Update on the Epidemiology of Concussion/Mild Traumatic Brain Injury

TRANSCENDENT (Transforming Research by Assessing Neuroinformatics across the Spectrum of Concussion by Embedding iNterdisciplinary Data-collection to Enable Novel Treatments): protocol for a prospective observational cohort study of concussion patients with embedded comparative effectiveness research within a network of learning health system concussion clinics in Canada

INTRODUCTION

Concussion affects over 400 000 Canadians annually, with a range of causes and impacts on health-related quality of life. Research to date has disproportionately focused on athletes, military personnel and level I trauma centre patients, and may not be applicable to the broader community. The TRANSCENDENT Concussion Research Program aims to address patient- and clinician-identified research priorities, through the integration of clinical data from patients of all ages and injury mechanisms, patient-reported outcomes and objective biomarkers across factors of intersectionality. Seeking guidance from our Community Advisory Committee will ensure meaningful patient partnership and research findings that are relevant to the wider concussion community.

METHODS AND ANALYSIS

This prospective observational cohort study will recruit 5500 participants over 5 years from three 360 Concussion Care clinic locations across Ontario, Canada, with a subset of participants enrolling in specific objective assessments including testing of autonomic function, exercise tolerance, vision, advanced neuroimaging and fluid biomarkers. Analysis will be predicated on pre-specified research questions, and data shared with the Ontario Brain Institute's Brain-CODE database. This work will represent one of the largest concussion databases to date, and by sharing it, we will advance the field of concussion and prevent siloing within brain health research.

ETHICS AND DISSEMINATION

This study was approved by the Children's Hospital of Eastern Ontario Research Ethics Board and preregistered on OSF (25 June 2024); https://doi.org/10.17605/OSF.IO/HYDZC. Dissemination of findings will be multifaceted, including conference presentations, peer-reviewed publications and sharing of adapted materials (eg, videos, infographics, plain language summaries) with community groups and key knowledge users.

Prevalence of traumatic brain injury among adults and children

PURPOSE

Surveillance of traumatic brain injury (TBI) in the United States has historically relied on healthcare administrative datasets, but these sources likely underestimate the true burden of TBI. Surveys that ask individuals to self- or proxy-report their experiences with their injuries are an alternative source for surveillance. This paper provides results from a large national survey that ascertained TBI among sampled adults and children.

METHODS

Data from the 2023 National Health Interview Survey, a nationally representative household survey of the civilian non-institutionalized US population, were examined. Descriptive and bivariate statistics of demographic and injury characteristics of children and adults who sustained a TBI in the past 12 months were calculated.

RESULTS

Analyses reveal that 3.0 % (n = 9757,000) of Americans (3.3 % of adults and 2.2 % of children (aged ≤17 years)) reported a TBI in the past year. Among children who sustained a TBI in the past year, over half (55.5 %) sustained their TBI during a sport or recreational activity, and 62.4 % were evaluated by a medical professional. The prevalence of TBI and injury characteristics varied by select demographics.

CONCLUSION

These findings demonstrate that TBI affects a large number of Americans and highlight the value of TBI surveillance through nationally representative surveys, providing a broad picture of prevalence, healthcare utilization, and setting of injury.

Health and Health Care Utilization Outcomes for Individuals With Traumatic Brain Injury: A 1-Year Longitudinal Study

OBJECTIVE

Traumatic brain injury (TBI) can result in new onset of comorbidities and limited studies suggest health care utilization following TBI may be high. Setting, Participants, Mean Measures, and Design: This study used 2018 and 2019 MarketScan Commercial Claims and Encounters data to examine differences in longitudinal health outcomes (health care utilization and new diagnoses) by various demographic factors (age, sex, U.S. region, intent/mechanism of injury, urbanicity, and insurance status) among individuals with and without a TBI in the year following an index health care encounter.

RESULTS

Results show that within 1 year of the initial encounter, a higher percentage of patients with TBI versus without TBI had at least one outpatient visit (96.7% vs 86.1%), emergency department (ED) visit (28.5% vs 13.1%), or hospital admission (6.4% vs 2.6%). Both children (33.8% vs 23.4%) and adults (43.8% vs 31.4%) who sustained a TBI had a higher percentage of new diagnoses within 1 year compared to the non-TBI group. Additionally, individuals with a TBI had greater health care utilization across all types of health care settings (outpatient and inpatient), visits (ED visits and hospital admissions), and across all demographic factors (P < .001).

CONCLUSION

These results may inform future research around the development of systems of care to improve longer-term outcomes in individuals with TBI.

Regression-Based Classification of the Middle-Latency Auditory-Evoked Potentials in Vestibular Migraine and Concussion Patients with Dizziness

BACKGROUND/OBJECTIVES

The auditory middle-latency responses (AMLRs) assess central sensory processing beyond the brainstem and serve as a measure of sensory gating. They have clinical relevance in the diagnosis of neurological conditions. In this study, magnitude and habituation of the AMLRs were tested for sensitivity and specificity in classifying dizzy patients with vestibular migraine (VM) and post-concussive syndrome.

METHODS

Twenty-three healthy individuals, 12 concussion and 26 VM patients were recruited. AMLR were recorded performing five blocks of 200 binaural click-stimulations at 60 dB sensation level with a repetition rate of 6.1 Hz. Reduction in P0, Na and Pa magnitudes between blocks was measured. Group classifications were performed through logistic and multiple regression.

RESULTS

Among healthy subjects, a consistent P0 and Na habituation can be observed. Concussed subjects show control-like Na habituation, despite a lower magnitude, while P0 habituation was negligible. VM patients showed poor habituation for all waves. Regression analyses suggest that P0 and Na better distinguish healthy subjects from neurological patients, whereas Pa best distinguishes concussion from VM patients.

CONCLUSIONS

The results support that AMLR habituation can contribute to unraveling different mechanisms of dizziness due to concussion compared to VM, providing insights that can complement routine diagnostic assessments.

The beneficial effects of modafinil administration on repeat mild traumatic brain injury (RmTBI) pathology in adolescent male rats are not dependent upon the orexinergic system

The sleep-wake cycle plays an influential role in the development and progression of repeat mild traumatic brain injury (RmTBI)-related pathology. Therefore, we first aimed to manipulate the sleep-wake cycle post-RmTBI using modafinil, a wake-promoting substance used for the treatment of narcolepsy. We hypothesized that modafinil would exacerbate RmTBI-induced deficits. Chronic behavioural analyses were completed along with a 27-plex serum cytokine array, metabolomic and proteomic analyses of cerebrospinal fluid (CSF), as well as immunohistochemical staining in structures important for sleep/wake cycles, to examine orexin, melanin-concentrating hormone, tyrosine hydroxylase, and choline acetyltransferase, in the lateral hypothalamus, locus coeruleus, and basal forebrain, respectively. Contrary to expectation, modafinil administration attenuated behavioural deficits, metabolomic changes, and neuropathological modifications. Therefore, the second aim was to determine if the beneficial effects of modafinil treatment were driven by the orexinergic system. The same experimental protocol was used; however, RmTBI rats received chronic orexin-A administration instead of modafinil. Orexin-A administration produced drastically different outcomes, exacerbating anxiety-related and motor deficits, while also significantly disrupting their metabolomic and neuropathological profiles. These results suggest that the beneficial effects of modafinil administration post-RmTBI, work independently of its wake-promoting properties, as activation of the orexinergic wake-promoting system with orexin-A was detrimental. Overall, these findings highlight the complexity of sleep-wake changes in the injured brain and showcase the potential of the arousal and sleep systems in its treatment.

Using machine learning to discover traumatic brain injury patient phenotypes: national concussion surveillance system Pilot

OBJECTIVE

The objective is to determine whether unsupervised machine learning identifies traumatic brain injury (TBI) phenotypes with unique clinical profiles.

METHODS

Pilot self-reported survey data of over 10,000 adults were collected from the Centers for Disease Control and Prevention (CDC)'s National Concussion Surveillance System (NCSS). Respondents who self-reported a head injury in the past 12 months (n = 1,364) were retained and queried for injury, outcome, and clinical characteristics. An unsupervised machine learning algorithm, partitioning around medoids (PAM), that employed Gower's dissimilarity matrix, was used to conduct a cluster analysis.

RESULTS

PAM grouped respondents into five TBI clusters (phenotypes A-E). Phenotype C represented more clinically severe TBIs with a higher prevalence of symptoms and association with worse outcomes. When compared to individuals in Phenotype A, a group with few TBI-related symptoms, individuals in Phenotype C were more likely to undergo medical evaluation (odds ratio [OR] = 9.8, 95% confidence interval[CI] = 5.8-16.6), have symptoms that were not currently resolved or resolved in 8+ days (OR = 10.6, 95%CI = 6.2-18.1), and more likely to report at least moderate impact on social (OR = 54.7, 95%CI = 22.4-133.4) and work (OR = 25.4, 95%CI = 11.2-57.2) functioning.

