodegenerative symptoms such as compromised motor skills, decreased cognitive abilities, and emotional and behavioral changes have caused the scientific community to consider chronic aspects of the disorder. The injury causing impact prompts multiple cell death processes, starting with neuronal necrosis, and progressing to various secondary cell death mechanisms. Secondary cell death mechanisms, including excitotoxicity, oxidative stress, mitochondrial dysfunction, blood-brain barrier disruption, and inflammation accompany chronic traumatic brain injury (TBI) and often contribute to long-term disabilities. One hallmark of both acute and chronic TBI is neuroinflammation. In acute stages, neuroinflammation is beneficial and stimulates an anti-inflammatory response to the damage. Conversely, in chronic TBI, excessive inflammation stimulates the aforementioned secondary cell death. Converting inflammatory cells from pro-inflammatory to anti-inflammatory may expand the therapeutic window for treating TBI, as inflammation plays a role in all stages of the injury. By expanding current research on the role of inflammation in TBI, treatment options and clinical outcomes for afflicted individuals may improve. This paper is a review article. Referred literature in this paper has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors' experiences.

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.

Inter-rater agreement of the Turkish version of the Neurobehavioral Rating Scale-Revised form

Objectives

This study aims to adapt the Neurobehavioral Rating Scale-revised form (NBRS-R) for Turkish traumatic brain injury (TBI) patients and to investigate the inter-rater agreement of the Turkish revised scale.

Patients and methods

A total of 45 patients (36 males, 9 females; mean age 31.1±13.0 years; range 18 to 60 years) with TBI were included in this study between September 2013 and August 2014. A semi-structured interview was set up for Turkish patients using a multidisciplinary approach (physiatrist, psychiatrist, neurologist and psychologist) with the participation of four rehabilitation centers. Questions were prepared for each of the 29 items, based on the recommendations of the original NBRS-R form. Four different interviewers from the four centers applied this form to a total of 45 TBI patients.

Results

The items evaluated by intra-class correlation coefficient showed satisfactory stability and the reliability of the items ranged from moderate to very good.

Conclusion

The NBRS-R form can be suggested to provide a reliable and easily reproducible evaluation method of neurobehavioral deficits in TBI patients who speak Turkish.

Multimodal MR Imaging Signatures of Cognitive Impairment in Active Professional Fighters

Purpose To investigate whether combining multiple magnetic resonance (MR) imaging modalities such as T1-weighted and diffusion-weighted MR imaging could reveal imaging biomarkers associated with cognition in active professional fighters. Materials and Methods Active professional fighters (n = 297; 24 women and 273 men) were recruited at one center. Sixty-two fighters (six women and 56 men) returned for a follow-up examination. Only men were included in the main analysis of the study. On the basis of computerized testing, fighters were separated into the cognitively impaired and nonimpaired groups on the basis of computerized testing. T1-weighted and diffusion-weighted imaging were performed, and volume and cortical thickness, along with diffusion-derived metrics of 20 major white matter tracts were extracted for every subject. A classifier was designed to identify imaging biomarkers related to cognitive impairment and was tested in the follow-up dataset. Results The classifier allowed identification of seven imaging biomarkers related to cognitive impairment in the cohort of active professional fighters. Areas under the curve of 0.76 and 0.69 were obtained at baseline and at follow-up, respectively, with the optimized classifier. The number of years of fighting had a significant (P = 8.8 × 10^-7) negative association with fractional anisotropy of the forceps major (effect size [d] = 0.34) and the inferior longitudinal fasciculus (P = .03; d = 0.17). A significant difference was observed between the impaired and nonimpaired groups in the association of fractional anisotropy in the forceps major with number of fights (P = .03, d = 0.38) and years of fighting (P = 6 × 10^-8, d = 0.63). Fractional anisotropy of the inferior longitudinal fasciculus was positively associated with psychomotor speed (P = .04, d = 0.16) in nonimpaired fighters but no association was observed in impaired fighters. Conclusion Without enforcement of any a priori assumptions on the MR imaging-derived measurements and with a multivariate approach, the study revealed a set of seven imaging biomarkers that were associated with cognition in active male professional fighters. ^© RSNA, 2017 Online supplemental material is available for this article.

Traumatic Brain Injuries Associated With Consumer Products at Home Among US Children Younger Than 5 Years of Age

This study investigated the epidemiology of traumatic brain injuries (TBIs) occurring to young children, associated with consumer products at home in the United States. Data from the National Electronic Injury Surveillance System were analyzed. There were an estimated 2 292 896 (95% CI = 1 707 891-2 877 900) children <5 years of age treated in US emergency departments for a TBI associated with a consumer product at home during 1991-2012, which equals an annual average of 104 223 (95% CI = 77 631-130 814) children. During the 22-year study period, the number and rate of TBIs increased significantly by 283.3% (estimated annual rate of change, m = 7182.6; P < .001) and 266.5% ( m = 0.35; P < .001), respectively. The number of TBIs decreased with increasing age of the child. Falls from household products were the leading mechanism of injury (53.7%). To our knowledge, this is the first nationally representative study of TBIs associated with consumer products at home among young children. These findings underscore the need for increased prevention efforts.

When friend turns foe: central and peripheral neuroinflammation in central nervous system injury

Injury to the central nervous system (CNS) is common, and though it has been well studied, many aspects of traumatic brain injury (TBI) and stroke are poorly understood. TBI and stroke are two pathologic events that can cause severe, immediate impact to the neurostructure and function of the CNS, which has been recognized recently to be exacerbated by the body’s own immune response. Although the brain damage induced by the initial trauma is most likely unsalvageable, the secondary immunologic deterioration of neural tissue gives ample opportunity for therapeutic strategists seeking to mitigate TBI’s secondary detrimental effects. The purpose of this paper is to highlight the cell death mechanisms associated with CNS injury with special emphasis on inflammation. The authors discuss sources of inflammation, and introduce the role of the spleen in the systemic response to inflammation after CNS injury.

