Sports-related Mild Traumatic Brain Injury Research Articles

Utility of Structured Oculomotor, Balance, and Exercise Testing in Civilian Adults With Mild Traumatic Brain Injury.

Assessments of oculomotor, balance, and exercise function detect different responses to mild traumatic brain injury in sports-related mild traumatic brain injury. These assessments are understudied in the adult community mild traumatic brain injury population. We evaluated level 1 trauma center patients with nonsports-related mild traumatic brain injury on oculomotor functioning (near point of convergence and accommodation), balance (Balance Error Scoring System), and exercise tolerance (Buffalo Concussion Treadmill Test). A prospective, cohort study of adults with mild traumatic brain injury ( n = 36) were assessed at 1 wk and 1-mo post-mild traumatic brain injury ( n = 26) using near point of convergence, near point of accommodation, Balance Error Scoring System, Buffalo Concussion Treadmill Test, and the Rivermead Post Concussion Symptoms Questionnaire. Prevalence of test impairment and association between performance and mild traumatic brain injury-related symptom burden (Rivermead Post Concussion Symptoms Questionnaire scores) were characterized. Participants demonstrated varying levels of impairment (e.g., 33.3% oculomotor, 44.1% balance, and 55.6% exercise impairment at 1 wk). Participants displayed diverse impairment profiles across assessments. We observed medium-to-large correlations between poorer near point of convergence and Buffalo Concussion Treadmill Test performance and greater mild traumatic brain injury symptom burden. Clinical examinations of oculomotor function, balance, and exercise adopted from sports-related concussion assessments detect impairment in adult community members with mild traumatic brain injury. While findings warrant larger-scale replication, they imply that incorporating these simple, structured examinations into the assessment of mild traumatic brain injury may facilitate more personalized management strategies.

Modal analysis of computational human brain dynamics during helmeted impacts

Sports-related mild traumatic brain injury (mTBI) is a growing public health concern, affecting millions in the U.S., annually. Current helmets are primarily designed to mitigate head kinematics, despite the importance of the brain substructures mechanics in mTBI mechanism. Therefore, it is crucial to consider the dynamical behavior of brain substructures, which has been shown in prior studies to be associated with strain concentration. Here, we studied the modal behavior and strain patterns of the substructures of the brain finite element (FE) model through Dynamic Mode Decomposition. We conducted side and front impact pendulum tests on a dummy headform equipped with hockey, football, ski, and bicycle helmets. After simulating the impact tests using a brain FE model, we calculated the dynamic modes of this computational model for the whole brain, corpus callosum, brainstem, and cerebellum. The main mode of oscillation in all regions for all helmet types occurred around the frequency regime of 7–15 Hz. Also, in cerebellum, a second harmonic was observed at 40–50 Hz in front impact, and 38 and 62 Hz in side impact in bicycle and ski helmets, respectively. Furthermore, we analyzed the correlation between the modal response and peak maximum principal strain (MPS). These analyses mostly showed a direct association between the computational modal behavior and MPS, where helmet tests with closely spaced modes and high-frequency modal amplitudes led to higher MPS values. This association between the computational modal behavior and strain patterns demonstrated a potential for improving helmet designs through a novel design objective.Statement of significance: Sport-related mild traumatic brain injury (mTBI), which is one of the leading cause of death, can be reduced in severity by using headgears including helmets. Despite the recent innovations and technologies in helmet design, there are important factors that still have been missed. While it’s been shown that the brain substructures mechanics play an important role in mTBI mechanism, current helmets are designed to only mitigate the head kinematics. Moreover, dynamical behavior of these substructures, and existence of multimodal behavior in the brain are factors that have not been addressed in designing helmets. This paper shows the effect of different helmet types on modal behavior of the brain substructures and how the dynamical modes of these regions can be affected by using various helmet types.

Can the Buffalo Concussion Treadmill Test Be Used as a Prognostic Indicator for Patients With Sport-Related Mild Traumatic Brain Injury?

