Traumatic brain injury in sports: a review

Full-field, frequency-domain comparison of simulated and measured human brain deformation

We propose a robust framework for quantitatively comparing model-predicted and experimentally measured strain fields in the human brain during harmonic skull motion. Traumatic brain injuries (TBIs) are typically caused by skull impact or acceleration, but how skull motion leads to brain deformation and consequent neural injury remains unclear and comparison of model predictions to experimental data remains limited. Magnetic resonance elastography (MRE) provides high-resolution, full-field measurements of dynamic brain deformation induced by harmonic skull motion. In the proposed framework, full-field strain measurements from human brain MRE in vivo are compared to simulated strain fields from models with similar harmonic loading. To enable comparison, the model geometry and subject anatomy, and subsequently, the predicted and measured strain fields are nonlinearly registered to the same standard brain atlas. Strain field correlationsC v , both global (over the brain volume) and local (over smaller sub-volumes), are then computed from the inner product of the complex-valued strain tensors from model and experiment at each voxel. To demonstrate our approach, we compare strain fields from MRE in six human subjects to predictions from two previously developed models. Notably, globalC v values are higher when comparing strain fields from different subjects (C v ~ 0.6 - 0.7 ) than when comparing strain fields from either of the two models to strain fields in any subject. The proposed framework provides a quantitative method to assess similarity (and to identify discrepancies) between model predictions and experimental measurements of brain deformation, and thus can aid in the development and evaluation of improved models of brain biomechanics.

Deplete and repeat: microglial CSF1R inhibition and traumatic brain injury

Traumatic brain injury (TBI) is a public health burden affecting millions of people. Sustained neuroinflammation after TBI is often associated with poor outcome. As a result, increased attention has been placed on the role of immune cells in post-injury recovery. Microglia are highly dynamic after TBI and play a key role in the post-injury neuroinflammatory response. Therefore, microglia represent a malleable post-injury target that could substantially influence long-term outcome after TBI. This review highlights the cell specific role of microglia in TBI pathophysiology. Microglia have been manipulated via genetic deletion, drug inhibition, and pharmacological depletion in various pre-clinical TBI models. Notably, colony stimulating factor 1 (CSF1) and its receptor (CSF1R) have gained much traction in recent years as a pharmacological target on microglia. CSF1R is a transmembrane tyrosine kinase receptor that is essential for microglia proliferation, differentiation, and survival. Small molecule inhibitors targeting CSF1R result in a swift and effective depletion of microglia in rodents. Moreover, discontinuation of the inhibitors is sufficient for microglia repopulation. Attention is placed on summarizing studies that incorporate CSF1R inhibition of microglia. Indeed, microglia depletion affects multiple aspects of TBI pathophysiology, including neuroinflammation, oxidative stress, and functional recovery with measurable influence on astrocytes, peripheral immune cells, and neurons. Taken together, the data highlight an important role for microglia in sustaining neuroinflammation and increasing risk of oxidative stress, which lends to neuronal damage and behavioral deficits chronically after TBI. Ultimately, the insights gained from CSF1R depletion of microglia are critical for understanding the temporospatial role that microglia develop in mediating TBI pathophysiology and recovery.

Physics-Informed Machine Learning Improves Detection of Head Impacts

In this work we present a new physics-informed machine learning model that can be used to analyze kinematic data from an instrumented mouthguard and detect impacts to the head. Monitoring player impacts is vitally important to understanding and protecting from injuries like concussion. Typically, to analyze this data, a combination of video analysis and sensor data is used to ascertain the recorded events are true impacts and not false positives. In fact, due to the nature of using wearable devices in sports, false positives vastly outnumber the true positives. Yet, manual video analysis is time-consuming. This imbalance leads traditional machine learning approaches to exhibit poor performance in both detecting true positives and preventing false negatives. Here, we show that by simulating head impacts numerically using a standard Finite Element head-neck model, a large dataset of synthetic impacts can be created to augment the gathered, verified, impact data from mouthguards. This combined physics-informed machine learning impact detector reported improved performance on test datasets compared to traditional impact detectors with negative predictive value and positive predictive values of 88 and 87% respectively. Consequently, this model reported the best results to date for an impact detection algorithm for American football, achieving an F₁ score of 0.95. In addition, this physics-informed machine learning impact detector was able to accurately detect true and false impacts from a test dataset at a rate of 90% and 100% relative to a purely manual video analysis workflow. Saving over 12 h of manual video analysis for a modest dataset, at an overall accuracy of 92%, these results indicate that this model could be used in place of, or alongside, traditional video analysis to allow for larger scale and more efficient impact detection in sports such as American Football.

