Concussions and Football By The Numbers

December 6, 2013

By Benjamin G. Wu

Peer Reviewed

The news of a large $675 million dollar settlement on concussions has headlined on both the sports news channels and in popular media during this 2013 National Football League (N.F.L.) season [1]. Heralded as a victory mainly for the N.F.L., the settlement not only allows the league to avoid larger amounts in potential liability payments but also the public scrutiny of a discovery phase if a case were to move forward [1]. In the wake of this settlement there are many lingering questions regarding the research of sports-related concussions, helmet design, and safety regulations to protect players at all levels of the popular American pastime.

As concern grew that concussive and sub-concussive impacts may contribute to mild traumatic brain injury (MTBI) and concussive traumatic encephalopathy (CTE) high school, college, and professional football leagues have started tracking the prevalence of concussions over the past decade. [2,4]. High profile cases have the medical and legal world paying more attention to the response and actions taken by the N.FL. [1,4]. The death of the ex-N.F.L. player Andre Waters made national headlines in 2006 as a partial autopsy by Dr. Bennet Omalu revealed diffuse cerebral taupathy [5,6]. Even the United States Congress has attempted to pass a bill to create national guidelines for concussions in young athletes. The bill currently sits in Committee [7,8].

The question is: how widespread are concussions in sports? Surprisingly, an estimated 3.8 million concussions happen every year during competitive and recreational activities [2,9-10]. The rate of concussions found in high school and collegiate sports is 2.4-2.5 concussions per 10,000 athletic exposures [10]. The highest rate of concussions for females occurred in soccer. Predictably, male football players had the highest incidence of concussions [10]. The overall incidence of concussions in sports is estimated to be much higher secondary to under-reporting; an estimated 50% of concussions may go un-reported [2]. A concussion is a clinical diagnosis and involves several criteria including a change in consciousness from confusion or amnesia [11-13]. As we understand more about concussions and their sequelae, the threshold for diagnosis is lowered and the list of activities associated with concussions grows. This research also has clear implications beyond recreational and profressional sports for armed service members returning from Afghanistan and Iraq who have experienced repetitive explosions from improvised explosive devices (IEDs).

There have been many technological advances protecting players and service-members alike from the perils of concussion. The first football helmet was invented in 1896. The helmet had rudimentary strips of leather protecting the players’ skulls [14]. Despite the use of helmets over the past century there have been no substantial studies that show a decrease in concussions due to helmet use [2]. Researchers recorded a total of 101,944 impacts in a study of 95 high school football players in Michigan over 4 years using the Head Impact Telemetry System (HITS). The average player had 652 impacts over the course of the study [15]. The high school player study raised the question of sub-concussive impacts on the neurologic skills of football players. However, this was inconclusively addressed in a research study of 46 collegiate football players at the University of North Carolina, Chapel Hill. On average, the college players sustained more than 1000 impacts during the football season [16]. Neurological performance markers pre-season and post-season did not differ statistically in the study [16]. The researchers suggested that higher acceleration cutoffs may potentially discern changes, but their lower cutoffs for sub-concussive impacts was to discriminate between normal motions of the head to low intensity impacts. Thus, the authors implied that their threshold might be too low to study small and incremental effects of sub-concussive impacts in their cohort [16].

Despite this, data from the N.F.L. shows that there were a total of 887 MTBIs recorded from 1996-2001 and a total of 854 MTBIs recorded from 2002-2007 [17]. Of these concussions, 152 players had repeat concussions in 2002-2007 and 44 players had more than 3 head injuries [18]. Five players had concussions on the same day and 18 players reported concussions within the next seven days [18]. The data suggest that the most important risk factor of receiving concussions is a history of concussions, those players that receive concussions are at 2-5.8 risk of receiving another [2]. This does not imply that players have underlying physiological factors that promote concussions rather differences may likely be explained by riskier play and adherence to safety guidelines. Thankfully, the advances in the rules and technology have greatly improved the safety of football players.

Decreasing the risk of concussions addresses the immediate and short-term health of our athletes, but also begs the question of long-term effects of being punch-drunk. Health workers and researchers have long noted the connection of repeated blows to the head and dementia pugilistica. The first published description of being punch-drunk was in 1928 by Dr. Martland in New Jersey [19]. Since then, multiple studies have addressed the connection of pathological findings such as abnormal deposition of proteins, neuropathies, and other neurological disorders as a result of multiple concussions or MTBIs [20]. The association of concussions to CTE is not new, but while associations exist, the natural history of mild TBI and its progression to CTE is not well understood. Highly publicized cases and recent congressional hearings signal that there are changes coming to American football, and with this attention comes funding for research that may help us understand these challenges.

As a bellwether, the increasing incidence of concussions has been attributed less to risky play, but better and quicker recognition of concussions in the field [2]. In fact, researchers acknowledge that it is not only the force of the impact that dictates long term sequelae of concussions, but the consistency and repetitive nature of these injuries that lead to pathological damage [13]. In response to the attention, the American Academy of Neurology (AAN) has recommended expert involvement in the evaluation of concussions [21]. The benefit of heightened public attention and the involvement experts for concussions and MTBIs remain to be seen. Psychological factors and expectations of recovery influence the recovery from MTBI and the small implication of permanent brain damage currently colors the debate behind the concussion discussion. Research studies that prognosticate and predict trauma in athletes can help those who lack attention and advocacy to do so. Hopefully with better recognition, research, and rules we can eliminate dangerous head injuries in sports to make them not only safer for players, but also more enjoyable for players, their families, and their fans.

Dr. Benjamin Wu is a 3rd year resident at NYU Langone Medical Center

Peer reviewed by Laura Boylan, MD, Neurology, NYU Langone Medical Center

References:

1. Belson, Ken. “N.F.L. Agrees to Settle Concussion Suit for $765 Million“ New York Times on the Web. 29 Aug. 2013. Retrieved 5 Sept. 2013. http://www.nytimes.com/2013/08/30/sports/football/judge-announces-settlement-in-nfl-concussion-suit.html

2. Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. British Journal of Sports Medicine (2013) vol. 47 (1) pp. 15-26. http://bjsm.bmj.com/content/47/1/15.long

3. Roehr B. Why the NFL is investing in health research. BMJ (2012) vol. 345 pp. e6626. http://www.bmj.com/content/345/bmj.e6626.pdf%2Bhtml

4. Belson, Ken. “Concussion Liability Costs May Rise, and Not Just for N.F.L.” New York Times on the Web. 10 Dec. 2012. Retrieved 3 Jan. 2013. http://www.nytimes.com/2012/12/11/sports/football/insurance-liability-in-nfl-concussion-suits-may-have-costly-consequences.html

5. Omalu BI, Hamilton RL, Kamboh MI, DeKosky ST, Bailes J. Chronic traumatic encephalopathy (CTE) in a National Football League Player: Case report and emerging medicolegal practice questions. J Forensic Nurs (2010) Spring 6 (1) pp. 40-6. http://onlinelibrary.wiley.com/doi/10.1111/j.1939-3938.2010.01078.x/abstract

6. Schwarz, Alan. Expert Ties Ex-Player’s Suicide to Brain Damage. New York Times on the Web. 18 Jan. 2007. Retrieved 3 Jan. 2013. http://www.nytimes.com/2007/01/18/sports/football/18waters.html

7. Schwarz, Alan. Congress Considers Concussion Protections. New York Times on the Web. 23 Sep. 2010. Retrieved 3 Jan. 2013. http://www.nytimes.com/2010/09/24/sports/football/24concussion.html

8. S. 2840–111th Congress: Concussion Treatment and Care Tools Act of 2009. (2009). In www.GovTrack.us. Retrieved January 5, 2013. http://www.govtrack.us/congress/bills/111/s2840

9. Browne GJ, Lam LT. Concussive head injury in children and adolescents related to sports and other leisure physical activities. Br J Sports Med 2006; 40 pp. 163 – 168. http://bjsm.bmj.com/content/40/2/163.long

10. Guerriero RM, Proctor MR, Mannix R, Meehan WP 3rd. Epidemiology, trends, assessment and management of sport-related concussion in United States high schools. Current Opinion in Pediatrics (2012) vol. 24 (6) pp. 696-701. http://journals.lww.com/co-pediatrics/pages/articleviewer.aspx?year=2012&issue=12000&article=00008&type=abstract

11. McCrory P, Johnston K, Meeuwisse W, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. British Journal of Sports Medicine (2005) vol. 39 (4) pp. 196-204. https://physsportsmed.org/doi/10.3810/psm.2005.04.76

12. Casson IR, Pellman EJ, Viano DC.. Concussion in the national football league: an overview for neurologists. Neurol Clin (2008) vol. 26 (1) pp. 217-41; x-xi. http://www.sciencedirect.com/science/article/pii/S0733861907001284

13. Khurana VG, Kaye AH.. An overview of concussion in sport. J Clin Neurosci (2012) vol. 19 (1) pp. 1-11. http://www.jocn-journal.com/article/S0967-5868(11)00441-3/pdf

14. Levy ML, Ozgur BM, Berry C, Aryan HE, Apuzzo ML. Birth and evolution of the football helmet. Neurosurgery (2004) vol. 55 (3) pp. 656-61; discussion 661-2. http://journals.lww.com/neurosurgery/pages/articleviewer.aspx?year=2004&issue=09000&article=00022&type=abstract

15. Broglio SP, Eckner JT, Martini D, et al. Cumulative head impact burden in high school football. Journal of Neurotrauma (2011) vol. 28 (10) pp. 2069-78. http://online.liebertpub.com/doi/abs/10.1089/neu.2011.1825

16. Gysland SM, Mihalik JP, Register-Mihalik JK, Trulock SC, Shields EW, Guskiewicz KM. The relationship between subconcussive impacts and concussion history on clinical measures of neurologic function in collegiate football players. Ann Biomed Eng. 2012 Jan;40(1):14-22. http://link.springer.com/article/10.1007%2Fs10439-011-0421-3

17. Casson IR, Viano DC, Powell JW, Pellman EJ. Twelve years of national football league concussion data. Sports Health: A Multidisciplinary Approach (2010) vol. 2 (6) pp. 471-83. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3438866/

18. Casson IR, Viano DC, Powell JW, Pellman EJ. Repeat concussions in the national football league. Sports Health: A Multidisciplinary Approach (2011) vol. 3 (1) pp. 11-24. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445193/

19. Martland HS. Punch drunk. Journal of the American Medical Association (1928) vol. 91 (15) pp. 1103-1107. http://jama.jamanetwork.com/article.aspx?articleid=260461

20. McKee AC, Cantu RC, Nowinski CJ, et al. Chronic traumatic encephalopathy in athletes: progressive tauopathy after repetitive head injury. Journal of Neuropathology and Experimental Neurology (2009) vol. 68 (7) pp. 709-35. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2945234/

21. Giza CG, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013 Jun 11;80(24):2250-7. doi: 10.1212/WNL.0b013e31828d57dd. Epub 2013 Mar 18. http://http://www.neurology.org/content/80/24/2250.long

 

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