To establish whether time to exercise cessation using the Buffalo Concussion Treadmill Test (BCTT) protocol can be used as a prognostic indicator of recovery after sport-related mild traumatic brain injury (SR-mTBI). Retrospective analysis of prospectively collected data. Specialist Concussion Clinic. Three hundred and twenty one patients presenting between 2017 and 2019 who underwent BCTT for SR-mTBI. Participants who remained symptomatic at a 2-week follow-up appointment after SR-mTBI underwent BCTT to develop a progressive subsymptom threshold exercise program with fortnightly follow-up until clinical recovery. Clinical recovery was the primary outcome measure. A total of 321 participants were eligible to participate in this study (mean age 22.94% and 46% female). The BCTT test duration was divided into 4-minute intervals and those who completed full 20 minutes. There was higher probability of clinical recovery in those who finished the entire 20-minute BCTT protocol compared with those who managed 17-<20 minutes (Hazard Ratio, HR 0.57), 13 to 16 minutes (HR 0.53), 9 to 12 minutes (HR 0.6), 5 to 8 minutes (HR 0.4), and 1 to 4 minutes (HR 0.7), respectively. Those seen earlier after injury ( P = 0.009), male patients ( P = 0.116), younger patients ( P = 0.0003), and those with physiological or cervical dominant ( P = 0.416) symptom clusters were more likely to achieve clinical recovery. Fifty percent of those who completed the full BCTT protocol achieved clinical recovery at day 19 post-injury. The group completing full 20 minutes of BCTT achieved clinical recovery more quickly than those who did not complete full BCTT.

A Pilot Investigation of Visual Pathways in Patients with Mild Traumatic Brain Injury.

In this study, we examined visual processing within primary visual areas (V1) in normal and visually impaired individuals who exhibit significant visual symptomology due to sports-related mild traumatic brain injury (mTBI). Five spatial frequency stimuli were applied to the right, left and both eyes in order to assess the visual processing of patients with sports-related mild traumatic brain injuries who exhibited visual abnormalities, i.e., photophobia, blurriness, etc., and controls. The measurement of the left/right eye and binocular integration was accomplished via the quantification of the spectral power and visual event-related potentials. The principal results have shown that the power spectral density (PSD) measurements display a distinct loss in the alpha band-width range, which corresponded to more instances of medium-sized receptive field loss. Medium-size receptive field loss may correspond to parvocellular (p-cell) processing deprecation. Our major conclusion provides a new measurement, using PSD analysis to assess mTBI conditions from primary V1 areas. The statistical analysis demonstrated significant differences between the mTBI and control cohort in the Visual Evoked Potentials (VEP) amplitude responses and PSD measurements. Additionally, the PSD measurements were able to assess the improvement in the mTBI primary visual areas over time through rehabilitation.

RWD125 Demographics and Healthcare Resource Utilization of Patients With Sports-Related Mild Traumatic Brain Injury (SR-MTBI) in the US

RWD125 Demographics and Healthcare Resource Utilization of Patients With Sports-Related Mild Traumatic Brain Injury (SR-MTBI) in the US

Memory Impairments Associated With Mild Traumatic Brain Injury: A Critically Appraised Topic

Clinical Question: Do sports-related mild traumatic brain injury in adolescents and young adults produce changes that can be identified with functional magnetic resonance imaging that are associated with memory impairment? Clinical Bottom Line: After sport-related mild traumatic brain injury, functional magnetic resonance imaging identified inconsistent structural changes (e.g., cortical thickness changes, brain activation patterns), and negative performance changes in memory function (e.g., lower neuropsychological scores) in adolescents and young adults 9 days to more than a year following injury.

White matter abnormalities characterize the acute stage of sports-related mild traumatic brain injury.