Adverse childhood experiences and traumatic brain injury among adolescents: findings from the 2016-2018 National Survey of Children's Health

Exposure to adverse childhood experiences (ACEs) is a significant public health issue for youth. However, traumatic brain injury (TBI) has been almost entirely overlooked in the ACEs and health outcomes literature, which has largely focused on the significant mental and behavioral health impact of ACEs. The goal the current study is to examine the association between ACEs and TBI among a nationally representative sample of adolescents in the United States and the extent to which ADHD and conduct problems inform this association. To assess this relationship, we use a sample of 42,204 adolescents (ages 12-17 years) in the United States whose caregivers were surveyed during the three most recent cohorts (2016-2018) of the National Survey of Children's Health (NSCH). The results revealed a dose-response relationship between ACEs and TBI, even after accounting for an array of confounding variables. Findings also indicated that associations were of a greater magnitude among youth who are not sports-involved. Supplemental mediation analyses showed that ADHD and conduct problems attenuated associations between ACE exposure and TBI, but only in the absence of youth sports involvement. Given that both ACEs and TBI carry long-term consequences for health and well-being, the findings from this study draw attention to the need for early intervention and prevention programming (e.g. home visiting) that can reduce the prevalence of ACEs and a history of TBI among adolescents.

Repeated mild traumatic brain injury impairs fracture healing in male mice

Objectives

The goal of this study was to evaluate the long-term impact of repeated (r) mild traumatic brain injury (mTBI) on the healing of fractures in a mouse model. Ten week-old male mice were subjected to r-mTBI once per day for 4 days followed by closed femoral fracture using a three-point bending technique, 1 week post impact and fracture healing phenotype evaluated at 20 weeks of age.

Results

Micro-CT analysis of the fracture callus region at nine weeks post fracture revealed reduced bone volume (30%, p < 0.05) in the r-mTBI fracture group compared to the control-fracture group. The connectivity density of the fracture callus bone was reduced by 40% (p < 0.01) in the r-mTBI fracture group. Finite element analysis of the fracture callus region showed reduced failure load (p = 0.08) in the r-mTBI group compared to control group. There was no residual cartilage in the fracture callus region of either the r-mTBI or control fracture group. The reduced fracture callus bone volume and mechanical strength of fracture callus in r-mTBI mice 9 weeks post fracture are consistent with negative effects of r-mTBI on fracture healing over a long-term resulting in decreased mechanical strength of the fracture callus.

Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future

The ketone bodies acetoacetate (AcAc) and β-hydroxybutyrate (βHB) have pleiotropic effects in multiple organs including brain, heart, and skeletal muscle by serving as an alternative substrate for energy provision, and by modulating inflammation, oxidative stress, catabolic processes, and gene expression. Of particular relevance to athletes are the metabolic actions of ketone bodies to alter substrate utilisation through attenuating glucose utilisation in peripheral tissues, anti-lipolytic effects on adipose tissue, and attenuation of proteolysis in skeletal muscle. There has been long-standing interest in the development of ingestible forms of ketone bodies that has recently resulted in the commercial availability of exogenous ketone supplements (EKS). These supplements in the form of ketone salts and ketone esters, in addition to ketogenic compounds such as 1,3-butanediol and medium chain triglycerides, facilitate an acute transient increase in circulating AcAc and βHB concentrations, which has been termed 'acute nutritional ketosis' or 'intermittent exogenous ketosis'. Some studies have suggested beneficial effects of EKS to endurance performance, recovery, and overreaching, although many studies have failed to observe benefits of acute nutritional ketosis on performance or recovery. The present review explores the rationale and historical development of EKS, the mechanistic basis for their proposed effects, both positive and negative, and evidence to date for their effects on exercise performance and recovery outcomes before concluding with a discussion of methodological considerations and future directions in this field.

