Association of Premorbid Anxiety and Depression Symptoms in Concussion Recovery in Collegiate Student-Athletes.

BACKGROUND: Mental health disorders are linked to prolonged concussion symptoms. However, the association of premorbid anxiety/depression symptoms with postconcussion return-to-play timelines and total symptom burden is unclear. OBJECTIVE: To examine the association of self-reported premorbid anxiety/depression symptoms in collegiate student-athletes with (1) recovery times until asymptomatic, (2) return-to-play, and (3) postconcussion symptom burden. STUDY DESIGN: Athletes in the Concussion Assessment, Research and Education Consortium completed baseline concussion assessments (Sport Concussion Assessment Tool [SCAT3] and Brief Symptom Inventory-18 [BSI-18]). Athletes were tested postinjury at <6 hours, 24 to 48 hours, time of asymptomatic and start of return-to-play protocol, unrestricted return-to-play, and 6 months after injury. Injured athletes were categorized into 4 groups based on BSI-18 scores: (1) B-ANX, elevated anxiety symptoms only; (2) B-DEP, elevated depression symptoms only; (3) B-ANX&DEP, elevated anxiety and depression symptoms; and (4) B-NEITHER, no elevated anxiety or depression symptoms. Relationship between age, sex, BSI-18 group, SCAT3 total symptom and severity scores, and time to asymptomatic status and return-to-play was assessed with Pearson's chi-squared test and robust analysis of variance. LEVEL OF EVIDENCE: Level 3. RESULTS: Among 1329 athletes with 1352 concussions, no respondents had a self-reported premorbid diagnosis of anxiety/depression. There was no difference in time until asymptomatic or time until return-to-play between BSI-18 groups (P = 0.15 and P = 0.11, respectively). B-ANX, B-DEP, and B-ANX&DEP groups did not have higher total symptom or severity scores postinjury compared with the B-NEITHER group. CONCLUSION: Baseline anxiety/depression symptoms in collegiate student-athletes without a mental health diagnosis are not associated with longer recovery times until asymptomatic, longer time to return-to-play, or higher postconcussion total symptom and severity scores compared with athletes without baseline symptoms. CLINICAL RELEVANCE: Anxiety and depression symptoms without a clear mental health diagnosis should be considered differently from other comorbidities when discussing prolonged recovery in collegiate student-athletes.

Mechanisms of Injury Leading to Concussions in Collegiate Soccer Players: A CARE Consortium Study.

BACKGROUND: Few previous studies have investigated how different injury mechanisms leading to sport-related concussion (SRC) in soccer may affect outcomes. PURPOSE: To describe injury mechanisms and evaluate injury mechanisms as predictors of symptom severity, return to play (RTP) initiation, and unrestricted RTP (URTP) in a cohort of collegiate soccer players. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The Concussion Assessment, Research and Education (CARE) Consortium database was used. The mechanism of injury was categorized into head-to-ball, head-to-head, head-to-body, and head-to-ground/equipment. Baseline/acute injury characteristics-including Sports Concussion Assessment Tool-3 total symptom severity (TSS), loss of consciousness (LOC), and altered mental status (AMS); descriptive data; and recovery (RTP and URTP)-were compared. Multivariable regression and Weibull models were used to assess the predictive value of the mechanism of injury on TSS and RTP/URTP, respectively. RESULTS: Among 391 soccer SRCs, 32.7% were attributed to a head-to-ball mechanism, 27.9% to a head-to-body mechanism, 21.7% to a head-to-head mechanism, and 17.6% to a head-to-ground/equipment mechanism. Event type was significantly associated with injury mechanism [χ2(3) = 63; P < .001), such that more head-to-ball concussions occurred in practice sessions (n = 92 [51.1%] vs n = 36 [17.1%]) and more head-to-head (n = 65 [30.8%] vs n = 20 [11.1]) and head-to-body (n = 76 [36%] vs n = 33 [18.3%]) concussions occurred in competition. The primary position was significantly associated with injury mechanism [χ2(3) = 24; P < .004], with goalkeepers having no SRCs from the head-to-head mechanism (n = 0 [0%]) and forward players having the least head-to-body mechanism (n = 15 [19.2%]). LOC was also associated with injury mechanism (P = .034), with LOC being most prevalent in head-to-ground/equipment. Finally, AMS was most prevalent in head-to-ball (n = 54 [34.2%]) and head-to-body (n = 48 [30.4%]) mechanisms [χ2(3) = 9; P = .029]. In our multivariable models, the mechanism was not a predictor of TSS or RTP; however, it was associated with URTP (P = .044), with head-to-equipment/ground injuries resulting in the shortest mean number of days (14 ± 9.1 days) to URTP and the head-to-ball mechanism the longest (18.6 ± 21.6 days). CONCLUSION: The mechanism of injury differed by event type and primary position, and LOC and AMS were different across mechanisms. Even though the mechanism of injury was not a significant predictor of acute symptom burden or time until RTP initiation, those with head-to-equipment/ground injuries spent the shortest time until URTP, and those with head-to-ball injuries had the longest time until URTP.