Overview of Traumatic Brain Injury: An Immunological Context

Traumatic brain injury (TBI) afflicts people of all ages and genders, and the severity of injury ranges from concussion/mild TBI to severe TBI. Across all spectrums, TBI has wide-ranging, and variable symptomology and outcomes. Treatment options are lacking for the early neuropathology associated with TBIs and for the chronic neuropathological and neurobehavioral deficits. Inflammation and neuroinflammation appear to be major mediators of TBI outcomes. These systems are being intensively studies using animal models and human translational studies, in the hopes of understanding the mechanisms of TBI, and developing therapeutic strategies to improve the outcomes of the millions of people impacted by TBIs each year. This manuscript provides an overview of the epidemiology and outcomes of TBI, and presents data obtained from animal and human studies focusing on an inflammatory and immunological context. Such a context is timely, as recent studies blur the traditional understanding of an “immune-privileged” central nervous system. In presenting the evidence for specific, adaptive immune response after TBI, it is hoped that future studies will be interpreted using a broader perspective that includes the contributions of the peripheral immune system, to central nervous system disorders, notably TBI and post-traumatic syndromes.

Traumatic brain injury as a risk factor for Alzheimer's disease: current knowledge and future directions

There is growing concern about the late effects of traumatic brain injury (TBI). This scoping review summarizes clinical research from the past 10 years that evaluates the relationship between TBI and Alzheimer's disease. This review identified five studies that found increased risk for dementia after TBI, two studies that found no increased risk and four studies that found a relationship only under certain conditions or in specified subsamples. Methodological differences across studies preclude direct comparison of results, and discrepant findings elucidate the complex course of post-TBI neurodegeneration. We discuss the factors that influence the strength and direction of the relationship between TBI and Alzheimer's disease, and the implications of this body of research for patient care and future research.

Theta burst stimulation to characterize changes in brain plasticity following mild traumatic brain injury: A proof-of-principle study

PURPOSE

Recent studies investigating the effects of mild traumatic brain injury (mTBI) suggest the presence of unbalanced excitatory and inhibitory mechanisms within primary motor cortex (M1). Whether these abnormalities are associated with impaired synaptic plasticity remains unknown.

METHODS

The effects of continuous theta burst stimulation (cTBS) on transcranial magnetic stimulation-induced motor evoked potentials (MEPs) were assessed on average two weeks and six weeks following mTBI in five individuals.

RESULTS

The procedure was well-tolerated by all participants. Continuous TBS failed to induce a significant reduction of MEP amplitudes two weeks after the injury, but response to cTBS normalized six weeks following injury, as a majority of patients became asymptomatic.

CONCLUSIONS

These preliminary results suggest that cTBS can be used to assess M1 synaptic plasticity in subacute phase following mTBI and may provide insights into neurobiological substrates of symptoms and consequences of mTBI.

Practice Update: What Professionals Who Are Not Brain Injury Specialists Need to Know About Intimate Partner Violence-Related Traumatic Brain Injury

There is growing recognition of the risk for traumatic brain injury (TBI) among victims and survivors of intimate partner violence (IPV). A wide range of physically abusive behaviors may lead to injuries to the head or neck and place an individual at risk for a TBI. The purpose of this article is to consolidate current research and present practical guidelines for professionals, who are not brain injury specialists, but work with clients who may have sustained a TBI in the context of IPV. Recommendations are provided for TBI risk screening, making appropriate referrals, and providing services in light of a potential TBI.

Diffuse traumatic axonal injury in mice induces complex behavioural alterations that are normalized by neutralization of interleukin-1β

Widespread traumatic axonal injury (TAI) results in brain network dysfunction, which commonly leads to persisting cognitive and behavioural impairments following traumatic brain injury (TBI). TBI induces a complex neuroinflammatory response, frequently located at sites of axonal pathology. The role of the pro-inflammatory cytokine interleukin (IL)-1β has not been established in TAI. An IL-1β-neutralizing or a control antibody was administered intraperitoneally at 30 min following central fluid percussion injury (cFPI), a mouse model of widespread TAI. Mice subjected to moderate cFPI (n = 41) were compared with sham-injured controls (n = 20) and untreated, naive mice (n = 9). The anti-IL-1β antibody reached the target brain regions in adequate therapeutic concentrations (up to ~30 μg/brain tissue) at 24 h post-injury in both cFPI (n = 5) and sham-injured (n = 3) mice, with lower concentrations at 72 h post-injury (up to ~18 μg/g brain tissue in three cFPI mice). Functional outcome was analysed with the multivariate concentric square field (MCSF) test at 2 and 9 days post-injury, and the Morris water maze (MWM) at 14-21 days post-injury. Following TAI, the IL-1β-neutralizing antibody resulted in an improved behavioural outcome, including normalized behavioural profiles in the MCSF test. The performance in the MWM probe (memory) trial was improved, although not in the learning trials. The IL-1β-neutralizing treatment did not influence cerebral ventricle size or the number of microglia/macrophages. These findings support the hypothesis that IL-1β is an important contributor to the processes causing complex cognitive and behavioural disturbances following TAI.