Heads-Up: Risk-Specific Neurodegenerative Mortality and Years-Saved Analysis on the US Olympian Cohort

Purpose: This study aimed to identify the risk of neurodegenerative death (ND) that former Olympians endure due to their participation in sports grouped based on presumed repeated shocks to the head, and to understand the impact of their participation in such elite sports on their total longevity.

Materials and Methods: The cohort included all former US Olympians, who participated in the Olympic Games (OG) between 1948 and 1972, and whose vital status and causes of death were verified (n = 2,193). Olympic sports were classified into three categories of exposure: Collision (the highest presumed risk of repeated shocks to the head), Contact, and No-Contact. The Fine-Gray competing risk regression model was used to compare the risk of ND where the No-Contact category was a reference group. The years-saved analysis was performed to quantify the number of years saved or lost to ND and total longevity compared with the US general population.

Results: A total of 65 NDs were identified. Collision sports Olympians had a 3.11 (95% CI: 1.31–7.40) higher risk of ND while the Contact group showed a risk of 0.56 (95% CI: 0.21–1.48) compared with the No-Contact sports Olympians. Compared with the general population, the Collision group lost 0.61 (95% CI: -1.16—0.06) years of life from ND, while the Contact group saved 0.4 (95% CI: 0.26–0.54) and the No-Contact group saved 0.09 (-0.09–0.28) years of life up to the age of 90. Regarding the total longevity, Collision, Contact, and No-Contact groups saved 4.67 (95% CI: 3.13–6.22), 5.8 (95% CI: 4.93–6.67), and 6.24 (95% CI: 5.57–6.92) years of life, respectively, from all causes of death.

Conclusion: There is an elevated risk of ND among US Olympians, who engaged in sports with the highest presumed risk of repeated shocks to the head compared with those exposed to no such hazard. Such risk does not jeopardize the total longevity among Olympians in Collision sports.

Incidence of Benign Meningiomas in the United States: Current and Future Trends

Background

Benign meningiomas are the most frequently reported central nervous system tumors in the United States, with increasing incidence in past decades. However, the future trajectory of this neoplasm remains unclear.

Methods

We analyzed benign meningioma incidence of cases identified by any means (eg, radiographically with or without microscopic confirmation) in US Surveillance, Epidemiology, and End Results cancer registries among groups aged 35 to 84 years during 2004-2017 by sex and race and ethnicity using age-period-cohort models. We employed age-period-cohort forecasting models to glean insights regarding the etiology, distribution, and anticipated future (2018-2027) public health impact of this neoplasm.

Results

In all groups, meningioma incidence overall increased through 2010, then stabilized. Temporal declines were statistically significant overall and in most groups. JoinPoint analysis of cohort rate-ratios identified substantial acceleration in White men born after 1963 (from 1.1% to 3.2% per birth year); cohort rate-ratios were stable or increasing in all groups and all birth cohorts. We forecast that meningioma incidence through 2027 will remain stable or decrease among groups aged 55-84 years but remain similar to current levels among groups aged 35-54 years. The case count of total meningioma burden in 2027 is expected to be approximately 30 470, similar to the expected case count of 27 830 in 2018.

Conclusions

Between 2004 and 2017, overall incidence of benign meningioma increased and then stabilized or declined. For 2018-2027, our forecast is incidence will remain generally stable in younger age groups but decrease in older age groups. Nonetheless, the total future burden will remain similar to current levels because the population is aging.

Osteopathic Manipulative Treatment to Optimize the Glymphatic Environment in Severe Traumatic Brain Injury Measured With Optic Nerve Sheath Diameter, Intracranial Pressure Monitoring, and Neurological Pupil Index

Background

Traumatic brain injury (TBI) has a complex pathophysiology that has historically been poorly understood. New evidence on the pathophysiology, molecular biology, and diagnostic studies involved in TBI have shed new light on optimizing rehabilitation and recovery. The goal of this study was to assess the effect of osteopathic manipulative treatment (OMT) on peripheral and central glial lymphatics in patients with severe TBI, brain edema, and elevated intracranial pressure (ICP) by measuring changes in several parameters regularly used in management.

Methodology

This was a retrospective study at a level II trauma center that occurred in 2018. The study enrolled patients with TBI, increased ICP, or brain edema who had an external ventricular drain placed. Patients previously underwent a 51-minute treatment with OMT with an established protocol. Patients received 51 minutes of OMT to the head, neck, and peripheral lymphatics. The ICP, cerebrospinal fluid (CSF) drainage, optic nerve sheath diameter (ONSD) measured by ultrasonography, and Neurological Pupil Index (NPi) measured by pupillometer were recorded before, during, and after receiving OMT.