CONCLUSION

Machine learning can be used to classify patients into unique TBI phenotypes. Further research might examine the utility of such classifications in supporting clinical diagnosis and patient recovery for this complex health condition.

Analyzing Dual-Task Paradigms to Improve Postconcussion Assessment and Management

CONTEXT

Dual-task (simultaneous cognitive-motor activities) assessments have been adapted into reliable and valid clinical concussion measures. However, abundant motor and cognitive variations leave researchers and clinicians uncertain about which combinations elicit the intended dual-task effect. Our objective was to examine differences between commonly employed dual-task motor and cognitive combinations among healthy, college-aged individuals.

DESIGN

Cross-sectional laboratory study.

METHODS

Twenty participants (age: 21.3 [2.4] y; height: 176.0 [9.1] cm; mass: 76.0 [16.4] kg; 20% with concussion history) completed 4 motor tasks (gait, tandem gait, single-leg balance, and tandem balance) under 5 cognitive conditions (single task, subtraction, month reversal, spelling backward, and visual Stroop) in a research laboratory. The motor performance outcomes were spatiotemporal variables for gait and tandem gait and center of pressure path length (in centimeters) for single-leg and tandem balance. Cognitive outcomes were response rate (responses/second) and cognitive accuracy. We used separate repeated-measures analyses of variance for each motor and cognitive outcome with post hoc Tukey t tests.

RESULTS

Gait velocity, gait stride length, and tandem gait velocity demonstrated significant cognitive-motor interactions (P's < .001) such that all dual-task conditions resulted in varyingly slower or shorter movement than single task. Conversely, single-leg balance (P = .627) and tandem balance (P = .434) center of pressure path length did not significantly differ among the dual-task cognitive conditions or relative to single task. Statistically significant cognitive-motor interactions were observed only for spelling backward accuracy (P = .004) and response rates for spelling backward, month reversal, and visual Stroop (P's < .001) such that worse accuracy, but faster response rates, occurred during motor tasks.

CONCLUSIONS

Gait and tandem gait motor tasks accompanied with spelling backward or subtraction cognitive tasks demonstrated consistently strong dual-task effects and, therefore, may be the best suited for clinical and research use following concussion.

Development of a time-resolved immunochromatographic test strip for rapid and quantitative determination of GFAP in serum

Glial fibrillary acidic protein (GFAP) in serum has been shown as a biomarker of traumatic brain injury (TBI) which is a significant global public health concern. Accurate and rapid detection of serum GFAP is critical for TBI diagnosis. In this study, a time-resolved fluorescence immunochromatographic test strip (TRFIS) was proposed for the quantitative detection of serum GFAP. This TRFIS possessed excellent linearity ranging from 0.05 to 2.5 ng/mL for the detection of serum GFAP and displayed good linearity (Y = 598723X + 797198, R2 = 0.99), with the lowest detection limit of 16 pg/mL. This TRFIS allowed for quantitative detection of serum GFAP within 15 min and showed high specificity. The intra-batch coefficient of variation (CV) and the inter-batch CV were both < 4.0%. Additionally, this TRFIS was applied to detect GFAP in the serum samples from healthy donors and patients with cerebral hemorrhage, and the results of TRFIS could efficiently discern the patients with cerebral hemorrhage from the healthy donors. Our developed TRFIS has the characteristics of high sensitivity, high accuracy, and a wide linear range and is suitable for rapid and quantitative determination of serum GFAP on-site.

Patient-centered mild traumatic brain injury interventions in the emergency department

INTRODUCTION

Traumatic brain injury (TBI) results in 2.5 million emergency department (ED) visits per year in the US, with mild traumatic brain injury (mTBI) accounting for 90% of cases. There is considerable evidence that many experience chronic symptoms months to years later. This population is rarely represented in interventional studies. Management of adult mTBI in the ED has remained unchanged, without consensus of therapeutic options. The aim of this review was to synthesize existing literature of patient-centered ED treatments for adults who sustain an mTBI, and to identify practices that may offer promise.

METHODS

A systematic review was conducted using the PubMed and Cochrane databases, while following PRISMA guidelines. Studies describing pediatric patients, moderate to severe TBI, or interventions outside the ED were excluded. Two reviewers independently performed title and abstract screening. A third blinded reviewer resolved discrepancies. The Mixed Methods Appraisal Tool (MMAT) was employed to assess the methodological quality of the studies.

RESULTS

Our search strategy generated 1002 unique titles. 95 articles were selected for full-text screening. The 26 articles chosen for full analysis were grouped into one of the following intervention categories: (1) predictive models for Post-Concussion Syndrome (PCS), (2) discharge instructions, (3) pharmaceutical treatment, (4) clinical protocols, and (5) functional assessment. Studies that implemented a predictive PCS model successfully identified patients at highest risk for PCS. Trials implementing discharge related interventions found the use of video discharge instructions, encouragement of daily light exercise or bed rest, and text messaging did not significantly reduce mTBI symptoms. The use of electronic clinical practice guidelines (eCPG) and longer leaves of absence from work following injury reduced symptoms. Ondansetron was shown to reduce nausea in mTBI patients. Studies implementing ED Observation Units found significant declines in inpatient admissions and length of hospital stay. The use of tablet-based tasks was found to be superior to many standard cognitive assessments.

CONCLUSION

Validated instruments are available to aid clinicians in identifying patients at risk for PCS or serious cognitive impairment. EDOU management and evidence-based modifications to discharge instructions may improve mTBI outcomes. Additional research is needed to establish the therapeutic value of medications and lifestyle changes for the treatment of mTBI in the ED.

Awareness and understanding of concussion among Aboriginal Australians with high health literacy

Aim

Indigenous Australians have higher rates of traumatic brain injury, with 74-90% of such injuries being concussion. This study explores concussion awareness and knowledge in Aboriginal Western Australians with high health literacy.

Materials & methods

Participants, aged 18-65 years, engaged in research topic yarning, and thematic analysis of the qualitative data then undertaken.

Results

There was awareness that direct head trauma can result in concussion, but a lack of differentiation between concussion and other head injuries. Knowledge was gained from sport, media or lived-experience. Symptom minimization and diversity of concussion symptoms prevented participants from seeking medical treatment. This was exacerbated by a mistrust of the medical system.

Conclusion

Research findings highlight knowledge and service gaps where co-designed strategies can be targeted.

Rationale for the Development of a Traumatic Brain Injury Case Definition for the Pilot National Concussion Surveillance System

BACKGROUND

Current methods of traumatic brain injury (TBI) morbidity surveillance in the United States have primarily relied on hospital-based data sets. However, these methods undercount TBIs as they do not include TBIs seen in outpatient settings and those that are untreated and undiagnosed. A 2014 National Academy of Science Engineering and Medicine report recommended that the Centers for Disease Control and Prevention (CDC) establish and manage a national surveillance system to better describe the burden of sports- and recreation-related TBI, including concussion, among youth. Given the limitations of TBI surveillance in general, CDC took this recommendation as a call to action to formulate and implement a robust pilot National Concussion Surveillance System that could estimate the public health burden of concussion and TBI among Americans from all causes of brain injury. Because of the constraints of identifying TBI in clinical settings, an alternative surveillance approach is to collect TBI data via a self-report survey. Before such a survey was piloted, it was necessary for CDC to develop a case definition for self-reported TBI.

OBJECTIVE

This article outlines the rationale and process the CDC used to develop a tiered case definition for self-reported TBI to be used for surveillance purposes.

CONCLUSION

A tiered TBI case definition is proposed with tiers based on the type of sign/symptom(s) reported the number of symptoms reported, and the timing of symptom onset.

Refinement of a Preliminary Case Definition for Use in Traumatic Brain Injury Surveillance

OBJECTIVE

Current methods used to measure incidence of traumatic brain injury (TBI) underestimate its true public health burden. The use of self-report surveys may be an approach to improve these estimates. An important step in public health surveillance is to define a public health problem using a case definition. The purpose of this article is to outline the process that the Centers for Disease Control and Prevention undertook to refine a TBI case definition to be used in surveillance using a self-report survey.

SETTING

Survey.

PARTICIPANTS

A total of 10 030 adults participated via a random digit-dial telephone survey from September 2018 to September 2019.

MAIN MEASURES

Respondents were asked whether they had sustained a hit to the head in the preceding 12 months and whether they experienced a series of 12 signs and symptoms as a result of this injury.

DESIGN

Head injuries with 1 or more signs/symptoms reported were initially categorized into a 3-tiered TBI case definition (probable TBI, possible TBI, and delayed possible TBI), corresponding to the level of certainty that a TBI occurred. Placement in a tier was compared with a range of severity measures (whether medical evaluation was sought, time to symptom resolution, self-rated social and work functioning); case definition tiers were then modified in a stepwise fashion to maximize differences in severity between tiers.