Diminished amygdala activation and behavioral threat response following traumatic brain injury

Each year, approximately 3.8 million people suffer mild to moderate traumatic brain injuries (mTBI) that result in an array of neuropsychological symptoms and disorders. Despite these alarming statistics, the neurological bases of these persistent, debilitating neuropsychological symptoms are currently poorly understood. In this study we examined the effects of mTBI on the amygdala, a brain structure known to be critically involved in the processing of emotional stimuli. Seven days after lateral fluid percussion injury (LFPI), mice underwent a series of physiological and behavioral experiments to assess amygdala function. Brain-injured mice exhibited a decreased threat response in a cued fear conditioning paradigm, congruent with a decrease in amygdala excitability determined with basolateral amygdala (BLA) field excitatory post-synaptic potentials together with voltage-sensitive dye imaging (VSD). Furthermore, beyond exposing a general decrease in the excitability of the primary input of the amygdala, the lateral amygdala (LA), VSD also revealed a decrease in the relative strength or activation of internuclear amygdala circuit projections after LFPI. Thus, not only does activation of the LA require increased stimulation, but the proportion of this activation that is propagated to the primary output of the amygdala, the central amygdala, is also diminished following LFPI. Intracellular recordings revealed no changes in the intrinsic properties of BLA pyramidal neurons after LFPI. This data suggests that mild to moderate TBI has prominent effects on amygdala function and provides a potential neurological substrate for many of the neuropsychological symptoms suffered by TBI patients.

Analysis of the Role of CX3CL1 (Fractalkine) and Its Receptor CX3CR1 in Traumatic Brain and Spinal Cord Injury: Insight into Recent Advances in Actions of Neurochemokine Agents

CX3CL1 (fractalkine) is the only member of the CX3C (delta) subfamily of chemokines which is unique and combines the properties of both chemoattractant and adhesion molecules. The two-form ligand can exist either in a soluble form, like all other chemokines, and as a membrane-anchored molecule. CX3CL1 discloses its biological properties through interaction with one dedicated CX3CR1 receptor which belongs to a family of G protein-coupled receptors (GPCR). The CX3CL1/CX3CR1 axis acts in many physiological phenomena including those occurring in the central nervous system (CNS), by regulating the interactions between neurons, microglia, and immune cells. Apart from the role under physiological conditions, the CX3CL1/CX3CR1 axis was implied to have a role in different neuropathologies such as traumatic brain injury (TBI) and spinal cord injury (SCI). CNS injuries represent a serious public health problem, despite improvements in therapeutic management. To date, no effective treatment has been determined, so they constitute a leading cause of death and severe disability. The course of TBI and SCI has two consecutive poorly demarcated phases: the initial, primary injury and secondary injury. Recent evidence has implicated the role of the CX3CL1/CX3CR1 axis in neuroinflammatory processes occurring after CNS injuries. The importance of the CX3CL1/CX3CR1 axis in the pathophysiology of TBI and SCI in the context of systemic and direct local immune response is still under investigation. This paper, based on a review of the literature, updates and summarizes the current knowledge about CX3CL1/CX3CR1 axis involvement in TBI and SCI pathogenesis, indicating possible molecular and cellular mechanisms with a potential target for therapeutic intervention.

Trends in Sports- and Recreation-Related Traumatic Brain Injuries Treated in US Emergency Departments: The National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) 2001-2012

IMPORTANCE

Sports- and recreation-related traumatic brain injuries (SRR-TBIs) are a growing public health problem affecting persons of all ages in the United States.

OBJECTIVE

To describe the trends of SRR-TBIs treated in US emergency departments (EDs) from 2001 to 2012 and to identify which sports and recreational activities and demographic groups are at higher risk for these injuries.

DESIGN

Data on initial ED visits for an SRR-TBI from the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) for 2001-2012 were analyzed.

SETTING

NEISS-AIP data are drawn from a nationally representative sample of hospital-based EDs.

PARTICIPANTS

Cases of TBI were identified from approximately 500,000 annual initial visits for all causes and types of injuries treated in EDs captured by NEISS-AIP.

MAIN OUTCOME MEASURE(S)

Numbers and rates by age group, sex, and year were estimated. Aggregated numbers and percentages by discharge disposition were produced.

RESULTS

Approximately 3.42 million ED visits for an SRR-TBI occurred during 2001-2012. During this period, the rates of SRR-TBIs treated in US EDs significantly increased in both males and females regardless of age (all Ps < .001). For males, significant increases ranged from a low of 45.8% (ages 5-9) to a high of 139.8% (ages 10-14), and for females, from 25.1% (ages 0-4) to 211.5% (ages 15-19) (all Ps < .001). Every year males had about twice the rates of SRR-TBIs than females. Approximately 70% of all SRR-TBIs were reported among persons aged 0 to 19 years. The largest number of SRR-TBIs among males occurred during bicycling, football, and basketball. Among females, the largest number of SRR-TBIs occurred during bicycling, playground activities, and horseback riding. Approximately 89% of males and 91% of females with an SRR-TBI were treated and released from EDs.

CONCLUSION AND RELEVANCE

The rates of ED-treated SRR-TBIs increased during 2001-2012, affecting mainly persons aged 0 to 19 years and males in all age groups. Increases began to appear in 2004 for females and 2006 for males. Activities associated with the largest number of TBIs varied by sex and age. Reasons for the reported increases in ED visits are unknown but may be associated with increased awareness of TBI through increased media exposure and from campaigns, such as the Centers for Disease Control and Prevention's Heads Up. Prevention efforts should be targeted by sports and recreational activity, age, and sex.

Detecting Behavioral Deficits Post Traumatic Brain Injury in Rats

Traumatic brain injury (TBI), ranging from mild to severe, almost always elicits an array of behavioral deficits in injured subjects. Some of these TBI-induced behavioral deficits include cognitive and vestibulomotor deficits as well as anxiety and other consequences. Rodent models of TBI have been (and still are) fundamental in establishing many of the pathophysiological mechanisms of TBI. Animal models are also utilized in screening and testing pharmacological effects of potential therapeutic agents for brain injury treatment. This chapter details validated protocols for each of these behavioral deficits post traumatic brain injury in Sprague-Dawley male rats. The elevated plus maze (EPM) protocol is described for assessing anxiety-like behavior; the Morris water maze protocol for assessing cognitive deficits in learning memory and spatial working memory and the rotarod test for assessing vestibulomotor deficits.

