Zachary Y. Kerr

Nine-Year Risk of Depression Diagnosis Increases With Increasing Self-Reported Concussions in Retired Professional Football Players

Background: Concussions may accelerate the progression to long-term mental health outcomes such as depression in athletes. Purpose: To prospectively determine the effects of recurrent concussions on the clinical diagnosis of depression in a group of retired football players. Study Design: Cohort study; Level of evidence, 2. Methods: Members of the National Football League Retired Players Association responded to a baseline General Health Survey (GHS) in 2001. They also completed a follow-up survey in 2010. Both surveys asked about demographic information, number of concussions sustained during their professional football career, physical/mental health, and prevalence of diagnosed medical conditions. A physical component summary (Short Form 36 Measurement Model for Functional Assessment of Health and Well-Being [SF-36 PCS]) was calculated from responses for physical health. The main exposure, the history of concussions during the professional playing career (self-report recalled in 2010), was stratified into 5 categories: 0 (referent), 1 to 2, 3 to 4, 5 to 9, and 10+ concussions. The main outcome was a clinical diagnosis of depression between the baseline and follow-up GHS. Classic tabular methods computed crude risk ratios. Binomial regression with a Poisson residual and robust variance estimation to stabilize the fitting algorithm estimated adjusted risk ratios. χ2 analyses identified associations and trends between concussion history and the 9-year risk of a depression diagnosis. Results: Of the 1044 respondents with complete data from the baseline and follow-up GHS, 106 (10.2%) reported being clinically diagnosed as depressed between the baseline and follow-up GHS. Approximately 65% of all respondents self-reported sustaining at least 1 concussion during their professional careers. The 9-year risk of a depression diagnosis increased with an increasing number of self-reported concussions, ranging from 3.0% in the “no concussions” group to 26.8% in the “10+” group (linear trend: P < .001). A strong dose-response relationship was observed even after controlling for confounders (years retired from professional football and 2001 SF-36 PCS). Retired athletes with a depression diagnosis also had a lower SF-36 PCS before diagnosis. The association between concussions and depression was independent of the relationship between decreased physical health and depression. Conclusion: Professional football players self-reporting concussions are at greater risk for having depressive episodes later in life compared with those retired players self-reporting no concussions.

Epidemiology of Sports-Related Concussion in NCAA Athletes From 2009-2010 to 2013-2014 Incidence, Recurrence, and Mechanisms

Background: The epidemiology of sports-related concussion (SRC) among student-athletes has been extensively researched. However, recent data at the collegiate level are limited. Purpose: To describe the epidemiology of SRC in 25 National Collegiate Athletic Association (NCAA) sports. Study Design: Descriptive epidemiology study. Methods: SRC data from the NCAA Injury Surveillance Program during the 2009-2010 to 2013-2014 academic years were analyzed. Concussion injury rates, rate ratios (RRs), and injury proportion ratios were reported with 95% CIs. National estimates were also calculated to examine linear trends across time. Results: During the study period, 1670 SRCs were reported, representing a national estimate of 10,560 SRCs reported annually. Among the 25 sports, the overall concussion rate was 4.47 per 10,000 athlete-exposures (AEs) (95% CI, 4.25-4.68). Overall, more SRCs occurred in competitions (53.2%). The competition rate (12.81 per 10,000 AEs) was larger than the practice rate (2.57 per 10,000 AEs) (competition vs practice, RR = 4.99; 95% CI, 4.53-5.49). Of all SRCs, 9.0% were recurrent. Most SRCs occurred from player contact (68.0%). The largest concussion rates were in men’s wrestling (10.92 per 10,000 AEs; 95% CI, 8.62-13.23), men’s ice hockey (7.91 per 10,000 AEs; 95% CI, 6.87-8.95), women’s ice hockey (7.50 per 10,000 AEs; 95% CI, 5.91-9.10), and men’s football (6.71 per 10,000 AEs; 95% CI, 6.17-7.24). However, men’s football had the largest annual estimate of reported SRCs (n = 3417), followed by women’s soccer (n = 1113) and women’s basketball (n = 998). Among all SRCs, a linear trend did not exist in national estimates across time (P = .17). However, increases were found within specific sports, such as men’s football, women’s ice hockey, and men’s lacrosse. Conclusion: The estimated number of nationally reported SRCs has increased within specific sports. However, it is unknown whether these increases are attributable to increased reporting or frequency of concussions. Many sports report more SRCs in practice than in competition, although competition rates are higher. Men’s wrestling and men’s and women’s ice hockey have the highest reported concussion rates. Men’s football had the highest annual national estimate of reported SRCs, although the annual participation count was also the highest. Future research should continue to longitudinally examine SRC incidence while considering differences by sex, division, and level of competition.