Results

A total of 11 patients were included in the study, and 21 points of data were collected from the patients meeting inclusion criteria who received OMT. There was a mean decrease in the ONSD of 0.62 mm from 6.24 mm to 5.62 mm (P = 0.0001). The mean increase in NPi was 0.18 (P = 0.01). The mean decrease in ICP was 3.33 mmHg (P= 0.0001). There was a significant decrease in CSF output after treatment (P = 0.0001). Each measurement of ICP, ONSD, and NPi demonstrated a decrease in overall CSF volume and pressure after OMT compared to CSF output and ICP prior to OMT.

Conclusions

This study demonstrates that OMT may help optimize glial lymphatic clearance of CSF and improve brain edema, interstitial waste product removal, NPi, ICP, CSF volume, and ONSD. A holistic approach including OMT may be considered to enhance management in TBI patients. As TBI is a spectrum of disease, utilizing similar techniques may be considered for all forms of TBI including concussions and other diseases with brain edema. The results of this study can better inform future trials to specifically study the effectiveness of OMT in post-concussive treatment and in those with mild-to-moderate TBI.

An Overview and Therapeutic Promise of Nutraceuticals against Sports-Related Brain Injury

Sports-related traumatic brain injury (TBI) is one of the common neurological maladies experienced by athletes. Earlier the term 'punch drunk syndrome' was used in the case TBI of boxers and now this term is replaced by chronic traumatic encephalopathy (CTE). Sports-related brain injury can either be short term or long term. A common instance of brain injury encompasses subdural hematoma, concussion, cognitive dysfunction, amnesia, headache, vision issue, axonopathy, or even death if remain undiagnosed or untreated. Further, chronic TBI may lead to pathogenesis of neuroinflammation and neurodegeneration via tauopathy, formation of neurofibrillary tangles, and damage to the blood-brain barrier, microglial, and astrocyte activation. Thus, altered pathological, neurochemical, and neurometabolic attributes lead to the modulation of multiple signaling pathways and cause neurological dysfunction. Available pharmaceutical interventions are based on one drug one target hypothesis and thereby unable to cover altered multiple signaling pathways. However, in recent time's pharmacological intervention of nutrients and nutraceuticals have been explored as they exert a multifactorial mode of action and maintain over homeostasis of the body. There are various reports available showing the positive therapeutic effect of nutraceuticals in sport-related brain injury. Therefore, in the current article we have discussed the pathology, neurological consequence, sequelae, and perpetuation of sports-related brain injury. Further, we have discussed various nutraceutical supplements as well as available animal models to explore the neuroprotective effect/ upshots of these nutraceuticals in sports-related brain injury.

Do Toxic Synergies of Underlying Etiologies Predispose the Positive Association Between Traumatic Brain Injury and ADHD?

Objective: In their meta-analysis, Adeyemo et al. reported a strong association between mild traumatic brain injury (mTBI) and ADHD. However, less is understood about why such an association exists. Method: This commentary focuses on the underlying etiologies of both conditions to reveal potential toxic synergisms that could explain this association. Results: Alcohol and substance abuse are recognized comorbidities in both conditions. The author of this commentary has recently been the first to propose that chronic exposure to nitrous oxide (N₂O), an increasing environmental air pollutant and greenhouse gas, may contribute to the cognitive impairment seen in conditions such as ADHD and autism. The toxic synergisms from combined GABA-mimetics, such as ethanol, and nontoxic N₂O exposure have been previously elucidated and are further contextualized here. Conclusion: The conclusion of this commentary is that the toxicological interdependence of the underlying etiologies for mTBI and ADHD may help to explain their association as found in the meta-analysis conducted by Adeyemo et al. This commentary explores this dynamic further and, in so doing, underscores the need for additional research to validate these important conclusions.

A Mobile Phone App for the Self-Management of Pediatric Concussion: Development and Usability Testing

BACKGROUND

Concussion is a common injury among Canadian children and adolescents that leads to a range of neurobehavioral deficits. However, noticeable gaps continue to exist in the management of pediatric concussion, with poor health outcomes associated with the inadequate application of best practice guidelines.