Post-traumatic growth following acquired brain injury: a systematic review and meta-analysis

The idea that acquired brain injury (ABI) caused by stroke, hemorrhage, infection or traumatic insult to the brain can result in post-traumatic growth (PTG) for individuals is increasingly attracting psychological attention. However, PTG also attracts controversy as a result of ambiguous empirical findings. The extent that demographic variables, injury factors, subjective beliefs, and psychological health are associated with PTG following ABI is not clear. Consequently, this systematic review and meta-analysis explores the correlates of variables within these four broad areas and PTG. From a total of 744 published studies addressing PTG in people with ABI, eight studies met inclusion criteria for detailed examination. Meta-analysis of these studies indicated that growth was related to employment, longer education, subjective beliefs about change post-injury, relationship status, older age, longer time since injury, and lower levels of depression. Results from homogeneity analyses indicated significant inter-study heterogeneity across variables. There is general support for the idea that people with ABI can experience growth, and that various demographics, injury-related variables, subjective beliefs and psychological health are related to growth. The contribution of social integration and the forming of new identities post-ABI to the experience of PTG is explored. These meta-analytic findings are however constrained by methodological limitations prevalent in the literature. Clinical and research implications are discussed with specific reference to community and collective factors that enable PTG.

Prediction of brain age suggests accelerated atrophy after traumatic brain injury

Objective

The long-term effects of traumatic brain injury (TBI) can resemble observed in normal ageing, suggesting that TBI may accelerate the ageing process. We investigate this using a neuroimaging model that predicts brain age in healthy individuals and then apply it to TBI patients. We define individuals' differences in chronological and predicted structural "brain age," and test whether TBI produces progressive atrophy and how this relates to cognitive function.

Methods

A predictive model of normal ageing was defined using machine learning in 1,537 healthy individuals, based on magnetic resonance imaging–derived estimates of gray matter (GM) and white matter (WM). This ageing model was then applied to test 99 TBI patients and 113 healthy controls to estimate brain age.

Results

The initial model accurately predicted age in healthy individuals (r * 0.92). TBI brains were estimated to be "older," with a mean predicted age difference (PAD) between chronological and estimated brain age of 4.66 years (±10.8) for GM and 5.97 years (±11.22) for WM. This PAD predicted cognitive impairment and correlated strongly with the time since TBI, indicating that brain tissue loss increases throughout the chronic postinjury phase.

Interpretation

TBI patients' brains were estimated to be older than their chronological age. This discrepancy increases with time since injury, suggesting that TBI accelerates the rate of brain atrophy. This may be an important factor in the increased susceptibility in TBI patients for dementia and other age-associated conditions, motivating further research into the age-like effects of brain injury and other neurological diseases.

Posttraumatic parkinsonism

Amantadine hydrochloride is one of the most commonly used drugs in the pharmacotherapeutic treatment of disorders of consciousness (DOCs) following traumatic brain injury (TBI). Indeed, its actions as a pro-dopaminergic drug and as an N-methyl-D-aspartate antagonist makes amantadine an interesting candidate to improve consciousness and responsiveness in individuals with DOC, including vegetative state and minimally conscious state. Giacino et al (N Engl J Med. 2012;366(9):819-826) recently reported that amantadine was able to accelerate the functional recovery course of subjects after TBI with DOC, during a 4-week treatment period. Some patients with DOC following severe TBI have been reported to have parkinsonian symptoms. Severe TBI and posttraumatic parkinsonism may share a common midbrain network dysfunction. In fact, both vegetative state and minimally conscious state following severe TBI can include features of akinetic mutism and parkinsonism. Responsiveness to pro-dopaminergic agents in some patients and to deep brain stimulation in others, might depend, respectively, on the integrity, or lack thereof, of the dopaminergic postsynaptic receptors. We are of the strong opinion that more attention should be given to parkinsonian findings in persons with DOC after severe TBI and would advocate for multicenter, randomized, controlled trials to assess risk factors for parkinsonism following severe TBI.

Attenuation of traumatic brain injury-induced cognitive impairment in mice by targeting increased cytokine levels with a small molecule experimental therapeutic

Background

Evidence from clinical studies and preclinical animal models suggests that proinflammatory cytokine overproduction is a potential driving force for pathology progression in traumatic brain injury (TBI). This raises the possibility that selective targeting of the overactive cytokine response, a component of the neuroinflammation that contributes to neuronal dysfunction, may be a useful therapeutic approach. MW151 is a CNS-penetrant, small molecule experimental therapeutic that selectively restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis. We previously reported that MW151 administered post-injury (p.i.) is efficacious in a closed head injury (CHI) model of diffuse TBI in mice. Here we test dose dependence of MW151 to suppress the target mechanism (proinflammatory cytokine up-regulation), and explore the therapeutic window for MW151 efficacy.

Methods

We examined suppression of the acute cytokine surge when MW151 was administered at different times post-injury and the dose-dependence of cytokine suppression. We also tested a more prolonged treatment with MW151 over the first 7 days post-injury and measured the effects on cognitive impairment and glial activation.

Results

MW151 administered up to 6 h post-injury suppressed the acute cytokine surge, in a dose-dependent manner. Administration of MW151 over the first 7 days post-injury rescues the CHI-induced cognitive impairment and reduces glial activation in the focus area of the CHI.

Conclusions

Our results identify a clinically relevant time window post-CHI during which MW151 effectively restores cytokine production back towards normal, with a resultant attenuation of downstream cognitive impairment.

