Gary S. Solomon

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.

Baseline Neurocognitive Testing in Sports-Related Concussions The Importance of a Prior Night’s Sleep

Background: The management of sports-related concussions (SRCs) utilizes serial neurocognitive assessments and self-reported symptom inventories to assess recovery and safety for return to play (RTP). Because postconcussive RTP goals include symptom resolution and a return to neurocognitive baseline levels, clinical decisions rest in part on understanding modifiers of this baseline. Several studies have reported age and sex to influence baseline neurocognitive performance, but few have assessed the potential effect of sleep. We chose to investigate the effect of reported sleep duration on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) performance and the number of patient-reported symptoms. Hypothesis: We hypothesized that athletes receiving less sleep before baseline testing would perform worse on neurocognitive metrics and report more symptoms. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We retrospectively reviewed 3686 nonconcussed athletes (2371 male, 1315 female; 3305 high school, 381 college) with baseline symptom and ImPACT neurocognitive scores. Patients were stratified into 3 groups based on self-reported sleep duration the night before testing: (1) short, <7 hours; (2) intermediate, 7-9 hours; and (3) long, ≥9 hours. A multivariate analysis of covariance (MANCOVA) with an α level of .05 was used to assess the influence of sleep duration on baseline ImPACT performance. A univariate ANCOVA was performed to investigate the influence of sleep on total self-reported symptoms. Results: When controlling for age and sex as covariates, the MANCOVA revealed significant group differences on ImPACT reaction time, verbal memory, and visual memory scores but not visual-motor (processing) speed scores. An ANCOVA also revealed significant group differences in total reported symptoms. For baseline symptoms and ImPACT scores, subsequent pairwise comparisons revealed these associations to be most significant when comparing the short and intermediate sleep groups. Conclusion: Our results indicate that athletes sleeping fewer than 7 hours before baseline testing perform worse on 3 of 4 ImPACT scores and report more symptoms. Because SRC management and RTP decisions hinge on the comparison with a reliable baseline evaluation, clinicians should consider sleep duration before baseline neurocognitive testing as a potential factor in the assessment of athletes’ recovery.

Prevalence of Invalid Computerized Baseline Neurocognitive Test Results in High School and Collegiate Athletes

CONTEXT Limited data are available regarding the prevalence and nature of invalid computerized baseline neurocognitive test data. OBJECTIVE To identify the prevalence of invalid baselines on the desktop and online versions of ImPACT and to document the utility of correcting for left-right (L-R) confusion on the desktop version of ImPACT. DESIGN Cross-sectional study of independent samples of high school (HS) and collegiate athletes who completed the desktop or online versions of ImPACT. Participants or Other Participants: A total of 3769 HS (desktop = 1617, online = 2152) and 2130 collegiate (desktop = 742, online = 1388) athletes completed preseason baseline assessments. MAIN OUTCOME MEASURE(S) Prevalence of = ImPACT validity indicators, with correction for L-R confusion (reversing left and right mouse-click responses) on the desktop version, by test version and group. Chi-square analyses were conducted for sex and attentional or learning disorders. RESULTS At least 1 invalid indicator was present on 11.9% (desktop) versus 6.3% (online) of the HS baselines and 10.2% (desktop) versus 4.1% (online) of collegiate baselines; correcting for L-R confusion (desktop) decreased this overall prevalence to 8.4% (HS) and 7.5% (collegiate). Online Impulse Control scores alone yielded 0.4% (HS) and 0.9% (collegiate) invalid baselines, compared with 9.0% (HS) and 5.4% (collegiate) on the desktop version; correcting for L-R confusion (desktop) decreased the prevalence of invalid Impulse Control scores to 5.4% (HS) and 2.6% (collegiate). Male athletes and HS athletes with attention deficit or learning disorders who took the online version were more likely to have at least 1 invalid indicator. Utility of additional invalidity indicators is reported. CONCLUSIONS The online ImPACT version appeared to yield fewer invalid baseline results than did the desktop version. Identification of L-R confusion reduces the prevalence of invalid baselines (desktop only) and the potency of Impulse Control as a validity indicator. We advise test administrators to be vigilant in identifying invalid baseline results as part of routine concussion management and prevention programs.

Predictors of clinical recovery from concussion: a systematic review.

