Factors and expectations influencing concussion disclosure within NCAA Division I athletes: A mixed methodological approach.

BACKGROUND: Participation in sports is associated with many benefits to all aspects of health; however, it also comes with the risk of injury, particularly concussions. Self-disclosure and care seeking following a concussion are especially important because of the lack of outwardly visible signs and/or symptoms. Although recent research has explored factors affecting concussion disclosure, use of isolated methodologies limits the ability to contextualize how disclosure or nondisclosure occurs. Therefore, the purpose of this study was to describe the factors and expectations of National Collegiate Athletic Association (NCAA) athletes that may influence concussion disclosure. METHODS: This mixed-methods convergent parallel research study included 25 NCAA Division I athletes representing 13 sports, all of whom completed a concussion-education session with pre-/post-test surveys and a semistructured interview. Eligible athletes were at least 18 years old and on an NCAA roster. The surveys focused on previous concussion-related disclosure behaviors, knowledge, attitudes, beliefs, norms, and intentions about disclosing concussion. Interviews focused on the athletes' experiences related to concussion disclosure. Survey data were analyzed using descriptive statistics and Mann-Whitney U tests. Interviews were analyzed using a Consensual Qualitative Research tradition. RESULTS: Participants had good concussion knowledge (median = 46.0), positive attitudes (median = 38.0), strong beliefs (median = 13.0), and strong intentions to disclose concussion symptoms (median = 7.0). None of the constructs differed by participants' gender. Although quantitative findings were mostly positive, interview data highlighted factors that may explain why some participants are successful in disclosing concussions and why others may find disclosure difficult. Educational efforts, sport culture, and medical professional presence were the primary facilitators discussed by participants. Stigma, pressure, and a lack of team support were perceived as disclosure barriers. CONCLUSION: The context in which concussion disclosure occurs or does not occur is vital to the success of educational interventions. Interventions must prioritize stakeholder- and team-based perspectives on concussion to establish a network supportive to disclosure.

Time Delta Head Impact Frequency: An Analysis on Head Impact Exposure in the Lead Up to a Concussion: Findings from the NCAA-DOD Care Consortium.

Sport-related concussions can result from a single high magnitude impact that generates concussive symptoms, repeated subconcussive head impacts aggregating to generate concussive symptoms, or a combined effect from the two mechanisms. The array of symptoms produced by these mechanisms may be clinically interpreted as a sport-related concussion. It was hypothesized that head impact exposure resulting in concussion is influenced by severity, total number, and frequency of subconcussive head impacts. The influence of total number and magnitude of impacts was previously explored, but frequency was investigated to a lesser degree. In this analysis, head impact frequency was investigated over a new metric called 'time delta', the time difference from the first recorded head impact of the day until the concussive impact. Four exposure metrics were analyzed over the time delta to determine whether frequency of head impact exposure was greater for athletes on their concussion date relative to other dates of contact participation. Those metrics included head impact frequency, head impact accrual rate, risk weighted exposure (RWE), and RWE accrual rate. Athletes experienced an elevated median number of impacts, RWE, and RWE accrual rate over the time delta on their concussion date compared to non-injury sessions. This finding suggests elevated frequency of head impact exposure on the concussion date compared to other dates that may precipitate the onset of concussion.

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

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

Exploratory factor analysis of the fear-avoidance beliefs questionnaire in patients with chronic ankle instability.

PURPOSE: To perform an exploratory factor analysis of the Fear-Avoidance Beliefs Questionnaire in patients with chronic ankle instability. METHODS: A cross-sectional survey study was utilized. The Fear-Avoidance Beliefs Questionnaire was administered to patients with chronic ankle instability who met the inclusion criteria. Both an unrestricted and restricted factor analysis with varimax rotation were utilized to explore the factor structure of the instrument. Kaiser-Meyer-Olkin values were used to determine sampling adequacy. Bartlett's test of sphericity was used to justify that the correlations were suitable for the principal component analysis. RESULTS: The restricted two-factor analysis resulted in two factors with acceptable internal consistency values. The Keiser-Meyer-Olkin value was acceptable (0.81), and Bartlett's test of sphericity was significant (χ2 (55) = 515.59, p < 0.001). CONCLUSION: The ankle-specific Fear-Avoidance Beliefs Questionnaire consists of two stable factors and should be used to further examine fear-avoidance beliefs in people with chronic ankle instability.