Cognitive changes and dementia risk after traumatic brain injury: implications for aging military personnel

Traumatic brain injury (TBI) is recognized as an important risk factor for the long-term cognitive health of military personnel, particularly in light of growing evidence that TBI increases risk for Alzheimer's disease and other dementias. In this article, we review the neurocognitive and neuropathologic changes after TBI with particular focus on the potential risk for cognitive decline across the life span in military service members. Implications for monitoring and surveillance of cognition in the aging military population are discussed. Additional studies are needed to clarify the factors that increase risk for later life cognitive decline, define the mechanistic link between these factors and dementia, and provide empirically supported interventions to mitigate the impact of TBI on cognition across the life span.

Repeated head trauma is associated with smaller thalamic volumes and slower processing speed: the Professional Fighters' Brain Health Study

Objectives

Cumulative head trauma may alter brain structure and function. We explored the relationship between exposure variables, cognition and MRI brain structural measures in a cohort of professional combatants.

Methods

224 fighters (131 mixed martial arts fighters and 93 boxers) participating in the Professional Fighters Brain Health Study, a longitudinal cohort study of licensed professional combatants, were recruited, as were 22 controls. Each participant underwent computerised cognitive testing and volumetric brain MRI. Fighting history including years of fighting and fights per year was obtained from self-report and published records. Statistical analyses of the baseline evaluations were applied cross-sectionally to determine the relationship between fight exposure variables and volumes of the hippocampus, amygdala, thalamus, caudate, putamen. Moreover, the relationship between exposure and brain volumes with cognitive function was assessed.

Results

Increasing exposure to repetitive head trauma measured by number of professional fights, years of fighting, or a Fight Exposure Score (FES) was associated with lower brain volumes, particularly the thalamus and caudate. In addition, speed of processing decreased with decreased thalamic volumes and with increasing fight exposure. Higher scores on a FES used to reflect exposure to repetitive head trauma were associated with greater likelihood of having cognitive impairment.

Conclusions

Greater exposure to repetitive head trauma is associated with lower brain volumes and lower processing speed in active professional fighters.

Interactions between traumatic brain injury and frontotemporal degeneration

BACKGROUND/AIMS

Prior work in smaller cohorts suggests that traumatic brain injury (TBI) may be a risk factor for frontotemporal degeneration (FTD). We sought to confirm and extend these results using the National Alzheimer's Coordinating Center Uniform Data Set.

METHODS

We compared the TBI prevalence between FTD subjects and matched normal controls. Indices of cognitive, behavioral, functional, and global dementia severity were compared between FTD subjects with and without prior TBI.

RESULTS

Remote TBI with extended loss of consciousness (TBI-ext) was more common in individuals with FTD than in controls (OR: 1.67; 95% CI: 1.004-2.778). With TBI-ext, less functional and global impairment was seen in the behavioral variant of FTD, but more behavioral pathology was seen in the semantic variant.

CONCLUSION

TBI may increase the FTD risk and influence clinical symptomatology and severity in FTD subtypes.

Neuroinflammatory responses to traumatic brain injury: etiology, clinical consequences, and therapeutic opportunities

Traumatic brain injury (TBI) is a serious public health problem accounting for 1.4 million emergency room visits by US citizens each year. Although TBI has been traditionally considered an acute injury, chronic symptoms reminiscent of neurodegenerative disorders have now been recognized. These progressive neurodegenerative-like symptoms manifest as impaired motor and cognitive skills, as well as stress, anxiety, and mood affective behavioral alterations. TBI, characterized by external bumps or blows to the head exceeding the brain's protective capacity, causes physical damage to the central nervous system with accompanying neurological dysfunctions. The primary impact results in direct neural cell loss predominantly exhibiting necrotic death, which is then followed by a wave of secondary injury cascades including excitotoxicity, oxidative stress, mitochondrial dysfunction, blood-brain barrier disruption, and inflammation. All these processes exacerbate the damage, worsen the clinical outcomes, and persist as an evolving pathological hallmark of what we now describe as chronic TBI. Neuroinflammation in the acute stage of TBI mobilizes immune cells, astrocytes, cytokines, and chemokines toward the site of injury to mount an antiinflammatory response against brain damage; however, in the chronic stage, excess activation of these inflammatory elements contributes to an "inflamed" brain microenvironment that principally contributes to secondary cell death in TBI. Modulating these inflammatory cells by changing their phenotype from proinflammatory to antiinflammatory would likely promote therapeutic effects on TBI. Because neuroinflammation occurs at acute and chronic stages after the primary insult in TBI, a treatment targeting neuroinflammation may have a wider therapeutic window for TBI. To this end, a better understanding of TBI etiology and clinical manifestations, especially the pathological presentation of chronic TBI with neuroinflammation as a major component, will advance our knowledge on inflammation-based disease mechanisms and treatments.

Non-Invasive Brain Stimulation for the Treatment of Symptoms Following Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) is a common cause of physical, psychological, and cognitive impairment, but many current treatments for TBI are ineffective or produce adverse side effects. Non-invasive methods of brain stimulation could help ameliorate some common trauma-induced symptoms.

OBJECTIVE

This review summarizes instances in which repetitive Transcranial Magnetic Stimulation (rTMS) and transcranial Direct Current Stimulation (tDCS) have been used to treat symptoms following a TBI. A subsequent discussion attempts to determine the value of these methods in light of their potential risks.

METHODS

The research databases of PubMed/MEDLINE and PsycINFO were electronically searched using terms relevant to the use of rTMS and tDCS as a tool to decrease symptoms in the context of rehabilitation post-TBI.

RESULTS

Eight case-studies and four multi-subject reports using rTMS and six multi--subject studies using tDCS were found. Two instances of seizure are discussed.