RESULTS

There were statistically significant differences in the severity measure between cases in the probable and possible TBI tiers but not between other tiers. Timing of symptom onset did not meaningfully differentiate between cases on severity measures; therefore, the delayed possible tier was eliminated, resulting in 2 tiers: probable and possible TBI.

CONCLUSION

The 2-tiered TBI case definition that was derived from this analysis can be used in future surveillance efforts to differentiate cases by certainty and from noncases for the purpose of reporting TBI prevalence and incidence estimates. The refined case definition can help researchers increase the confidence they have in reporting survey respondents' self-reported TBIs as well as provide them with the flexibility to report an expansive (probable + possible TBI) or more conservative (probable TBI only) estimate of TBI prevalence.

Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential

Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.

Prevalence of Neck Pain in Soldiers as a Result of Mild Traumatic Brain Injury-Associated Trauma

INTRODUCTION

Many of the injury mechanisms that cause mild traumatic brain injury (mTBI) also create forces commonly associated with whiplash, resulting in cervical pain injury. The prevalence of associated neck pain with mTBI is not well established. There is a strong indication that injury to the cervical spine may aggravate, cause, and/or impact recovery of symptoms and impairments associated with the concussive event and its primary effect on the brain. The purpose of this study is to help identify the prevalence of ensuing cervical pain within 90 days of a previously documented mTBI and to examine the role of neck pain during concurrent concussive symptoms, in a military population stationed at a large military installation.

MATERIALS AND METHODS

This retrospective design utilized a de-identified dataset using predetermined search and filter criteria, which included male active duty service members (SMs), 20 to 45 years of age, who received medical care at any clinic on Fort Liberty (Fort Bragg, NC) during fiscal year (FY) 2012 to FY 2019, with documented cervicalgia and mTBI (via the International Classification of Diseases, 9th and 10th Revision, Clinical Modification codes), verified using electronic medical records. The final dataset served as the basis for subject sampling and was analyzed to determine the total number of documented cervicalgia and mTBI diagnoses. Results are presented as descriptive statistics. Approval for this study was received from the Andrews University Office of Research (18-097) and the Womack Army Medical Center Human Protections Office.

RESULTS

Between FY 2012 and FY 2019, 14,352 unique SMs accessed a Fort Bragg, NC health care facility, at least once (Table I). Overall, 52% of SMs diagnosed with cervicalgia were found to have a previously diagnosed mTBI during the 90 days before the cervicalgia diagnosis. In contrast, the prevalence of same-day cervicalgia and mTBI diagnosis was <1% (Table IV). The prevalence of isolated cervicalgia diagnosis at any time during the reporting period was 3%, whereas isolated mTBI diagnosis was 1% (Table III).

CONCLUSIONS

Over 50% of SMs diagnosed with cervicalgia had sustained a documented mTBI within 90 days prior, whereas less than 1% were diagnosed with cervicalgia at the time of initial primary care or emergency room encounter following the mTBI event. This finding suggests that the close anatomical and neurophysiological connections between the head and the cervical spine are both likely to be impacted through the same mechanism of injury. Delayed evaluation (and treatment) of the cervical spine may contribute to lingering post-concussive symptoms. Limitations of this retrospective review include the inability to assess the causality of the relationship between neck pain and mTBI, as only the existence and strength of the prevalence relationship can be identified. The outcome data are exploratory and intended to identify relationships and trends that may suggest further study across installations and across mTBI populations.

The knowledge and attitude concerning sport-related concussion among coaches: A survey study

Background

There are no studies investigating the level of knowledge about and attitude towards sports-related concussions (SRC) among sports coaches in Jordan.

Objectives

This study aimed to examine the knowledge about and attitude towards SRC among Jordanian sports coaches.

Method

Our study was based on a cross-sectional survey. An Arabic version of the questionnaire from the Centers for Disease Control and Prevention was used to collect data. The survey identified participants' demographics and knowledge about (0-10 points with higher scores indicating a higher knowledge) and attitude towards (8-40 with lower scores indicating favourable attitudes) SRC. Descriptive statistics and the Kruskal-Wallis test were used to examine knowledge and attitude differences by demographic factors. Spearman's correlation examined the correlation between the total knowledge and attitude scores.

Results

Participants included 193 coaches (62 basketball, 66 martial arts, 30 soccer, and 35 swimming). The median total knowledge and attitude scores were 4 and 30, respectively. The total knowledge score was the highest in martial arts coaches (median = 4) and those with graduate degrees (median = 5). The total attitude score was the lowest among basketball coaches (median = 28) and those who were 40-50 years old (median = 28). No significant correlation between knowledge and attitude scores was observed.

Conclusion

Jordanian coaches have a deficiency in knowledge about SRC and hold attitudes that are not consistent with current practice recommendations.

Clinical implications

Knowledge and attitude about SRC can be improved through education, access to healthcare providers, and adherence to SRC management guidelines.

The Role of Level of Play in Concussions in High School Athletes

OBJECTIVES

To examine level of play (LOP) as a risk factor for concussion severity and recovery-related outcomes among high school athletes, stratified by sex, and among boys, by sport (football, non-football male sports).

DESIGN/SETTING

Secondary analysis of data collected through the High School Reporting Information Online surveillance system for academic years 2007-2008 through 2018-2019.

PARTICIPANTS

A total of 9916 concussions were reported between the academic years 2007-2008 and 2018-2019 from 9 sports (5189 from football; 2096 from non-football male sports; 2631 from female sports).

MAIN OUTCOME MEASURE

Examined the association between LOP (Freshman, Junior Varsity [JV], and Varsity teams) and concussion outcomes (number of concussion symptoms, symptom resolution time [SRT], and time to return to play [RTP]).

RESULTS

Compared with Varsity football athletes, concussed JV football athletes had on average 0.19 fewer concussion symptoms, longer SRT (>1 week vs <1 week: odds ratio [OR] = 1.3; 95% confidence interval [CI], 1.1-1.5), and longer RTP (1-3 weeks vs <1 week: OR = 1.5; 95% CI, 1.2-1.9; >3 weeks vs <1 week: OR = 1.6; 95% CI, 1.1-2.3). Compared with Varsity football athletes, Freshman football athletes had on average 0.48 fewer concussion symptoms, longer SRT (OR = 1.3; 95% CI, 1.1-1.5), and longer RTP (1-3 weeks vs <1 week: OR = 1.5; 95% CI, 1.1-2.0; >3 weeks vs <1 week: OR = 2.0; 95% CI, 1.3-3.0). Similarly, compared with female athletes on Varsity teams, concussed JV female athletes had longer RTP (1-3 weeks vs <1 week: OR = 1.8; 95% CI, 1.2-2.7). Trend analyses revealed an increase in the number of concussion symptoms between 2015-2016 and 2018-2019, a decrease between 2009-2010 and 2018-2019 for SRT of less than 1 week, and an increase between 2014-2015 and 2018-2019 for RTP of less than 1 week among Varsity football athletes. Among Varsity female athletes, there was a linear decrease during the study period for RTP of less than 1 week.

CONCLUSIONS

Despite a higher number of symptoms overall and in recent years, Varsity football players had shorter RTP than Freshman and JV athletes.

Cerebral microhaemorrhage count is related to processing speed, but not level of symptom reporting, independently of age, psychological status and premorbid functioning, after first-ever mild traumatic brain injury

Cerebral microhaemorrhage is a commonly identified neuropathological consequence of mild traumatic brain injury (mTBI) and can be identified in vivo using susceptibility weighted imaging (SWI). This study aimed to determine whether SWI-detected microhaemorrhages are more common in individuals after a single, first-ever, mTBI event relative to trauma controls (TC) and to investigate whether a linear relationship exists between microhaemorrhage numbers and cognition or symptom reporting in the post-acute period after injury, independently of age, psychological status and premorbid level of functioning. Microhaemorrhagic lesions were identified by expert clinical examination of SWI for 78 premorbidly healthy adult participants who were admitted to hospital after a traumatic injury and had suffered a first-ever mTBI (n = 47) or no head strike (n = 31). Participants underwent objective cognitive examination of processing speed, attention, memory, and executive function as well as self-reported post-concussion symptomatology. Bootstrapping analyses were used as data were not normally distributed. Analyses revealed that the mTBI group had significantly more microhaemorrhages than the TC group (Cohen's d = 0.559). These lesions were only evident in 28% of individuals. The mTBI participants demonstrated a significant linear association between number of microhaemorrhages and processing speed, independently of age, psychological status, or premorbid level of functioning. This study shows that a single mTBI causes cerebral microhaemorrhages to occur in a minority of premorbidly healthy individuals. Greater microhaemorrhage count is independently associated with slower processing speed, but not symptom reporting, during the post-acute injury period.

Neck Symptoms and Associated Clinical Outcomes in Patients Following Concussion

OBJECTIVE

To examine the frequency and association of neck pain symptoms in patients with a concussion.