Association between Sensation-Seeking Behaviors and Concussion-Related Knowledge, Attitudes, Perceived Norms, and Care-Seeking Behaviors among Collegiate Student-Athletes.

There are limited data connecting personality and behavioral tendencies and traits related to concussion care-seeking/disclosure behaviors and minimal research exists surrounding the relationship between risky behaviors, sensation-seeking, and concussion-related outcomes. This study examined the association between sensation-seeking and a student-athlete's concussion-related knowledge, attitudes, perceived social norms, and concussion care-seeking/disclosure behaviors (intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury). The current study utilized a retrospective cohort of collegiate student-athletes at a single National Collegiate Athletic Association Division I institution. Separate multivariable linear regression models estimating mean differences (MD) and 95% Confidence Intervals (CI) estimated the association between sensation-seeking and concussion knowledge, concussion attitudes, and perceived social norms. Separate multivariable binomial regression models estimating adjusted prevalence ratios (PR) and 95%CI estimated the association between sensation-seeking and intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury. All models were adjusted for sex, sport participation, and concussion history. Higher sensation-seeking was significantly associated with less favorable concussion attitudes (adjusted MD = -1.93; 95%CI = -3.04,-0.83), less favorable perceived social norms surrounding concussion (adjusted MD = -1.39; 95%CI = -2.06,-0.72), and continuing to play while experiencing concussion symptoms (adjusted PR = 1.50; 95%CI = 1.10, 2.06). Student-athletes with increased sensation-seeking could be at risk for failing to disclose a concussion, decreasing athlete safety and resulting in less optimal care post-injury. Results will inform future theory-based concussion education programs which consider behavioral tendencies and traits as well as sport culture to promote concussion care-seeking/disclosure and individualized interventions based on risky behavior engagement.

Association Between Symptom Burden at Initiation of a Graduated Return to Activity Protocol and Time to Return to Unrestricted Activity After Concussion in Service Academy Cadets.

BACKGROUND: Current consensus and position statements recommend that concussed patients be asymptomatic upon the initiation of the graduated return to activity (RTA) protocol. However, a significant number of concussed patients are beginning their RTA protocols while endorsing symptoms. PURPOSE: To characterize symptom endorsement at the beginning of the RTA protocol and examine the association between symptom endorsement and RTA protocol duration in service academy cadets. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A prospective cohort study was conducted with cadets at 3 US service academies. Postconcussion symptom inventories were recorded upon the initiation of an RTA protocol. The Sport Concussion Assessment Tool Symptom Inventory was used to classify participants into 3 groups (0 symptoms, 1 symptom, and ≥2 symptoms) upon the initiation of the RTA protocol. The primary outcome of interest was RTA protocol duration. Kaplan-Meier survival estimates were calculated to estimate RTA protocol duration by symptom endorsement, sex, varsity status, academic break, and time to graduated RTA initiation. Univariate and multivariable Cox proportional hazards models were used to estimate the association between symptom endorsement at the initiation of the RTA protocol and RTA protocol duration (α < .05). RESULTS: Data were analyzed from 966 concussed cadets (36% women). Headache (42%) and faintness/dizziness (44%) were the most commonly endorsed symptoms on the Sport Concussion Assessment Tool-Third Edition and the Brief Symptom Inventory-18, respectively. Univariate results revealed a significant association between endorsing ≥2 symptoms and RTA protocol duration. In the multivariable model, endorsing ≥2 symptoms maintained a statistically significant association with RTA protocol duration. Significant associations were observed between RTA protocol duration and nonvarsity status (27% longer), women (15% longer), academic breaks (70% longer), and time to the initiation of the RTA protocol (1.1% longer daily incremental increase) after controlling for covariates. CONCLUSION: Symptom endorsement at the initiation of an RTA protocol was associated with RTA protocol duration. Cadets who had returned to preinjury baseline symptom burden or improved from baseline symptom burden and endorsed ≥2 symptoms at the initiation of the RTA protocol took longer to RTA.

Leadership Lessons in Concussion Management for Team Physicians.