National Collegiate Athletic Association Injury Surveillance System: Review of Methods for 2004–2005 Through 2013–2014 Data Collection

BACKGROUND Since 1982, the National Collegiate Athletic Association has used the Injury Surveillance System (ISS) to collect injury and athlete-exposure data from a representative sample of collegiate institutions and sports. At the start of the 2004-2005 academic year, a Web-based ISS replaced the paper-based platform previously used for reporting injuries and exposures. OBJECTIVE To describe the methods of the Web-based National Collegiate Athletic Association ISS for data collection as implemented from the 2004-2005 to 2013-2014 academic years. DESCRIPTION The Web-based ISS monitored National Collegiate Athletic Association-sanctioned practices and competitions, the number of participating student-athletes, and time-loss injuries during the preseason, regular season, and postseason in 25 collegiate sports. Starting in the 2009-2010 academic year, non-time-loss injuries were also tracked. Efforts were made to better integrate ISS data collection into the workflow of collegiate athletic trainers. Data for the 2004-2005 to 2013-2014 academic years are available to researchers through a standardized application process available at the Datalys Center Web site. CONCLUSIONS As of February 2014, more than 1 dozen data sets have been provided to researchers. The Datalys Center encourages applications for access to the data.

Incidence of concussion during practice and games in youth, high school, and collegiate American football players

IMPORTANCE A report by the Institute of Medicine called for comprehensive nationwide concussion incidence data across the spectrum of athletes aged 5 to 23 years. OBJECTIVE To describe the incidence of concussion in athletes participating in youth, high school, and collegiate American football. DESIGN, SETTING, AND PARTICIPANTS Data were collected by athletic trainers at youth, high school, and collegiate football practices and games to create multiple prospective observational cohorts during the 2012 and 2013 football seasons. Data were collected from July 1, 2012, through January 31, 2013, for the 2012 season and from July 1, 2013, through January 31, 2014, for the 2013 season. The Youth Football Surveillance System included 118 youth football teams, providing 4092 athlete-seasons. The National Athletic Treatment, Injury and Outcomes Network program included 96 secondary school football programs, providing 11 957 athlete-seasons. The National Collegiate Athletic Association Injury Surveillance Program included 24 member institutions, providing 4305 athlete-seasons. EXPOSURES All injuries regardless of severity, including concussions, and athlete exposure information were documented by athletic trainers during practices and games. MAIN OUTCOMES AND MEASURES Injury rates, injury rate ratios, risks, risk ratios, and 95% CIs were calculated. RESULTS Concussions comprised 9.6%, 4.0%, and 8.0% of all injuries reported in the Youth Football Surveillance System; National Athletic Treatment, Injury and Outcomes Network; and National Collegiate Athletic Association Injury Surveillance Program, respectively. The game concussion rate was higher than the practice concussion rate across all 3 competitive levels. The game concussion rate for college athletes (3.74 per 1000 athlete exposures) was higher than those for high school athletes (injury rate ratio, 1.86; 95% CI, 1.50-2.31) and youth athletes (injury rate ratio, 1.57; 95% CI, 1.17-2.10). The practice concussion rate in college (0.53 per 1000 athlete exposures) was lower than that in high school (injury rate ratio, 0.80; 95% CI, 0.67-0.96). Youth football had the lowest 1-season concussion risks in 2012 (3.53%) and 2013 (3.13%). The 1-season concussion risk was highest in high school (9.98%) and college (5.54%) in 2012. CONCLUSIONS AND RELEVANCE Football practices were a major source of concussion at all 3 levels of competition. Concussions during practice might be mitigated and should prompt an evaluation of technique and head impact exposure. Although it is more difficult to change the intensity or conditions of a game, many strategies can be used during practice to limit player-to-player contact and other potentially injurious behaviors.

Identifying Impairments after Concussion: Normative Data versus Individualized Baselines

PURPOSE This study aimed to determine whether agreement exists between baseline comparison (comparison of postconcussion scores to individualized baseline scores) and normative comparison (comparison of postconcussion scores to a normative mean) in identifying impairments after concussion. METHODS A total of 1060 collegiate student-athletes completed baseline testing as part of an ongoing clinical program. Gender-specific normative means were obtained from a subset of 673 athletes with no history of self-reported concussion, learning disabilities, or attention-deficit disorders. Concussions were later diagnosed in 258 athletes who had completed baseline testing. The athletes completed their first assessment within 10 d after injury. Athletes completed a computerized neurocognitive test (Automated Neuropsychological Assessment Metrics), postural control assessment (Sensory Organization Test), and a 15-item graded symptom checklist at baseline and again after injury. We computed two postconcussion difference scores for each outcome measure: 1) baseline difference = postconcussion score--individualized baseline score and 2) normative difference = postconcussion score--normative mean. Athletes were considered impaired if postconcussion difference exceeded the reliable change parameters. McNemar tests were used to assess agreement on impairment status (impaired and unimpaired) between comparison methods for each outcome measure. RESULTS The baseline comparison method identified 2.6 times more impairments than the normative comparison method for the Simple Reaction Time Test 1 (P = 0.043). The normative comparison method identified 7.6 times more impairments than the baseline comparison method for Mathematical Processing (P < 0.001). No other disagreements were observed for postural control or symptom severity. CONCLUSIONS Our findings suggest that, when using these concussion assessment tools, clinicians may consider using normative data in lieu of individualized baseline measures. This may be especially useful to clinicians with limited resources and an inability to capture valid baselines on all athletes.