Sports-related concussion, a form of mild traumatic brain injury, is characterized by transient disturbances of brain function. There is increasing evidence that functional brain changes may be driven by subtle abnormalities in white matter microstructure, and diffusion MRI has been instrumental in demonstrating these white matter abnormalities in vivo. However, the reported location and direction of the observed white matter changes in mild traumatic brain injury are variable, likely attributable to the inherent limitations of the white matter models used. This cross-sectional study applies an advanced and robust technique known as fixel-based analysis to investigate fibre tract-specific abnormalities in professional Australian Football League players with a recent mild traumatic brain injury. We used the fixel-based analysis framework to identify common abnormalities found in specific fibre tracts in participants with an acute injury (≤12 days after injury; n = 14). We then assessed whether similar changes exist in subacute injury (>12 days and <3 months after injury; n = 15). The control group was 29 neurologically healthy control participants. We assessed microstructural differences in fibre density and fibre bundle morphology and performed whole-brain fixel-based analysis to compare groups. Subsequent tract-of-interest analyses were performed within five selected white matter tracts to investigate the relationship between the observed tract-specific abnormalities and days since injury and the relationship between these tract-specific changes with cognitive abnormalities. Our whole-brain analyses revealed significant increases in fibre density and bundle cross-section in the acute mild traumatic brain injury group when compared with controls. The acute mild traumatic brain injury group showed even more extensive differences when compared with the subacute injury group than with controls. The fibre structures affected in acute concussion included the corpus callosum, left prefrontal and left parahippocampal white matter. The fibre density and cross-sectional increases were independent of time since injury in the acute injury group, and were not associated with cognitive deficits. Overall, this study demonstrates that acute mild traumatic brain injury is characterized by specific white matter abnormalities, which are compatible with tract-specific cytotoxic oedema. These potential oedematous changes were absent in our subacute mild traumatic brain injury participants, suggesting that they may normalize within 12 days after injury, although subtle abnormalities may persist in the subacute stage. Future longitudinal studies are needed to elucidate individualized recovery after brain injury.

Test–retest reliability of the neurotracker compared to the impact test for the management of mild traumatic brain injuries during two consecutive university sport seasons

ABSTRACT Introduction Neurocognitive assessment tools such as the Neurotracker and ImPACT have been proposed to optimize sports-related mild traumatic brain injury (mTBI) management. Baseline testing is recommended with such assessments to individualize monitoring of athletes' remission. While the ideal timeframe between baseline updates has been studied for the ImPACT, these data are missing for the Neurotracker. Objective The current study aimed to compare the test–retest reliability of the ImPACT and Neurotracker for two consecutive seasons in university athletes participating in sports at risk for mTBI. Methods At the start of two consecutive seasons, 30 athletes with no recent history of mTBI completed a baseline assessment including the Neurotracker and the ImPACT. The test–retest reliability of the results was analyzed by considering intra-class correlation (ICC), Becker’s standardized mean difference (dB) and Bland-Altman’ plot of each outcome. Results The Neurotracker and the Visual Motor Speed composite score of the ImPAC were the only outcomes with significative ICCs and acceptable d B between the two seasons. Neurotracker was the only outcome with a significative bias (+0.179). Conclusion Our research suggests that the Neurotracker has an acceptable level of test–retest reliability after one year in comparison to the ImPACT.

Preliminary Evidence for the Clinical Utility of Tactile Somatosensory Assessments of Sport-Related mTBI