Over the last decade, with emphasis on concussion awareness and potential long-term deficits, concussions have become a public health concern. Although common, concussions are complex in nature and often require a collaborative treatment approach across multiple disciplines. In an athletic setting, the Team Physician plays a critical leadership role in the organization, management, and provision of care for concussed athletes. However, leadership strategies for the provision of concussion care utilized by the Team Physician have not been adequately described. This manuscript intends to describe advanced planning for concussion management and highlight best practices for the provision of care for the concussed athlete, to assist the Team Physician in coordinating optimal care. Specific emphasis will be placed on outlining a concussion management protocol aligned with evidence-based best practices.

The Epidemiology of Meniscus Injury.

Meniscus surgery is one of the most commonly performed orthopedic procedures worldwide. Modifiable risk factors for meniscus injury include body mass index, participation in athletics and occupation. Nonmodifiable risk factors include age, sex, lower extremity alignment, discoid meniscus, ligamentous laxity, and biconcave tibial plateau. Conditions commonly associated with meniscal injury are osteoarthritis, anterior cruciate ligament injury, and tibial plateau fractures. Tear type and location vary by patient age and functional status. Surgical management of meniscus injury is typically cost-effective in terms of quality-adjusted life years. The purpose of this review is to provide an overview of meniscal injury epidemiology by summarizing tear types and locations, associated conditions, and factors that increase the risk for meniscal injury. The economic burden of meniscus injury and strategies to prevent injury to the meniscus are also reviewed.

Reference Values for the Headache Impact Test-6 Questionnaire.

OBJECTIVE: To determine reference values for the Headache Impact Test-6 (HIT-6) in a young, physically active cohort and to examine the influence of sex, concussion history, headache history, and competitive sport level on HIT-6 scores. DESIGN: Cross-sectional. SETTING: United States Service Academy. PARTICIPANTS: United States Service Academy cadets (N=2678) completed an HIT-6 questionnaire as part of their annual concussion baseline assessment. Cadets with a recent concussion were excluded from baseline testing. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Reference values were calculated and stratified by sex, concussion history, headache history, and competitive sport level. Mann-Whitney U and Kruskal-Wallis tests were used to examine the effect of sex, concussion history, headache history, and competitive sport level on HIT-6 scores (P<.05). RESULTS: Of the 3599 cadets baselined, 2687 cadets (23% female) agreed to participate in the study and completed the HIT-6. Female participants reported significantly worse HIT-6 scores compared with male participants both with (P<.001) and without (P<.001) a concussion history. In both sexes, participants with a headache history reported worse scores than those with no headache/concussion history and a concussion history (all P<.005). Female cadets who participated in intramural athletics reported worse HIT-6 scores at baseline than female intercollegiate athletes (P=.003). CONCLUSIONS: This is the first study to stratify HIT-6 data by sex, concussion history, headache history, and sport level in a collegiate population at risk for concussions. Sex and headache history appear to influence HIT-6 scores and should be given special consideration when interpreting health-related quality of life deficits due to headache.

Association Between Previous Concussion Education and Concussion Care-Seeking Outcomes Among National Collegiate Athletic Association Division I Student-Athletes.

CONTEXT: Limited data exist concerning differences in concussion-education exposure and how education exposures relate to care seeking and symptom disclosure, specifically by National Collegiate Athletic Association Division I student-athletes. OBJECTIVE: To investigate demographic characteristics associated with concussion-education exposure and examine whether overall education exposure (yes versus no) and education-source exposure number (multiple sources versus a single source) affect concussion care-seeking and disclosure factors in Division I student-athletes. DESIGN: Cross-sectional study. SETTING: Classroom or online survey. PATIENTS OR OTHER PARTICIPANTS: Division I student-athletes (n = 341). MAIN OUTCOME MEASURE(S): Frequencies and proportions were computed for sex, race, school year, sport, and concussion history across concussion-education groups. Prevalence ratios (PRs) and 95% CIs were calculated to quantify the associations between student-athlete characteristics and (1) overall concussion-education exposure and (2) source-exposure number. Separate multivariable linear regression models estimated adjusted mean differences (MDs) and 95% CIs, which allowed us to assess differences in concussion knowledge, attitudes, and perceived social norms relative to concussion-education exposure and exposure to multiple sources. Separate multivariable binomial regression models were performed to estimate adjusted PRs and 95% CIs in order to evaluate associations of intention, perceived control, and care-seeking or disclosure behaviors and overall concussion-education exposure and exposure to multiple sources. All models controlled for sex, sport, and concussion history. RESULTS: Overall, 276 (80.9%) participants reported previous concussion education, with 179 (64.9%) being exposed to multiple sources. Student-athletes who participated in a contact sport (adjusted PR = 1.24; 95% CI = 1.06, 1.44) and those who had a concussion history (adjusted PR = 1.19; 95% CI = 1.09, 1.31) had higher prevalences of concussion-education exposure. Females had a lower prevalence of reporting multiple sources (adjusted PR = 0.82; 95% CI = 0.68, 0.99). Overall concussion-education exposure was significantly associated with more favorable perceived social norms surrounding concussion care seeking (adjusted MD = 1.37; 95% CI = 0.13, 2.61). CONCLUSIONS: These findings highlighted the potential differences in overall concussion-education exposure and provide clinicians with information on groups who may benefit from additional targeted education.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium.