STUDY SETTING AND PARTICIPANTS

Three-hundred and thirty-one consecutively enrolled patients aged 9 to 68 years with a diagnosed concussion 1 to 384 days post-injury were enrolled at a concussion clinic from a single integrated healthcare system in Western Pennsylvania between 2019 and 2021.

DESIGN

Retrospective cohort analysis of prospectively collected concussion screening tool intake survey responses and clinical outcomes data. The primary outcome was self-reported neck pain or difficulty with neck movement on the Concussion Clinical Profiles Screening (CP Screen) tool, recovery time, and incidence of treatment referral. Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) composite scores, Vestibular/Ocular Motor Screening (VOMS) item scores, type and severity of neck symptoms, mechanism of injury, time from injury to clinic presentation, medical history, and concussion symptom profile were secondary outcomes.

RESULTS

Of the 306 consecutively enrolled eligible patients in the registry, 145 (47%) reported neck pain, 68 (22.2%) reported difficulty moving their neck, and 146 (47.7%) reported either symptom. A total of 47 (15.4%) participants reported more severe neck symptoms, and this group took longer to recover (40 ± 27 days) than those not reporting neck symptoms (30 ± 28 days; U = 8316, P < .001). Stepwise logistic regression predicting more severe neck symptoms was significant (Nagelkerke R2 = 0.174, χ 2 = 9.315, P = .316) with older age ( P = .019) and mechanism of injury including motor vehicle collisions (MVCs) ( P = .047) and falls ( P = .044) as risk factors. MVCs and falls were associated with over 4 times and 2 times greater risk, respectively, for reporting more severe neck symptoms.

CONCLUSION

Neck pain and stiffness symptoms are common in patients with a concussion following high-energy mechanisms of injury including MVCs or falls from height. These symptoms are associated with prolonged recovery. Providers should evaluate neck symptoms and consider targeted treatment strategies to limit their effects in patients with a concussion.

Prognostic factors for persistent symptoms in adults with mild traumatic brain injury: an overview of systematic reviews

BACKGROUND

Mild traumatic brain injury (mTBI) is an increasing public health problem, because of its persistent symptoms and several functional consequences. Understanding the prognosis of a condition is an important component of clinical decision-making and can help to guide the prevention of persistent symptoms following mTBI. The prognosis of mTBI has stimulated several empirical primary research papers and many systematic reviews leading to the identification of a wide range of factors. We aim to synthesize these factors to get a better understanding of their breadth and scope.

METHODS

We conducted an overview of systematic reviews. We searched in databases systematic reviews synthesizing evidence about the prognosis of persistent symptoms after mTBI in the adult population. Two reviewers independently screened all references and selected eligible reviews based on eligibility criteria. They extracted relevant information using an extraction grid. They also rated independently the risk of bias using the ROBIS tool. We synthesized evidence into a comprehensive conceptual map to facilitate the understanding of prognostic factors that have an impact on persistent post-concussion symptoms.

RESULTS

From the 3857 references retrieved in a database search, we included 25 systematic reviews integrating the results of 312 primary articles published between 1957 and 2019. We examined 35 prognostic factors from the systematics reviews. No single prognostic factor demonstrated convincing and conclusive results. However, age, sex, and multiple concussions showed an affirmatory association with persistent post-concussion outcomes in systematic reviews.

CONCLUSION

We highlighted the need for a comprehensive picture of prognostic factors related to persistent post-concussion symptoms. We believe that these prognostic factors would guide clinical decisions and research related to prevention and intervention regarding persistent post-concussion symptoms.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020176676.

Putting the Mind to Rest: A Historical Foundation for Rest as a Treatment for Traumatic Brain Injury

Rest after traumatic brain injury (TBI) has been a part of clinical practice for more than a century but the use of rest as a treatment has ancient roots. In contemporary practice, rest recommendations have been significantly reduced but are still present. This advice to brain injured patients, on the face of it makes some logical sense but was not historically anchored in either theory or empirical data. The definition and parameters of rest have evolved over time but have encompassed recommendations including avoiding physical exercise, sensory stimulation, social contact, and even cognitive exertion. The goals and theoretical explanations for this approach have evolved and in modern conception include avoiding reinjury and reducing the metabolic demands on injured tissue. Moreover, as cellular and molecular understanding of the physiology of TBI developed, scientists and clinicians sometimes retroactively cited these new data in support of rest recommendations. Here, we trace the history of this approach and how it has been shaped by new understanding of the underlying pathology associated with brain injury.

Single Neuron Modeling Identifies Potassium Channel Modulation as Potential Target for Repetitive Head Impacts

Traumatic brain injury (TBI) and repetitive head impacts can result in a wide range of neurological symptoms. Despite being the most common neurological disorder in the world, repeat head impacts and TBI do not have any FDA-approved treatments. Single neuron modeling allows researchers to extrapolate cellular changes in individual neurons based on experimental data. We recently characterized a model of high frequency head impact (HFHI) with a phenotype of cognitive deficits associated with decreases in neuronal excitability of CA1 neurons and synaptic changes. While the synaptic changes have been interrogated in vivo, the cause and potential therapeutic targets of hypoexcitability following repetitive head impacts are unknown. Here, we generated in silico models of CA1 pyramidal neurons from current clamp data of control mice and mice that sustained HFHI. We use a directed evolution algorithm with a crowding penalty to generate a large and unbiased population of plausible models for each group that approximated the experimental features. The HFHI neuron model population showed decreased voltage gated sodium conductance and a general increase in potassium channel conductance. We used partial least squares regression analysis to identify combinations of channels that may account for CA1 hypoexcitability after HFHI. The hypoexcitability phenotype in models was linked to A- and M-type potassium channels in combination, but not by any single channel correlations. We provide an open access set of CA1 pyramidal neuron models for both control and HFHI conditions that can be used to predict the effects of pharmacological interventions in TBI models.

Repeat mild traumatic brain injuries (RmTBI) modify nociception and disrupt orexinergic connectivity within the descending pain pathway

Repeat mild traumatic brain injuries (RmTBI) result in substantial burden to the public health system given their association with chronic post-injury pathologies, such as chronic pain and post-traumatic headache. Although this may relate to dysfunctional descending pain modulation (DPM), it is uncertain what mechanisms drive changes within this pathway. One possibility is altered orexinergic system functioning, as orexin is a potent anti-nociceptive neuromodulator. Orexin is exclusively produced by the lateral hypothalamus (LH) and receives excitatory innervation from the lateral parabrachial nucleus (lPBN). Therefore, we used neuronal tract-tracing to investigate the relationship between RmTBI and connectivity between lPBN and the LH, as well as orexinergic projections to a key site within the DPM, the periaqueductal gray (PAG). Prior to injury induction, retrograde and anterograde tract-tracing surgery was performed on 70 young-adult male Sprague Dawley rats, targeting the lPBN and PAG. Rodents were then randomly assigned to receive RmTBIs or sham injuries before undergoing testing for anxiety-like behaviour and nociceptive sensitivity. Immunohistochemical analysis identified distinct and co-localized orexin and tract-tracing cell bodies and projections within the LH. The RmTBI group exhibited altered nociception and reduced anxiety as well as a loss of orexin cell bodies and a reduction of hypothalamic projections to the ventrolateral nucleus of the PAG. However, there was no significant effect of injury on neuronal connectivity between the lPBN and orexinergic cell bodies within the LH. Our identification of structural losses and the resulting physiological changes in the orexinergic system following RmTBI begins to clarify acute post-injury mechanistic changes that drive may drive the development of post-traumatic headache and the chronification of pain.

Repetitive Transcranial Magnetic Stimulation for Depression and Posttraumatic Stress Disorder in Veterans With Mild Traumatic Brain Injury

OBJECTIVES

Mild traumatic brain injury (mTBI) is a signature injury of military conflicts and is prevalent in veterans with major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). Although therapeutic transcranial magnetic stimulation (TMS) can reduce symptoms of depression and PTSD, whether traumatic brain injury (TBI) affects TMS responsiveness is not yet known. We hypothesized mTBI would be associated with higher pretreatment symptom burden and poorer TMS response.

MATERIALS AND METHODS

We investigated a registry of veterans (N = 770) who received TMS for depression across the US Veterans Affairs system. Of these, 665 (86.4%) had data on TBI and lifetime number of head injuries while 658 had complete data related to depression outcomes. Depression symptoms were assessed using the nine-item Patient Health Questionnaire and PTSD symptoms using the PTSD Checklist for DSM-5. Linear mixed effects models and t-tests evaluated whether head injuries predicted symptom severity before treatment, and how TBI status affected clinical TMS outcomes.

RESULTS

Of the 658 veterans included, 337 (50.7%) reported previous mTBI, with a mean of three head injuries (range 1-20). TBI status did not predict depressive symptom severity or TMS-associated changes in depression (all p's > 0.1). TBI status was associated with a modest attenuation of TMS-associated improvement in PTSD (in patients with PTSD Checklist for DSM-5 scores > 33). There was no correlation between the number of head injuries and TMS response (p > 0.1).