ObjectivesTo evaluate the clinical utility of tactile somatosensory assessments to assist clinicians in diagnosing sport-related mild traumatic brain injury (SR-mTBI), classifying recovery trajectory based on performance at initial clinical assessment, and determining if neurophysiological recovery coincided with clinical recovery.Research DesignProspective cohort study with normative controls.MethodsAt admission (n = 79) and discharge (n = 45/79), SR-mTBI patients completed the SCAT-5 symptom scale, along with the following three components from the Cortical Metrics Brain Gauge somatosensory assessment (BG-SA): temporal order judgement (TOJ), TOJ with confounding condition (TOJc), and duration discrimination (DUR). To assist SR-mTBI diagnosis on admission, BG-SA performance was used in logistic regression to discriminate cases belonging to the SR-mTBI sample or a healthy reference sample (pooled BG-SA data for healthy participants in previous studies). Decision trees evaluated how accurately BG-SA performance classified SR-mTBI recovery trajectories.ResultsBG-SA TOJ, TOJc, and DUR poorly discriminated between cases belonging to the SR-mTBI sample or a healthy reference sample (0.54–0.70 AUC, 47.46–64.71 PPV, 48.48–61.11 NPV). The BG-SA evaluated did not accurately classify SR-mTBI recovery trajectories (> 14-day resolution 48%, ≤14–day resolution 54%, lost to referral/follow-up 45%). Mann-Whitney U tests revealed differences in BG-SA TOJc performance between SR-mTBI participants and the healthy reference sample at initial clinical assessment and at clinical recovery (p < 0.05).ConclusionsBG-SA TOJ, TOJc, and DUR appear to have limited clinical utility to assist clinicians with diagnosing SR-mTBI or predicting recovery trajectories under ecologically valid conditions. Neurophysiological abnormalities persisted beyond clinical recovery given abnormal BG-SA TOJc performance observed when SR-mTBI patients achieved clinical recovery.

Post-concussion symptoms in sports-related mild traumatic brain injury compared to non-sports-related mild traumatic brain injury.

To compare post-concussion symptoms in patients who sustained a sports-related mild traumatic brain injury (TBI) to those with non-sports-related mild TBIat 7 and 90 days post-injury. This prospective multicentre cohort study took place in seven Canadian Emergency Departments (ED). Non-hospitalized patients aged ≥ 14years with a documented mild TBI that occurred ≤ 24h of ED visit and a Glasgow Coma Scale score ≥ 13 were included. Main outcome measure was the presence of ≥ 3 symptoms on the Rivermead Post-concussion Questionnaire at 90days post-injury. Secondary outcomes were the prevalence of (1) individual Rivermead Post-concussion Questionnaire symptom, (2) total Rivermead Post-concussion Questionnaire score ≥ 21 and (3) return to normal daily activities. Adjusted risk ratios (RR) were calculated. 1727 patients were included, 363 (21.0%) sustained a sports-related mild TBI. Similar proportions of patients with ≥ 3 symptoms, a Rivermead Post-concussion Questionnaire score ≥ 21 and those who returned to their normal daily activities were observed at 7 and 90days post-injury. Sports-related mild TBI patients were at higher risk of poor concentration [RR: 1.3 (95% CI 1.05-1.54)] and non-return to sports activities [RR: 2.2 (95% CI 1.69-2.94)] at 7days post-injury. At 90days, sports-relate -mild TBI patients reported less fatigue [RR: 0.7 (95% CI 0.51-0.98)] and feeling of dizziness [RR: 0.6 (95% CI 0.35-0.99)]. Patients who sustained sports-related mild TBI could be at lower risk of experiencing symptoms such as fatigue and dizziness 90days post-injury. Clinicians should be mindful that non-sports-related mild TBI patients may experience more post-concussion symptoms and that the level of physical activity may influence the patient's rehabilitation.

Incidence of Combat Sport-Related Mild Traumatic Brain Injuries Presenting to the Emergency Department From 2012 to 2016.