Disclosure and non-disclosure of concussion and concussion symptoms in athletes: review and application of the socio-ecological framework

Abstract Primary objective: To summarize the factors associated with athletes’ disclosure—and non-disclosure—of sports-related concussion and concussion symptoms within the context of the socio-ecological framework and to identify research gaps in the current literature. Methods: Searches using electronic databases identified studies written in English, published through October 2013 and addressing some aspect of disclosure of concussion and concussion symptoms. The literature search aimed to be comprehensive and inclusive of all previous contributions. Main outcomes and results: Of the 30 identified studies, most originated from the US (n = 19) and sampled athletes (n = 21) and coaches (n = 10) from high school (n = 11) and college levels (n = 9). The identified reasons for non-disclosure were organized into four levels using the socio-ecological framework: intra-personal (e.g. lack of knowledge; internal pressure; sex; concussion history; n = 20 studies); inter-personal (e.g. others’ knowledge/attitudes; external pressure; external support; n = 15 studies); environment (e.g. access to concussion prevention materials; sports culture; n = 4 studies); and policy (e.g. concussion-related legislation; n = 3 studies). No study examined all four levels. Conclusions: Research gaps exist concerning factors influencing athletes’ disclosure of sports-related concussions and concussion symptoms. Notably, researchers have focused on intra-personal and inter-personal levels, placing less emphasis on the environment and policy levels.

Reliable change, sensitivity, and specificity of a multidimensional concussion assessment battery: implications for caution in clinical practice.

Objective:To provide reliable change confidence intervals for common clinical concussion measures using a healthy sample of collegiate athletes and to apply these reliable change parameters to a sample of concussed collegiate athletes. Methods:Two independent samples were included in the study and evaluated on common clinical measures of concussion. The healthy sample included male, collegiate football student-athletes (n = 38) assessed at 2 time points. The concussed sample included college-aged student-athletes (n = 132) evaluated before and after a concussion. Outcome measures included symptom severity scores, Automated Neuropsychological Assessment Metrics throughput scores, and Sensory Organization Test composite scores. Results:Application of the reliable change parameters suggests that a small percentage of concussed participants were impaired on each measure. We identified a low sensitivity of the entire battery (all measures combined) of 50% but high specificity of 96%. Conclusions:Clinicians should be trained in understanding clinical concussion measures and should be aware of evidence suggesting the multifaceted battery is more sensitive than any single measure. Clinicians should be cautioned that sensitivity to balance and neurocognitive impairments was low for each individual measure. Applying the confidence intervals to our injured sample suggests that these measures do not adequately identify postconcussion impairments when used in isolation.

Epidemiology of Exertional Heat Illness Among U.S. High School Athletes

BACKGROUND It is estimated that more than 9000 high school athletes are treated for exertional heat illness annually. Risk factors include being obese and beginning practice during hot and humid weather, when athletes are not yet acclimated to physical exertion in heat. PURPOSE To describe the epidemiology of exertional heat illness in high school athletes. METHODS National High School Sports-Related Injury Surveillance System data (2005/2006-2010/2011) were analyzed in 2012 to calculate rates and describe circumstances of exertional heat illness. RESULTS Exertional heat illness occurred at a rate of 1.20 per 100,000 athlete exposures (95% CI=1.12, 1.28). Exertional heat illnesses were widely distributed geographically, and most occurred in August (60.3%). Of the exertional heat illnesses reported during practice, almost one third (32.0%) occurred more than 2 hours into the practice session. The exertional heat illness rate in football (4.42 per 100,000 athlete exposures) was 11.4 times that in all other sports combined (95% CI=8.3, 15.5, p<0.001). In addition, approximately one third (33.6%) of exertional heat illnesses occurred when a medical professional was not onsite at the time of onset. CONCLUSIONS Although most exertional heat illnesses occurred in football, athletes in all sports and all geographic areas are at risk. Because exertional heat illness frequently occurs when medical professionals are not present, it is imperative that high school athletes, coaches, administrators, and parents are trained to identify and respond to it. Implementing effective preventive measures depends on increasing awareness of exertional heat illness and relevant preventive and therapeutic countermeasures.