OBJECTIVE

The aim of this study was to describe the development and assess the usability of a mobile phone app to aid youth in the self-management of concussion. A secondary objective was to assess the usefulness of the app.

METHODS

An agile user-centered design approach was used to develop the technology, followed by a formative lab-based usability study for assessment and improvement proposals. Youths aged 10 to 18 years with a history of concussion and health care professionals involved in concussion management were recruited. This study included participants performing 12 tasks with the mobile phone app while using the think aloud protocol and the administration of the System Usability Scale (SUS), posttest questionnaire, and a semistructured interview.

RESULTS

A mobile phone app prototype called NeuroCare, an easily accessible pediatric concussion management intervention that provides easy access to expert-informed concussion management strategies and helps guide youth in self-managing and tracking their concussion recovery, was developed. A total of 7 youths aged between 10 and 18 years with a history of concussion and 7 health care professionals were recruited. The mean SUS score was 81.9, mean task success rates were greater than 90% for 92% (11/12) of the tasks, 92% (11/12) of tasks had a total error frequency of less than 11 errors, and mean task completion times were less than 2 min for 100% of the tasks.

CONCLUSIONS

Results suggest that participants rated this app as highly usable, acceptable to users, and that it may be useful in helping youth self-manage concussion.

The development of the Brain Injury Screening Index (BISI): A self-report measure

The aim of this study was to investigate the psychometric properties and screening accuracy of the Brain Injury Screening Index (BISI), a self-report questionnaire designed to identify a history of acquired brain injury. The study was conducted in a closed male prison in the UK. The purposive sample comprised 55 male prisoners who arrived at the establishment during the study. A repeated measures design was used, where the Brain Injury Screening Index (BISI) was administered on three occasions. Inter-rater reliability was poor to moderate, but test retest reliability was moderate to good. Medical records were not available for all participants, but the limited number obtained resulted in a sensitivity of .38 to .71 and specificity of .47 to .70 across the three screening administrations of the BISI. The limitations of the present findings are discussed in the context of the use of the tool in custodial environments. It is argued that these results suggest that, when used as recommended, the BISI has acceptable reliability and validity as an initial screen for identifying individuals who should receive support and a comprehensive neuropsychological assessment, and it merits further investigation and development.

Concentrated Conditioned Media from Adipose Tissue Derived Mesenchymal Stem Cells Mitigates Visual Deficits and Retinal Inflammation Following Mild Traumatic Brain Injury

Blast concussions are a common injury sustained in military combat today. Inflammation due to microglial polarization can drive the development of visual defects following blast injuries. In this study, we assessed whether anti-inflammatory factors released by the mesenchymal stem cells derived from adipose tissue (adipose stem cells, ASC) can limit retinal tissue damage and improve visual function in a mouse model of visual deficits following mild traumatic brain injury. We show that intravitreal injection of 1 μL of ASC concentrated conditioned medium from cells pre-stimulated with inflammatory cytokines (ASC-CCM) mitigates loss of visual acuity and contrast sensitivity four weeks post blast injury. Moreover, blast mice showed increased retinal expression of genes associated with microglial activation and inflammation by molecular analyses, retinal glial fibrillary acidic protein (GFAP) immunoreactivity, and increased loss of ganglion cells. Interestingly, blast mice that received ASC-CCM improved in all parameters above. In vitro, ASC-CCM not only suppressed microglial activation but also protected against Tumor necrosis alpha (TNFα) induced endothelial permeability as measured by transendothelial electrical resistance. Biochemical and molecular analyses demonstrate TSG-6 is highly expressed in ASC-CCM from cells pre-stimulated with TNFα and IFNγ but not from unstimulated cells. Our findings suggest that ASC-CCM mitigates visual deficits of the blast injury through their anti-inflammatory properties on activated pro-inflammatory microglia and endothelial cells. A regenerative therapy for immediate delivery at the time of injury may provide a practical and cost-effective solution against the traumatic effects of blast injuries to the retina.