Importance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, Setting, and Participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main Outcomes and Measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and Relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

Opportunities for Prevention of Concussion and Repetitive Head Impact Exposure in College Football Players: A Concussion Assessment, Research, and Education (CARE) Consortium Study.

Importance: Concussion ranks among the most common injuries in football. Beyond the risks of concussion are growing concerns that repetitive head impact exposure (HIE) may increase risk for long-term neurologic health problems in football players. Objective: To investigate the pattern of concussion incidence and HIE across the football season in collegiate football players. Design, Setting, and Participants: In this observational cohort study conducted from 2015 to 2019 across 6 Division I National Collegiate Athletic Association (NCAA) football programs participating in the Concussion Assessment, Research, and Education (CARE) Consortium, a total of 658 collegiate football players were instrumented with the Head Impact Telemetry (HIT) System (46.5% of 1416 eligible football players enrolled in the CARE Advanced Research Core). Players were prioritized for instrumentation with the HIT System based on their level of participation (ie, starters prioritized over reserves). Exposure: Participation in collegiate football games and practices from 2015 to 2019. Main Outcomes and Measures: Incidence of diagnosed concussion and HIE from the HIT System. Results: Across 5 seasons, 528 684 head impacts recorded from 658 players (all male, mean age [SD], 19.02 [1.25] years) instrumented with the HIT System during football practices or games met quality standards for analysis. Players sustained a median of 415 (interquartile range [IQR], 190-727) recorded head impacts (ie, impacts) per season. Sixty-eight players sustained a diagnosed concussion. In total, 48.5% of concussions (n = 33) occurred during preseason training, despite preseason representing only 20.8% of the football season (0.059 preseason vs 0.016 regular-season concussions per team per day; mean difference, 0.042; 95% CI, 0.020-0.060; P = .001). Total HIE in the preseason occurred at twice the proportion of the regular season (324.9 vs 162.4 impacts per team per day; mean difference, 162.6; 95% CI, 110.9-214.3; P < .001). Every season, HIE per athlete was highest in August (preseason) (median, 146.0 impacts; IQR, 63.0-247.8) and lowest in November (median, 80.0 impacts; IQR, 35.0-148.0). Over 5 seasons, 72% of concussions (n = 49) (game proportion, 0.28; 95% CI, 0.18-0.40; P < .001) and 66.9% of HIE (262.4 practices vs 137.2 games impacts per player; mean difference, 125.3; 95% CI, 110.0-140.6; P < .001) occurred in practice. Even within the regular season, total HIE in practices (median, 175.0 impacts per player per season; IQR, 76.0-340.5) was 84.2% higher than in games (median, 95.0 impacts per player per season; IQR, 32.0-206.0). Conclusions and Relevance: Concussion incidence and HIE among college football players are disproportionately higher in the preseason than regular season, and most concussions and HIE occur during football practices, not games. These data point to a powerful opportunity for policy, education, and other prevention strategies to make the greatest overall reduction in concussion incidence and HIE in college football, particularly during preseason training and football practices throughout the season, without major modification to game play. Strategies to prevent concussion and HIE have important implications to protecting the safety and health of football players at all competitive levels.