We sought to investigate the incidence and characteristics of traumatic brain injuries [mild traumatic brain injury (MTBI)] presenting to the emergency department as a result of boxing, wrestling, and martial arts (MA). Retrospective cross-sectional study of MTBI in combat sport athletes who were evaluated in emergency departments in the United States. Patient data were taken from the National Electronic Injury Surveillance System. All patients with MTBI from 2012 to 2016, which occurred during participation in boxing, MA, or wrestling. None. The incidence of combat sport-related MTBI presenting to emergency departments in the United States. The mean annual incidence of MTBI due to wrestling was significantly larger (269.3 per 100 000 person-years) than boxing (85.6 per 100 000 person-years) and MA (61.0 per 100 000 person-years) (P < 0.01). The average age at injury was significantly lower for wrestling compared with boxing and MA (15.0 years [SD ± 3.9] vs 21.7 years [SD ± 8.2] vs 19.9 years [SD ± 10.5]; P < 0.01). A significantly larger proportion of MTBIs (95.3%; P < 0.01) in patients younger than 20 years were related to wrestling, compared with boxing (55.8%) and MA (54.1%). Most patients with combat sport-related MTBIs were treated and discharged (96.3%), with only 1.7% of patients being admitted and 0.6% of patients being held for observation. Combat sports athletes are at high risk of sustaining an MTBI. Such athletes presenting to the emergency department for combat sport-related MTBI were more likely to be male and younger than 20 years. Of these athletes, wrestlers experience the highest incidence of MTBI-related emergency department visits.

Plasma glial fibrillary acidic protein and neurofilament light chain, but not tau, are biomarkers of sports-related mild traumatic brain injury.

Mild traumatic brain injury is a relatively common event in contact sports and there is increasing interest in the long-term neurocognitive effects. The diagnosis largely relies on symptom reporting and there is a need for objective tools to aid diagnosis and prognosis. There are recent reports that blood biomarkers could potentially help triage patients with suspected injury and normal CT findings. We have measured plasma concentrations of glial and neuronal proteins and explored their potential in the assessment of mild traumatic brain injury in contact sport. We recruited a prospective cohort of active male rugby players, who had pre-season baseline plasma sampling. From this prospective cohort, we recruited 25 players diagnosed with mild traumatic brain injury. We sampled post-match rugby players without head injuries as post-match controls. We measured plasma neurofilament light chain, tau and glial fibrillary acidic protein levels using ultrasensitive single molecule array technology. The data were analysed at the group and individual player level. Plasma glial fibrillary acidic protein concentration was significantly increased 1-h post-injury in mild traumatic brain injury cases compared to the non-injured group (P = 0.017). Pairwise comparison also showed that glial fibrillary acidic protein levels were higher in players after a head injury in comparison to their pre-season levels at both 1-h and 3- to 10-day post-injury time points (P = 0.039 and 0.040, respectively). There was also an increase in neurofilament light chain concentration in brain injury cases compared to the pre-season levels within the same individual at both time points (P = 0.023 and 0.002, respectively). Tau was elevated in both the non-injured control group and the 1-h post-injury group compared to pre-season levels (P = 0.007 and 0.015, respectively). Furthermore, receiver operating characteristic analysis showed that glial fibrillary acidic protein and neurofilament light chain can separate head injury cases from control players. The highest diagnostic power was detected when biomarkers were combined in differentiating 1-h post-match control players from 1-h post-head injury players (area under curve 0.90, 95% confidence interval 0.79–1.00, P < 0.0002). The brain astrocytic marker glial fibrillary acidic protein is elevated in blood 1 h after mild traumatic brain injury and in combination with neurofilament light chain displayed the potential as a reliable biomarker for brain injury evaluation. Plasma total tau is elevated following competitive rugby with and without a head injury, perhaps related to peripheral nerve trauma and therefore total tau does not appear to be suitable as a blood biomarker.

Less Than Half of Patients Recover Within 2 Weeks of Injury After a Sports-Related Mild Traumatic Brain Injury: A 2-Year Prospective Study.