Postinjury Outcomes After Non-Sport-Related Concussion: A CARE Consortium Study.

CONTEXT: Concussion research has primarily focused on sport-related mechanisms and excluded non-sport-related mechanisms. In adult populations, non-sport-related concussions (non-SRCs) demonstrated worse clinical outcomes compared with sport-related concussions (SRCs); however, investigations of non-SRCs in college-aged patients are limited. OBJECTIVES: To examine clinical outcomes in collegiate athletes with non-SRCs compared with SRCs and explore sex differences in outcomes among collegiate athletes with non-SRCs. DESIGN: Prospective cohort study. SETTING: Clinical setting. PATIENTS OR OTHER PARTICIPANTS: A total of 3500 athletes were included (n = 555 with non-SRCs, 42.5% female) from colleges or universities and service academies participating in the National Collegiate Athletic Association Department of Defense Concussion Assessment, Research and Education (CARE) Consortium. MAIN OUTCOME MEASURE(S): Dichotomous outcomes (yes or no) consisted of immediate reporting, mental status alterations, loss of consciousness, posttraumatic amnesia, retrograde amnesia, motor impairments, delayed symptom presentation, and required hospital transport. Continuous outcomes were symptom severity, days with concussion symptoms, and days lost to injury. Data were collected within 24 to 48 hours of injury and at return to play. Adjusted relative risks (ARRs) compared the likelihood of dichotomous outcomes by mechanism and by sex within patients with non-SRCs. Multivariate negative binomial regressions were used to assess group differences in continuous variables. RESULTS: Athletes with non-SRCs were less likely to report immediately (ARR = 0.73, 95% CI = 0.65, 0.81) and more likely to report delayed symptom presentation (ARR = 1.17, 95% CI = 1.03, 1.32), loss of consciousness (ARR = 3.15, 95% CI = 2.32, 4.28), retrograde amnesia (ARR = 1.77, 95% CI = 1.22, 2.57), and motor impairment (ARR = 1.45, 95% CI = 1.14, 1.84). Athletes with non-SRCs described greater symptom severity, more symptomatic days, and more days lost to injury (P < .001) compared with those who had SRCs. Within the non-SRC group, female athletes indicated greater symptom severity, more symptomatic days, and more days lost to injury (P < .03) than male athletes. CONCLUSIONS: Athletes with non-SRCs had worse postinjury outcomes compared with those who had SRCs, and female athletes with non-SRCs had worse recovery metrics than male athletes. Our findings suggest that further investigation of individuals with non-SRCs is needed to improve concussion reporting and management.

Sex Differences in Recovery Trajectories of Assessments for Sport-Related Concussion Among NCAA Athletes: A CARE Consortium Study.