A primer on traumatic brain injury for nursing faculty

Incidence of traumatic brain injury (TBI) is increasing on campuses. Despite growing media attention and athletic program protocols to address the issue, many are unaware of the potential effects such an injury can cause. This may be true for nursing faculty who teach or advise students recovering from TBI. This article will examine relevant aspects of injury and recovery, as well as ways faculty can advocate for and support students who struggle during what can be a protracted period of recovery. Students' symptoms while recovering from TBI may diminish cognitive, emotional, and physical resources. Because individual responses to similar injuries may vary significantly, an individualized plan of academic support is important. A key component to academic support for students with TBI is integrated communication between athletic department staff, students, faculty, and administration.

The effectiveness of clinical pathway-directed care on hospitalisation-related outcomes in patients with severe traumatic brain injury: A quasi-experimental study

AIMS AND OBJECTIVES

To compare the effectiveness of clinical pathway-directed care to usual care on hospitalisation-related outcomes in patients with severe traumatic brain injury (STBI).

BACKGROUND

Severe traumatic brain injury is a major cause of disability and mortality in young adults. Clinical pathways endeavour to bring evidence and clinical practice closer together to foster the delivery of best practice and to improve patient outcomes.

DESIGN

Quasi-experimental study.

METHODS

The study was conducted in a trauma intensive care unit of a large teaching hospital in Egypt. Patients aged 18-60 years with a diagnosis of STBI, a Glasgow Coma Scale score between 3-8 and a nonpenetrating head injury were consecutively assigned to 15 days of care. The outcomes assessed were complications related to hospitalisation, clinical variances, length of intensive care unit (ICU) stay, ICU readmission rate and patient/family satisfaction.

RESULTS

Sixty participants completed the study (30 in each arm). Apart from age, there were no significant differences between groups in baseline characteristics. The clinical pathway group demonstrated statistically significantly fewer cases of hospitalisation-related complications on day 15, and a significantly shorter length of ICU stay, lower ICU readmission rate and a high level of patient/family satisfaction when compared with the usual care group. The effect of the intervention on fever, pressure ulceration, hyperglycaemia and readmission to the ICU was no longer statistically significant after controlling for age.

CONCLUSIONS

The findings of the current study suggest that the implementation of a clinical pathway for patients with severe TBI may be helpful in improving the patient experience as well as some hospitalisation-related outcomes.

RELEVANCE TO CLINICAL PRACTICE

The provision of clinical pathway-directed care in a trauma ICU may offer benefits to the patient, family and institution beyond that provided by usual care.

The Effects of Intimate Partner Violence and Probable Traumatic Brain Injury on Central Nervous System Symptoms

INTRODUCTION

Abused women often report a wide range of physical and psychological symptoms that present challenges to providers. Specifically, injuries to the head or strangulation, may initiate neurological changes that contribute to central nervous system (CNS) symptoms. These symptoms are often attributed to mental health diagnoses in this population. The purpose of this analysis is to examine the prevalence of and associations between reported probable traumatic brain injury (TBI) and CNS symptoms in a sample of women of African descent.

METHODS

A convenience sample of 901 women of African descent from Baltimore, MD and the US Virgin Islands, aged 18-55, was used to examine relationships among self-reported intimate partner violence (IPV), TBI, and CNS symptoms. Data were collected via Audio Computer-Assisted Self-Interview.

RESULTS

Abused women who experienced a probable TBI were more likely to report CNS symptoms than those who did not. When controlling for demographics, IPV, and mental health symptoms, probable TBI was associated with a two point increase in CNS symptom frequency score (95% confidence interval: 1.55-2.93, p < 0.001).

CONCLUSIONS

Women who reported both probable TBI and IPV were more likely than their abused counterparts who reported no TBI to report CNS symptoms. This relationship held true even when controlling for symptoms of depression and post-traumatic stress disorder (PTSD). Clinicians working with women should be aware of TBI as a possible etiology for symptoms in abused women. Appropriate screening and treatment protocols should be designed and implemented across medical settings to improve outcomes for women who have experienced IPV and TBI.