CONCLUSION

There is evidence that rTMS can be an effective treatment option for some post-TBI symptoms, such as depression, tinnitus, and neglect. Although the safety of this method remains uncertain, the use of rTMS in cases of mild TBI without obvious structural damage may be justified. Evidence on the effectiveness of tDCS is mixed, highlighting the need for additional investigations.

Tau reduction diminishes spatial learning and memory deficits after mild repetitive traumatic brain injury in mice

OBJECTIVE

Because reduction of the microtubule-associated protein Tau has beneficial effects in mouse models of Alzheimer's disease and epilepsy, we wanted to determine whether this strategy can also improve the outcome of mild traumatic brain injury (TBI).

METHODS

We adapted a mild frontal impact model of TBI for wildtype C57Bl/6J mice and characterized the behavioral deficits it causes in these animals. The Barnes maze, Y maze, contextual and cued fear conditioning, elevated plus maze, open field, balance beam, and forced swim test were used to assess different behavioral functions. Magnetic resonance imaging (MRI, 7 Tesla) and histological analysis of brain sections were used to look for neuropathological alterations. We also compared the functional effects of this TBI model and of controlled cortical impact in mice with two, one or no Tau alleles.

RESULTS

Repeated (2-hit), but not single (1-hit), mild frontal impact impaired spatial learning and memory in wildtype mice as determined by testing of mice in the Barnes maze one month after the injury. Locomotor activity, anxiety, depression and fear related behaviors did not differ between injured and sham-injured mice. MRI imaging did not reveal focal injury or mass lesions shortly after the injury. Complete ablation or partial reduction of tau prevented deficits in spatial learning and memory after repeated mild frontal impact. Complete tau ablation also showed a trend towards protection after a single controlled cortical impact. Complete or partial reduction of tau also reduced the level of axonopathy in the corpus callosum after repeated mild frontal impact.

INTERPRETATION

Tau promotes or enables the development of learning and memory deficits and of axonopathy after mild TBI, and tau reduction counteracts these adverse effects.

Neurologically-related sequelae associated with mild traumatic brain injury

OBJECTIVE

Mild traumatic brain injury (mTBI) accounts for more than 75% of traumatic brain injuries every year. This study examines the temporal association between non-blast mTBI and the onset of neurologic sequelae to illuminate risks of post-concussive syndrome, epilepsy and chronic pain.

METHODS

A large historical prospective study was conducted utilizing electronically-recorded demographic, medical and military-specific data for over half a million active duty US Air Force Airmen. This study utilized diagnostic codes to identify mTBI exposures, two control groups and three post-mTBI time periods. Adjusted hazard ratios (HRs) were calculated using Cox proportional hazards modelling.

RESULTS

HRs were higher when mTBI exposed Airmen were compared with the full cohort and lower when compared with the other injured group. When compared to the other injured group, mTBI was positively associated with epilepsy/recurrent seizure outcomes, post-concussive syndrome and pain disorders. HRs tended to be highest within the first 30 days and decreased over time.

CONCLUSIONS

Findings support that mTBI may have a prolonged neurological impact. Findings are also likely generalizable to young adult populations with exposure to non-blast related mTBI, including civilians, as those included in this study were young adults with a high prevalence of recreational/sports and motor vehicle injuries.

Chronic traumatic encephalopathy: a critical appraisal

Chronic traumatic encephalopathy (CTE) formerly known as dementia pugilistica is a long-term neurodegenerative disorder associated with repeated subconcussive head injuries in high-contact sports. We reviewed the existing literature on CTE and examined epidemiological trends, risk factors, and its temporal progression, and proposed the underlying pathophysiological mechanisms that may provide unique insights to clinicians with an in-depth understanding of the disease to aid in the diagnosis and prevention, and provide future perspectives for research via search of Medline and Cochrane databases as well as manual review of bibliographies from selected articles and monographs. The prevalence of CTE in recent years is on the rise and almost exclusively affects men, with pathologic signs characterized by progressive memory loss, behavioral changes, and violent tendencies with some patients demonstrating Parkinsonian-like symptoms and signs. Many patients with CTE die following suicide, accident, or complications of drug or alcohol use. Postmortem pathologic analysis is characterized by neurofibrillary tangles and Aβ plaques in 50 % of cases. Currently, there are no ante-mortem diagnostic criteria, but modern imaging techniques such as functional magnetic resonance (MR) imaging, MR spectroscopy, and diffusion tension imaging hold promise for delineating the future diagnostic criteria. Further long-term longitudinal studies are warranted to investigate risk factors that will enhance understanding of the disease progression and its pathogenesis.

Increased risk of ischemic stroke in patients with mild traumatic brain injury: a nationwide cohort study

Background

It is known that the risk of stroke in patients with traumatic brain injury might be increased. However, the relationship between mild traumatic brain injury and ischemic stroke has never been established. We conducted a study of patients in Taiwan with mild traumatic brain injury to evaluate if they had a higher risk of stroke compared with the general population.

Methods

We utilized a sampled National Health Insurance claims database containing one million beneficiaries. We followed all adult beneficiaries older than 18 years from January 1, 2007 to December 31, 2010 to determine if they were diagnosed with ischemic stroke. We further identified patients with mild traumatic brain injury and compared their risk of ischemic stroke with the general population.

Results

We identified 24,905 patients with mild traumatic brain injury and 719,811 patients without mild traumatic brain injury. After controlling for age, gender, urbanization level, socioeconomic status, diabetes, hypertension, coronary artery disease, hyperlipidemia, history of alcohol intoxication, malignancies, heart failure, atrial fibrillation, smoking, obesity, epilepsy, peripheral artery disease and Charlson Comorbidity Index score, the adjusted hazard ratio for ischemic stroke was 1.46 (95% confidence interval, 1.33—1.62).