Objective A systematic review of factors that might be associated with, or influence, clinical recovery from sport-related concussion. Clinical recovery was defined functionally as a return to normal activities, including school and sports, following injury. Design Systematic review. Data sources PubMed, PsycINFO, MEDLINE, CINAHL, Cochrane Library, EMBASE, SPORTDiscus, Scopus and Web of Science. Eligibility criteria for selecting studies Studies published by June of 2016 that addressed clinical recovery from concussion. Results A total of 7617 articles were identified using the search strategy, and 101 articles were included. There are major methodological differences across the studies. Many different clinical outcomes were measured, such as symptoms, cognition, balance, return to school and return to sports, although symptom outcomes were the most frequently measured. The most consistent predictor of slower recovery from concussion is the severity of a person’s acute and subacute symptoms. The development of subacute problems with headaches or depression is likely a risk factor for persistent symptoms lasting greater than a month. Those with a preinjury history of mental health problems appear to be at greater risk for having persistent symptoms. Those with attention deficit hyperactivity disorder (ADHD) or learning disabilities do not appear to be at substantially greater risk. There is some evidence that the teenage years, particularly high school, might be the most vulnerable time period for having persistent symptoms—with greater risk for girls than boys. Conclusion The literature on clinical recovery from sport-related concussion has grown dramatically, is mostly mixed, but some factors have emerged as being related to outcome.

Statements of Agreement From the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion Meeting Held in Pittsburgh, October 15-16, 2015

BACKGROUND Conventional management for concussion involves prescribed rest and progressive return to activity. Recent evidence challenges this notion and suggests that active approaches may be effective for some patients. Previous concussion consensus statements provide limited guidance regarding active treatment. OBJECTIVE To describe the current landscape of treatment for concussion and to provide summary agreements related to treatment to assist clinicians in the treatment of concussion. METHODS On October 14 to 16, 2015, the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion meeting was convened in Pittsburgh, Pennsylvania. Thirty-seven concussion experts from neuropsychology, neurology, neurosurgery, sports medicine, physical medicine and rehabilitation, physical therapy, athletic training, and research and 12 individuals representing sport, military, and public health organizations attended the meeting. The 37 experts indicated their agreement on a series of statements using an audience response system clicker device. RESULTS A total of 16 statements of agreement were supported covering (1) Summary of the Current Approach to Treating Concussion, (2) Heterogeneity and Evolving Clinical Profiles of Concussion, (3) TEAM Approach to Concussion Treatment: Specific Strategies, and (4) Future Directions: A Call to Research. Support (ie, response of agree or somewhat agree) for the statements ranged from to 97% to 100%. CONCLUSION Concussions are characterized by diverse symptoms and impairments and evolving clinical profiles; recovery varies on the basis of modifying factors, injury severity, and treatments. Active and targeted treatments may enhance recovery after concussion. Research is needed on concussion clinical profiles, biomarkers, and the effectiveness and timing of treatments. ABBREVIATIONS ARS, audience response systemCDC, Centers for Disease Control and PreventionDoD, Department of DefensemTBI, mild traumatic brain injuryNCAA, National Collegiate Athletic AssociationNFL, National Football LeagueNIH, National Institutes of HealthRCT, randomized controlled trialRTP, return to playSRC, sport- and recreation-related concussionTBI, traumatic brain injuryTEAM, Targeted Evaluation and Active Management.

Long-term Neurocognitive Dysfunction in Sports: What Is the Evidence?

Although the immediate neurocognitive effects of sports-related concussion are well known, less is known about the intermediate or long-term effects of sports-related concussions. A sample of selected studies of high-school and collegiate athletes is reviewed and the intermediate effects of concussive injuries are discussed, because no long-term empiric data are available with these populations. The evidence for intermediate neurocognitive effects is mixed and not convincing at present in these groups of athletes. Selected studies of professional boxers and American professional football players are also reviewed, and the available data regarding long-term neurocognitive and neuropathologic effects are assessed. The evidence for long-term adverse neurocognitive effects in professional boxers is compelling. Suggestions for future research on relevant biopsychosocial variables affecting response to concussive injury are presented.

Depression as a Modifying Factor in Sport-Related Concussion: A Critical Review of the Literature

Abstract Since its third iteration in 2008, the international Concussion in Sport Group (CISG) has delineated several ‘modifying factors’ that have the potential to influence the management of sport-related concussions (SRC). One of these factors is co- and pre-morbidities, which includes migraines, mental health disorders, attention-deficit hyperactive disorder (ADHD), learning disability, and sleep disorders. Mental health disorders, and in particular, depression, have received some attention in the management of SRC and in this review we summarize the empirical evidence for its inclusion as a modifying factor. This review is divided into three main bodies of findings: (1) the incidence and prevalence of depression and depressive symptoms in non-concussed and concussed athletes, with comparison made to the general population; (2) managing the post-concussion athlete and accounting for premorbid depressive symptoms; and (3) depression as a long-term effect of repetitive head trauma. Overall, it has been reported that certain subpopulations of athletes have similar or even higher rates of depressive symptoms when compared to the general population. The challenge of accounting for these baseline-depressive symptoms while managing the post-concussive athlete is stressed. And lastly, the prevalence of depression and its relationship to concussion in later-life is discussed.

Chronic traumatic encephalopathy in professional sports: Retrospective and prospective views

Abstract Primary objective: The purposes of this paper are to review: (1) the history of chronic traumatic encephalopathy (CTE) in sports, (2) the similarities and differences between historic and current definitions of CTE, (3) recent epidemiology and cohort studies of CTE and (4) controversies regarding the current CTE positions. Research design: Not applicable. Methods and procedures: Selective review of published articles relevant to CTE. Main outcome and results: The current definitions of CTE have evolved from its original definition and now rely heavily on the post-mortem detection of hyperphosphorylated tau for diagnosis. As of 2013, there is a blended cohort of 110 professional athletes diagnosed with CTE. It is being assumed that concussions and/or sub-concussive impacts in contact sports are the sole cause of CTE. Conclusions: There are multiple causes of abnormal tau protein deposition in the human brain and the pathogenesis of CTE may not be related solely to concussion and/or sub-concussive injury. In all likelihood, the causes of CTE are a multivariate, as opposed to a univariate, phenomenon.

Participation in Pre–High School Football and Neurological, Neuroradiological, and Neuropsychological Findings in Later Life A Study of 45 Retired National Football League Players

Background: A recent study found that an earlier age of first exposure (AFE) to tackle football was associated with long-term neurocognitive impairment in retired National Football League (NFL) players. Purpose: To assess the association between years of exposure to pre–high school football (PreYOE) and neuroradiological, neurological, and neuropsychological outcome measures in a different sample of retired NFL players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Forty-five former NFL players were included in this study. All participants prospectively completed extensive history taking, a neurological examination, brain magnetic resonance imaging, and a comprehensive battery of neuropsychological tests. To measure the associations between PreYOE and these outcome measures, multiple regression models were utilized while controlling for several covariates. Results: After applying a Bonferroni correction for multiple comparisons, none of the neurological, neuroradiological, or neuropsychological outcome measures yielded a significant relationship with PreYOE. A second Bonferroni-corrected analysis of a subset of these athletes with self-reported learning disability yielded no significant relationships on paper-and-pencil neurocognitive tests but did result in a significant association between learning disability and computerized indices of visual motor speed and reaction time. Conclusion: The current study failed to replicate the results of a prior study, which concluded that an earlier AFE to tackle football might result in long-term neurocognitive deficits. In 45 retired NFL athletes, there were no associations between PreYOE and neuroradiological, neurological, and neuropsychological outcome measures.

What domains of clinical function should be assessed after sport-related concussion? A systematic review

Background Sport-related concussion (SRC) is a clinical diagnosis made after a sport-related head trauma. Inconsistency exists regarding appropriate methods for assessing SRC, which focus largely on symptom-scores, neurocognitive functioning and postural stability. Design Systematic literature review. Data sources MEDLINE, EMBASE, PsycINFO, Cochrane-DSR, Cochrane CRCT, CINAHL, SPORTDiscus (accessed July 9, 2016). Eligibility criteria for selecting studies Original (prospective) studies reporting on postinjury assessment in a clinical setting and evaluation of diagnostic tools within 2 weeks after an SRC. Results Forty-six studies covering 3284 athletes were included out of 2170 articles. Only the prospective studies were considered for final analysis (n=33; 2416 athletes). Concussion diagnosis was typically made on the sideline by an (certified) athletic trainer (55.0%), mainly on the basis of results from a symptom-based questionnaire. Clinical domains affected included cognitive, vestibular and headache/migraine. Headache, fatigue, difficulty concentrating and dizziness were the symptoms most frequently reported. Neurocognitive testing was used in 30/33 studies (90.9%), whereas balance was assessed in 9/33 studies (27.3%). Summary/conclusions The overall quality of the studies was considered low. The absence of an objective, gold standard criterion makes the accurate diagnosis of SRC challenging. Current approaches tend to emphasise cognition, symptom assessment and postural stability with less of a focus on other domains of functioning. We propose that the clinical assessment of SRC should be symptom based and interdisciplinary. Whenever possible, the SRC assessment should incorporate neurological, vestibular, ocular motor, visual, neurocognitive, psychological and cervical aspects.