CONCLUSIONS

Contrary to our hypothesis, presence of mTBI did not meaningfully change TMS outcomes. Veterans with mTBI had greater PTSD symptoms, yet neither TBI status nor cumulative head injuries reduced TMS effectiveness. Limitations include those inherent to retrospective registry studies and self-reporting. Although these findings are contrary to our hypotheses, they support the safety and effectiveness of TMS for MDD and PTSD in patients who have comorbid mTBI.

A Scoping Review of Magnetic Resonance Modalities Used in Detection of Persistent Postconcussion Symptoms in Pediatric Populations

Up to 30% of youth with concussion experience PPCSs (PPCS) lasting 4 weeks or longer, and can significantly impact quality of life. Magnetic resonance imaging (MRI) has the potential to increase understanding of causal mechanisms underlying PPCS. However, there are no clear modalities to assist in detecting PPCS. This scoping review aims to synthesize findings on utilization of MRI among children and youth with PPCS, and summarize progress and limitations. Thirty-six studies were included from 4907 identified papers. Many studies used multiple modalities, including (1) structural (n = 27) such as T1-weighted imaging, diffusion weighted imaging, and susceptibility weighted imaging; and (2) functional (n = 23) such as functional MRI and perfusion-weighted imaging. Findings were heterogeneous among modalities and regions of interest, which warrants future reviews that report on the patterns and potential advancements in the field. Consideration of modalities that target PPCS prediction and sensitive modalities that can supplement a biopsychosocial approach to PPCS would benefit future research.

Co-administration of Nanowired Oxiracetam and Neprilysin with Monoclonal Antibodies to Amyloid Beta Peptide and p-Tau Thwarted Exacerbation of Brain Pathology in Concussive Head Injury at Hot Environment

Environmental temperature adversely affects the outcome of concussive head injury (CHI)-induced brain pathology. Studies from our laboratory showed that animals reared at either cold environment or at hot environment exacerbate brain pathology following CHI. Our previous experiments showed that nanowired delivery of oxiracetam significantly attenuated CHI-induced brain pathology and associated neurovascular changes. Military personnel are the most susceptible to CHI caused by explosion, blasts, missile or blunt head trauma leading to lifetime functional and cognitive impairments affecting the quality of life. Severe CHI leads to instant death and/or lifetime paralysis. Military personnel engaged in combat operations are often subjected to extreme high or low environmental temperature zones across the globe. Thus, further exploration of novel therapeutic agents at cold or hot ambient temperatures following CHI are the need of the hour. CHI is also a major risk factor for developing Alzheimer's disease by enhancing amyloid beta peptide deposits in the brain. In this review, effect of hot environment on CHI-induced brain pathology is discussed. In addition, whether nanodelivery of oxiracetam together with neprilysin and monoclonal antibodies (mAb) to amyloid beta peptide and p-tau could lead to superior neuroprotection in CHI is explored. Our results show that co-administration of oxiracetam with neprilysin and mAb to AβP and p-tau significantly induced superior neuroprotection following CHI in hot environment, not reported earlier.

Personality disorder and mild traumatic brain injury

Mild traumatic brain injury (mTBI) poses risk to the neurocognitive, emotional, and financial well-being of affected individuals. While aggression and impulsivity have been examined in relation to mTBI, little work has been done to evaluate the relationship between history of mTBI and personality disorder (PD). The authors examined the associations between history of mTBI and PD in a control group without history of mTBI (N = 1189) and individuals with history of mTBI (N = 267). Results demonstrated that any PD diagnosis is a significant risk factor for mTBI (p < 0.001). Cluster B diagnoses, particularly borderline and antisocial PD, were independently significant risk factors for mTBI. These data suggest a role for screening for a history of mTBI in patients with PDs and associated traits.

Concussion in the UK: a contemporary narrative review

Concussion has been receiving an increasing amount of media exposure following several high-profile professional sports controversies and multimillion-dollar lawsuits. The potential life-changing sequalae of concussion and the rare, but devasting, second impact syndrome have also gained much attention. Despite this, our knowledge of the pathological processes involved is limited and often extrapolated from research into more severe brain injuries. As there is no objective diagnostic test for concussion. Relying on history and examination only, the diagnosis of concussion has become the rate-limiting step in widening research into the disease. Clinical study protocols therefore frequently exclude the most vulnerable groups of patients such as those with existing cognitive impairment, concurrent intoxication, mental health issues or learning difficulties. This up-to-date narrative review aims to summarize our current concussion knowledge and provides an insight into promising avenues for future research.

Relationship between Anterior Pituitary Volume and IGF-1 Serum Levels in Soldiers with Mild Traumatic Brain Injury History

PURPOSE

A high mild traumatic brain injury (mTBI) incidence rate exists in military and sport. Hypopituitarism is an mTBI sequela; however, few studies have examined this phenomenon in those with an mTBI history. This cross-sectional study of Special Operations Forces combat soldiers aimed 1) to relate anterior pituitary gland volumes (actual and normalized) to insulin-like growth factor 1 (IGF-1) concentrations, 2) to examine the effect of mTBI history on anterior pituitary gland volumes (actual and normalized) and IGF-1 concentrations, and 3) to measure the odds of demonstrating lower anterior pituitary gland volumes (actual and normalized) or IGF-1 concentrations if self-reporting mTBI history.

METHODS

Anterior pituitary gland volumes were manually segmented from T1-weighted 3D brain MRI sequences; IGF-1 serum concentrations were quantified using commercial enzyme-linked immunosorbent assays. Correlations and linear regression were used to determine the association between IGF-1 serum concentration and anterior pituitary gland volume (n = 74). Independent samples t-tests were used to compare outcomes between mTBI groups and logistic regression models were fit to test the odds of demonstrating IGF-1 concentration or anterior pituitary volume less than sample median based on mTBI group (n = 54).

RESULTS

A significant linear relationship between the subjects' anterior pituitary gland volumes and IGF-1 concentrations (r72 = 0.35, P = 0.002) was observed. Soldiers with mTBI history had lower IGF-1 concentrations (P < 0.001) and lower anterior pituitary gland volumes (P = 0.037) and were at greater odds for IGF-1 serum concentrations less than the sample median (odds ratio = 5.73; 95% confidence interval = 1.77-18.55).

CONCLUSIONS

Anterior pituitary gland volume was associated with IGF-1 serum concentrations. Mild TBI history may be adversely associated with anterior pituitary gland volumes and IGF-1 concentrations. Longitudinal IGF-1 and anterior pituitary gland monitoring may be indicated in those who report one or more mTBI.

Special Section: Relationships Between Executive Function and Sports / Exercise

This short article is a commentary on this special section of Perceptual and Motor Skills entitled Relationships between Executive Function and Sports/Exercise. Given the vast executive function research in sports already published, this moment is opportune for highlighting (a) progress to date, (b) research limitations yet to address, and (c) inspirational new findings. The articles that follow illustrate these themes.

A non-invasive biomechanical model of mild TBI in larval zebrafish

A mild traumatic brain injury is a neurological dysfunction caused by biomechanical forces transmitted to the brain in physical impacts. The current understanding of the neuropathological cascade resulting in the manifested clinical signs and symptoms is limited due to the absence of sensitive brain imaging methods. Zebrafish are established models for the reproduction and study of neurobiological pathologies. However, all available models mostly recreate moderate-to-severe focal injuries in adult zebrafish. The present work has induced a mild brain trauma in larval zebrafish through a non-invasive biomechanical approach. A custom-made apparatus with a commercially available motor was employed to expose larvae to rapidly decelerating linear movements. The neurophysiological changes following concussion were assessed through behavioural quantifications of startle reflex locomotor distance and habituation metrics. Here we show that the injury was followed, within five minutes, by a transient anxiety state and CNS dysfunction manifested by increased startle responsivity with impaired startle habituation, putatively mirroring the human clinical sign of hypersensitivity to noise. Within a day after the injury, chronic effects arose, as evidenced by an overall reduced responsivity to sensory stimulation (lower amplitude and distance travelled along successive stimuli), reflecting the human post-concussive symptomatology. This study represents a step forward towards the establishment of a parsimonious (simple, less ethically concerning, yet sensitive) animal model of mild TBI. Our behavioural findings mimic aspects of acute and chronic effects of human concussion, which warrant further study at molecular, cellular and circuit levels. While our model opens wide avenues for studying the underlying cellular and molecular pathomechanisms, it also enables high-throughput testing of therapeutic interventions to accelerate post-concussive recovery.

The impact of mild traumatic brain injury on reading comprehension and eye movements: preliminary results

INTRODUCTION

Individuals who sustain a mild traumatic brain injury (mTBI) can suffer from executive function, working memory, and attention deficits, which can impact functional task performance, including reading comprehension. Individuals with mTBI commonly report reading difficulties, but such difficulties have been historically difficult to capture using behavioral measures. The current study examined reading performance in those with and without mTBI using eye-tracking measures, which may be more sensitive to reading impairment in mTBI.