Differences in Lower Extremity Movement Quality by Level of Sport Specialization in Cadets Entering a United States Service Academy.

BACKGROUND: Sport specialization in youth athletes is associated with increased risk for musculoskeletal injury; however, little is known about whether sport specialization is associated with lower extremity movement quality. The purpose of this study was to examine differences in lower extremity movement quality by level of sport specialization in US Service Academy cadets. HYPOTHESIS: Cadets who report an increased level of sport specialization would have a lower level of movement quality than those who are less specialized. STUDY DESIGN: Cross-sectional analysis from an ongoing prospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: Cadets completed the Landing Error Scoring System (LESS) and a baseline questionnaire evaluating level of sport specialization during high school. Data were analyzed using separate 1-way analysis of variance models. RESULTS: Among all participants (n = 1950), 1045 (53.6%) reported low sport specialization, 600 (30.8%) reported moderate sport specialization, and 305 (15.6%) reported high sport specialization at the time of data collection during the first week. Ages ranged from 17 to 23 years. Men (1491) and women (459) reported comparable specialization levels (P = 0.45). There were no statistically significant differences in lower extremity movement quality by level of specialization for all subjects combined (P = 0.15) or when only men were included in the analyses (P = 0.69). However, there were statistically significant differences in movement quality by level of specialization in women (P = 0.02). Moderately specialized women had the best movement quality (mean, 4.63; SD, 2.21) followed by those with high specialization (mean, 4.90; SD, 2.08) and those with low levels of specialization (mean, 5.23; SD, 2.07). CONCLUSION: Women reporting moderate sport specialization had improved movement quality and significantly better LESS scores compared to those with high/low specialization. CLINICAL RELEVANCE: Athletes, especially women, should be encouraged to avoid early sport specialization to optimize movement quality, which may affect injury risk.

Detailed description of Division I ice hockey concussions: Findings from the NCAA and Department of Defense CARE Consortium.

OBJECTIVE: Since concussion is the most common injury in ice hockey, the objective of the current study was to elucidate risk factors, specific mechanisms, and clinical presentations of concussion in men's and women's ice hockey. METHODS: Ice hockey players from 5 institutions participating in the Concussion Assessment, Research, and Education Consortium were eligible for the current study. Participants who sustained a concussion outside of this sport were excluded. There were 332 (250 males, 82 females) athletes who participated in ice hockey, and 47 (36 males, 11 females) who sustained a concussion. RESULTS: Previous concussion (odds ratio (OR) = 2.00; 95% confidence interval (95% CI): 1.02‒3.91) was associated with increased incident concussion odds, while wearing a mouthguard was protective against incident concussion (OR = 0.43; 95%CI: 0.22‒0.85). Overall, concussion mechanisms did not significantly differ between sexes. There were specific differences in how concussions presented clinically across male and female ice hockey players, however. Females (9.09%) were less likely than males (41.67%) to have a delayed symptom onset (p = 0.045). Additionally, females took significantly longer to reach asymptomatic (p = 0.015) and return-to-play clearance (p = 0.005). Within the first 2 weeks post-concussion, 86.11% of males reached asymptomatic, while only 45.50% of females reached the same phase of recovery. Most males (91.67%) were cleared for return to play within 3 weeks of their concussion, compared to less than half (45.50%) of females. CONCLUSION: The current study proposes possible risk factors, mechanisms, and clinical profiles to be validated in future concussions studies with larger female sample sizes. Understanding specific risk factors, concussion mechanisms, and clinical profiles of concussion in collegiate ice hockey may generate ideas for future concussion prevention or intervention studies.

Factors Associated with Symptom Reporting in U.S. Service Academy Cadets and NCAA Student Athletes without Concussion: Findings from the CARE Consortium.