BDNF genotype is associated with hippocampal volume in mild traumatic brain injury

The negative long-term effects of mild traumatic brain injury (mTBI) have been a growing concern in recent years, with accumulating evidence suggesting that mTBI combined with additional vulnerability factors may induce neurodegenerative-type changes in the brain. However, the factors instantiating risk for neurodegenerative disease following mTBI are unknown. This study examined the link between mTBI and brain-derived neurotrophic factor (BDNF) genotype, which has previously been shown to regulate processes involved in neurodegeneration including synaptic plasticity and facilitation of neural survival through its expression. Specifically, we examined nine BDNF single-nucleotide polymorphisms (SNPs; rs908867, rs11030094, rs6265, rs10501087, rs1157659, rs1491850, rs11030107, rs7127507 and rs12273363) previously associated with brain atrophy or memory deficits in mTBI. Participants were 165 white, non-Hispanic Iraq and Afghanistan war veterans between the ages of 19 and 58, 110 of whom had at least one mTBI in their lifetime. Results showed that the BDNF SNP rs1157659 interacted with mTBI to predict hippocampal volume. Furthermore, exploratory analysis of functional resting state data showed that rs1157659 minor allele homozygotes with a history of mTBI had reduced functional connectivity in the default mode network compared to major allele homozygotes and heterozygotes. Apolipoprotein E (APOE) was not a significant predictor of hippocampal volume or functional connectivity. These results suggest that rs1157659 minor allele homozygotes may be at greater risk for neurodegeneration after exposure to mTBI and provide further evidence for a potential role for BDNF in regulating neural processes following mTBI.

Head Injury and Substance Use in Young Adults

BACKGROUND

Prior studies suggest a link between head injuries and substance use but do not routinely capture mechanisms connecting the two.

OBJECTIVES

The goal of the study was to explore whether past head injuries predicted current substance use among young adults, taking factors such as stress, self-esteem, temper, and risk-taking into consideration.

METHODS

Data were drawn from a web-based survey conducted in 2014 and 2015 at a public university in the United States (n = 897). Questions were asked about history of head injuries as well as past 12-month binge drinking, marijuana use, and prescription drug misuse. To evaluate the association between head injury and substance use, two logistic regression models were performed for each substance. Head injury was first regressed on the outcome, then related risk factors were entered into the models to determine whether they explained any association between injury and outcome.

RESULTS

A history of multiple head injuries was associated with increased odds of bingeing, marijuana, and prescription drug use. Prior delinquency and risk-taking accounted for the associations with bingeing and marijuana use. Taking all variables into consideration, multiple head injuries were associated with greater odds for prescription drug misuse.

CONCLUSIONS

Results suggest the need to give consideration to a range of concomitant variables when considering behavioral outcomes associated with head injury. Head injuries may be a marker of a constellation of risk-taking behaviors that contributes to substance use. For those with multiple injuries, misuse of prescription drugs may be an attempt to cope with lingering side effects.

The effect of concussion history on cognitive-motor integration in elite hockey players

AIM

To observe the effects of concussion history on cognitive-motor integration in elite-level athletes.

METHODS

The study included 102 National Hockey League draft prospects (n = 51 concussion history [CH]; n = 51 no history [NC]). Participants completed two computer-based visuomotor tasks, one involved 'standard' visuomotor mapping and one involved 'nonstandard' mapping in which vision and action were decoupled.

RESULTS

We observed a significant effect of group on reaction time (CH slower) and accuracy (CH worse), but a group by condition interaction only for reaction time (p < 0.05). There were no other deficits found. We discussed these findings in comparison to our previous work with non-elite athletes.

CONCLUSION

Previously concussed elite-level athletes may have lingering neurological deficits that are not detected using standard clinical assessments.

Prohibiting Headgear for Safety in Amateur Boxing? Opinion of the Canadian Boxing Community: an Online Poll

Background

In 2013, the Amateur International Boxing Association (AIBA) introduced a rule banning headgear for male-senior open class boxers during competition. The AIBA has defended the rule change as motivated by safety and supported by internal unpublished studies. As a result, in 2018, the AIBA plans to universally prohibit headgear in competition: for all competitors (male and female), all ages and all levels. Within Canada, this ruling has generated controversy in the boxing community, yet there has been no overall measure of opinion.

Methods

To address this, we instituted a voluntary, anonymous, online open-access poll to allow members of the boxing community to express their stance on headgear use in competition.

Results

In total, 636 responses were received. A total of 71.5 % of Canadian respondents believed headgear should be mandatory at all levels. Only 5.8 % agreed that headgear should be prohibited, as planned for 2018. Estimating results on a representative breakdown of boxing membership in Canada, a similar pattern emerged, whereby 68.2 % concurred with mandatory headgear while only 4.95 % supported its prohibition. Parents of boxers were almost unanimously against banning headgear, stating they would change sports as a result. Similarly, only 1.7 % of women believed headgear should be prohibited.