To describe clinical recovery time and factors that might impact on recovery after a sports-related mild traumatic brain injury (SR-mTBI; concussion). Prospective cohort study (level IV evidence). New Zealand Sports Concussion Clinic. Eight hundred twenty-two patients presenting within 14 days of a SR-mTBI/concussion over a 2-year period. Clinical recovery measured as number of days after injury. Participants were assessed and managed using a standardized protocol consisting of relative rest followed by controlled cognitive and physical loading. A reassessment was performed 14 days after injury with initiation of an active rehabilitation program consisting of a subsymptom threshold exercise program ± cervicovestibular rehabilitation (if required) for participants who remained symptomatic. Participants were then assessed every 2 weeks until clinical recovery. A total of 594 participants were eligible for analysis (mean age 20.2 ± 8.7 years, 77% males) and were grouped into 3 age cohorts: children (≤12 years), adolescents (13-18 years), and adults (≥19 years). Forty-five percent of participants showed clinical recovery within 14 days of injury, 77% by 4 weeks after injury, and 96% by 8 weeks after injury. There was no significant difference in recovery time between age groups. Prolonged recovery was more common in females (P = 0.001), participants with "concussion modifiers" (P = 0.001), and with increased time between injury and the initial appointment (P = 0.003). This study challenges current perceptions that most people with a SR-mTBI (concussion) recover within 10 to 14 days and that age is a determinant of recovery rate. Active rehabilitation results in high recovery rates after SR-mTBI.

Predicting Sport-related mTBI Symptom Resolution Trajectory Using Initial Clinical Assessment Findings: A Retrospective Cohort Study.

To identify which aspects of initial clinical assessment for sport-related mild traumatic brain injury (SR-mTBI) predict whether an athlete achieves symptom resolution within 14days of the injury. Retrospective cohort study using prospectively collected data. Clinical assessment data were collected from 568 patients diagnosed with SR-mTBI at a single medical clinic between February 2017 and December 2018. Demographic data, medical history, SCAT-5 testing, and physician notes were included in the data set. Data were processed and analysed to identify a shortlist of predictor variables to develop a logistic regression model to discriminate between SR-mTBI symptom resolution that occurred in ≤ 14-days or > 14-days. The data were randomly divided into model development and validation subsamples. The top 15 models were analysed to determine the predictor variables to be included in the final logistic regression model. The final model was then applied to the validation subsample. Half of the athlete participants in this study experienced > 14-day symptom resolution. The final logistic regression model included sex, symptom reporting at initial assessment and presentation with a physiological predominant symptom cluster. The model accounted for 0.90 and 0.85 of the area under the curve and predicted recovery trajectory with 81% and 76% accuracy for the training and validation subsamples, respectively. Being female, reporting a higher Positive Symptom Total at initial assessment, and being less likely to have a physiological predominant symptom cluster at initial assessment predicted > 14 versus ≤ 14-day SR-mTBI symptom resolution with a high level of accuracy.

Management and Recovery Patterns Following Sport-Related Mild Traumatic Brain Injury in Male and Female College Athletes

Purpose: We examined patterns in mild traumatic brain injury (mTBI) management and recovery exhibited by male and female athletes over the 19-year history of a Division 1 University Concussion Management Program. Methods: We examined 234 diagnosed mTBIs and compared time required to return to baseline on neurocognitive and self-report symptom measures for male and female athletes. Results: Males and females sustained 63.3% and 36.7% of mTBI, respectively. Athletes required on average 11.89 days to return to baseline on neurocognitive assessments and 11.83 days to report being symptom-free. There was a significant difference in the number of days until genders were symptom-free, with males and females requiring on average 10.11 days and 14.30 days, respectively. Discussion: More collegiate athletes received pre- and post-mTBI management than in the past. There is a continued need to examine patterns of neurocognitive and symptom recovery, which may lead to earlier detection of athletes at risk for persistent post-mTBI symptoms.

Altered levels of plasma neuron-derived exosomes and their cargo proteins characterize acute and chronic mild traumatic brain injury.