METHOD/RESULTS

In Experiment 1, 26 participants with a history of mTBI and 26 healthy control participants completed working memory (WM) and reading comprehension tasks. We found no differences in behavioral measures but found that spontaneous eye-blinking frequency was lower during the reading task in the mTBI group. In Experiment 2, we explored the impact of auditory distraction (e.g., multi-talker babble) on reading and memory performance. Twenty-three new participants with a history of mTBI and 26 healthy control participants completed a short-term memory (STM) task, a WM task, and a reading comprehension task under two distraction conditions. As in Experiment 1, we found no differences on behavioral measures, but observed significant differences on spontaneous eye-blinking frequency between those with and without mTBI. Group differences in distraction effects were also observed and performance on the WM task predicted reading comprehension performance.

CONCLUSIONS

The lack of differences on behavioral measures between groups, but lower frequencies of spontaneous eye blinking in the mTBI group suggests that while these individuals successfully completed the reading comprehension task, they may require more cognitive resources to do so.

Rolling Circle Amplification-Coupled Glass Nanopore Counting of Mild Traumatic Brain Injury-Related Salivary miRNAs

Mild traumatic brain injury (mTBI) could be underdiagnosed and underreported due to the delayed onset of symptoms and the conventional subjective assessment. Recent studies have suggested that salivary microRNAs (miRNAs) could be reliable biomarkers for objective mTBI diagnosis. In this work, we demonstrated a rolling circle amplification (RCA)-coupled resistive pulse-counting platform for profiling mTBI-related miRNAs, using easy-to-fabricate large glass nanopores (200 nm diameter). The method relies on the linear and specific elongation of the miRNA to a much larger RCA product, which the large glass nanopore can digitally count with a high signal-to-noise ratio. We developed and validated the RCA assay against let-7a, miR-30e, and miR-21. We demonstrated the quantification capability of this large glass nanopore counting platform for purified miRNAs as well as miRNAs in salivary total RNA background. Finally, we quantitatively evaluated the performance of profiling each individual miRNAs in a mixed analyte. Our results showed that the RCA-coupled large glass nanopore counting provides a promising and accessible alternative toward the clinical diagnosis of mTBI using salivary miRNAs.

Neuropsychiatric Treatment for Mild Traumatic Brain Injury: Nonpharmacological Approaches

Postconcussive symptoms following mild traumatic brain injury (mTBI)/concussion are common, disabling, and challenging to manage. Patients can experience a range of symptoms (e.g., mood disturbance, headaches, insomnia, vestibular symptoms, and cognitive dysfunction), and neuropsychiatric management relies heavily on nonpharmacological and multidisciplinary approaches. This article presents an overview of current nonpharmacological strategies for postconcussive symptoms including psychoeducation; psychotherapy; vestibular, visual, and physical therapies; cognitive rehabilitation; as well as more novel approaches, such as neuromodulation. Ultimately, treatment and management of mTBI should begin early with appropriate psychoeducation/counseling, and be tailored based on core symptoms and individual goals.

Concussion reporting intentions for incoming military athletes and cadets

Cultures of concussion reporting exist outside athletics; however, athlete-only studies dominate the literature. Comparing athletes and similar high-risk populations broadens our understanding of concussion reporting acculturation. We aimed to (1) describe and compare concussion self-report willingness as measured by anticipated concussion reporting (ACR), perceived costs, perceived rewards, brain health knowledge, and correct symptom identification for incoming cadets at the United States Air Force Academy (USAFA) (n = 1,136; female = 276, 24.43%) and (2) determine whether those variables predict ACR. Univariate analyses were performed to compare intercollegiate status, sex, and parental income for perceived costs and rewards, and brain health knowledge (α = 0.05) and multinomial logistic regressions to determine if those variables predicted ACR. A $40,000 parental increase in income resulted in one additional symptom identified (β = 0.80, p = 0.026). Athletes demonstrated greater brain health knowledge by nearly one symptom correctly identified (β = 0.98, p = 0.002); non-athletes reported significantly greater ACR (β = 5.92; p < 0.001). Our model accounted for 37% of the variance in ACR (χ2 = 393.86, p < 0.001, Nagelkerke R2 = 0.37). Before military acculturation, athletes had less intention to seek medical care for concussion, likely from prior athletic experiences.

Learning and Attention Deficit/Hyperactivity Disorders as Risk Factors for Prolonged Concussion Recovery in Children and Adolescents

OBJECTIVE

Examine pre-existing learning disorders (LD) and attention deficit/hyperactivity disorders (ADHD) as risk factors for prolonged recovery and increased symptomology following pediatric mild traumatic brain injury (mTBI).

METHODS

We conducted a retrospective cohort study of children/adolescents (5-17 years) with mTBI who presented to a Children's Minnesota Concussion Clinic between April 2018 and March 2019. Differences across strata of pre-existing conditions (present vs. absent) in time to recovery measures were estimated via Kaplan-Meier and Cox proportional hazards analyses and differences in symptom trajectories were examined via linear mixed-effects regression models. Regression models were adjusted for age, sex and other confounders.

RESULTS

In our cohort of 680 mTBI patients, those with LD (n = 70) or ADHD (n = 107) experienced significantly longer median durations of symptoms (58 and 68 days, respectively) than those without (43 days). Accordingly, LD was significantly associated with delayed symptom recovery (adjusted hazard ratio (aHR) = 1.63, 95% CI: 1.16-2.29), return to school (1.47, 1.08-2.00), and return to physical activity (1.50, 1.10-2.04). Likewise, ADHD was associated with delayed recovery (1.69, 1.28-2.23), return to school (1.52, 1.17-1.97) and physical activity (1.55, 1.19-2.01). Further, patients with LD or ADHD reported, on average, significantly more concussion symptoms and higher vision symptom scores throughout recovery versus those without. There was no evidence that concussion or vision symptom recovery trajectories varied over time between those with/without LD or ADHD (joint P-interactions > 0.05).

CONCLUSION

Pre-existing LD and ADHD are risk factors for prolonged and more symptomatic mTBI recovery in youth. These results can inform clinical concussion management and recovery expectations.

Discourse Performance in Adults With Mild Traumatic Brain Injury, Orthopedic Injuries, and Moderate to Severe Traumatic Brain Injury, and Healthy Controls

INTRODUCTION

Adults with mild traumatic brain injury (mTBI) are at risk for communication disorders, yet studies exploring cognitive-communication performance are currently lacking.

AIMS

This aim of this study was to characterize discourse-level performance by adults with mTBI on a standardized elicitation task and compare it to (a) healthy adults, (b) adults with orthopedic injuries (OIs), and (c) adults with moderate to severe TBI.

METHOD

This study used a cross-sectional design. The participants included mTBI and OI groups recruited prospectively from an emergency medicine department. Moderate to severe TBI and healthy data were acquired from TalkBank. One-way analyses of variance were used to compare mean linguistic scores.

RESULTS

Seventy participants across all groups were recruited. Groups did not differ on demographic variables. The study found significant differences in both content and productivity measures among the groups. Variables did not appear sensitive to differentiate between mTBI and OI groups.

DISCUSSION

Cognitive and language performance of adults with mTBI is a pressing clinical issue. Studies exploring language with carefully selected control groups can influence the development of sensitive measures to identify individuals with cognitive-communication deficits.

High-Frequency Head Impact Disrupts Hippocampal Neural Ensemble Dynamics

We have recently shown that the cognitive impairments in a mouse model of high-frequency head impact (HFHI) are caused by chronic changes to synaptic physiology. To better understand these synaptic changes occurring after repeat head impact, we used Thy1-GcCAMP6f mice to study intracellular and intercellular calcium dynamics and neuronal ensembles in HFHI mice. We performed simultaneous calcium imaging and local field potential (LFP) recordings of the CA1 field during an early-LTP paradigm in acute hippocampal slice preparations 24 h post-impact. As previously reported, HFHI causes a decrease in early-LTP in the absence of any shift in the input-output curve. Calcium analytics revealed that HFHI hippocampal slices have similar numbers of active ROIs, however, the number of calcium transients per ROI was significantly increased in HFHI slices. Ensembles consist of coordinated activity between groups of active ROIs. We exposed the CA1 ensemble to Schaffer-collateral stimulation in an abbreviated LTP paradigm and observed novel coordinated patterns of post stimulus calcium ensemble activity. HFHI ensembles displayed qualitatively similar patterns of post-stimulus ensemble activity to shams but showed significant changes in quantitative ensemble inactivation and reactivation. Previous in vivo and in vitro reports have shown that ensemble activity frequently occurs through a similar set of ROIs firing in a repeating fashion. HFHI slices showed a decrease in such coordinated firing patterns during post stimulus ensemble activity. The present study shows that HFHI alters synaptic activity and disrupts neuronal organization of the ensemble, providing further evidence of physiological synaptic adaptation occurring in the brain after a high frequency of non-pathological head impacts.