Conclusions

The consensus of the Canadian boxing community largely opposes the rule changes that the AIBA has implemented. The results highlight risks posed to the long-term viability of the sport, if significant grassroots safety concerns are disregarded.

Distribution and Morphology of Calcium-Binding Proteins Immunoreactive Neurons following Chronic Tungsten Multielectrode Implants

The development of therapeutic approaches to improve the life quality of people suffering from different types of body paralysis is a current major medical challenge. Brain-machine interface (BMI) can potentially help reestablishing lost sensory and motor functions, allowing patients to use their own brain activity to restore sensorimotor control of paralyzed body parts. Chronic implants of multielectrodes, employed to record neural activity directly from the brain parenchyma, constitute the fundamental component of a BMI. However, before this technique may be effectively available to human clinical trials, it is essential to characterize its long-term impact on the nervous tissue in animal models. In the present study we evaluated how chronic implanted tungsten microelectrode arrays impact the distribution and morphology of interneurons reactive to calcium-binding proteins calbindin (CB), calretinin (CR) and parvalbumin (PV) across the rat’s motor cortex. Our results revealed that chronic microelectrode arrays were well tolerated by the nervous tissue, with recordings remaining viable for up to 6 months after implantation. Furthermore, neither the morphology nor the distribution of inhibitory neurons were broadly impacted. Moreover, restricted microglial activation was observed on the implanted sites. On the whole, our results confirm and expand the notion that tungsten multielectrodes can be deemed as a feasible candidate to future human BMI studies.

Increased brain activation during working memory processing after pediatric mild traumatic brain injury (mTBI)

PURPOSE

The neural substrate of post-concussive symptoms following the initial injury period after mild traumatic brain injury (mTBI) in pediatric populations remains poorly elucidated. This study examined neuropsychological, behavioral, and brain functioning in adolescents post-mTBI to assess whether persistent differences were detectable up to a year post-injury.

METHODS

Nineteen adolescents on average 7.5 months post-mTBI completed neuropsychological testing and an fMRI auditory-verbal N-back working memory task. Parents completed behavioral ratings. The comparison group included 19 healthy controls matched to the mTBI group for demographic variables and N-back task performance.

RESULTS

There were no between-group differences for cognition or behavior ratings. The expected decreased accuracy and increased reaction time as N-back task difficulty increased were apparent. The mTBI group showed significantly greater brain activation than controls during the most difficult working memory load condition.

CONCLUSION

Greater working memory task-related activation was found in adolescents up to one year post-mTBI relative to controls, potentially indicating compensatory activation to support normal task performance. Differences in brain activation in the mTBI group so long after injury may indicate residual alterations in brain function much later than would be expected based on the typical pattern of symptom recovery, which could have important clinical implications.

Diminished brain resilience syndrome: A modern day neurological pathology of increased susceptibility to mild brain trauma, concussion, and downstream neurodegeneration

The number of sports-related concussions has been steadily rising in recent years. Diminished brain resilience syndrome is a term coined by the lead author to describe a particular physiological state of nutrient functional deficiency and disrupted homeostatic mechanisms leading to increased susceptibility to previously considered innocuous concussion. We discuss how modern day environmental toxicant exposure, along with major changes in our food supply and lifestyle practices, profoundly reduce the bioavailability of neuro-critical nutrients such that the normal processes of homeostatic balance and resilience are no longer functional. Their diminished capacity triggers physiological and biochemical 'work around' processes that result in undesirable downstream consequences. Exposure to certain environmental chemicals, particularly glyphosate, the active ingredient in the herbicide, Roundup(®), may disrupt the body's innate switching mechanism, which normally turns off the immune response to brain injury once danger has been removed. Deficiencies in serotonin, due to disruption of the shikimate pathway, may lead to impaired melatonin supply, which reduces the resiliency of the brain through reduced antioxidant capacity and alterations in the cerebrospinal fluid, reducing critical protective buffering mechanisms in impact trauma. Depletion of certain rare minerals, overuse of sunscreen and/or overprotection from sun exposure, as well as overindulgence in heavily processed, nutrient deficient foods, further compromise the brain's resilience. Modifications to lifestyle practices, if widely implemented, could significantly reduce this trend of neurological damage.