Neuron-derived exosomes (NDEs) were enriched by anti-L1CAM antibody immunoabsorption from plasmas of subjects ages 18-26 yr within 1 wk after a sports-related mild traumatic brain injury (acute mTBI) ( n = 18), 3 mo or longer after the last of 2-4 mTBIs (chronic mTBI) ( n = 14) and with no recent history of TBI (controls) ( n = 21). Plasma concentrations of NDEs, assessed by counts and levels of extracted exosome marker CD81, were significantly depressed by a mean of 45% in acute mTBI ( P < 0.0001), but not chronic mTBI, compared with controls. Mean CD81-normalized NDE levels of a range of functional brain proteins were significantly abnormal relative to those of controls in acute but not chronic mTBI, including ras-related small GTPase 10, 73% decrease; annexin VII, 8.8-fold increase; ubiquitin C-terminal hydrolase L1, 2.5-fold increase; AII spectrin fragments, 1.9-fold increase; claudin-5, 2.7-fold increase; sodium-potassium-chloride cotransporter-1, 2.8-fold increase; aquaporin 4, 8.9-fold increase (3.6-fold increase in chronic mTBI); and synaptogyrin-3, 3.1-fold increase (1.3-fold increase in chronic mTBI) (all acute mTBI proteins P < 0.0001). In chronic mTBI, there were elevated CD81-normalized NDE levels of usually pathologic β-amyloid peptide 1-42 (1.6-fold, P < 0.0001), P-T181-tau (2.2-fold, P < 0.0001), P-S396-tau (1.6-fold, P < 0.01), IL-6 (16-fold, P < 0.0001), and prion cellular protein (PRPc) (5.1-fold, P < 0.0001) with lesser or greater (IL-6, PRPc) increases in acute mTBI. Increases in NDE levels of most neurofunctional proteins in acute, but not chronic, mTBI, and elevations of most NDE neuropathological proteins in chronic and acute mTBI delineated phase-specificity. Longitudinal studies of more mTBI subjects may identify biomarkers predictive of and etiologically involved in mTBI-induced neurodegeneration.-Goetzl, E. J., Elahi, F. M., Mustapic, M., Kapogiannis, D., Pryhoda, M., Gilmore, A., Gorgens, K. A., Davidson, B., Granholm, A.-C., Ledreux, A. Altered levels of plasma neuron-derived exosomes and their cargo proteins characterize acute and chronic mild traumatic brain injury.

Neurobehavioural profile following cumulative mild traumatic brain injury in adolescent rugby players in South Africa

The study investigated the neurobehavioural components of executive dysfunction following sport-related Mild Traumatic Brain Injury (MTBI) in Grade 12 adolescent rugby players over a rugby season. In a non-equivalent quasi-experimental design, a rugby group (n = 90) were compared with demographically equivalent noncontact sport controls (n = 59). The Behaviour Rating Inventory of Executive Functions – Self Report (BRIEF-SR) was employed to assess the neurobehavioural component of executive functions. Independent and dependent t-test analyses were conducted to compare the groups at baseline and end-of-season intervals. The overall findings suggest more pronounced deleterious effects on executive functioning from exposure to the concussive and sub-concussive events among the rugby group. High school rugby players experience adverse neurobehavioural effects in executive dysfunction from contact rugby sport injuries.

Recovery progression and symptom resolution in sport-related mild traumatic brain injury

ABSTRACTObjective: To characterize the recovery progression of a group of athletes who participated in a concussion management program based on (1) group analysis and (2) individual analysis.Setting: Concussion management clinic.Participants: Thirty athletes (22 males, 8 females; baseline age = 16.23 ± 2.40 years) who had undergone four assessments: one baseline and three post-injury assessments at 3, 8, 15 days post-injury.Design: Retrospective clinical.Main Measures: Four neurocognitive scores of the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) including verbal memory, visual memory, speed of processing and reaction time and also a total symptom score.Results: Group-analysis showed a clear decline in verbal memory (F(3, 87) = 7.36, p < 0.000) and an increase in self-reported symptoms (χ2(3, N = 30) = 48.703, p < 0.000), 3 days post-injury. By day 8, athletes had returned to their baseline levels for verbal memory and were not experiencing symptoms. When athletes’ scores were examined individually, at 3 days post-injury, 60% of the athletes showed deficits on two or more of the ImPACT variables. This rate dropped to 23% at 8 days post-injury and remained the same (23%) 15 days post-injury.Conclusions: In concussion recovery, variability is the rule, rather than the exception, with regard to both impaired neurocognitive functions and recovery duration.