BACKGROUND: Symptom resolution is a key marker in determining fitness for return to activity following concussion, but in some cases, distinguishing persistent symptoms due to concussion versus symptoms related to other factors can be challenging. OBJECTIVE: To determine base rates of postconcussional syndrome (PCS) diagnostic categorization in healthy cadets and student athletes with no recent concussion. METHODS: 13,009 cadets and 21,006 student athletes completed baseline preseason testing. After inclusion/exclusion criteria were applied, the final sample included 12,039 cadets [9123 men (75.8%); 2916 women (24.2%)] and 18,548 student athletes [10,192 men (54.9%); 8356 women (45.1%)]. Participants completed the Sport Concussion Assessment Tool-3rd Edition (SCAT3) symptom evaluation as part of baseline preseason testing. The PCS diagnostic categorization was classified by the International Classification of Diseases, 10th Revision (ICD-10) symptom criteria for PCS. RESULTS: In the absence of recent concussion, subgroups of cadets (17.8% of men; 27.6% of women) and student athletes (11.4% of men; 20.0% of women) reported a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS. Participants with insufficient sleep and/or preexisting conditions (e.g., mental health problems), freshmen cadets, and cadets at the U.S. Coast Guard Academy and at the U.S. Air Force Academy (freshmen were tested during basic cadet training) were more likely to report a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS. CONCLUSION: The ICD-10 symptom criteria for PCS can be mimicked by preexisting conditions, insufficient sleep, and/or stress. Findings support person-specific assessment and management of symptoms following concussion.

Perceived social norms and concussion-disclosure behaviours among first-year NCAA student-athletes: implications for concussion prevention and education.

Timely disclosure and identification of concussion symptoms are essential to proper care. Perceived social norms are a potential driving factor in many health-related decisions. The study purpose was to describe concussion disclosure behaviours and identify the association between perceived social norms and these disclosure behaviours. First-year student-athletes (n = 391) at two NCAA institutions completed a cross-sectional survey about concussion disclosure and disclosure determinants. Log-binomial regression models identified factors associated with concussion disclosure behaviour prevalence for: higher intention to disclose symptoms, disclosed all at time of injury, eventually disclosed all, and never participated with concussion symptoms. More favourable perceived social norms were associated with higher prevalence of intention to disclose (PR = 1.34; 95%CI: 1.18, 1.53) and higher prevalence of never participating in sports with concussion symptoms (PR = 1.50; 95%CI: 1.07, 2.10). Clinicians, coaches, sports administrators, and healthcare practitioners should be mindful of the need to create supportive social environments to improve concussion symptom disclosure.

Test-Retest Reliability of Concussion Baseline Assessments in United States Service Academy Cadets: A Report from the National Collegiate Athletic Association (NCAA)-Department of Defense (DoD) CARE Consortium.

OBJECTIVE: In response to advancing clinical practice guidelines regarding concussion management, service members, like athletes, complete a baseline assessment prior to participating in high-risk activities. While several studies have established test stability in athletes, no investigation to date has examined the stability of baseline assessment scores in military cadets. The objective of this study was to assess the test-retest reliability of a baseline concussion test battery in cadets at U.S. Service Academies. METHODS: All cadets participating in the Concussion Assessment, Research, and Education (CARE) Consortium investigation completed a standard baseline battery that included memory, balance, symptom, and neurocognitive assessments. Annual baseline testing was completed during the first 3 years of the study. A two-way mixed-model analysis of variance (intraclass correlation coefficent (ICC)3,1) and Kappa statistics were used to assess the stability of the metrics at 1-year and 2-year time intervals. RESULTS: ICC values for the 1-year test interval ranged from 0.28 to 0.67 and from 0.15 to 0.57 for the 2-year interval. Kappa values ranged from 0.16 to 0.21 for the 1-year interval and from 0.29 to 0.31 for the 2-year test interval. Across all measures, the observed effects were small, ranging from 0.01 to 0.44. CONCLUSIONS: This investigation noted less than optimal reliability for the most common concussion baseline assessments. While none of the assessments met or exceeded the accepted clinical threshold, the effect sizes were relatively small suggesting an overlap in performance from year-to-year. As such, baseline assessments beyond the initial evaluation in cadets are not essential but could aid concussion diagnosis.

Association Between Previous Concussion Education and Concussion Care-Seeking Outcomes among NCAA Division I Student-Athletes.

CONTEXT: There are limited data concerning differences in concussion education exposure and how education exposures relates to care-seeking and symptom disclosure, specifically in Division I student-athletes. OBJECTIVE: Investigate demographic characteristics associated with concussion education exposure and examine whether overall education exposure (yes vs. no) and education source exposure number (multiple sources vs. single source) affects concussion care-seeking and disclosure factors in Division I student-athletes. DESIGN: Cross-sectional survey. SETTING: Classroom or online. PARTICIPANTS: NCAA Division I student-athletes (n=341). MAIN OUTCOME MEASURE(S): Frequencies and proportions were computed for sex, race, school year, sport, and concussion history across concussion education groups. Prevalence ratios (PR) and 95% confidence intervals (CI) quantified the association between student-athlete characteristics and 1) overall concussion education exposure and 2) source exposure number. Separate multivariable linear regression models estimated adjusted mean differences (MD) and 95%CI to assess differences in concussion knowledge, attitudes, and perceived social norms relative to concussion education exposure and exposure to multiple sources. Separate multivariable binomial regression models estimated adjusted PRs and 95%CI to assess associations of intention, perceived control, and care-seeking/disclosure behaviors and overall concussion education exposure and exposure to multiple sources. All models controlled for sex, sport, and concussion history. RESULTS: Overall, n=276 (80.9%) reported previous concussion education, with 179 (64.9%) exposed to multiple sources. Student-athletes that participated in a contact sport (adjusted PR=1.24, 95%CI=1.06,1.44) and those who had a concussion history (adjusted PR=1.19, 95%CI=1.09,1.31) had higher prevalence of previous concussion education exposure. Females had a lower prevalence of reporting multiple sources (adjusted PR=0.82, 95%CI=0.68, 0.99). Overall concussion education exposure was significantly associated with more favorable perceived social norms surrounding concussion care-seeking (adjusted MD=1.37, 95%CI=0.13,2.61). CONCLUSIONS: Findings highlight potential differences in overall concussion education exposure and provide clinicians with information on groups who may benefit from targeted additional education.

High Energy Side and Rear American Football Head Impacts Cause Obvious Performance Decrement on Video.

The objective of this study was to compare head impact data acquired with an impact monitoring mouthguard (IMM) to the video-observed behavior of athletes' post-collision relative to their pre-collision behaviors. A total of n = 83 college and high school American football players wore the IMM and were video-recorded over 260 athlete-exposures. Ex-athletes and clinicians reviewed the video in a two-step process and categorized abnormal post-collision behaviors according to previously published Obvious Performance Decrement (OPD) definitions. Engineers qualitatively reviewed datasets to check head impact and non-head impact signal frequency and magnitude. The ex-athlete reviewers identified 2305 head impacts and 16 potential OPD impacts, 13 of which were separately categorized as Likely-OPD impacts by the clinical reviewers. All 13 Likely-OPD impacts were in the top 1% of impacts measured by the IMM (ranges 40-100 g, 3.3-7.0 m/s and 35-118 J) and 12 of the 13 impacts (92%) were to the side or rear of the head. These findings require confirmation in a larger data set before proposing any type of OPD impact magnitude or direction threshold exists. However, OPD cases in this study compare favorably with previously published impact monitoring studies in high school and college American football players that looked for OPD signs, impact magnitude and direction. Our OPD findings also compare well with NFL reconstruction studies for ranges of concussion and sub-concussive impact magnitudes in side/rear collisions, as well as prior theory, analytical models and empirical research that suggest a directional sensitivity to brain injury exists for single high-energy impacts.

Concussion Risk Between Individual Football Players: Survival Analysis of Recurrent Events and Non-events.

Concussion tolerance and head impact exposure are highly variable among football players. Recent findings highlight that head impact data analyses need to be performed at the subject level. In this paper, we describe a method of characterizing concussion risk between individuals using a new survival analysis technique developed with real-world head impact data in mind. Our approach addresses the limitations and challenges seen in previous risk analyses of football head impact data. Specifically, this demonstrative analysis appropriately models risk for a combination of left-censored recurrent events (concussions) and right-censored recurrent non-events (head impacts without concussion). Furthermore, the analysis accounts for uneven impact sampling between players. In brief, we propose using the Consistent Threshold method to develop subject-specific risk curves and then determine average risk point estimates between subjects at injurious magnitude values. We describe an approach for selecting an optimal cumulative distribution function to model risk between subjects by minimizing injury prediction error. We illustrate that small differences in distribution fit can result in large predictive errors. Given the vast amounts of on-field data researchers are collecting across sports, this approach can be applied to develop population-specific risk curves that can ultimately inform interventions that reduce concussion incidence.