Conclusion

Mild traumatic brain injury is an independent significant risk factor for ischemic stroke.

Molecular hydrogen in drinking water protects against neurodegenerative changes induced by traumatic brain injury

Traumatic brain injury (TBI) in its various forms has emerged as a major problem for modern society. Acute TBI can transform into a chronic condition and be a risk factor for neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, probably through induction of oxidative stress and neuroinflammation. Here, we examined the ability of the antioxidant molecular hydrogen given in drinking water (molecular hydrogen water; mHW) to alter the acute changes induced by controlled cortical impact (CCI), a commonly used experimental model of TBI. We found that mHW reversed CCI-induced edema by about half, completely blocked pathological tau expression, accentuated an early increase seen in several cytokines but attenuated that increase by day 7, reversed changes seen in the protein levels of aquaporin-4, HIF-1, MMP-2, and MMP-9, but not for amyloid beta peptide 1-40 or 1-42. Treatment with mHW also reversed the increase seen 4 h after CCI in gene expression related to oxidation/carbohydrate metabolism, cytokine release, leukocyte or cell migration, cytokine transport, ATP and nucleotide binding. Finally, we found that mHW preserved or increased ATP levels and propose a new mechanism for mHW, that of ATP production through the Jagendorf reaction. These results show that molecular hydrogen given in drinking water reverses many of the sequelae of CCI and suggests that it could be an easily administered, highly effective treatment for TBI.

Traumatic Injury and Multiple Sclerosis: A Systematic Review and Meta-Analysis

A systematic review/meta-analysis of literature addressing a possible association between traumatic injury and onset of multiple sclerosis was conducted. Medline, Embase, Cochrane DSR, Ovid HealthStar, CINAHL, ISI Web of Science and Scopus were searched for analytical studies from 1950 to 2011. Two investigators independently reviewed articles for inclusion, assessing their quality using the Newcastle-Ottawa Scale. Of the 13 case-control studies included, 8 were moderate quality and 5 low; of the 3 cohort studies 2 were high and 1 moderate. Meta-analysis including moderate and low quality case-control studies produced a modest but significant odds ratio: 1.41 (95% confidence interval: 1.03, 1.93). However, when low quality studies were excluded, the resulting odds ratio was non-significant. Cohort studies produced a non-significant standardized incidence ratio of 1.00 (95% confidence interval: 0.86, 1.16). These findings support the conclusion that there is no association between traumatic injury and multiple sclerosis onset; more high quality cohort studies would help to confirm this observation.

The impacts of injury at the individual, community and societal levels: a systematic meta-review

OBJECTIVES

Injury is a major public health problem. While the impacts of injury on the injured person are well documented, there is relatively little knowledge about the impacts of injury on those individuals and groups in the community connected to the injured person. This study seeks to describe this breadth of research using a meta-review methodology.

STUDY DESIGN

Systematic meta-review.

METHODS

To gain a better understanding of the known impacts of injury on family, community and society, a systematic meta-review of injury outcomes research literature was conducted. Seventy-eight peer-reviewed published literature reviews were included in the meta-review.

RESULTS

Of these, 70 reported outcomes at the level of the injured person including mortality, body functions, activity and participation limitations. Nine reviews reported impacts at the level of the community including impacts on family members, work colleagues and carers. Six studies reported impacts at the societal level including economic, health system and injury compensation system impacts.

CONCLUSIONS

In summary, the meta-review identified a substantial body of knowledge at the individual level outcomes of injury, and a relative lack of information regarding the community and societal impacts of injury. An injury outcome framework is proposed on the basis of the findings of the meta-review to guide future research activity, particularly with regard to injury outcome domains where there is currently limited evidence. A comprehensive framework that takes account of all levels of impact is necessary for effective policies, systems and strategies to support recovery following injury.

Predictors of new-onset seizures: a 10-year follow-up of head trauma subjects with and without traumatic brain injury

BACKGROUND

It is not known whether alcohol-related head trauma predicts the new-onset seizures, particularly alcohol-related seizures.

OBJECTIVE

We investigated risk factors for new-onset seizures in a cohort of 739 head trauma subjects.

METHODS

All subjects with head trauma attending Oulu University Hospital during 1999, including children and very old people but excluding persons with previous seizures and/or neurological diseases, were enrolled and followed up until the end of 2009. The Finnish National Hospital Discharge Register was used to identify all visits due to seizures during the 10-year follow-up. Dates of death were obtained from the official Cause-of-Death Statistics. Cox proportional hazard regression models and Kaplan-Meier survival curves were used to identify predictors of new-onset seizures.

RESULTS

New-onset seizures were observed in 42 out of the 739 subjects (5.7%). An alcohol-related index injury (adjusted HR 2.50, 95% CI 1.30 to 4.82, p=0.006), moderate-to-severe traumatic brain injury (TBI) as the index trauma (3.13, 1.46 to 6.71, p=0.003) and preceding psychiatric disease (3.23, 1.23 to 9.21, p=0.028) were significant predictors of new-onset seizures during the follow-up after adjustment for age and sex. An alcohol-related index injury was the only independent predictor of the occurrence of an alcohol-related new-onset seizure (adjusted HR 12.13, 95% CI 2.70 to 54.50, p=0.001), and these seizures (n=19) developed more frequently among subjects without (n=14) than with (n=5) TBI.

CONCLUSIONS

We conclude that alcohol-related head trauma predicts new-onset seizures, particularly alcohol-related seizures. A brief intervention is needed in order to prevent the development of alcohol-related seizures.