Evidence of brain functional deficits following sport-related mild traumatic brain injury.

Sport related mild traumatic brain injury (mTBI), generally known as a concussion, is a worldwide critical public health concern nowadays. Despite growing concern emphasized by scientific research and recent media presentation regarding mTBI and its effect in athletics life, the management, and prevention of mTBI are still not properly done. The evaluation mainly hampered due to the lack of proper knowledge, subjective nature of assessment tools including the fact that the brain functional deficits after mTBI can be mild or hidden. As a result, development of an effective tool for proper management of these mild incidents is a subject of active research. In this paper, to examine the neural substrates following mTBI, an analysis based on electroencephalogram (EEG) from twenty control and twenty concussed athletes is presented. Preliminary results suggest that the concussed athletes have a significant increase in delta, theta and alpha power but a decrease in beta power. We also calculated the power for individual frequencies from 1 Hz to 40 Hz in order to find out the specific frequencies with the highest deficits. The significant deficiencies were found at 1-2 Hz of delta band, 6-7 Hz of theta band, 8-10 Hz of the alpha band, and 16-18 Hz and 24-29 Hz of the beta band. Though there was no significant difference as observed in gamma band, we found the deficit was significant at 34-36 Hz range within the gamma band. The observed deficits at various frequencies demonstrate that even if there is no significant difference in the traditional frequency bands, there may be hidden deficits at some specific frequencies within a frequency band. These preliminary results suggest that the EEG analysis at each unity frequency may be more promising means of identifying the neuronal damage than the traditional frequency band based analysis. Eventually, the proposed analysis can provide an improved approximation to monitor the pathophysiological recovery after a concussion.

Diffusion tensor imaging (DTI) findings in adult civilian, military, and sport-related mild traumatic brain injury (mTBI): a systematic critical review.

This review seeks to summarize diffusion tensor imaging (DTI) studies that have evaluated structural changes attributed to the mechanisms of mild traumatic brain injury (mTBI) in adult civilian, military, and athlete populations. Articles from 2002 to 2016 were retrieved from PubMed/MEDLINE, EBSCOhost, and Google Scholar, using a Boolean search string containing the following terms: "diffusion tensor imaging", "diffusion imaging", "DTI", "white matter", "concussion", "mild traumatic brain injury", "mTBI", "traumatic brain injury", and "TBI". We added studies not identified by this method that were found via manually-searched reference lists. We identified 86 eligible studies from English-language journals using, adult, human samples. Studies were evaluated based on duration between injury and DTI assessment, categorized as acute, subacute/chronic, remote mTBI, and repetitive brain trauma considerations. Since changes in brain structure after mTBI can also be affected by other co-occurring medical and demographic factors, we also briefly review DTI studies that have addressed socioeconomic status factors (SES), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD). The review describes population-specific risks and the complications of clinical versus pathophysiological outcomes of mTBI. We had anticipated that the distinct population groups (civilian, military, and athlete) would require separate consideration, and various aspects of the study characteristics supported this. In general, study results suggested widespread but inconsistent differences in white matter diffusion metrics (primarily fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) following mTBI/concussion. Inspection of study designs and results revealed potential explanations for discrepant DTI findings, such as control group variability, analytic techniques, the manner in which regional differences were reported, and the presence or absence of persistent functional disturbances. DTI research in adult mTBI would benefit from more standardized imaging and analytic approaches. We also found significant overlap in white matter abnormalities reported in mTBI with those commonly affected by SES or the presence of MDD and ADHD. We conclude that DTI is sensitive to a wide range of group differences in diffusion metrics, but that it currently lacks the specificity necessary for meaningful clinical application. Properly controlled longitudinal studies with consistent and standardized functional outcomes are needed before establishing the utility of DTI in the clinical management of mTBI and concussion.