Cerebrolysin restores balance between excitatory and inhibitory amino acids in brain following concussive head injury. Superior neuroprotective effects of TiO2 nanowired drug delivery

Concussive head injury (CHI) often associated with military personnel, soccer players and related sports personnel leads to serious clinical situation causing lifetime disabilities. About 3-4k head injury per 100k populations are recorded in the United States since 2000-2014. The annual incidence of concussion has now reached to 1.2% of population in recent years. Thus, CHI inflicts a huge financial burden on the society for rehabilitation. Thus, new efforts are needed to explore novel therapeutic strategies to treat CHI cases to enhance quality of life of the victims. CHI is well known to alter endogenous balance of excitatory and inhibitory amino acid neurotransmitters in the central nervous system (CNS) leading to brain pathology. Thus, a possibility exists that restoring the balance of amino acids in the CNS following CHI using therapeutic measures may benefit the victims in improving their quality of life. In this investigation, we used a multimodal drug Cerebrolysin (Ever NeuroPharma, Austria) that is a well-balanced composition of several neurotrophic factors and active peptide fragments in exploring its effects on CHI induced alterations in key excitatory (Glutamate, Aspartate) and inhibitory (GABA, Glycine) amino acids in the CNS in relation brain pathology in dose and time-dependent manner. CHI was produced in anesthetized rats by dropping a weight of 114.6g over the right exposed parietal skull from a distance of 20cm height (0.224N impact) and blood-brain barrier (BBB), brain edema, neuronal injuries and behavioral dysfunctions were measured 8, 24, 48 and 72h after injury. Cerebrolysin (CBL) was administered (2.5, 5 or 10mL/kg, i.v.) after 4-72h following injury. Our observations show that repeated CBL induced a dose-dependent neuroprotection in CHI (5-10mL/kg) and also improved behavioral functions. Interestingly when CBL is delivered through TiO₂ nanowires superior neuroprotective effects were observed in CHI even at a lower doses (2.5-5mL/kg). These observations are the first to demonstrate that CBL is effectively capable to attenuate CHI induced brain pathology and behavioral disturbances in a dose dependent manner, not reported earlier.

Prognostic factors for persistent symptoms in adults with mild traumatic brain injury: protocol for an overview of systematic reviews

BACKGROUND

Mild traumatic brain injury (mTBI) is an increasing public health problem that can lead to persistent symptoms that have several functional consequences. Understanding the prognosis of a condition is an important component of clinical decision-making and can help guide the prevention of long-term disabilities of patients with mTBI. Several studies and systematic reviews have been conducted in order to understand prognosis of chronic symptoms following mTBI. We aim to synthesize evidence from systematic reviews on factors that affect the risk of persistent symptoms in mTBI-affected adults.

METHODS

We will conduct an overview of systematic reviews following steps described in the Cochrane Handbook. We will search in Cochrane, Medline, CINAHL, Embase, PsycINFO, and Epistemonikos for systematic reviews about the prognosis of persistent symptoms following mTBI in the adult population. Two reviewers will independently screen all references and then select eligible reviews based on eligibility criteria. A data extraction grid will be used to extract relevant information. The risk of bias in the included reviews will be assessed using the ROBIS tool. Data will be synthesized into a comprehensive conceptual model in order to have a better understanding of the predictive factors of post-concussion symptoms following mTBI.

DISCUSSION

Results will help multiple stakeholders, such as clinicians and rehabilitation program managers, to understand the prognosis of long-term consequences following mTBI. It could guide stakeholders to recognize their patients' prognostic factors and to invest their time and resources in patients who need it the most.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020176676 .

Symptom profile of affirmative responses to a self-report concussion question, United States 2019

Information is limited about signs and symptoms experienced by individuals who self-report a concussion within surveys. The objective of this study was to assess the number and types of signs/symptoms adults experienced and whether or not medical attention was reported after sustaining a self-reported concussion in the past year. A sample of 3,624 adults responded to the web-based 2019 FallStyles survey. Respondents were asked if they had sustained a concussion in the past 12 months and if so, which (if any) signs/symptoms they experienced following the injury. The frequency and percentages of symptoms were calculated. Approximately 2.9% of respondents reported a concussion in the past year. Approximately two-thirds of respondents who reported sustaining a recent concussion stated that they experienced two or more signs/symptoms; the remaining one-third reported zero or one symptom. The findings suggest self-report concussion questions need additional improvement, particularly those that capture concussion using a single question, to improve the validity of self-reports.

Level of knowledge and misconceptions about brain concussion in Brazilian adults

BACKGROUND

Brain concussion (BC) is seen as a public health priority due to its high incidence and morbidity rate, among thousands of people around the world. There are needs for fast identification, accurate diagnosis and correct management in order to reduce the short and long-term problems relating to BC. Proper knowledge of BC in the population and among clinicians is a critical factor in achieving this.

OBJECTIVES

To evaluate the level of self-reported BC knowledge and gaps/misconceptions, and to identify variables correlated with this level.

METHODS

A cross-sectional descriptive survey was performed. A Brain Concussion Knowledge Questionnaire (BCKQ) that had been created to capture data was widely distributed. Total scores, domain partial scores and percentages of correct and incorrect answers were calculated to ascertain the level of knowledge relating to BC.

RESULTS

The sample was formed by 1,247 Brazilian adults (age: 41.7±11.8 years). Partial scores of the BCKQ revealed the existence of poor knowledge and misconceptions in all domains of the questionnaire, especially regarding questions about recovery from and management of BC. Moderate correlations between BCKQ scores and professions (p=0.312; P=0.00) or previous brain concussion knowledge (p=0.489; P=0.00) were observed. In a multiple linear regression model, age, profession and sports practice were predictors of BC knowledge.

CONCLUSION

This first study to analyze the level of BC knowledge in a sample of Brazilian adults suggests that poor knowledge and misconceptions are present. Thus, meaningful and useful information was provided by this study for developing health education programs about BC for the population in order to improve fast diagnosis and correct BC management.

The Effect of Aerobic Exercise on Concussion Recovery: A Pilot Clinical Trial

OBJECTIVE

The purpose of this study was to pilot safety and tolerability of a 1-week aerobic exercise program during the post-acute phase of concussion (14-25 days post-injury) by examining adherence, symptom response, and key functional outcomes (e.g., cognition, mood, sleep, postural stability, and neurocognitive performance) in young adults.

METHOD

A randomized, non-blinded pilot clinical trial was performed to compare the effects of aerobic versus non-aerobic exercise (placebo) in concussion patients. The study enrolled three groups: 1) patients with concussion/mild traumatic brain injury (mTBI) randomized to an aerobic exercise intervention performed daily for 1-week, 2) patients with concussion/mTBI randomized to a non-aerobic (stretching and calisthenics) exercise program performed daily for 1-week, and 3) non-injured, no intervention reference group.

RESULTS

Mixed-model analysis of variance results indicated a significant decrease in symptom severity scores from pre- to post-intervention (mean difference = -7.44, 95% CI [-12.37, -2.20]) for both concussion groups. However, the pre- to post-change was not different between groups. Secondary outcomes all showed improvements by post-intervention, but no differences in trajectory between the groups. By three months post-injury, all outcomes in the concussion groups were within ranges of the non-injured reference group.

CONCLUSIONS

Results from this study indicate that the feasibility and tolerability of administering aerobic exercise via stationary cycling in the post-acute time frame following post-concussion (14-25 days) period are tentatively favorable. Aerobic exercise does not appear to negatively impact recovery trajectories of neurobehavioral outcomes; however, tolerability may be poorer for patients with high symptom burden.

Epidemiology of Injuries in National Collegiate Athletic Association Women's Field Hockey: 2014-2015 Through 2018-2019

CONTEXT

The National Collegiate Athletic Association has sponsored women's field hockey since 1981, and team membership as well as student-athlete participation has grown over time.

BACKGROUND

Routine examinations of injuries sustained by athletes are important for identifying and understanding patterns that can be used to inform sport safety practices.

METHODS

Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program from 2014-2015 through 2018-2019 were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates.

RESULTS

The overall injury rate was 6.27 per 1000 athlete-exposures (AEs). Head/face injuries (16.0%) and thigh injuries (12.3%) were the most commonly injured body parts during the 2014-2015 through 2018-2019 academic years. Concussion (8.6%) was the most commonly reported injury, and concussion rates notably decreased between 2017-2018 and 2018-2019.

SUMMARY

Study findings were generally consistent with the existing epidemiologic evidence. Incidence rates and trajectories of commonly observed injuries warrant particular attention in the future.

The effect of high-intensity physical exertion on measures of cervical spine, vestibular/ocular-motor screening, and vestibulo-ocular reflex function in university level collision and combative sport athletes

OBJECTIVES

To examine how high-intensity physical exertion affects clinical measures of cervical spine (CSp), vestibular/ocular motor screen (VOMS), and vestibulo-ocular reflex (VOR) function.