Application of high-intensity focused ultrasound to the study of mild traumatic brain injury

Though intrinsically of much higher frequency than open-field blast overpressures, high-intensity focused ultrasound (HIFU) pulse trains can be frequency modulated to produce a radiation pressure having a similar form. In this study, 1.5-MHz HIFU pulse trains of 1-ms duration were applied to intact skulls of mice in vivo and resulted in blood-brain barrier disruption and immune responses (astrocyte reactivity and microglial activation). Analyses of variance indicated that 24 h after HIFU exposure, staining density for glial fibrillary acidic protein was elevated in the parietal and temporal regions of the cerebral cortex, corpus callosum and hippocampus, and staining density for the microglial marker, ionized calcium binding adaptor molecule, was elevated 2 and 24 h after exposure in the corpus callosum and hippocampus (all statistical test results, p < 0.05). HIFU shows promise for the study of some bio-effect aspects of blast-related, non-impact mild traumatic brain injuries in animals.

Decreased risk of stroke in patients with traumatic brain injury receiving acupuncture treatment: a population-based retrospective cohort study

BACKGROUND

Patients with traumatic brain injury (TBI) face increased risk of stroke. Whether acupuncture can help to protect TBI patients from stroke has not previously been studied.

METHODS

Taiwan's National Health Insurance Research Database was used to conduct a retrospective cohort study of 7409 TBI patients receiving acupuncture treatment and 29,636 propensity-score-matched TBI patients without acupuncture treatment in 2000-2008 as controls. Both TBI cohorts were followed until the end of 2010 and adjusted for immortal time to measure the incidence and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of new-onset stroke in the multivariable Cox proportional hazard models.

RESULTS

TBI patients with acupuncture treatment (4.9 per 1000 person-years) had a lower incidence of stroke compared with those without acupuncture treatment (7.5 per 1000 person-years), with a HR of 0.59 (95% CI = 0.50-0.69) after adjustment for sociodemographics, coexisting medical conditions and medications. The association between acupuncture treatment and stroke risk was investigated by sex and age group (20-44, 45-64, and ≥65 years). The probability curve with log-rank test showed that TBI patients receiving acupuncture treatment had a lower probability of stroke than those without acupuncture treatment during the follow-up period (p<0.0001).

CONCLUSION

Patients with TBI receiving acupuncture treatment show decreased risk of stroke compared with those without acupuncture treatment. However, this study was limited by lack of information regarding lifestyles, biochemical profiles, TBI severity, and acupuncture points used in treatments.

Stroke risk and outcomes in patients with traumatic brain injury: 2 nationwide studies

OBJECTIVE

To investigate whether patients with traumatic brain injury (TBI) have an increased risk of stroke or poststroke mortality.

PARTICIPANTS AND METHODS

Using Taiwan's National Health Insurance Research Database, we conducted a retrospective cohort study of 30,165 patients with new TBI and 120,660 persons without TBI between January 1, 2000, and December 31, 2004. The risk of stroke was compared between 2 cohorts through December 31, 2008. To investigate the association between in-hospital mortality after stroke and history of TBI, we conducted a case-control study of 7751 patients with newly diagnosed stroke between January 1, 2005, and December 31, 2008.

RESULTS

The TBI cohort had an increased stroke risk (hazard ratio [HR], 1.98; 95% CI, 1.86-2.11). Among patients with stroke, those with a history of TBI had a higher risk of poststroke mortality compared with those without TBI (odds ratio, 1.57; 95% CI, 1.13-2.19). In the TBI cohort, factors associated with stroke were history of TBI hospitalization (HR, 3.14; 95% CI, 2.77-3.56), emergency care for TBI (HR, 3.37; 95% CI, 2.88-3.95), brain hemorrhage (HR, 2.69; 95% CI, 2.43-2.99), skull fracture (HR, 3.00; 95% CI, 2.42-3.71), low income (HR, 2.65; 95% CI, 2.16-3.25), and high medical expenditure for TBI care (HR, 2.26; 95% CI, 2.09-2.43). The severity of TBI was also correlated with poststroke mortality.

CONCLUSIONS

Traumatic brain injury was associated with risk of stroke and poststroke mortality. The relationship between TBI and poststroke mortality does not seem to transcend all age groups. This research shows the importance of prevention, early recognition, and treatment of stroke in this vulnerable population.

Incidence, prevalence, costs, and impact on disability of common conditions requiring rehabilitation in the United States: stroke, spinal cord injury, traumatic brain injury, multiple sclerosis, osteoarthritis, rheumatoid arthritis, limb loss, and back pain

OBJECTIVE

To determine the relative incidence, prevalence, costs, and impact on disability of 8 common conditions treated by rehabilitation professionals.

DATA SOURCES

Comprehensive bibliographic searches using MEDLINE, Google Scholar, and UpToDate, (June, 2013).

DATA EXTRACTION

Two review authors independently screened the search results and performed data extraction. Eighty-two articles were identified that had relevant data on the following conditions: Stroke, Spinal Cord Injury, Traumatic Brain Injury, Multiple Sclerosis, Osteoarthritis, Rheumatoid Arthritis, Limb Loss, and Back Pain.

DATA SYNTHESIS

Back pain and arthritis (osteoarthritis, rheumatoid arthritis) are the most common and costly conditions we analyzed, affecting more than 100 million individuals and costing greater than $200 billion per year. Traumatic brain injury, while less common than arthritis and back pain, carries enormous per capita direct and indirect costs, mostly because of the young age of those involved and the severe disability that it may cause. Finally, stroke, which is often listed as the most common cause of disability, is likely second to both arthritis and back pain in its impact on functional limitations.

CONCLUSIONS

Of the common rehabilitation diagnoses we studied, musculoskeletal conditions such as back pain and arthritis likely have the most impact on the health care system because of their high prevalence and impact on disability.