OBJECTIVES: The purpose of this study was to determine sex differences in recovery trajectories of assessments for sport-related concussion using Concussion Assessment, Research and Education (CARE) Consortium data. METHODS: National Collegiate Athletic Association athletes (N = 906; 61% female) from sex-comparable sports completed a pre-season baseline assessment and post-sport-related concussion assessments within 6 h of injury, 24-48 h, when they initiated their return to play progression, when they were cleared for unrestricted return to play, and 6 months post-injury. Assessments included the Standardized Assessment of Concussion, Balance Error Scoring System, Brief Symptom Inventory-18, Immediate Post-concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool-3 symptom evaluation, Clinical Reaction Time, King-Devick test, Vestibular Ocular Motor Screen, 12-item Short-Form Health Survey, Hospital Anxiety and Depression Scale, and Satisfaction with Life Scale. RESULTS: Only the Vestibular Ocular Motor Screen Total Symptom Score at the 24-48 h timepoint (p = 0.005) was statistically significantly different between sexes. Specifically, female athletes (mean = 60.2, 95% confidence interval [CI] 51.5-70.4) had higher Vestibular Ocular Motor Screen Total Symptom Scores than male athletes (mean = 36.9, 95% CI 27.6-49.3), but this difference resolved by the time of return-to-play initiation (female athletes, mean = 1.8, 95% CI 1.1-2.9; male athletes, mean = 4.1, 95% CI 1.5-10.9). CONCLUSIONS: Sport-related concussion recovery trajectories for most assessments were similar for female and male National Collegiate Athletic Association athletes except for Vestibular Ocular Motor Screen symptoms within 48 h of sport-related concussion, which was greater in female athletes. Female athletes had a greater symptom burden across all timepoints, suggesting that cross-sectional observations may indicate sex differences despite similar recovery trajectories.

Premorbid Primary Headache and Vestibular and Oculomotor Baseline Assessments in Collegiate Athletes.

OBJECTIVE: The purpose of this study was to determine the effects of premorbid headache status on vestibular and oculomotor baseline tests in collegiate club athletes. DESIGN: Retrospective case-control study. SETTING: Sport Concussion Laboratory. PATIENTS OR PARTICIPANTS: Collegiate club athletes with a self-reported premorbid headache history (n = 32, 19.50 ± 1.98 years, and 31% women) and age-sex-sport-matched controls (n = 32, 19.56 ± 1.47 years, and 31% women) without a self-reported headache history were included. INTERVENTIONS: Participants were grouped based on a self-reported headache history at baseline. Controls were randomly matched to self-reported headache participants by age, sex, and sport. MAIN OUTCOME MEASURES: Vestibular/ocular motor screen (VOMS) baseline symptoms, symptom provocation, near point of convergence (NPC) distance, and King-Devick (K-D) test time were compared between groups. RESULTS: Athletes with a self-reported headache history at baseline are 3.82 times more likely to have abnormal NPC scores (P = 0.032) and 4.76 times more likely to have abnormal K-D test times (P = 0.014) than those without a headache history. There was no difference in VOMS baseline symptoms or symptom provocation between groups (P > 0.05). CONCLUSIONS: Club collegiate athletes with a headache history were more likely to screen as abnormal during a vestibular/ocular motor function assessment than athletes without a history of headaches. Healthcare professionals should screen for pre-existing headache during baseline concussion assessments before test interpretation. CLINICAL RELEVANCE: A premorbid headache history at preseason baseline assessment may influence vestibular and oculomotor function, and care should be taken when interpreting these individuals' tests.

Optimizing Concussion Care Seeking: The Influence of Previous Concussion Diagnosis Status on Baseline Assessment Outcomes.

BACKGROUND: The prevalence of unreported concussions is high, and undiagnosed concussions can lead to worse postconcussion outcomes. It is not clear how those with a history of undiagnosed concussion perform on subsequent standard concussion baseline assessments. PURPOSE: To determine if previous concussion diagnosis status was associated with outcomes on the standard baseline concussion assessment battery. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Concussion Assessment, Research, and Education (CARE) Consortium participants (N = 29,934) self-reported concussion history with diagnosis status and completed standard baseline concussion assessments, including assessments for symptoms, mental status, balance, and neurocognition. Multiple linear regression models were used to estimate mean differences and 95% CIs among concussion history groups (no concussion history [n = 23,037; 77.0%], all previous concussions diagnosed [n = 5315; 17.8%], ≥1 previous concussions undiagnosed [n = 1582; 5.3%]) at baseline for all outcomes except symptom severity and Brief Symptom Inventory-18 (BSI-18) score, in which negative binomial models were used to calculate incidence rate ratios (IRRs). All models were adjusted for sex, race, ethnicity, sport contact level, and concussion count. Mean differences with 95% CIs excluding 0.00 and at least a small effect size (≥0.20), and those IRRs with 95% CIs excluding 1.00 and at least a small association (IRR, ≥1.10) were considered significant. RESULTS: The ≥1 previous concussions undiagnosed group reported significantly greater symptom severity scores (IRR, ≥1.38) and BSI-18 (IRR, ≥1.31) scores relative to the no concussion history and all previous concussions diagnosed groups. The ≥1 previous concussions undiagnosed group performed significantly worse on 6 neurocognitive assessments while performing better on only 2 compared with the no concussion history and all previous concussions diagnosed groups. There were no between-group differences on mental status or balance assessments. CONCLUSION: An undiagnosed concussion history was associated with worse clinical indicators at future baseline assessments. Individuals reporting ≥1 previous undiagnosed concussions exhibited worse baseline clinical indicators. This may suggest that concussion-related harm may be exacerbated when injuries are not diagnosed.

Previous concussions increase risk of mental health disability in college athletes.

Background and Aim: Mental health concerns, particularly anxiety and depression, are leading causes of disability in young adults. Identifying pre-existing conditions that place individuals at-risk for mental health disability may enable health-care providers to increase patient outcomes with early interventions and condition management. Methods: Student-athletes were grouped by self-reported mental health disability status during pre-season baseline physicals. During the pre-season baseline assessment, student athletes completed the post-concussion symptom scale, hospital anxiety and disability scale, short-form 12 survey, and health history questionnaire. A logistic regression was performed to examine the predictive value of previous concussion history, anxiety, and/or depression mental health disability status. Results: Student-athletes with a previous concussion had a 46% higher risk for mental health disability. Higher PROM anxiety and depression scores were associated with a 1.29- and 1.19-times higher risk of mental health disability, respectively. Conclusion: The previous concussion history placed collegiate student-athletes at higher risk for mental health disability. Further, student-athletes that had higher anxiety and depression PROM scores were more likely to have self-reported diagnosed mental health disability. Health-care professionals working with collegiate student-athletes can identify pre-existing conditions that may put a student-athlete at higher risk for mental health disability. Relevance for Patients: The present study identifies previous concussion history and prior mental health diagnoses places individuals at higher risk for the future mental health disability. Identification of these individuals during routine health screenings may improve overall health outcomes.

Sex Differences in Neck Strength Force and Activation Patterns in Collegiate Contact Sport.

The purpose of this study was to assess changes in cervical musculature throughout contact-heavy collegiate ice hockey practices during a regular season of NCAA Division III ice hockey teams. In this cross-sectional study, 36 (male n = 13; female n = 23) ice hockey players participated. Data were collected over 3 testing sessions (baseline; pre-practice; post-practice). Neck circumference, neck length, head-neck segment length, isometric strength and electromyography (EMG) activity for flexion and extension were assessed. Assessments were completed approximately 1h before a contact-heavy practice and 15 min after practice. For sternocleidomastoid (SCM) muscles, males had significantly greater peak force and greater time to peak force versus females. For both left and right SCMs, both sexes had significantly greater peak EMG activity pre-practice versus baseline, and right (dominant side) SCM time to peak EMG activity was decreased post-practice compared to pre-practice. There were no significant differences for EMG activity of the upper trapezius musculature, over time or between sexes. Sex differences observed in SCM force and activation patterns of the dominant side SCM may contribute to head stabilization during head impacts. Our study is the first investigation to report changes in cervical muscle strength in men's and women's ice hockey players in the practical setting.

The Role of Cervical Symptoms in Post-concussion Management: A Systematic Review.

BACKGROUND: Patients with cervicogenic symptoms following a concussion have shown a disproportionate rate of delayed symptom resolution. However, the prevalence of cervicogenic symptoms in the acute stages following a concussion and the percentage of those patients who continue on to suffer delayed symptom resolution is poorly described in the literature. OBJECTIVES: To provide a comprehensive report on the clinical prevalence, diagnostic methods, and potential treatment options for cervicogenic symptoms that are elicited during acute and chronic phases following a concussion. METHODS: Electronic searches were conducted in PubMed, SPORTDiscus, ICL, CINAHL and PEDro, from inception to May 2020, to identify original research articles on concussion involving cervicogenic symptoms. We assessed each included article for risk of bias, methodological quality, level of evidence and evidence quality. The articles were categorized into three topics: (1) prevalence of post-concussion cervicogenic symptoms; (2) diagnostic testing for cervicogenic symptoms, and (3) treatment techniques for cervicogenic symptoms. RESULTS: The initial review resulted in 1443 abstracts, of which 103 abstracts met the inclusion criteria of our research. After the review of full text, 80 articles were excluded, which resulted in a total of 23 articles for this systematic review. Prevalence of cervicogenic symptoms in the acute stages ranged from 7 to 69% and increased to 90% in patients experiencing persistent post-concussive symptoms. Neck pain at initial evaluation increased risk of developing persistent post-concussive symptoms (PPCS) by 2.58-6.38 times. Patient-reported outcome measures (e.g., Neck Disability Index, Dizziness Handicap Inventory, and Rivermead Post-Concussion Questionnaire) can identify patients with cervicogenic symptoms that should be further differentiated by clinical testing. Lastly, treatment using graded cervical manual therapy has shown to reduce time to symptom resolution and medical clearance. CONCLUSIONS: Cervicogenic symptoms are prevalent in the acute and chronic stages following concussion, which if not diagnosed appropriately increase the likelihood of PPCS. Several clinical tests are available to help differentiate cervicogenic symptoms; however, lack of awareness and hesitation by practitioners limits their use. More randomized controlled trials are necessary to evaluate the effectiveness of cervical specific treatment programs for PPCS.

Unexpected Findings from a Pilot Study on Vision Training as a Potential Intervention to Reduce Subconcussive Head Impacts during a Collegiate Ice Hockey Season.

Player-to-player contact is the most frequent head impact mechanism in collegiate ice hockey. Training with three-dimensional multiple-object tracking (3D-MOT) could potentially reduce the quantity and severity of head impacts by enhancing player anticipation of these impacts. The purpose of this study was to evaluate the efficacy of 3D-MOT training to reduce the numbers of head impacts sustained by National Collegiate Athletic Association Division III men's and women's ice hockey players. Collegiate men's and women's ice hockey players (N = 33; men = 17, women = 16) were randomly assigned to a 3D-MOT group (n = 17) or a control (C) group (n = 16). Head impacts were monitored during practices and games, and 3D-MOT training occurred twice per week for 12 weeks throughout one regular season. 3D-MOT forwards sustained head impacts with greater mean peak linear acceleration (3D-MOT = 41.33 ± 28.54 g; C = 38.03 ± 24.30 g) and mean peak rotational velocity (3D-MOT = 13.59 ± 8.18 rad.sec-1; C = 12.47 ± 7.69 rad.sec-1) in games, and greater mean peak rotational velocity in practices versus C forwards (3D-MOT = 11.96 ± 6.77 rad.sec-1; C = 10.22 ± 6.95 rad.sec-1). Conversely, 3D-MOT defensemen sustained head impacts with a mean peak rotational velocity less than that of C defensemen (3D-MOT = 11.54 ± 6.76 rad.sec-1; C = 13.65 ± 8.43 rad.sec-1). There was no significant difference for all other parameters analyzed between 3D-MOT and C groups. Player position may play an important role in future interventions to reduce head impacts in collegiate ice hockey.

Astrocytes, HIV and the Glymphatic System: A Disease of Disrupted Waste Management?

The discovery of the glial-lymphatic or glymphatic fluid clearance pathway in the rodent brain led researchers to search for a parallel system in humans and to question the implications of this pathway in neurodegenerative diseases. Magnetic resonance imaging studies revealed that several features of the glymphatic system may be present in humans. In both rodents and humans, this pathway promotes the exchange of interstitial fluid (ISF) and cerebrospinal fluid (CSF) through the arterial perivascular spaces into the brain parenchyma. This process is facilitated in part by aquaporin-4 (AQP4) water channels located primarily on astrocytic end feet that abut cerebral endothelial cells of the blood brain barrier. Decreased expression or mislocalization of AQP4 from astrocytic end feet results in decreased interstitial flow, thereby, promoting accumulation of extracellular waste products like hyperphosphorylated Tau (pTau). Accumulation of pTau is a neuropathological hallmark in Alzheimer's disease (AD) and is accompanied by mislocalization of APQ4 from astrocyte end feet to the cell body. HIV infection shares many neuropathological characteristics with AD. Similar to AD, HIV infection of the CNS contributes to abnormal aging with altered AQP4 localization, accumulation of pTau and chronic neuroinflammation. Up to 30% of people with HIV (PWH) suffer from HIV-associated neurocognitive disorders (HAND), and changes in AQP4 may be clinically important as a contributor to cognitive disturbances. In this review, we provide an overview and discussion of the potential contributions of NeuroHIV to glymphatic system functions by focusing on astrocytes and AQP4. Although HAND encompasses a wide range of neurocognitive impairments and levels of neuroinflammation vary among and within PWH, the potential contribution of disruption in AQP4 may be clinically important in some cases. In this review we discuss implications for possible AQP4 disruption on NeuroHIV disease trajectory and how HIV may influence AQP4 function.

Association between (GT)n Promoter Polymorphism and Recovery from Concussion: A Pilot Study.

Variability in recovery among concussed athletes can be attributed to several risk factors. One risk factor not definitively explored is genetic variation. Genetic variations such as variable number tandem repeats (VNTR) in the promotor region are normal in the population, and can lead to disparities in the amount of protein produced, which could be associated with neuronal recovery. Little research has been conducted to investigate promoter VNTRs within genes responsible for recovery following a concussion. The authors implemented a prospective cohort design using a standardized concussion protocol to diagnose and follow 93 athletes to full recovery at three different sites to determine the association between promotor GT(n) VNTR polymorphisms and recovery time within concussed athletes. The GT(n) VNTR within the promoter region of glutamate ionotropic receptor N-methyl-d-aspartate (NMDA) type subunit 2A (GRIN2A), potassium voltage-gated channel subfamily H member 2 (KCNH2), glutamate ionotropic receptor kainate type subunit 1 (GRIK1), and neurofilament light (NEFL) were genotyped using capillary electrophoresis. GT(n) VNTR promotor polymorphisms were dichotomized into long (L) and short (s) alleles. Using adjusted negative binomial regression models we found that athletes carrying the LL GRIN2A GT(n) VNTR within the promoter region were more likely to experience a prolonged concussion recovery, which resulted in their not being able to return to play for ∼60 days. Additionally, there was a trend toward significance, in which the ss NEFL GT(n) Caucasian athletes had prolonged concussion recovery. This could presumably be attributed to altered proteins or protein levels that disrupt neuronal recovery. This pilot study suggests that these VNTRs are associated with prolonged concussion recovery. In future studies, we plan to measure the extent to which the L or s alleles alter the level and the activity of the GluNR2a and NEFL proteins that GRIN2A and NEFL produce, respectively.

Concussion Recovery Phase Affects Vestibular and Oculomotor Symptom Provocation.

Vestibular and oculomotor testing is emerging as a valuable assessment in sport-related concussion (SRC). However, their usefulness for tracking recovery and guiding return-to-play decisions remains unclear. Therefore the purpose of this study was to evaluate their clinical usefulness for tracking SRC recovery. Vestibular and oculomotor assessments were used to measure symptom provocation in an acute group (n=21) concussed≤10 days, prolonged symptoms group (n=10) concussed ≥16 days (median=84 days), healthy group (n=58) no concussions in >6 months. Known-groups approach was used with three groups at three time points (initial, 2-week and 6-week follow-up). Provoked symptoms for Gaze-Stabilization (GST), Rapid Eye Horizontal (REH), Optokinetic Stimulation (OKS), Smooth-Pursuit Slow (SPS) and Fast (SPF) tests, total combined symptoms scores and near point convergence (NPC) distance were significantly greater at initial assessment in both injury groups compared to controls. Injury groups improved on the King-Devick test and combined symptom provocation scores across time. The acute group improved over time on REH and SPF tests, while the prolonged symptoms group improved on OKS. A regression model (REH, OKS, GST) was 90% accurate discriminating concussed from healthy. Vestibular and ocular motor tests give valuable insight during recovery. They can prove beneficial in concussion evaluation given the modest equipment, training and time requirements. The current study demonstrates that when combined, vestibular and oculomotor clinical tests aid in the detection of deficits following a SRC. Additionally, tests such as NPC, GST, REH, SPS, SPF OKS and KD provide valuable information to clinicians throughout the recovery process and may aid in return to play decisions.

Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes.

BACKGROUND: Soccer players head the ball repetitively throughout their careers; this is also a potential mechanism for a concussion. Although not all soccer headers result in a concussion, these subconcussive impacts may impart acceleration, deceleration, and rotational forces on the brain, leaving structural and functional deficits. Stronger neck musculature may reduce head-neck segment kinematics. HYPOTHESIS: The relationship between anthropometrics and soccer heading kinematics will not differ between sexes. The relationship between anthropometrics and soccer heading kinematics will not differ between ball speeds. STUDY DESIGN: Pilot, cross-sectional design. LEVEL OF EVIDENCE: Level 3. METHODS: Division I soccer athletes (5 male, 8 female) were assessed for head-neck anthropometric and neck strength measurements in 6 directions (ie, flexion, extension, right and left lateral flexions and rotations). Participants headed the ball 10 times (25 or 40 mph) while wearing an accelerometer secured to their head. Kinematic measurements (ie, linear acceleration and rotational velocity) were recorded at 2 ball speeds. RESULTS: Sex differences were observed in neck girth ( t = 5.09, P < 0.001), flexor and left lateral flexor strength ( t = 3.006, P = 0.012 and t = 4.182, P = 0.002, respectively), and rotational velocity at both speeds ( t = -2.628, P = 0.024 and t = -2.227, P = 0.048). Neck girth had negative correlations with both linear acceleration ( r = -0.599, P = 0.031) and rotational velocity at both speeds ( r = -0.551, P = 0.012 and r = -0.652, P = 0.016). Also, stronger muscle groups had lower linear accelerations at both speeds ( P < 0.05). CONCLUSION: There was a significant relationship between anthropometrics and soccer heading kinematics for sex and ball speeds. CLINICAL RELEVANCE: Neck girth and neck strength are factors that may limit head impact kinematics.

Genetic findings in sport-related concussions: potential for individualized medicine?

Concussion is a traumatic transient disturbance of the brain. In sport, the initial time and severity of concussion is known giving an opportunity for subsequent analysis. Variability in susceptibility and recovery between individual athletes depends, among other parameters, on genetic factors. The genes-encoding polypeptides that determine incidence, severity and prognosis for concussion are the primary candidates for genetic analysis. Genetic polymorphisms in the genes contributing to plasticity and repair (APOE), synaptic connectivity (GRIN2A), calcium influx (CACNA1E), uptake and deposit of glutamate (SLC17A7) are potential biomarkers of concussion incidence and recovery rate. With catalogued genetic variants, prospective genotyping of athletes at the beginning of their career will allow medical professionals to improve concussion management and return-to-play decisions.

Assessing subacute mild traumatic brain injury with a portable virtual reality balance device.

PURPOSE: Balance impairment is a common sensorimotor symptom in mild traumatic brain injury (mTBI). We designed an affordable, portable virtual reality (VR)-based balance screening device (Virtual Environment TBI Screen [VETS]), which will be validated relative to the Neurocom Sensory Organization Test (SOT) to determine if it can replace commonly used postural assessments. METHODS: This preliminary study examines healthy adults (n = 56) and adults with mTBI (n = 11). Participants performed six upright postural tasks on the VETS and the SOT. Analysis of variance was used to determine between-group differences. Pearson's correlations were used to establish construct validity. Known-groups approach was used to establish classification accuracy. RESULTS: The mTBI cohort performed significantly worse than the healthy cohort on the new device (p = 0.001). The new device has 91.0% accuracy and an ROC curve with a significant area-under-the-curve (AUC = 0.865, p < 0.001). Conditions with dynamic visual stimulation were the most sensitive to health status. The SOT had an 84.8% accuracy and AUC =0.703 (p = 0.034). CONCLUSIONS: The new VR-based device is a valid measure for detecting balance impairment following mTBI and can potentially replace more expensive and cumbersome equipment. Assessments that test visual-vestibular processing, such as VETS, increase sensitivity to mTBI-related balance deficits, which can be used to guide rehabilitation. Implications for rehabilitation Emerging technology using virtual reality can be economically integrated into the clinical setting for easy testing of postural control in neurologically impaired populations. Tailoring postural assessments to include tasks that rely on visual and vestibular integration will increase the accuracy of detecting balance impairment following mild traumatic brain injury.

Genetic variation in SLC17A7 promoter associated with response to sport-related concussions.

OBJECTIVE: To determine the association of the single nucleotide polymorphism (SNP) rs74174284 within SLC17A7 promoter with concussion severity or duration. DESIGN: A between-subjects design was utilized. METHODS: Saliva samples and concussion severity and duration data were collected from 40 athletes diagnosed with a sport-related concussion by a physician, utilizing a standardized concussion assessment protocol. DNA was extracted, estimated and genotyped. RESULTS: An association was found between the dominant genetic model (CC vs GG + GC; p = 0.0179) and recovery, where those carrying the minor allele were 6.33-times more likely to experience prolonged recovery rates. Within the ImPACT assessment, those carrying the CC genotype (33.38 ± 10.15, p = 0.01) had worse motor speed scores upon initial assessment compared to both heterozygous (CG) and homozygous (GG) genotypes (41.59 ± 7.39). CONCLUSIONS: This study was the first to demonstrate an association between genetic polymorphism at rs7417284 SNP in the promoter region of the SLC17A7 gene and concussion severity and duration. Based upon these findings, rs74174284 is a potential predictive genetic marker for identifying athletes who are more susceptible for altered recovery times and worse motor speed ImPACT scores after sport-related concussion.

Association between GRIN2A promoter polymorphism and recovery from concussion.

OBJECTIVE: To determine genetic variability within the N-methyl-D-aspartate receptor 2A sub-unit (GRIN2A) gene promoter and its association with concussion recovery time. The hypothesis tested was that there would be a difference in allele and/or genotype distribution between two groups of athletes with normal and prolonged recovery. METHODS: DNA was extracted from saliva collected from a total of 87 athletes with a physician-diagnosed concussion. The (GT) variable number tandem repeats (VNTR) within the promoter region of GRIN2A was genotyped. The long (L) allele was an allele with ≥25 repeats and the short (S) allele was an allele with <25 repeats in the GT tract. Participants' recovery time was followed prospectively and was categorized as normal (≤60 days) or prolonged (>60 days). RESULTS: LL carriers were 6-times more likely to recover longer than 60 days following the concussive event (p = 0.0433) when compared to SS carriers. Additionally, L allele carriers were found more frequently in the prolonged recovery group (p = 0.048). CONCLUSION: Determining genetic influence on concussion recovery will aid in future development of genetic counselling. The clinical relevance of genotyping athletes could improve management of athletes who experience concussion injuries.

Effect of soccer heading ball speed on S100B, sideline concussion assessments and head impact kinematics.

OBJECTIVE: To examine the effect of soccer heading ball speed on S-100B serum concentration, concussion sideline assessments and linear head impact acceleration. METHODS: Sixteen division I soccer players participated in this pre-test post-test design study. Athletes performed five standing headers over a 10 minute period at 30 (n = 5), 40 (n = 5) or 50 (n = 6) miles per hour (mph) (randomized). S-100B serum concentration (ng mL-1) and sideline concussion assessments were measured prior to and post-heading. Peak resultant linear head acceleration (gravitational units; g) was measured during soccer heading. RESULTS: No statistically significant interaction effects were identified between ball velocity groups over time on S100B (effect sizes ranged from 0.03-0.23) or concussion assessments tests. There was a non-significant increase (p = 0.06) in head impact acceleration from the 30 (30.6; SD = 6.2 g) to 50 mph (50.7; SD = 7.7 g) ball speed. CONCLUSIONS: In this controlled setting, an acute bout of soccer heading across various ball velocities did not affect S100B or concussion assessment test scores. These findings are preliminary, as the small sample size in each group may have played a role in the lack of significant findings.

Neuronal structural protein polymorphism and concussion in college athletes.

OBJECTIVE: To examine the association between a neuronal structural protein polymorphism and the frequency and severity of concussions in college athletes. METHODS: Forty-eight athletes with previous self-reported history of a concussion were matched with 48 controls that did not report a history of concussion. Each group was genotyped for neurofilament heavy (NEFH) polymorphism rs#165602 in this retrospective case-control study. RESULTS: There was no significant association (χ(2 )= 0.487, p = 0.485) between carrying the NEFH rare allele and a history of one or more concussions due to small effect sizes. A Fisher's exact test revealed no significant association (p = 1.00, ϕ = -0.03) between the presence of NEFH rare allele and a history of multiple concussions. The independent t-tests revealed no significant differences in duration of signs and symptoms (t = 1.41, p = 0.17, d = 0.48) or return to play (t = 0.23, p = 0.82, d = 0.08) between NEFH rare allele carrier and non-carriers. CONCLUSIONS: Among college athletes, carrying the rare allele assessed may not influence an athlete's susceptibility to sustaining a concussion or return to play duration following a concussion.