DESIGN

Case series.

SETTING

Sports Medicine Centre.

PARTICIPANTS

A total of 37 athletes consented to participate (22 rugby, 15 wrestling; 9 men, 28 women; median age = 19 years [range 17-23 years]).

MAIN OUTCOME MEASURES

Outcome measures included tests of CSp (cervical flexor endurance, head perturbation test, cervical flexion rotation test and anterolateral strength), VOR (head thrust test and dynamic visual acuity [DVA]), and a quantified version of the VOMS. These metrics were assessed prior to and after completing the 30-15 Intermittent Fitness Test. Bland-Altman plots and Wilcoxon signed-rank tests were utilized to analyze the data using an alpha of p < 0.004.

RESULTS

Cervical anterolateral strength (kg) was reduced post-exertion on the left (z = 3.87; p < 0.001), but not on the right between conditions (z = -1.49; p = 0.14). Athletes reported increased dizziness (z = -3.55; p = 0.004) and had reduced DVA following exertion (z = -2.78; p < 0.001). All other metrics were not significantly different following exertion (p > 0.011).

CONCLUSION

Reduced performance on DVA, decreased left-anterolateral strength, and increased dizziness occurred following high-intensity exertion in varsity collision and combative athletes, which has implications for sideline screening for sport-related concussion.

Inflammatory Regulation of CNS Barriers After Traumatic Brain Injury: A Tale Directed by Interleukin-1

Several barriers separate the central nervous system (CNS) from the rest of the body. These barriers are essential for regulating the movement of fluid, ions, molecules, and immune cells into and out of the brain parenchyma. Each CNS barrier is unique and highly dynamic. Endothelial cells, epithelial cells, pericytes, astrocytes, and other cellular constituents each have intricate functions that are essential to sustain the brain's health. Along with damaging neurons, a traumatic brain injury (TBI) also directly insults the CNS barrier-forming cells. Disruption to the barriers first occurs by physical damage to the cells, called the primary injury. Subsequently, during the secondary injury cascade, a further array of molecular and biochemical changes occurs at the barriers. These changes are focused on rebuilding and remodeling, as well as movement of immune cells and waste into and out of the brain. Secondary injury cascades further damage the CNS barriers. Inflammation is central to healthy remodeling of CNS barriers. However, inflammation, as a secondary pathology, also plays a role in the chronic disruption of the barriers' functions after TBI. The goal of this paper is to review the different barriers of the brain, including (1) the blood-brain barrier, (2) the blood-cerebrospinal fluid barrier, (3) the meningeal barrier, (4) the blood-retina barrier, and (5) the brain-lesion border. We then detail the changes at these barriers due to both primary and secondary injury following TBI and indicate areas open for future research and discoveries. Finally, we describe the unique function of the pro-inflammatory cytokine interleukin-1 as a central actor in the inflammatory regulation of CNS barrier function and dysfunction after a TBI.

Gene Expression Changes in a Model Neuron Cell Line Exposed to Autoantibodies from Patients with Traumatic Brain Injury and/or Type 2 Diabetes

Traumatic brain injury and adult type 2 diabetes mellitus are each associated with the late occurrence of accelerated cognitive decline and Parkinson’s disease through unknown mechanisms. Previously, we reported increased circulating agonist autoantibodies targeting the 5-hydroxytryptamine 2A receptor in plasma from subsets of Parkinson’s disease, dementia, and diabetic patients suffering with microvascular complications. Here, we use a model neuron, mouse neuroblastoma (N2A) cell line, to test messenger RNA expression changes following brief exposure to traumatic brain injury and/or type 2 diabetes mellitus plasma harboring agonist 5-hydroxytryptamine 2A receptor autoantibodies. We now report involvement of the mitochondrial dysfunction pathway and Parkinson’s disease pathways in autoantibody-induced gene expression changes occurring in neuroblastoma cells. Functional gene categories upregulated significantly included cell death, cytoskeleton-microtubule function, actin polymerization or depolymerization, regulation of cell oxidative stress, mitochondrial function, immune function, protein metabolism, and vesicle function. Gene categories significantly downregulated included microtubule function, cell adhesion, neurotransmitter release, dopamine metabolism synaptic plasticity, maintenance of neuronal differentiation, mitochondrial function, and cell signaling. Taken together, these results suggest that agonist 5-hydroxytryptamine receptor autoantibodies (which increase in Parkinson’s disease and other forms of neurodegeneration) mediate a coordinating program of gene expression changes in a model neuron which predispose to neuro-apoptosis and are linked to human neurodegenerative diseases pathways.

Web-Based Exercise Program Increases Cervical Strength in Adolescent Athletes

ABSTRACT

Wilson, JC, Levek, C, Daoud, AK, Brewer, M, Brooks, K, Sochanska, A, Randall, M, and Provance, AJ. Web-based exercise program increases cervical strength in adolescent athletes. J Strength Cond Res 35(4): 1149-1155, 2021-This cohort study aimed to evaluate the efficacy of a web-based 6-week cervical strengthening program on cervical strength in adolescent athletes. It was hypothesized that subjects completing the program would demonstrate significant increase in cervical muscle strength compared with baseline strength. Eighty-three high school soccer athlete subjects were recruited from 2 local nationally competitive soccer clubs. Teams were assigned to either control or intervention groups to minimize information crossover. Fifty subjects were recruited to the intervention group (29 male, 21 female; average age 15.1 years). Thirty-three subjects were recruited to the control group (21 male, 12 female; average age 15.1 years). Intervention group subjects completed a web-based progressive cervical strengthening program over 6 weeks. Cervical strength in flexion, extension, right and left lateral flexion (LLF) was measured in Newton (N) of force at 3 time points during the competitive season for both control and intervention groups. Intervention group subjects significantly increased cervical strength [mean difference (95% confidence interval)] in LLF [24.1 (15.9-32.4)], extension [27.9 (18.4-37.5)], right lateral flexion [18.8 (11.6-26.1)], and flexion [mean ratio: 1.2 (1.1-1.2)] at follow-up testing; whereas control subjects did not see significant changes in strength. A web-based progressive cervical strengthening program improves cervical muscular strength in a population of adolescent athletes over a period of 6 weeks. Such a program could be used by researchers in future studies evaluating the influence on concussion risk and by practitioners as a means of reducing sport-related head and neck injuries.

A cross-sectional study reporting concussion exposure, assessment and management in Western Australian general practice

Background

General Practitioners (GPs) may be called upon to assess patients who have sustained a concussion despite limited information being available at this assessment. Information relating to how concussion is actually being assessed and managed in General Practice is scarce. This study aimed to identify characteristics of current Western Australian (WA) GP exposure to patients with concussion, factors associated with GPs’ knowledge of concussion, confidence of GPs in diagnosing and managing patients with concussion, typical referral practices and familiarity of GPs with guidelines.

Methods

In this cross-sectional study, GPs in WA were recruited via the RACGP WA newsletter and shareGP and the consented GPs completed an electronic survey. Associations were performed using Chi-squared tests or Fisher’s Exact test.

Results

Sixty-six GPs in WA responded to the survey (response rate = 1.7%). Demographics, usual practice, knowledge, confidence, identification of prolonged recovery as well as guideline and resource awareness of GPs who practised in regional and metropolitan areas were comparable (p > 0.05). Characteristics of GPs were similar between those who identified all symptoms of concussion and distractors correctly and those who did not (p > 0.05). However, 84% of the respondents who had never heard of concussion guidelines were less likely to answer all symptoms and distractors correctly (p = 0.039). Whilst 78% of the GPs who were confident in their diagnoses had heard of guidelines (p = 0.029), confidence in managing concussion was not significantly associated with GPs exposure to guidelines. It should be noted that none of the respondents correctly identified signs of concussion and excluded the distractors.

Conclusions

Knowledge surrounding concussion guidelines, diagnosis and management varied across GPs in WA. Promotion of available concussion guidelines may assist GPs who lack confidence in making a diagnosis. The lack of association between GPs exposure to guidelines and confidence managing concussion highlights that concussion management may be an area where GPs could benefit from additional education and support.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01384-1.

Slowed driving-reaction time following concussion-symptom resolution

BACKGROUND

Concussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT's relationship with traditional computerized neurocognitive testing (CNT) domains.

METHODS

We employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion, mean ± SD) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05).

RESULTS

Concussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95% confidence interval (95%CI): 70.18-515.54; p = 0.023; d = 0.992). Evasion-RT (p = 0.054; d = 0.806), pedestrian-RT (p = 0.258; d = 0.312), and stoplight-RT (p = 0.292; d = 0.585) outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range: -0.51 to 0.55; p > 0.05). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range: -0.52 to 0.72; p > 0.05).

CONCLUSION

Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns. Driving-RT and CNT-RT measures correlated moderately but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT.