The Natural History of Sport-Related Concussion in Collegiate Athletes: Findings from the NCAA-DoD CARE Consortium

Influence of Preexisting Conditions and Concussion History on Postconcussion Symptom Severity and Recovery Time in Collegiate Athletes

Mental health conditions and concussion history reported by a collegiate athlete may contribute to prolonged recovery and symptom severity after concussion. This work examined the potential associations among concussion history, preexisting conditions, and sex relative to initial symptom severity and recovery duration following sport-related concussion (SRC) in a cohort of Division 1 National Collegiate Athletic Association athletes. This prospective cohort study analyzed symptom severity, recovery, and return-to-play (RTP) times reported post-SRC using data collected as part of the Pac-12 Concussion Assessment, Research and Education Affiliated Program and Health Analytics Program. Health history questionnaires that included self-reported history of preexisting conditions were completed at baseline. When consented athletes were diagnosed with a concussion, daily postconcussion symptom scores were evaluated until an athlete was clinically determined to be asymptomatic. Generalized linear and Cox proportional hazards models were used to determine associations between preexisting conditions and recovery and RTP times. Ninety-two concussions met inclusion criteria. Notable differences in initial symptom severity existed between females and males who had mood disorders (effect size [d] = 0.51) and attention-deficit hyperactivity disorder (ADHD; d = 0.93). The number of previous concussions was a strong predictor of athletes reporting preexisting mood disorders, depression, anxiety, and ADHD (p = 0.008-0.04). Females with ≥2 previous concussions required more days to RTP than males (d = 0.31-0.72). Weekly recovery and RTP probabilities substantially differed between athletes who did or did not have learning disorders (LDs; hazard ratio [HR]Recovery = 0.32, HRRTP = 0.22, d = 1.96-2.30) and ADHD (HRRecovery = 3.38, HRRTP = 2.74, d = 1.71-4.14). Although no association existed between concussion history and acute symptom severity, collegiate athletes with a history of concussion had higher probabilities of reporting depression, mood disorders, anxiety, and ADHD. Having ADHD or LDs likely strongly affects time to recovery and RTP for collegiate athletes.

Bridging big data in the ENIGMA consortium to combine non-equivalent cognitive measures

Investigators in neuroscience have turned to Big Data to address replication and reliability issues by increasing sample size. These efforts unveil new questions about how to integrate data across distinct sources and instruments. The goal of this study was to link scores across common auditory verbal learning tasks (AVLTs). This international secondary analysis aggregated multisite raw data for AVLTs across 53 studies totaling 10,505 individuals. Using the ComBat-GAM algorithm, we isolated and removed the component of memory scores associated with site effects while preserving instrumental effects. After adjustment, a continuous item response theory model used multiple memory items of varying difficulty to estimate each individual's latent verbal learning ability on a single scale. Equivalent raw scores across AVLTs were then found by linking individuals through the ability scale. Harmonization reduced total cross-site score variance by 37% while preserving meaningful memory effects. Age had the largest impact on scores overall (- 11.4%), while race/ethnicity variable was not significant (p > 0.05). The resulting tools were validated on dually administered tests. The conversion tool is available online so researchers and clinicians can convert memory scores across instruments. This work demonstrates that global harmonization initiatives can address reproducibility challenges across the behavioral sciences.

Association of Sport Helmet Status on Concussion Presentation and Recovery in Male Collegiate Student-Athletes

Sporting helmets contain force attenuating materials which reduce traumatic head injury risk and may influence sport-related concussion (SRC) sequelae. The purpose of this study was to examine the association of sport helmet status with SRC-clinical presentation and recovery trajectories in men's collegiate athletes. Sport helmet status was based on the nature of sports being either helmeted/non-helmeted. 1070 SRCs in helmeted (HELM) sports (Men's-Football, Ice Hockey, and Lacrosse), and 399 SRCs in non-helmeted (NOHELM) sports (Men's-Basketball, Cheerleading, Cross Country/Track & Field, Diving, Gymnastics, Soccer, Swimming, Tennis, and Volleyball) were analyzed. Multivariable negative binomial regression models analyzed associations between sport helmet status and post-injury cognition, balance, and symptom severity, adjusting for covariate effects (SRC history, loss of consciousness, anterograde/retrograde amnesia, event type). Kaplan-Meier curves evaluated median days to: initiation of return to play (iRTP) protocol, and unrestricted RTP (URTP) by sport helmet status. Log-rank tests were used to evaluate differential iRTP/URTP between groups. Two independent multivariable Weibull accelerated failure time models were used to examine differential iRTP and URTP between groups, after adjusting for aforementioned covariates and symptom severity score. Overall, the median days to iRTP and URTP was 6.3 and 12.0, respectively, and was comparable across NOHELM- and HELM-SRCs. Post-injury symptom severity was lower (Score Ratio 0.90, 95%CI 0.82, 0.98), and cognitive test performance was higher (Score Ratio 1.03, 95%CI 1.02, 1.05) in NOHELM-compared to HELM-SRCs. Estimated time spent recovering to iRTP/URTP was comparable between sport helmet status groups. Findings suggest that the grouping of sports into helmeted and non-helmeted show slight differences in clinical presentation but not recovery.

Profile of brief symptom inventory-18 (BSI-18) scores in collegiate athletes: A CARE Consortium study

Objective: The goal of this study was to characterize normative scores for the Brief Symptom Inventory (BSI-18) in collegiate athletes to inform decision making about the need for psychological health services in this group. Methods: Collegiate student-athletes (N = 20,034) from 25 universities completed the BSI-18 at their preseason baseline assessment. A subgroup (n = 5,387) underwent multiple baseline assessments. Global Severity Index (GSI) scores were compared to community norms and across multiple timepoints. Results: Collegiate athletes reported significantly lower GSI scores than published community norms (p<.001). Published GSI threshold scores for "caseness", identified only 2 per 100 athletes (≥ the 98th percentile) as needing further evaluation. Using a GSI score ≥ than the cohort's 90th percentile, 11.4 per 100 athletes would merit additional evaluation. These individuals were more likely to report a history of psychiatric diagnosis (Odds ratio [95% CI] 2.745 [2.480, 3.039]), as well as ≥ 2 prior concussions (p<.001). GSI scores were not highly correlated across timepoints. Suicidal ideation was rare (n = 230; 1.15%). Conclusions: For collegiate student-athletes, published BSI-18 threshold scores identify only extreme outliers who might benefit from additional behavioral health evaluation. Alternatively, use of threshold scores ≥ the 90th percentile identifies a more realistic 11.4% of the population, with higher likelihood of prior concussion and/or psychiatric disorders.

Sport-Specific Recovery Trajectories for NCAA Collegiate Athletes Following Concussion

The recovery trajectories of collegiate athletes with sport-related concussion (SRC) are well characterized in contact/collision sports but are less well understood in limited contact sports with lower risk, reducing the ability of clinicians to effectively manage the return-to-play (RTP) process. The current study investigated the time to asymptomatic and RTP across a broad range of male and female collegiate sports and sought to group sports by recovery intervals. Data from the Concussion Assessment, Research and Education (CARE) Consortium included 1049 collegiate athletes who sustained a SRC while participating in game or practice/training of their primary sport. Injury setting and subsequent clinical presentation data were obtained. Survival analysis using the Cox Proportional Hazard model estimated the median recovery times for each sport. Optimal univariate K-means clustering grouped sports into recovery categories. Across all sports, median time to asymptomatic following SRC ranged from 5.9 (female basketball) to 8.6 days (male wrestling). Median RTP protocol duration ranged from 4.9 days (female volleyball) to 6.3 days (male wrestling). Median total RTP days ranged from 11.2 days (female lacrosse) to 16.9 days (male wrestling). Sport clusters based on recovery differences in time to asymptomatic (3) and RTP protocol duration (2) were identified. The findings from this study of a large sample of more than 1000 NCAA collegiate athletes with SRC show there exists ranges in recovery trajectories. Clinicians can thus manage athletes with similar guidelines, with individualized treatment and recovery plans.

Confidence to Return to Play After Concussion

CONTEXT

The sequelae of concussion may have psychological consequences that affect an athlete's ability to return to play (RTP). However, confidence of RTP readiness is rarely monitored after a concussion.

DESIGN

This study examined the acute and longitudinal implications of concussion on an athlete's confidence to RTP, the relationship between self-reported symptoms and athlete confidence to RTP, and interactions between concussion symptoms, sex, sport type (contact vs noncontact), and confidence to RTP.

METHODS

Forty-six college athletes (65% female) sustained a concussion and completed the Injury Psychological Readiness to Return to Sport (I-PRRS) scale at 3 timepoints: within 72 hours of injury (acute), within 72 hours of beginning the RTP protocol (pre-RTP), and within 72 hours of being fully cleared to RTP (post-RTP).

RESULTS

Athletes reported acute low confidence after concussion (I-PRRS mean [SD] = 32.59 [18.45]), which improved over time (pre-RTP mean [SD] = 52.11 [9.60]; post-RTP mean [SD] = 57.45 [5.96]). Some athletes returned to competition (post-RTP) with lingering confidence concerns (ie, I-PRRS < 50; 95% CI = 0.03-0.26). Acute symptom severity was associated with worse confidence (P < .001). Sex and sport type (contact vs noncontact) had no relationship with confidence (P = .406, P = .3314, respectively). These results indicate that athletes lack confidence acutely (within 72 h) following concussion.

CONCLUSIONS

Although confidence improves over time, those who report greater acute symptoms also exhibit decreased confidence, and some athletes are returning to play with lingering concerns about their confidence (I-PRRS < 50). This preliminary evidence of heterogeneous confidence following concussion encourages the assessment and monitoring of confidence throughout concussion rehabilitation.

Mental health symptom burden in elite ice hockey players and its association with self-reported concussive events

BACKGROUND

Some studies suggest that elite athletes experience adverse mental health symptoms at rates commensurate with the general population, despite the well-established buffering effects of exercise. Within contact sports, such as ice-hockey, recurrent concussions may be a source of this discrepancy. We compared the point prevalence of various mental health outcomes with other athlete and general population samples, as well as investigated their relationship with concussive events.

METHODS

We surveyed 648 active ice hockey players from the top two men's tiers and the top women's tier in Swedish elite ice hockey on lifetime concussive events, hazardous alcohol use, problematic social media use, depression, anxiety, and burnout.

RESULTS

Hazardous alcohol use was more prevalent among male ice hockey players (29.5% AUDIT-C ≥ 6) compared to other athlete and general population samples, while other mental health symptoms were less common. Female ice hockey players reported higher hazardous alcohol consumption (36.4% AUDIT-C ≥ 4) than another athlete sample and more burnout (19.1%) than the general population. After adjusting for covariates, athletes with 3+ concussive events had 2.1 times the odds of elevated depressive symptoms and 3.5 times the odds of elevated burnout symptoms compared to those with no concussion history. Treating lifetime concussive events as a continuous predictor revealed positive correlations with all outcomes except for hazardous alcohol use.

CONCLUSIONS

Mental health outcome rates among active elite ice hockey athletes differ from those of other athlete and general population samples, whilst concussive events may be particularly linked to elevated symptoms of depression and burnout.

SCAT Symptom Evolution in the Acute Concussion Phase: Findings from the NCAA-DoD CARE Consortium

The Sport Concussion Assessment Tool (SCAT) is the most widely used tool following sport-related concussion (SRC). Initial SCAT symptom burden is a strong predictor of recovery in collegiate athletes; however, it is unknown if symptom presentation varies within the acute (<48 h) post-SRC phase. The purpose of this cohort study was to examine acute SRC symptom presentation among the National Collegiate Athletic Association (NCAA) athletes. Concussed NCAA varsity athletes (n = 1,780) from 30 universities across the United States, which participated in the Concussion Assessment, Research, and Education (CARE) Consortium, were included. Time of injury occurrence and SCAT administration data were recorded, from which time-to-SCAT (hours, continuous) was calculated. The main outcome was SCAT total symptom severity [(TSS), 0-126]. Multivariable negative binomial regression was used to examine the association between time (hours) since injury and TSS. Covariates included sex, previous concussion, sport contact level, amnesia/loss of consciousness, immediate reporting of injury, and injury situation. A random effect (person level) accounted for multiple assessments. TSS score ratios (SR) with associated 95% confidence intervals (CI) were provided. The SCAT was administered an average of 14 (25th-75th percentile: 1.2-24) hours post-SRC, and average TSS was 27.35 ± 21.28 across all participants. Time-to-SCAT was associated with a 1% decrease in TSS after adjusting for covariate effects (SR: 0.99, 95% CI: 0.99-0.99, p < 0.001). Overall, we observed a small, but significant decrease in TSS with each hour post-SRC. Assessing a concussed athlete once in the acute phase will likely provide a sufficient sense of their symptomatic well-being, as measures did not fluctuate dramatically. Future research should aim to examine how acute symptom evolution influences recovery metrics.

Increased Auditory Dual Task Cost During Gait Initiation in Adult Patients With Persistent Concussion Symptoms

OBJECTIVE

To compare dual task cost (DTC) during gait initiation (GI) between a population of patients with persistent concussion symptoms (PCS) and age-matched healthy participants.

DESIGN

Cohort study.

SETTING

University research center.

PARTICIPANTS

A cohort sample including 15 participants with PCS (43.9±11.7y, 73.3% female) and 23 age-matched healthy participants (42.1±10.3y, 65.2% female) as controls.

INTERVENTIONS

Participants were tested on a single occasion where they performed 5 trials of single task and 5 trials of dual task GI with 12-camera motion capture and 3 force plates.

MAIN OUTCOME MEASURES

The dependent variables of interest were the DTC for the center of pressure (COP) displacement and velocity during the anticipatory postural adjustment (APA) phase, the COP-center of mass (COP-COM) separation, and the response accuracy during the auditory cognitive tasks.

RESULTS

There were significant group differences with worse DTC for the PCS participants in anterior (A)/posterior (P) displacement (PCS, -37.5±22.1%; Control, -9.7±39.2%; P=.016, d=0.874), APA medial (M)/lateral (L) velocity (PCS, -34.8±28.8%; Control, -17.0±40.21%; P=.041, d=0.866), and the peak COP-COM separation (PCS, -7.3±6.7%; Control, 0.6±6.5%; P=.023, d=1.200). There were no significant group differences in the APA A/P velocity (PCS, -38.8±33.1%; Control, -19.8±43.9%; P=.094), APA M/L displacement (PCS, -34.8±21.8%; Control, -10.6±25.3%; P=.313), or cognitive task performance (PCS, -2.7±10.8%; Control, -0.2±4.3%; P=.321).

CONCLUSIONS

PCS participants had greater (worse) DTC during both the planning and execution of the task, with large effect sizes (d>0.80). PCS participants also used a posture-second strategy whereby attentional resources were inappropriately allocated to the cognitive task. These deficits may challenge a patient's ability to complete activities of daily living and limit their functional independence.

Recovery Is Similar Between Black and White College Athletes Following Sport-Related Concussion

CONTEXT

Racial identity may associate with clinical outcomes following sport-related concussion (SRC). This study compared clinical outcome scores before and after recovery from a SRC between Black or White college athletes.

DESIGN

Prospective cohort.

METHODS

Participants were self-reported White (n = 61, 18.5 [1.1] y of age) and Black (n = 24, 18.3 [1.1] y of age) NCAA Division 1 college athletes. The revised Head Injury Scale (HIS-r), the Immediate Postconcussion and Cognitive Test (ImPACT) battery, and the Sensory Organization Test (SOT) at baseline (T1), upon symptom resolution (T2) following a diagnosed SRC, and upon establishing a new baseline assessment (T3). Race was collected from paper and electronic medical records. The revised Head Injury Scale total symptom severity, ImPACT's Verbal Memory, Visual Memory, Visual Motor Speed (VMS), and Reaction Time, and the SOT Equilibrium Score, were compared between groups at each time point. Multivariate analyses of variance (2 [group] × 3 [time]) were used to compare revised Head Injury Scale, ImPACT, and SOT outcome scores. Post hoc analyses consisted of independent and paired sample t tests.

RESULTS

A significant main effect for time (λ = 0.66, F2,82 = 21.55, P < .001, ηp2=.34) was observed for the SOT. White athletes significantly improved on the Equilibrium Score between all time points (all P < .006). Similarly, Black athletes significantly improved on the Equilibrium Score between T1-T2 and T1-T3 (all P < .001). A significant main effect of time was observed for ImPACT's Verbal Memory, Visual Memory, and VMS outcome scores (all P < .001). VMS improved for White athletes between T1-T2 (P = .02) and T3 (P = .006). Black athletes had improved VMS scores between T1-T3 (P = .015) and T2-T3 (P = .005). A between-group difference was observed for VMS at T2 (P = .004).

CONCLUSIONS

There was 1 small and not clinically significant difference between groups for the VMS score at T2. Overall, groups performed consistently or improved upon their baseline balance, cognition, and symptom outcome scores at clinically relevant time points following a SRC.

Silent Struggles: Traumatic Brain Injuries and Mental Health in Law Enforcement

OBJECTIVE

To determine the prevalence of head injuries (HIs), posttraumatic stress disorder (PTSD), and depressive symptoms in law enforcement officers (LEOs) and (2) the association between HIs and psychological health conditions.

SETTING

County-level survey administered via Research Electronic Data Capture.

PARTICIPANTS

A total of 381 LEOs completed the survey (age = 43 ± 11 years; 40 [11%] females; time as LEO = 1-50 years, median = 15 years).

DESIGN

Cross-sectional study.

MAIN MEASURES

We examined the prevalence of HIs (the Ohio State University Traumatic Brain Injury Identification Method), PTSD (PTSD Checklist-Civilian [PCL-C]), and depressive symptoms (Patient Health Questionnaire-9 [PHQ-9]). We used Mann-Whitney U and chi-square analyses to compare PTSD and depressive symptoms between those with and without a HI history.

RESULTS

There were 282 (74%) participants who reported a lifetime history of 1 or more HIs; 116 (30%) sustained 1 or more HIs on the job. PCL-C scores ranged 17 to 85 (median = 27); 33 (10%) participants met or exceeded the clinical cutoff score of 50 to indicate a positive PTSD screening. Participants with a HI history (median = 29) had higher PCL-C scores than those with no HI history (median = 24; P < .001), but the proportion of participants who met the clinical cutoff for PTSD was not different between those with (n = 28, 11%) and without (n = 5, 5%) a HI history (X2 = 2.52, P = .112, odds ratio = 2.18; 95% confidence interval, 0.82-5.83). PHQ-9 scores ranged 0 to 20 (median = 3); 124 (36%) participants reported mild or greater depressive symptoms. Participants with a HI history (median = 3) had higher depressive symptoms than those with no HI history (median = 2; P = .012). The proportion of participants with mild or greater depressive symptoms was higher among those with a HI history (n = 99, 39%) than without (n = 25, 27%; X2 = 4.34, odds ratio = 1.74; 95% confidence interval, 1.03-2.93).

CONCLUSION

HIs are prevalent in LEOs, which may have consequences for their performance, well-being, and career longevity. PTSD and depressive symptoms are higher in those with a HI history, suggesting LEOs need better traumatic brain injuries and mental health resources.

The Interval Between Concussions Does Not Influence Time to Asymptomatic or Return to Play: A CARE Consortium Study

INTRODUCTION

The purpose of this study was to determine if the time interval between two concussive events influences the number of days to asymptomatic status, days to return to play, or performance on common post-concussion assessments following the second concussion.

METHODS

Data from 448 collegiate athletes and service academy cadets with two concussions (time between concussions: median 295.0 days [interquartile range: 125.0-438.2]), 40.0% female) were analyzed from Concussion Assessment Research and Education (CARE) Consortium institutions between 2014 and 2020. Days between concussions was the primary predictor variable. Primary outcome measures included time to asymptomatic and time to return to play following the second concussion. Secondary outcome measures included total number of symptoms, total symptom severity, Balance Error Scoring System total score, and Standardized Assessment of Concussion total score within 48 h of their second concussion.

RESULTS

Time between concussions did not significantly contribute to the multivariate time to asymptomatic (p = 0.390), time to return to play (p = 0.859), or the secondary outcomes (p-range = 0.165-0.477) models. Time to asymptomatic (p = 0.619) or return to play (p = 0.524) did not differ between same-season and different-season concussions. Sex significantly contributed to the return to play (p = 0.005) multivariate model. Delayed symptom onset and immediate removal from play/competition significantly contributed to the total number of symptoms (p = 0.001, p = 0.014) and symptom severity (p = 0.011, p = 0.022) multivariate models.

CONCLUSION

These results suggest that in a population with a large period between injuries, the time between concussions may not be relevant to clinical recovery.

Diffusion tensor analysis of white matter tracts is prognostic of persisting post-concussion symptoms in collegiate athletes

BACKGROUND AND OBJECTIVES

After a concussion diagnosis, the most important issue for patients and loved ones is how long it will take them to recover. The main objective of this study is to develop a prognostic model of concussion recovery. This model would benefit many patients worldwide, allowing for early treatment intervention.

METHODS

The Concussion Assessment, Research and Education (CARE) consortium study enrolled collegiate athletes from 30 sites (NCAA athletic departments and US Department of Defense service academies), 4 of which participated in the Advanced Research Core, which included diffusion-weighted MRI (dMRI) data collection. We analyzed the dMRI data of 51 injuries of concussed athletes scanned within 48 h of injury. All athletes were cleared to return-to-play by the local medical staff following a standardized, graduated protocol. The primary outcome measure is days to clearance of unrestricted return-to-play. Injuries were divided into early (return-to-play < 28 days) and late (return-to-play >= 28 days) recovery based on the return-to-play clinical records. The late recovery group meets the standard definition of Persisting Post-Concussion Symptoms (PPCS). Data were processed using automated, state-of-the-art, rigorous methods for reproducible data processing using brainlife.io. All processed data derivatives are made available at https://brainlife.io/project/63b2ecb0daffe2c2407ee3c5/dataset. The microstructural properties of 47 major white matter tracts, 5 callosal, 15 subcortical, and 148 cortical structures were mapped. Fractional Anisotropy (FA) and Mean Diffusivity (MD) were estimated for each tract and structure. Correlation analysis and Receiver Operator Characteristic (ROC) analysis were then performed to assess the association between the microstructural properties and return-to-play. Finally, a Logistic Regression binary classifier (LR-BC) was used to classify the injuries between the two recovery groups.

RESULTS

The mean FA across all white matter volume was negatively correlated with return-to-play (r = -0.38, p = 0.00001). No significant association between mean MD and return-to-play was found, neither for FA nor MD for any other structure. The mean FA of 47 white matter tracts was negatively correlated with return-to-play (rμ = -0.27; rσ = 0.08; rmin = -0.1; rmax = -0.43). Across all tracts, a large mean ROC Area Under the Curve (AUCFA) of 0.71 ± 0.09 SD was found. The top classification performance of the LR-BC was AUC = 0.90 obtained using the 16 statistically significant white matter tracts.

DISCUSSION

Utilizing a free, open-source, and automated cloud-based neuroimaging pipeline and app (https://brainlife.io/docs/tutorial/using-clairvoy/), a prognostic model has been developed, which predicts athletes at risk for slow recovery (PPCS) with an AUC=0.90, balanced accuracy = 0.89, sensitivity = 1.0, and specificity = 0.79. The small number of participants in this study (51 injuries) is a significant limitation and supports the need for future large concussion dMRI studies and focused on recovery.

Association of Alzheimer's disease polygenic risk score with concussion severity and recovery metrics

Identification of genetic alleles associated with both Alzheimer's disease (AD) and concussion severity/recovery could help explain the association between concussion and elevated dementia risk. However, there has been little investigation into whether AD risk genes associate with concussion severity/recovery, and the limited findings are mixed. We used AD polygenic risk scores (PRS) and APOE genotypes to investigate any such associations in the NCAA-DoD Grand Alliance CARE Consortium (CARE) dataset. We assessed six outcomes in 931 total participants. The outcomes were two concussion recovery measures (number of days to asymptomatic status, number of days to return to play (RTP)) and four concussion severity measures (scores on SAC and BESS, SCAT symptom severity, and total number of symptoms). We calculated PRS using a published score [1] and performed multiple linear regression (MLR) to assess the relationship of PRS with the outcomes. We also used t-tests and chi-square tests to examine outcomes by APOE genotype, and MLR to analyze outcomes in European and African genetic ancestry subgroups. Higher PRS was associated with longer injury to RTP in the normal RTP (<24 days) subgroup ( p = 0.024), and one standard deviation increase in PRS resulted in a 9.89 hour increase to the RTP interval. There were no other consistently significant effects, suggesting that high AD genetic risk is not strongly associated with more severe concussions or poor recovery in young adults. Future studies should attempt to replicate these findings in larger samples with longer follow-up using PRS calculated from diverse populations.

Longitudinal changes in sodium concentration and in clinical outcome in mild traumatic brain injury

Ionic imbalances and sodium channel dysfunction, well-known sequelae of traumatic brain injury (TBI), promote functional impairment in affected subjects. Therefore, non-invasive measurement of sodium concentrations using 23Na MRI has the potential to detect clinically relevant injury and predict persistent symptoms. Recently, we reported diffusely lower apparent total sodium concentrations (aTSC) in mild TBI patients compared to controls, as well as correlations between lower aTSC and worse clinical outcomes. The main goal of this study was to determine whether these aTSC findings, and their changes over time, predict outcomes at 3- and 12-month from injury. Twenty-seven patients previously studied with 23Na MRI and outcome measures at 22 ± 10 days (average ± standard deviation) after injury (visit-1, v1) were contacted at 3- (visit-2, v2) and 12-month after injury (visit-3, v3) to complete the Rivermead post-concussion symptoms questionnaire (RPQ), the extended Glasgow outcome scale (GOSE), and the brief test of adult cognition by telephone (BTACT). Follow-up 1H and 23Na MRI were additionally scheduled at v2. Linear regression was used to calculate aTSC in global grey and white matters. Six hypotheses were tested in relation to the serial changes in outcome measures and in aTSC, and in relation to the cross-sectional and serial relationships between aTSC and outcome. Twenty patients contributed data at v2 and fifteen at v3. Total RPQ and composite BTACT z-scores differed significantly for v2 and v3 in comparison to v1 (each P < 0.01), reflecting longitudinally reduced symptomatology and improved performance on cognitive testing. No associations between aTSC and outcome were observed at v2. Previously lower grey and white matter aTSC normalized at v2 in comparison to controls, in line with a statistically detectable longitudinal increase in grey matter aTSC between v1 and v2 (P = 0.0004). aTSC values at v1 predicted a subset of future BTACT subtest scores, but not future RPQ scores nor GOSE-defined recovery status. Similarly, aTSC rates of change correlated with BTACT rates of change, but not with those of RPQ. Tissue aTSC, previously shown to be diffusely decreased compared to controls at v1, was no longer reduced by v2, suggesting normalization of the sodium ionic equilibrium. These changes were accompanied by marked improvement in outcome. The results support the notion that early aTSC from 23Na MRI predicts future BTACT, but not RPQ scores, nor future GOSE status.

What are the Protocols and Resources for Sport-Related Concussion Among Top National Collegiate Athletic Association Football Programs? A Cross-Sectional Survey of A5 Schools

OBJECTIVE

This study summarizes findings from a cross-sectional survey conducted among National Collegiate Athletic Association (NCAA) Division 1 football programs, focusing on sport-related concussion (SRC) protocols for the 2018 season.

DESIGN

Cross-sectional survey study.

SETTING

65 football programs within the Autonomy Five (A5) NCAA conferences.

PARTICIPANTS

Athletic trainers and team physicians who attended a football safety meeting at the NCAA offices June 17 to 18, 2019, representing their respective institutions.

INTERVENTION

Electronic surveys were distributed on June 14, 2019, before the football safety meeting.

MAIN OUTCOME MEASURES

Results for 16 unique questions involving SRC protocols and resources were summarized and evaluated.

RESULTS

The survey garnered responses from 46 of 65 programs (response rate = 71%). For baseline testing, 98% measured baseline postural stability and balance, 87% used baseline neurocognitive testing, while only 61% assessed baseline vestibular and/or ocular function. Regarding concussion prevention, 51% did not recommend additional measures, while 4% and 24% recommended cervical compression collars and omega-3 supplementation, respectively. In postconcussion treatment, 26% initiated aerobic exercise 1 day postconcussion if symptoms were stable, 24% waited at least 48 hours, 4% waited for the athlete to return to baseline, 11% waited until the athlete became asymptomatic, and 35% determined procedures on a case-by-case basis.

CONCLUSIONS

Most institutions assessed postural stability/balance and neurocognitive functioning at baseline and introduced light aerobic exercise within 48 h postconcussion. There was variation in baseline assessment methods and concussion prevention recommendations. These survey findings deepen our understanding of diverse SRC protocols in NCAA football programs.

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.

Optimizing baseline and post-concussion assessments through identification, confirmation, and equivalence of latent factor structures: Findings from the NCAA-DoD CARE Consortium

Objective: Concussion evaluations use a multidimensional assessment to evaluate unique patient function dimensions (e.g., subjective symptoms differ from balance assessments), but the overarching latent factor structure has not been empirically substantiated. Our objective was to determine the cumulative latent factor structure of pre-injury baseline and acute (<48-h) post-concussion assessment battery outcomes, and determine measurement equivalence among common factors in collegiate student-athletes. Methods: Collegiate student-athletes at baseline (n = 21,865) and post-concussion (n = 1,537) across 25-institutions completed standardized assessments. Individual items were used from the baseline and post-concussion assessments and consisted of: Sport Concussion Assessment Tool, Brief Symptom Inventory-18, Standardized Assessment of Concussion, Balance Error Scoring System, Immediate Post-Concussion Assessment and Cognitive Test, and vestibular-ocular motor screening. Exploratory factor analysis was used on half the baseline data, and confirmatory factor analysis on the remaining baseline data and post-concussion data separately. Measurement equivalence was assessed between sex, sport contact classification, concussion history, and time. Results: A 10-factor exploratory model was established and comprised of: depression, somatic, vestibulo-ocular, headache, postural stability, neurocognition, emotional, fatigue, cognitive, consciousness clouding. The 10-factor model was confirmed at baseline and post-concussion with strong measurement equivalence between timepoints. Strong to strict measurement equivalence was observed for sex, sport contact classification, and concussion history at both timepoints separately. Conclusion: Our findings established a robust 10-factor latent factor model equivalent across timepoints and common factors among healthy and concussed collegiate athletes. Clinicians can use these findings to target specific factors while reducing redundant elements to provide efficient, comprehensive post-concussion assessments.

Optimizing Concussion Care Seeking: Using Machine Learning to Predict Delayed Concussion Reporting

BACKGROUND

Early medical attention after concussion may minimize symptom duration and burden; however, many concussions are undiagnosed or have a delay in diagnosis after injury. Many concussion symptoms (eg, headache, dizziness) are not visible, meaning that early identification is often contingent on individuals reporting their injury to medical staff. A fundamental understanding of the types and levels of factors that explain when concussions are reported can help identify promising directions for intervention.

PURPOSE

To identify individual and institutional factors that predict immediate (vs delayed) injury reporting.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This study was a secondary analysis of data from the Concussion Assessment, Research and Education (CARE) Consortium study. The sample included 3213 collegiate athletes and military service academy cadets who were diagnosed with a concussion during the study period. Participants were from 27 civilian institutions and 3 military institutions in the United States. Machine learning techniques were used to build models predicting who would report an injury immediately after a concussive event (measured by an athletic trainer denoting the injury as being reported "immediately" or "at a delay"), including both individual athlete/cadet and institutional characteristics.

RESULTS

In the sample as a whole, combining individual factors enabled prediction of reporting immediacy, with mean accuracies between 55.8% and 62.6%, depending on classifier type and sample subset; adding institutional factors improved reporting prediction accuracies by 1 to 6 percentage points. At the individual level, injury-related altered mental status and loss of consciousness were most predictive of immediate reporting, which may be the result of observable signs leading to the injury report being externally mediated. At the institutional level, important attributes included athletic department annual revenue and ratio of athletes to athletic trainers.

CONCLUSION

Further study is needed on the pathways through which institutional decisions about resource allocation, including decisions about sports medicine staffing, may contribute to reporting immediacy. More broadly, the relatively low accuracy of the machine learning models tested suggests the importance of continued expansion in how reporting is understood and facilitated.

More Than Skin Deep: Patient-Provider Racial and Ethnic Concordance and Discordance in Collegiate Athletics and Concussion Management

CONTEXT

There is strong evidence that racial and ethnic disparities exist in multiple arenas of health and wellness. The causes of racial and ethnic differences in health care are multidimensional; one factor that may affect injury/illness communication, interactions, and outcomes is patient-provider racial and ethnic concordance. At present, it is unclear what role patient-provider racial and ethnic concordance and discordance plays in facilitating concussion care for collegiate athletes.

OBJECTIVE

To investigate the presence of athlete-athletic trainer (AT) racial and ethnic concordance and discordance among diagnosed concussion cases and examine if racial and ethnic concordance and discordance influences time (in days) until diagnosis, symptom resolution, or return-to-sport clinical milestones in collegiate athletes.

DESIGN

Retrospective cohort study.

SETTING

Collegiate athletics.

PATIENTS OR OTHER PARTICIPANTS

A total of 694 concussion cases (38.6% [n = 268] sustained by women, 61.4% [n = 426] sustained by men) that occurred within the 2015-2016 through 2019-2020 sport seasons at 9 institutions.

MAIN OUTCOME MEASURE(S)

The number of days from the date of injury to diagnosis, symptom resolution, and return to sport and from the date of diagnosis to symptom resolution and return to sport.

RESULTS

Overall, 68.4% (n = 475) of concussion cases had patient-provider racial and ethnic concordance, and 31.6% (n = 219) were discordant. All concordant pairs included a White athlete and White AT. Time to diagnosis differed between the concordant and discordant groups (median [interquartile range] = 1 [0-2] versus 0 [0-1], respectively) only in the model adjusted for sex, sport type, and availability of an AT (odds ratio [95% CI] = 1.46 [1.07-1.85]). There were no other group differences.

CONCLUSIONS

One-third of concussion cases had athlete-AT racial and ethnic discordance. Although this group was diagnosed with a concussion 1 day sooner than the concordant group, no differences were observed for any concussion recovery milestones. These findings suggest that patient-provider racial and ethnic concordance may play a minor role in concussion recognition or reporting but not necessarily in the management and recovery thereafter.

Verbal Learning and Memory Deficits across Neurological and Neuropsychiatric Disorders: Insights from an ENIGMA Mega Analysis

Deficits in memory performance have been linked to a wide range of neurological and neuropsychiatric conditions. While many studies have assessed the memory impacts of individual conditions, this study considers a broader perspective by evaluating how memory recall is differentially associated with nine common neuropsychiatric conditions using data drawn from 55 international studies, aggregating 15,883 unique participants aged 15-90. The effects of dementia, mild cognitive impairment, Parkinson's disease, traumatic brain injury, stroke, depression, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder on immediate, short-, and long-delay verbal learning and memory (VLM) scores were estimated relative to matched healthy individuals. Random forest models identified age, years of education, and site as important VLM covariates. A Bayesian harmonization approach was used to isolate and remove site effects. Regression estimated the adjusted association of each clinical group with VLM scores. Memory deficits were strongly associated with dementia and schizophrenia (p < 0.001), while neither depression nor ADHD showed consistent associations with VLM scores (p > 0.05). Differences associated with clinical conditions were larger for longer delayed recall duration items. By comparing VLM across clinical conditions, this study provides a foundation for enhanced diagnostic precision and offers new insights into disease management of comorbid disorders.

Association Between Co-occurring Anxiety and Depressive Symptoms at Baseline and Risk for Sports-Related Concussion in Collegiate Athletes

Background

There is limited research examining whether mental health problems increase the risk for future concussions, even though these problems are highly prevalent in college-aged populations-including student-athletes.

Purpose/Hypothesis

To examine whether affective disturbance (ie, depressive and anxiety symptoms) at baseline increases the risk for prospective concussion. It was hypothesized that athletes with co-occurring depressive/anxiety symptoms would incur the greatest risk for injury.

Methods

A total of 878 collegiate athletes completed baseline neuropsychological testing. Athletes were separated into the following 4 groups based on self-reported anxiety and depressive symptoms at baseline: healthy controls; depressive symptoms alone; anxiety symptoms alone; and co-occurring depressive and anxiety symptoms. Of the 878 athletes, 88 sustained future concussions. Logistic regression was conducted with prospective concussion (yes/no) as the outcome and the affective group as the predictor. Sport was included as a covariate.

Results

After controlling for sport, athletes in the co-occurring depressive/anxiety symptoms group were more than twice as likely to be diagnosed with a future concussion compared with healthy controls (odds ratio, 2.72 [95% CI, 1.33-5.57]; P = .01). The co-occurring depressive/anxiety symptoms group also showed an increased risk for prospective concussion compared with the depressive symptoms alone and anxiety symptoms alone groups, respectively. However, the results were not statistically significant. Athletes in the depressive symptoms alone and anxiety symptoms alone groups did not show a significantly increased risk for prospective concussion compared with healthy controls.

Conclusion

Athletes with co-occurring depressive/anxiety symptoms at baseline showed a notably increased risk of being diagnosed with a future concussion, even after controlling for sport. This suggests that co-occurring depressive/anxiety symptoms infer a unique risk that is associated with a greater susceptibility to concussion diagnosis.

Barriers to concussion reporting in collegiate athletes: an analysis of a peer-led worksheet activity

Objective: To determine if a peer-led concussion reporting worksheet activity could elucidate barriers to reporting in collegiate athletes. Participants: Five hundred and three athletes from 7 universities across all three NCAA divisions. Methods: A supplementary qualitative analysis of responses to a concussion reporting worksheet completed during an RCT of a novel peer concussion education program. The first column of the worksheet required participants to list thoughts that prevent reporting and the second column required replacement thoughts that facilitate reporting. Results: A qualitative phenomenological thematic analysis of responses to the first column of the worksheets identified themes that coalesced into three areas: 1) missing out on athletic and social events, 2) losing one's competitive edge, and 3) negative interpersonal interaction/self-perception. Conclusions: Barriers to concussion reporting from several areas central to the collegiate athlete experience were identified. These barriers should be considered during clinical assessment and when developing concussion education programs.

Recovery duration and concussion severity in sport- and non-sport-related concussion among Pac-12 collegiate athletes: a retrospective cohort study

OBJECTIVES

To examine non-sport- and sport-related concussion severity, clinical care frequency and delayed reporting in relation to recovery duration among collegiate athletes.

DESIGN

Retrospective cohort study.

SETTING

Pac-12 varsity collegiate athletes.

PARTICIPANTS

461 collegiate male and female athletes PRIMARY AND SECONDARY OUTCOME MEASURES: The incidence of sport-related concussion (SRC) and non-sport-related concussion (NRC) were collected as well as times to recovery and return-to-play (RTP), symptom score and symptom severity and reported a loss of consciousness (LOC), retrograde amnesia (RGA) and post-traumatic amnesia (PTA) following concussion incidence.

RESULTS

Among 461 concussions, 388 (84%) occurred within sport and 73 (16%) occurred outside of sport. NRC, on average, required 3.5 more days to become asymptomatic (HR: 0.73, 95%confidence interval: 0.56 to 0.96, p=0.02) and 7 more days to RTP (HR: 0.64, 95% confidence interval: 0.49 to 0.85, p<0.01) compared with SRC. NRC were associated with an increase of 1.83 (p=0.07) symptoms reported at the time of diagnosis, an increase of 6.95 (p=0.06) in symptom severity and a higher prevalence of reported LOC (22% NRC vs. 3% SRC, p<0.001), PTA (15% NRC vs. 5% SRC, p<0.01) and RGA (10% NRC vs. 4% SRC, p=0.06), compared with SRC. There was no significant difference in clinical care (p=0.28) or immediate reporting (p=0.35) between NRC and SRC.

CONCLUSION

NRC were associated with greater severity and longer recovery duration when compared with SRC in a cohort of collegiate athletes.

Nominal Differences in Acute Symptom Presentation and Recovery Duration of Sport-Related Concussion Between Male and Female Collegiate Athletes in the PAC-12

BACKGROUND

Sport-related concussion (SRC) is a heterogenous injury that often presents with varied symptoms and impairment. Recently, research has focused on identifying subtypes, or clinical profiles of concussion to be used in assessing and treating athletes with SRC. The purpose of this study was to investigate sex differences in clinical profiles, recovery duration, and initial symptom severity after SRC in a cohort of collegiate athletes in the Pacific-12 Conference (Pac-12).

METHODS

This prospective cohort study examined post-SRC symptoms, recovery, and return-to-play times using data from the Pac-12 CARE Affiliated Program and Pac-12 Health Analytics Program. Clinical profiles reported by student-athletes were defined by the number (> 50%) of specific symptoms frequently reported for each profile. Generalized linear mixed models were used to examine associations among sex, clinical profiles, time-to-recovery, and return-to-play times.

RESULTS

479 concussion incidents met inclusion criteria. The probabilities of initial presentation of each clinical profile, initial injury severity scores, and recovery times within a profile did not differ between sexes (p = 0.33-0.98). However, both males and females had > 0.75 probabilities of exhibiting cognitive and ocular profiles. Initial injury severity score was a strong nonlinear predictor of initial number of clinical profiles (p < 0.0001), which did not differ between sexes. The number of clinical profiles was also a nonlinear predictor of time-to-recovery (p = 0.03) and return-to-play times (p < 0.0001).

CONCLUSIONS

Initial symptom severity was strongly predictive of the number of acute clinical profiles experienced post-SRC. As the number of clinical profiles increased, time-to-recovery and time to return-to-play also increased. Factors other than sex may be better associated with acute symptom presentation post-concussion as no sex differences were found in reported clinical profiles or recovery. Understanding the number and type of clinical profiles experienced post-SRC may help inform concussion diagnostics and management.

Gene Expression Alterations in Peripheral Blood Following Sport-Related Concussion in a Prospective Cohort of Collegiate Athletes: A Concussion Assessment, Research and Education (CARE) Consortium Study

BACKGROUND

Molecular-based approaches to understanding concussion pathophysiology provide complex biological information that can advance concussion research and identify potential diagnostic and/or prognostic biomarkers of injury.

OBJECTIVE

The aim of this study was to identify gene expression changes in peripheral blood that are initiated following concussion and are relevant to concussion response and recovery.

METHODS

We analyzed whole blood transcriptomes in a large cohort of concussed and control collegiate athletes who were participating in the multicenter prospective cohort Concussion Assessment, Research, and Education (CARE) Consortium study. Blood samples were collected from collegiate athletes at preseason (baseline), within 6 h of concussion injury, and at four additional prescribed time points spanning 24 h to 6 months post-injury. RNA sequencing was performed on samples from 230 concussed, 130 contact control, and 102 non-contact control athletes. Differential gene expression and deconvolution analysis were performed at each time point relative to baseline.

RESULTS

Cytokine and immune response signaling pathways were activated immediately after concussion, but at later time points these pathways appeared to be suppressed relative to the contact control group. We also found that the proportion of neutrophils increased and natural killer cells decreased in the blood following concussion.

CONCLUSIONS

Transcriptome signatures in the blood reflect the known pathophysiology of concussion and may be useful for defining the immediate biological response and the time course for recovery. In addition, the identified immune response pathways and changes in immune cell type proportions following a concussion may inform future treatment strategies.

Academic adjustments and concussion recoveries in NCAA student-athletes: a LIMBIC MATARS investigation

OBJECTIVE

The aim of this study was to investigate the association between academic adjustments and recovery from sport-related concussions (SRCs) in collegiate athletes.

MATERIALS AND METHODS

A retrospective medical chart review was performed between the 2015-2016 and 2019-2020 sport seasons at 11 Long-term Impact of Military-relevant Brain Injury Consortium Military and Tactical Athlete Research Study (LIMBIC MATARS) sites. Days between injury and symptom resolution, and injury and return to sport (dependent variables) for collegiate athletes who did or did not receive academic adjustments (independent variable) were analyzed using Mann-Whitney U tests.

RESULTS

The number of days between date of injury and symptom-resolution between those who did (median = 9 [interquartile range = 5,16]) and did not have (7[3,12]) academic adjustments were statistically different (z=-2.76, p < 0.01, r=-0.17). However, no differences were observed between days to return to sport among those who did (14[10,22]) and did not (13[8,20]) receive assigned academic adjustments (z= -1.66, p = 0.10, r= -.10).

CONCLUSIONS

Recovery trajectories were similar between athletes diagnosed with a SRC who did or did not receive academic adjustments.. Our findings suggest academic adjustments supported recovery for those who needed academic adjustments. Clinicians and healthcare professionals should assist and support collegiate athletes after SRCs on an individual basis, including academic adjustments when appropriate based on patient presentation.

Collegiate student-athletes concussion knowledge and attitudes: what a difference a decade Makes

OBJECTIVE

The purpose of this study was to assess changes in concussion knowledge and attitudes amongst incoming intercollegiate student-athletes over the course of a decade (2010-2012 vs 2021-2023).

METHODS

There were 592 student-athletes from 2 cohorts (2010-2012, 2021-2023) who completed the Rosenbaum Concussion Knowledge and Attitudes Survey (ROCKaS) questionnaire which is comprised of a concussion knowledge index (CKI, 0-24) and attitude index (CAI, 15-75) with higher scores reflecting better performance. A three factor ANOVA (Group, Sex, Concussion History) compared performance on the CKI and CAI. Individual questions were compared between groups with a Chi-Square analysis.

RESULTS

For the CKI, there was a significant main effect for Group (2010-2012: 18.5 ± 2.6, 2021-2023: 19.4 ± 2.5, p < 0.001, η 2 = 0.032 ) . For the CAI, there was also a significant main effect for group (2010-2012: 52.9 ± 6.0, 2021-2023: 62.2 ± 6.5, p < 0.001, η 2 = 0.359 ) .

CONCLUSIONS

The results of this study show a modest increase in concussion knowledge; however, large improvements in concussion attitudes were observed between groups. These results suggest a continued improvement in student-athlete concussion awareness and provide specific areas to continue addressing persistent misconceptions.

Concussion-Related Disruptions to Hub Connectivity in the Default Mode Network Are Related to Symptoms and Cognition

Concussions present with a myriad of symptomatic and cognitive concerns; however, the relationship between these functional disruptions and the underlying changes in the brain are not yet well understood. Hubs, or brain regions that are connected to many different functional networks, may be specifically disrupted after concussion. Given the implications in concussion research, we quantified hub disruption within the default mode network (DMN) and between the DMN and other brain networks. We collected resting-state functional magnetic resonance imaging data from collegiate student-athletes (n = 44) at three time points: baseline (before beginning their athletic season), acute post-injury (approximately 48h after a diagnosed concussion), and recovery (after starting return-to-play progression, but before returning to contact). We used self-reported symptoms and computerized cognitive assessments collected across similar time points to link these functional connectivity changes to clinical outcomes. Concussion resulted in increased connectivity between regions within the DMN compared with baseline and recovery, and this post-injury connectivity was more positively related to symptoms and more negatively related to visual memory performance compared with baseline and recovery. Further, concussion led to decreased connectivity between DMN hubs and visual network non-hubs relative to baseline and recovery, and this post-injury connectivity was more negatively related to somatic symptoms and more positively related to visual memory performance compared with baseline and recovery. Relationships between functional connectivity, symptoms, and cognition were not significantly different at baseline versus recovery. These results highlight a unique relationship between self-reported symptoms, visual memory performance, and acute functional connectivity changes involving DMN hubs after concussion in athletes. This may provide evidence for a disrupted balance of within- and between-network communication highlighting possible network inefficiencies after concussion. These results aid in our understanding of the pathophysiological disruptions after concussion and inform our understanding of the associations between disruptions in brain connectivity and specific clinical presentations acutely post-injury.

An Urgent Call for Concussion Incidence Measures in Para Sport for Athletes with Vision Impairment: A Narrative Review

Concussion in para athletes with vision impairment (VI) is poorly understood. Recently published studies have suggested that athletes with VI may be more likely to sustain sport-related concussions compared to non-disabled athletes and athletes with other impairment types. There is a critical need for objective concussion incidence measures to determine concussion injury rates and risks more accurately. The aim of this review was to examine the limited available evidence of concussion incidence rates across six different para sports for athletes with VI and encourage the future collection of concussion incidence data and the adoption of injury prevention strategies in VI para sport. A literature search was conducted using four unique databases, which formed the basis of this narrative review. Injury prevention strategies such as modifying sport rules, introducing protective equipment, and incorporating additional safety measures into the field of play have been introduced sporadically, but the effectiveness of most strategies remains unknown. More prospective, sport-specific research examining mechanisms of injury and risk factors for concussion injuries in athletes with VI in both training and competition is needed. This research will help inform the development of targeted injury prevention strategies to reduce the likelihood of concussion for athletes with VI.

The Role of Concussion History and Biological Sex on Pupillary Light Reflex Metrics in Adolescent Rugby Players: A Cross-Sectional Study

Background: Concussion examination is based primarily on clinical evaluation and symptomatic reporting. Pupillary light reflex (PLR) metrics may provide an objective physiological marker to inform concussion diagnosis and recovery, but few studies have assessed PLR, and normative data are lacking, particularly for adolescents. Aim: To capture PLR data in adolescent rugby players and examine the effects of concussion history and biological sex. Design: Cross-sectional. Methods: Male and female adolescent rugby union players aged 16 to 18 years were recruited at the start of the 2022-2023 playing season. PLR was recorded using a handheld pupillometer which provided seven different metrics relating to pupil diameter, constriction/dilation latency, and velocity. Data were analysed using a series of 2 × 2 ANOVAs to examine the main effects of independent variables: biological sex, concussion history, and their interactions, using adjusted p-values (p < 0.05). Results: 149 participants (75% male) were included. A total of 42% reported at least one previous concussion. Most metrics were unaffected by the independent variables. There were however significant main effects for concussion history (F = 4.11 (1); p = 0.05) and sex (F = 5.42 (1); p = 0.02) in end pupil diameters, and a main effect for sex in initial pupil diameters (F = 4.45 (1); p = 0.04). Although no significant interaction effects were found, on average, females with a concussion history presented with greater pupillary diameters and velocity metrics, with many pairwise comparisons showing large effects (SMD > 0.8). Conclusions: Pupillary diameters in adolescent athletes were significantly affected by concussion history and sex. The most extreme PLR metrics were recorded in females with a history of concussion (higher pupillary diameters and velocities). This highlights the importance of establishing baseline PLR metrics prior to interpretation of the PLR post-concussion. Long-standing PLR abnormalities post-concussion may reflect ongoing autonomic nervous system dysfunction. This warrants further investigation in longitudinal studies.

The Influence of Race on Time to Symptom Resolution Following Sport Concussion in Collegiate Athletes

CONTEXT

Race has been shown to influence computerized neurocognitive test scores, motor function test scores, and reported symptomology following sport-related concussion (SRC). However, the effect race may have on recovery time following SRC remains unknown. The objective of this study was to determine the influence of race on days until symptom free from SRC in NCAA Division 1 collegiate athletes.

DESIGN

Prospective cohort study.

METHODS

Participants were Black (n = 53 [28% female]) and White (n = 150 [43.3% female]) who were on average 19.0 (1.21) and 20.2 (1.3) years of age, respectively. Data were collected from the 2015-2016 to 2020-2021 collegiate sport seasons. Participants were evaluated before and after an SRC at empirically derived time points. The primary outcome measure was time until symptom free (days). Additional outcomes included baseline and postinjury Immediate Postconcussion Assessment and Cognitive Test and Sensory Organization Test (SOT) scores. A Mann-Whitney U test compared days to symptom free between groups. Immediate Postconcussion Assessment and Cognitive Test and SOT outcome scores were analyzed using a 2 (group) × 2 (time) analysis of variance.

RESULTS

White participants had a longer median recovery time (9 d) to symptom free compared with Black participants (6 d [P = .04]). Statistically significant differences were observed between Black 87.3 (9.84) and White 90.4 (8.30) groups for Immediate Postconcussion Assessment and Cognitive Test's verbal memory composite score (P = .03). Postinjury, White participants scored significantly higher 44.5 (5.63) on visual motor speed compared with Black participants (42.4 (5.90) [P = .02]). Within-group SOT differences between baseline and postinjury testing were observed in both groups (all P < .001).

CONCLUSIONS

Black collegiate athletes achieved symptom resolution sooner than White athletes. We did not explore underlying sociocultural factors such as socioeconomic status or previous concussion education, which may have influenced our results. Future studies should explore factors that may contextualize these findings.

Concussion diagnosis and recovery in relation to collegiate athletic department classification: a LIMBIC MATARS consortium investigation

PURPOSE

We investigated time to reach concussion diagnosis and recovery milestones in collegiate athletes relative to their schools' National Collegiate Athletic Association (NCAA) classification.

METHODS

We retrospectively examined 849 (43.1% female) concussion cases from 11 NCAA institutions (Division I Power 5 [n = 4], Division I Non-Power 5 [n = 4], and Division II/III [n = 3]) from the 2015-16 to 2019-20 athletic seasons. Our primary outcome measures were days to reach specific clinical milestones following concussion.

RESULTS

Median (IQR) time from injury to diagnosis was significantly longer at Division II/III institutions (1 [0-4] days) compared to Division I Power 5 (0 [0-1] days) and Division I Non-Power 5 (0 [0-1] days) institutions (p < 0.001). Likewise, Division II/III athletes (15 [11-22] days) took significantly longer to return to sport after concussion than Division I Power 5 (10 [7-16] days) and Division I Non-Power 5 (11 [7-18.5] days) athletes (p < 0.001).

CONCLUSION

Division II/III athletes had delayed concussion diagnoses and return to sport timelines compared to Division I athletes. Our results suggest that differences in sports medicine resources across NCAA divisions may influence injury recognition and recovery in collegiate athletes with concussion.

Placing the keystone: the LIMBIC Military and Tactical Athlete Research Study

OBJECTIVE

The LIMBIC Military and Tactical Athletic Research Study (MATARS) framework was established to confirm and extend understanding of concussion with initial studies driven by clinical data collected between 2015 and 2020 in a collegiate sports setting. The LIMBIC MATARS framework will be leveraged to apply gold-standard and innovative research designs to advance the science of concussion. This manuscript provides the background, methodology, and initial demographic data associated with the LIMBIC MATARS.

METHODS

Consensus-based common data elements were used to conduct a retrospective chart review, specific to collegiate athletes diagnosed with concussions between 2015 and 2020 at 11 universities.

RESULTS

A final sample of 1,311 (47.8% female) concussions were diagnosed during the five-year study period from athletes participating in a variety of National Collegiate Athlete Association (NCAA) sports. The LIMBIC MATARS demographic data, align with the NCAA and other pioneering multi-site concussion-related studies in terms of biological sex, race and ethnicity, and sport participation.

CONCLUSION

This pragmatic, methodological approach was used to address several a priori hypotheses related to concussion, align with other multi-site studies of concussion, and establish a consortium for future investigations.

Access to athletic trainers and sex as modifiers of time to reach clinical milestones after sport-related concussion in collegiate athletes

OBJECTIVE

Investigate whether an athlete's biological sex and exposure to a dedicated athletic trainer (AT) were related to clinical milestones after a sports-related concussion (SRC).

DESIGN

Retrospective chart review.

METHODS

Medical charts of collegiate athletes (n = 196 [70.9% female]) diagnosed with SRC were reviewed to extract: biological sex, dedicated AT exposure for their sport (yes/no), and time (days) to reaching clinical milestones (diagnosis, symptom resolution, unrestricted return to sport [RTS]). Mann-Whitney U tests were used to determine whether time to clinical milestones differed by sex, AT exposure, or their interaction. Proportions of same-day diagnoses and times to diagnosis, symptom resolution, and unrestricted RTS were evaluated with chi-squared and spearman's rank correlations, respectively.

RESULTS

There were no significant differences in times to reaching any clinical milestone by sex, AT exposure, or their interaction (ps > 0.05). Forty-three percent of participants were diagnosed on the day of their SRC. This did not differ by sex or AT exposure (ps > 0.29). Longer times to SRC diagnosis were associated with more days to symptom resolution (ρ = 0.236, p = 0.001) and unrestricted RTS (ρ = 0.223, p < 0.001).

CONCLUSIONS

Athlete sex and AT exposure were not associated with times to reach any clinical milestone; however, delayed diagnosis was associated with longer times to reach clinical recovery.

Sport Type and Risk of Subsequent Injury in Collegiate Athletes Following Concussion: a LIMBIC MATARS Consortium Investigation

OBJECTIVE

To investigate the association between sport type (collision, contact, non-contact) and subsequent injury risk following concussion in collegiate athletes.

MATERIALS AND METHODS

This retrospective chart review of 248 collegiate athletes with diagnosed concussions (age: 20.0 ± 1.4 years; height: 179.6 ± 10.9 cm; mass: 79.0 ± 13.6 kg, 63% male) from NCAA athletic programs (n = 11) occurred between the 2015-2020 athletic seasons. Acute injuries that occurred within six months following concussion were evaluated. Subsequent injuries were grouped by lower extremity, upper extremity, trunk, or concussion. The independent variable was sport type: collision, contact, non-contact. A Cox proportional hazard model was used to assess the risk of subsequent injury between sport types.

RESULTS

Approximately 28% (70/248) of athletes sustained a subsequent acute injury within six months post-concussion. Collision sport athletes had a significantly higher risk of sustaining any injury (HR: 0.41, p < 0.001, 95% CI: 0.28, 0.62), lower extremity (HR: 0.55, p = 0.04, 95% CI: 0.32, 0.97), and upper extremity (HR: 0.41, p = 0.01, 95% CI: 0.20, 0.81) injuries following concussion. No differences between sport types were observed for other injuries.

CONCLUSION

Collision sport athletes had a higher rate of any subsequent injury, lower, and upper extremity injuries following concussion. Future research should focus on sport-specific secondary injury prevention efforts.

MicroRNA Biomarkers on Day of Injury Among Patients with Post Concussive Symptoms at 28-Days: A Prospective Cohort Study

BACKGROUND

After mild traumatic brain injury (mTBI), some patients experience symptoms that persist for weeks to months. Recovery from mTBI is primarily assessed using selfreported symptom questionnaires. Blood biomarkers, including microRNA species, have shown promise to assist diagnosis of mTBI, however, little is known about how blood microRNA measures might predict symptom recovery.

OBJECTIVE

The aim of this study was to investigate the variances in plasma microRNAs on the day of injury between individuals with mTBI who report post-concussive symptoms at the 28- day mark and those who do not.

METHODS

Patients who presented to an adult, tertiary referral hospital emergency department on the day of the injury and were diagnosed with isolated mTBI (n=35) were followed up for 28 days. Venous blood samples were collected and symptom severity was assessed using the Rivermead Post-Concussion Symptom Questionnaire (RPQ) on the day of injury and at 28 days. Patients who reported ongoing symptoms of total RPQ score ≥10 or at least one symptom severity ≥2, were compared to those with lesser symptom severity or symptom resolution.

RESULTS

There were 9 (25.7%; 95%CI: 12.5-43.3) patients who reported persistent symptoms. Day of injury plasma miR-223-3p levels were significantly higher in individuals with ongoing symptoms compared to those without, however, no such differences were observed for miRs 142- 3p, 423-3p, 32-5p, 144-3p, and let-7f-5p.

CONCLUSION

Acute plasma miR-223-3p levels appear to detect patients who later have persistent symptoms after mTBI. The results demonstrate the potential utility for such biomarkers to assist in decisions towards early referral for therapy after mTBI.

Estimating the Relationship Between the Symptom-Free Waiting Period and Injury Rates After Return-to-Play from Concussion: A Simulation Analysis Using CARE Consortium Data

BACKGROUND

A key component of return-to-play (RTP) from sport-related concussion is the symptom-free waiting period (SFWP), i.e., the period during which athletes must remain symptom-free before permitting RTP. Yet, the exact relationship between SFWP and post-RTP injury rates is unclear.

OBJECTIVE

We design computational simulations to estimate the relationship between the SFWP and rates of repeat concussion and non-concussion time-loss injury up to 30 days post-RTP for male and female collegiate athletes across 13 sports.

METHODS

We leverage N = 735 female and N = 1,094 male post-injury trajectories from the National Collegiate Athletic Association-Department of Defense Concussion Assessment, Research, and Education Consortium.

RESULTS

With a 6-day SFWP, the mean [95% CI] rate of repeat concussion per 1,000 simulations was greatest in ice hockey for females (20.31, [20.16, 20.46]) and American football for males (24.16, [24.05, 24.28]). Non-concussion time-loss injury rates were greatest in field hockey for females (153.66, [152.59, 154.74]) and wrestling for males (247.34, [246.20, 248.48]). Increasing to a 13-day SFWP, ice hockey for females (18.88, [18.79, 18.98]) and American football for males (23.16, [23.09, 24.22]) exhibit the greatest decrease in repeat concussion rates across all sports within their respective sexes. Field hockey for females (143.24, [142.53, 143.94]) and wrestling for males (237.73, [236.67, 237.90]) exhibit the greatest decrease in non-concussion time-loss injury rates. Males receive marginally smaller reductions in injury rates for increased SFWP compared to females (OR = 1.003, p ≤ 0.002).

CONCLUSION

Longer SFWPs lead to greater reductions in post-RTP injury rates for athletes in higher risk sports. Moreover, SFWPs should be tailored to sport-specific post-RTP injury risks.

Intersection of Race and Socioeconomic Status on Concussion Recovery among NCAA Student-Athletes: A CARE Consortium Study

PURPOSE

The objectives of this study are to 1) describe collegiate student-athlete (SA) race and household income and 2) evaluate time to normal academic performance (i.e., return to learn (RTL)), initiation of the return to play (iRTP) protocol, RTP protocol duration, and time to unrestricted RTP (URTP) after sustaining sport-related concussion (SRC).

METHODS

Data were collected between 2014 and 2020 by the Concussion Assessment, Research, and Education Consortium. Baseline data were used to characterize participant demographics ( N = 22,819) and post-SRC outcomes ( n = 5485 SRC) in time to RTL ( n = 1724) and RTP outcomes ( n = 2646) by race. Descriptive statistics and nonparametric tests examined differences across race by demographic and injury characteristics. Kaplan-Meier curves estimated median days to RTL, iRTP protocol, RTP protocol completion, and URTP by race and covariate measures. Multivariable Cox proportional hazards regression assessed the effect of race on risk of RTL and RTP recovery time points.

RESULTS

SA largely identified as White (75%) followed by Black (14%), multiracial (7%), and Asian (3%). More than half (53%) of all SA reported a household income of >$120,000, whereas 41% of Black SA reported a household income <$60,000. Race was not associated with relative risk of RTL or iRTP but was associated with RTP protocol completion and URTP. Non-Black/non-White SA were 17% less likely (adjusted hazard ratio = 0.83; 95% confidence interval = 0.71, 0.97) to complete the RTP protocol, and Black SA were 17% more likely (adjusted hazard ratio = 1.17; 95% confidence interval = 1.05, 1.31) to reach the URTP time point compared with White SA.

CONCLUSIONS

The present findings suggest collegiate SA enrolled in the Concussion Assessment, Research, and Education Consortium are primarily White and come from household incomes well above the US median. Race was not associated with RTL or iRTP but was associated with RTP protocol duration and total time to URTP. Clinicians should be conscientious of how their implicit or preconceived biases may influence SRC management among National Collegiate Athletic Association SA.

Ankle Sprain History Does Not Significantly Alter Single- and Dual-Task Spatiotemporal Gait Mechanics

CONTEXT

Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures.

DESIGN

Cross-sectional study.

METHODS

We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance.

RESULTS

Athletes with and without a history of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = .19).

CONCLUSIONS

Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments.

Contact or Collision Sport History, Repetitive Neurotrauma, and Patient-Reported Outcomes in Early to Midadulthood

CONTEXT

Data on the early to midlife effects of repetitive neurotrauma on patient-reported outcomes have been delimited to homogeneous samples of male athletes without comparison groups or accounting for modifying factors such as physical activity.

OBJECTIVE

To determine the effect of contact or collision sport participation and repetitive neurotrauma on patient-reported outcomes among early to middle-aged adults.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 113 adults (53 [46.9%] men, 60 [53.1%] women; age = 34.88 ± 11.80 years) in 4 groups: (1) physically inactive individuals with no repetitive head impact (RHI) exposure (NON); (2) noncontact sport athletes and nonathletes with no RHI exposure who were currently physically active (NCA); (3) former high-risk sport athletes with an RHI history who were physically active (HRS); and (4) former rugby players with prolonged RHI exposure who remained physically active.

MAIN OUTCOME MEASURE(S)

The 12-Item Short-Form Health Survey (SF-12), Apathy Evaluation Scale-self-rated version (AES-S), Satisfaction With Life Scale (SWLS), and Sport Concussion Assessment Tool-5th Edition (SCAT5) Symptom and Symptom Severity Checklist.

RESULTS

The NON group had worse self-rated physical function than the NCA group as assessed by the SF-12 physical component summary (P = .03) and worse self-rated apathy (AES-S) and satisfaction with life (SWLS) than the NCA (P = .03 for both) and HRS groups (P = .03 and P = .040, respectively). We observed no group differences for self-rated mental health (SF-12 mental component summary; P = .26) or symptoms (SCAT5; P = .42). Career duration was not associated with any patient-reported outcomes.

CONCLUSIONS

A history of contact or collision sport participation and career duration did not negatively affect patient-reported outcomes in physically active, early to middle-aged adults. However, physical inactivity status was negatively associated with patient-reported outcomes in these individuals in the absence of an RHI history.

National Collegiate Athletic Association athletic trainers' response to the Arrington settlement: management, compliance, and practice patterns

The primary purpose of this study was to assess Athletic Trainers' (ATs) report of NCAA member institution compliance with the Arrington settlement, the concussion lawsuit vs. the NCAA, and to elucidate compliance predictors. A secondary purpose was to provide a contemporary concussion management clinical practice pattern description among NCAA collegiate athletic trainers. Head Athletic Trainers from NCAA Division I, II, and III completed an electronic questionnaire in August 2020 regarding their institution's response to the Arrington Settlement and their current concussion management clinical practice patterns. The 37-item questionnaire included AT and institution demographics, current concussion management policies, and response to the Arrington settlement with a specific focus on the five settlement requirements. An overall compliance score on the five requirements, compliance on the individual requirements, and concussion management practices are reported with descriptives. Regression was used to identify specific predictors of both overall and individual settlement requirements. An ANOVA compared compliance by NCAA division level. Being pressured to be non-compliant was assessed between sexes by a chi-square. There were 223 respondents (21.8%), and overall compliance was high (4.1 ± 0.7) with the five required Arrington Settlement components. Settlement requirement 1, pre-season baseline testing, and requirement 5, presence of trained personnel at all contact sport practices, had the lowest compliance rates at 44.8% and 73.3%, respectively. The number of sports the institution offered was the only significant predictor of each requirement. There was no difference in compliance between NCAA divisions. Although the overall rate of being non-compliant pressure was low (13.8%), females were 3.28x more likely report being pressured than males. NCAA institutions are generally compliant with the Arrington settlement; however, lack of clarity in the requirements, particularly requirement 1, raises potential concerns. Concussion management practices continue to incorporate multifaceted approaches and are largely consistent with current best practices.

Early Exercise is Associated with Faster Concussion Recovery Among Collegiate Athletes: Findings from the NCAA-DoD CARE Consortium

BACKGROUND

Growing evidence indicates early exercise may improve symptoms and reduce clinical recovery time after concussion, but research examining collegiate student-athletes is scarce.

OBJECTIVE

The aim of this study was to compare symptom recovery time, clinical recovery time, and persisting post-concussion symptom (i.e., symptoms ≥ 28 days) prevalence by the timing of light exercise initiation before the graded return to play (RTP) protocol among concussed participants.

METHODS

Collegiate student-athletes (n = 1228; age 18.4 ± 0.9 years; 56.5% male, 76.3% division I; 33.7% ≥ 1 prior concussion) across 30 institutions enrolled in the CARE Consortium completed post-concussion assessments and were monitored over time. Symptom recovery (days from injury to symptom resolution) and clinical recovery (days from injury to return to play protocol completion) was determined by the student-athletes' clinicians. Student-athletes were categorized by timing of light exercise initiation. Early (< 2 days post-concussion; n = 161), typical (3-7 days post-concussion; n = 281), and late exercise (≥ 8 days post-concussion; n = 169) groups were compared with the no-exercise group (n = 617; i.e., did not exercise prior to beginning the RTP protocol) for all analyses. Multivariable Cox regression models with hazard ratios (HR) and survival curves and a multivariable binomial regression model with prevalence ratios (PR) compared recovery outcomes between exercise groups while accounting for covariates.

RESULTS

Compared to the no-exercise group, the early exercise group was 92% more probable to experience symptom recovery (HR 1.92; 95% CI 1.57-2.36), 88% more probable to reach clinical recovery (HR 1.88; 95% CI 1.55-2.28) and took a median of 2.4 and 3.2 days less to recover, respectively. The late exercise group relative to the no-exercise group was 57% less probable to reach symptom recovery (HR 0.43; 95% CI 0.35-0.53), 46% less probable to achieve clinical recovery (HR 0.54; 95% CI 0.45-0.66) and took 5.3 days and 5.7 days more to recover, respectively. The typical exercise group did not differ in hazard for symptom or clinical recovery (p ≥ 0.329) compared with the no-exercise group. The prevalence of persisting post-concussion symptoms in the combined sample was 6.6%. Early exercise had 4% lower prevalence (PR 0.96, 95% CI 0.94-0.99) and typical exercise had 3% lower prevalence (PR 0.97, 95% CI 0.94-0.99) of persisting post-concussion symptoms, while the late exercise group had an elevated prevalence (PR 1.11, 95% CI 1.04-1.18) compared with the no-exercise group.

CONCLUSION

Exercise < 2 days post-concussion was associated with more probable and faster symptom and clinical recovery, and lower persisting post-concussion symptom prevalence. When considering our findings and existing literature, qualified clinicians may implement early exercise into their clinical practice to provide therapeutic treatment and improve student-athlete recovery.

Racial identity and concussion diagnosis and recovery trajectories in collegiate athletes: a LIMBIC MATARS investigation

OBJECTIVE

To determine if there were concussion diagnosis and recovery disparities between collegiate athletes with Black and White racial identities.

DESIGN

Retrospective cohort study.

METHODS

Concussion information was extracted from NCAA athlete medical files at LIMBIC MATARS member institutions from the 2015-16' to 2019-20' academic years. A total of 410 concussions from 9 institutions were included that provided all independent (i.e. racial identity of Black or White) and dependent variable information (i.e. dates of injury, diagnosis, symptom resolution, and return to sport) that were analyzed using Mann-Whitney U tests. The sample consisted of 114 (27.8%) concussions sustained by Black athletes and 296 (72.1%) sustained by White athletes.

RESULTS

The overall sample had a median of 0 days between injury occurrence to diagnosis, 7 days to symptom resolution, and 12 days to return to sport. No significant timing differences were observed for concussion diagnosis (p = .14), symptom resolution (p = .39), or return to sport (p = 0.58) between collegiate athletes with Black versus White racial identities.

CONCLUSIONS

These findings may reflect equitable access to onsite sports medicine healthcare resources that facilitate concussion management in the collegiate sport setting. Future work should explore these associations with a larger and more diverse sample of collegiate athletes.

Association Between Symptom Cluster Endorsement at Initiation of a Graduated Return-to-Activity Protocol and Time to Return to Unrestricted Activity After Concussion in United States Service Academy Cadets

BACKGROUND

The endorsement of symptoms upon initiation of a graduated return-to-activity (GRTA) protocol has been associated with prolonged protocols. It is unclear whether there are specific symptom clusters affecting protocol durations.

PURPOSE

To describe the endorsement of specific concussion symptom clusters at GRTA protocol initiation and examine the association between symptom cluster endorsement and GRTA protocol duration.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This study was conducted among cadets enrolled at 3 US service academies. Participants completed an evaluation upon GRTA protocol initiation. Participants endorsing symptoms were binarized based on 6 symptom clusters (cognitive, emotional, insomnia, physical, sensitivity, and ungrouped). The primary outcome of interest was GRTA protocol duration based on symptom cluster endorsement severity. Prevalence rates were calculated to describe symptom cluster endorsement. Kaplan-Meier survival estimates and univariate and multivariable Cox proportional hazards regression models were calculated for all 6 symptom clusters to estimate GRTA protocol duration while controlling for significant covariates.

RESULTS

Data from 961 concussed participants were analyzed. Of these, 636 participants were asymptomatic upon GRTA protocol initiation. Among the 325 symptomatic participants, the physical symptom cluster (80%) was most endorsed, followed by the cognitive (29%), insomnia (23%), ungrouped (19%), sensitivity (15%), and emotional (9%) clusters. Univariate results revealed a significant association between endorsing cognitive (hazard ratio [HR], 0.79; p = .001), physical (HR, 0.84; p < .001), insomnia (HR, 0.83; p = .013), sensitivity (HR, 0.70; p < .001), and ungrouped (HR, 0.75; p = .005) symptom clusters and GRTA protocol duration. Endorsing physical (HR, 0.84; p < .001) and sensitivity (HR, 0.81; p = .036) clusters maintained a significant association with GRTA protocol duration in the multivariable models.

CONCLUSION

Participants endorsing physical or sensitivity symptom clusters displayed GRTA protocols prolonged by 16% to 19% compared with participants not endorsing that respective cluster after controlling for significant covariates.

MicroRNA biomarkers for diagnosis of mild traumatic brain injury and prediction of persistent symptoms: A prospective cohort study

The diagnosis of mild traumatic brain injury (mTBI) and early identification of patients who have persistent symptoms remains challenging. Symptoms are variably reported, and tests for cognitive impairment require specific expertise. The aim of this study was to assess the ability of plasma micro-ribonucleic acid (miRNA) biomarkers to distinguish between patients with mTBI and healthy controls. A secondary aim was to assess whether miRNA biomarker levels on the day of injury could predict persistent symptoms on day 7. Injured patients presented to an adult, tertiary referral hospital emergency department and were diagnosed with isolated mTBI (n = 75). Venous blood samples were collected within 6 h of injury. Symptom severity was assessed using the Rivermead Post-Concussion Symptom Questionnaire (RPQ) on the day of injury and at 7 days post-injury. The comparator group (n = 44) were healthy controls without any injury, who had bloods sampled and symptom severity assessed at the same time-point. Patients after mTBI reported higher symptom severity and had worse cognitive performance than the control group. Plasma miR423-3p levels were significantly higher among mTBI patients acutely post-injury compared to healthy controls and provided moderate discriminative ability (AUROC 0.67; 95 %CI: 0.57-0.77). None of the assessed miRNA biomarkers predicted persistent symptoms at 7 days. Plasma miR423-3p levels measured within 6 h of injury can discriminate for mTBI compared to healthy controls, with potential utility for screening after head injury or as an adjunct to the diagnosis of mTBI. Acute plasma miRNA levels did not predict patients who reported persistent symptoms at 7 days.

Concussion: Beyond the Cascade

Sport concussion affects millions of athletes each year at all levels of sport. Increasing evidence demonstrates clinical and physiological recovery are becoming more divergent definitions, as evidenced by several studies examining blood-based biomarkers of inflammation and imaging studies of the central nervous system (CNS). Recent studies have shown elevated microglial activation in the CNS in active and retired American football players, as well as in active collegiate athletes who were diagnosed with a concussion and returned to sport. These data are supportive of discordance in clinical symptomology and the inflammatory response in the CNS upon symptom resolution. In this review, we will summarize recent advances in the understanding of the inflammatory response associated with sport concussion and broader mild traumatic brain injury, as well as provide an outlook for important research questions to better align clinical and physiological recovery.

Hard-Headed Decisions: Intrapersonal Factors Underlying Concussion Reporting in University Athletes

Most of the research investigating sports concussion (SC) disclosure has been conducted using questionnaires with a pre-determined set of questions. Hence, significant gaps remain in our understanding of which factors weight in the decision-making process underlying SC disclosure and how they contribute to it. This present study aims to fill some of these gaps using qualitative methods to identify intrapersonal determinants of SC disclosure and describe their influence on an athlete's decision-making process. Our results are based on in-depth, semistructured interviews (range, 56-79 min; total = 587 min) with 9 university athletes (5 females, 4 males) from three team sports (soccer, rugby, and cheerleading). Using constant comparative analysis guided by Straussian grounded theory, we identified 13 concepts, across three major intrapersonal categories (i.e., attitudes and behaviors; concussion knowledge; and subjective evaluation of the concussion), contributing to SC disclosure, including novel determinants such as prioritization of athletic versus intellectual activities and maturity level. Our results suggest that a comparison between experiential knowledge and severity of the injury plays a major role in determining an athlete's disclosure behaviors. Athletes with a history of concussion seem to adopt a non-disclosure default strategy and are inclined to disclose their concussion symptoms only if they judge their current concussion to be worse than their previous most severe injury. Other concepts identified appear to contribute to the decisional process by modulating the adoption of this non-disclosure default strategy. Our work highlights the benefits and necessity of using qualitative methods to study the decision-making process underlying concussion disclosure.

The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016-2020

Purpose

There is limited research regarding the characteristics of those from the general population who seek care following acute concussion.

Methods

To address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury.

Results

Falls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p < 0.0001). A relatively high proportion of female and male participants in this study reported premorbid diagnoses of depression and anxiety compared to general population characteristics.

Conclusion

Although premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4-12 weeks.

Temporal Network Analysis of Neurocognitive Functioning and Psychological Symptoms in Collegiate Athletes After Concussion

Sport-related concussion (SRC) is associated with several post-injury consequences, including neurocognitive decrements and psychological distress. Yet, how these clinical markers interact with each other, the magnitude of their interrelationships, and how they may vary over time following SRC are not well understood. Network analysis has been proposed as a statistical and psychometric method to conceptualize and map the complex interplay of interactions between observed variables (e.g., neurocognitive functioning and psychological symptoms). For each collegiate athlete with SRC (n = 565), we constructed a temporal network as a weighted graph, with nodes, edges, and the set of weights associated with each edge at three time-points (baseline, 24-48 h post-injury, and asymptomatic), that graphically depicts the interrelated nature of neurocognitive functioning and symptoms of psychological distress throughout the recovery process. This graph shows that the inter-group relationships between neurocognitive functioning and symptoms of psychological distress were stronger at the 24-48 h time-point than at baseline or at the asymptomatic time-point. Further, all symptoms of psychological distress and neurocognitive functioning significantly improved from the 24-48 h time-point to asymptomatic status. The effect sizes of these changes ranged from 0.126 (small) to 0.616 (medium). This research suggests that significant improvements in symptoms of psychological distress appear necessary to drive related improvements in neurocognitive functioning and vice versa. Therefore, clinical interventions should consider the importance of managing psychological distress during the acute care of individuals with SRC to help ameliorate negative outcomes.