Recovery of Posttraumatic Migraine Characteristics in Patients After Mild Traumatic Brain Injury

Background: Headache-related symptoms may be predictive of delayed recovery in student athletes after sport-related concussion. Purpose and Hypothesis: To compare balance performance, cognitive function, and symptom recovery in concussed student athletes with no headache, those with posttraumatic headache, and those with characteristics of posttraumatic migraine following a sport-related concussion. It was hypothesized that those with posttraumatic migraine would take longer to recover on all clinical measures. Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: A total of 296 student athletes who sustained sport-related concussions (migraine, 52; headache, 176; no headache, 68) were evaluated on measures of balance performance, cognition, and symptoms. Patients were categorized into posttraumatic migraine, posttraumatic headache, and no headache groups based on symptoms reported 1 day after injury. Serial testing was conducted with the Balance Error Scoring System, the Standardized Assessment of Concussion, and a graded symptom checklist to evaluate balance performance, cognition, and symptoms, respectively, at baseline, at the time of injury, after the event, and at days 1, 2, 3, 5, 7, and 90. Results: Student athletes with posttraumatic migraine experienced greater symptom severity scores than did those with posttraumatic headache and no headache at the time of injury, after the event, and through day 7 (P < .001 for all). By day 7, symptom severity scores reported by patients with posttraumatic migraine still demonstrated deficits relative to baseline (Δ = 5.6 ± 1.2) compared with patients with headache (Δ = −0.8 ± 0.7) and those with no headache (Δ = −1.4 ± 1.1). Patients with headache experienced greater symptom severity scores than patients with no headache at the time of injury (P < .001), after the event (P < .001), and at day 1 (P < .001), day 2 (P = .005), and day 3 (P = .038). Much smaller differences were observed between the headache and no headache groups beyond day 3 (P > .05). There were no group differences on balance performance (P = .439) and cognitive testing (P = .200) over time. Female patients were 2.13 times more likely than males to report posttraumatic migraine characteristics after concussion. Conclusion: Posttraumatic migraine characteristics are related to prolonged symptom recovery after sport-related concussion. Clinicians should exercise caution in making decisions about return to participation for athletes with migraine-like symptoms given the increased short-term impairments and delayed symptom recovery we observed.

Epidemiology of Sports-Related Concussions in National Collegiate Athletic Association Athletes From 2009-2010 to 2013-2014: Symptom Prevalence, Symptom Resolution Time, and Return-to-Play Time

Background: Limited data exist among collegiate student-athletes on the epidemiology of sports-related concussion (SRC) outcomes, such as symptoms, symptom resolution time, and return-to-play time. Purpose: This study used the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) to describe the epidemiology of SRC outcomes in 25 collegiate sports. Study Design: Descriptive epidemiology study. Methods: SRC data from the NCAA ISP during the 2009-2010 to 2013-2014 academic years were analyzed regarding symptoms, time to resolution of symptoms, and time to return to play. Findings were also stratified by sex in sex-comparable sports (ie, ice hockey, soccer, basketball, lacrosse, baseball/softball) and whether SRCs were reported as recurrent. Results: Of the 1670 concussions reported during the 2009-2010 to 2013-2014 academic years, an average (±SD) of 5.29 ± 2.94 concussion symptoms were reported, with the most common being headache (92.2%) and dizziness (68.9%). Most concussions had symptoms resolve within 1 week (60.1%); however, 6.2% had a symptom resolution time of over 4 weeks. Additionally, 8.9% of concussions required over 4 weeks before return to play. The proportion of SRCs that required at least 1 week before return to play increased from 42.7% in 2009-2010 to 70.2% in 2013-2014 (linear trend, P < .001). Within sex-comparable sports analyses, the average number of symptoms and symptom resolution time did not differ by sex. However, a larger proportion of concussions in male athletes included amnesia and disorientation; a larger proportion of concussions in female athletes included headache, excess drowsiness, and nausea/vomiting. A total of 151 SRCs (9.0%) were reported as recurrent. The average number of symptoms reported with recurrent SRCs (5.99 ± 3.43) was greater than that of nonrecurrent SRCs (5.22 ± 2.88; P = .01). A greater proportion of recurrent SRCs also resulted in a long symptom resolution time (14.6% vs 5.4%, respectively; P < .001) and long return-to-play time (21.2% vs 7.7%, respectively; P < .001) compared with nonrecurrent SRCs. Conclusion: Trends in return-to-play time may indicate changing concussion management practices in which team medical staff members withhold players from participation longer to ensure symptom resolution. Concussion symptoms may differ by sex and recurrence. Future research should continue to examine the trends and discrepancies in symptom resolution time and return-to-play time.