Concussions – Part 3: Football and CTE
We’ve all heard much about the dangers of football and the alarming incidence of concussions in the sport. Also about the NFL’s initial resistance to acknowledging the probable relationship of concussions to Chronic Traumatic Encephalopathy (CTE), which currently can only be diagnosed on autopsy.
CTE – as defined by the Boston University CTE Center16 – is “a progressive degenerative disease of the brain found in athletes (and others) with a history of repetitive brain trauma, including symptomatic concussions as well as asymptomatic subconcussive hits to the head… This trauma triggers progressive degeneration of the brain tissue, including the build-up of an abnormal protein called tau. These changes in the brain can begin months, years, or even decades after the last brain trauma or end of active athletic involvement. The brain degeneration is associated with memory loss, confusion, impaired judgment, impulse control problems, aggression, depression, and, eventually, progressive dementia.”
The concern many have is not only for the health and safety of the athletes. Others who have suffered mild traumatic brain injury want to know if they are susceptible to CTE as well. No one really has that answer yet. However, lets look carefully at the information that is out there and how it can be interpreted.
First, scary as it may be, recognize that the high incidence of CTE reported in studies reflects several biases. The most significant of these is self-selection. The brains that have been examined on autopsy are primarily those of athletes who have donated their brains for research due to symptoms they’ve experienced, or those whose family has suspected the diagnosis. This clearly inflates the percentages of athletes diagnosed with the condition.
One such study done by Boston University and the US Department of Veteran’s Affairs17 established that 87 of 91 football players had signs of CTE on autopsy, while Boston University also found the condition in 79% (131 of 165) of football players across all levels.17
These frightening results are mildly contrasted by another study18 that looked at 60+ former NFL players – all aged 60-69 – to try to identify symptoms of CTE in living people. Their age range indicates that these were players who played before heightened concussion awareness and before protocols were initiated by the NFL. The results showed that 60% had completely normal age-appropriate cognitive decline. Of the remaining 40%, 6% met the criteria for dementia. It would be interesting – and possibly revealing – to be able to correlate the findings on these men with how their brains subsequently present on autopsy.
Though this group also played before helmets were improved, the sturdier helmets may even have encouraged harder hitting. The NFL’s response has included recent rule changes to modulate direct hits to the head, though the game will likely see an even greater proportion of debilitating but less threatening lower body injuries as a result. The players of today are also typically stronger, bigger and faster than those in the era of those tested in this study. This too likely influences the frequency and outcomes of traumas that they experience.
Though the brain has the ability to recover from one injury, long-term effects are more likely after multiple incidents.
However, keep in mind that football players sustain blows to the head (direct and/or indirect) on almost every play. This cumulative subconcussive microtrauma may be as much or more of a factor in causing CTE than one or few isolated incidents of concussive trauma. Not at all good for football or soccer players, but an encouraging note for others who fear the long term effects of having sustained a concussion, or even several of them.
Vulnerability differs amongst athletes on the field. Dr. Steven Erickson noted that offensive linemen face forces “that are generally linear and the players know they are coming. Consequently, the head doesn’t move very much, so the brain doesn’t move very much. This may still represent brain trauma, but less often to the degree of causing concussion.”
He contrasted this with receivers. Though the “magnitude of the forces they sustain may be lower, the rotational component to the trauma, the player not being able to anticipate the nature of the hit and the degree of subsequent brain motion all make it more likely they will sustain a clinical concussion.”
A study by the Mayo Clinic, published in December 2015, found that one in three amateur athletes who participated in contact sports while in school developed CTE. 19 That statistic will likely cause even more scrutiny of the games and cause some to weigh the risk-reward of participation differently than before. Again though, this study also reflected issues of self-selection.
I asked Dr. Erickson about the cheating (underperforming) on baseline screening that we have read about occurring in the NFL, and whether this effort by some players to lessen the likelihood that a subsequent concussion will be diagnosed can be detected.
His response was that “though it may be possible, there are internal checks with ImPACT™ whereby validity scores can generally identify when an individual is cheating.”
Dr. Erickson commented that “this is another advantage of the vestibular test (see Part 2 of this series) advocated at the Banner Concussion Center, because a non-physiologic response is detected with intentional underperformance or anxiety responses to testing, We benefit from the fact that athletes don’t know how to cheat to underperform on the test.”
He added that “of course, best medicine is for an athlete to put in best effort at baseline as well as post injury. The motivation factor is very real. Sometimes those not particularly motivated in baseline testing are very motivated to achieve in order to return to play,”
Hopefully more athletes and their coaches are acknowledging that playing through will not serve them well either in the short or long term.
So, does the Banner Concussion team advocate keeping kids from playing sports? Most definitely not… Each member acknowledges the many benefits of sport, such as exercise, physical development and emotional growth. Developing mental toughness and learning life lessons such as teamwork and how to deal with adversity while enjoying a healthy social outlet that is fun, challenging and productive trumps fear.
They stress that concussion can happen almost any time – even to those who don’t play sports – and that sports can be made safe. The key to addressing concussion is education and diligence. It is important to be able to identify concussion if/when it happens and seek appropriate assessment and care. By managing the symptoms, recovery is accelerated and the likelihood of recurrence minimized. The value of baseline testing cannot be stressed enough nor can the importance of not allowing an athlete of any age to return to play after sustaining a head trauma resulting in symptoms without undergoing an evaluation.
Though most who suffer a concussion recover fully and within a four-week period, the caution is to understand that symptoms left untreated – can result in long lasting consequences.
As for those who sustain multiple head traumas and, quite possibly – or especially – those who have also suffered repeated microtrauma, the long term effects are coming into better focus with the further study of CTE.
References for Parts 1-3 of the Concussion Series:
- Centers for Disease Control and Prevention (CDC), National Center for Injury Prevention and Control. Report to Congress on mild traumatic brain injury in the United States: steps to prevent a serious public health problem. Atlanta (GA): Centers for Disease Control and Prevention; 2003.
- Lescohier I, DiScala C. Blunt trauma in children: causes and outcomes of head versus intracranial injury. Pediatrics 1993;91(4):721-5.
- Langlois JA, Rutland-Brown W, Wald M. The epidemiology and impact of traumatic brain injury: a brief overview. Journal of Head Trauma Rehabilitation 2006;21(5):375-8
- Finkelstein E, Corso P, Miller T and associates. The Incidence and Economic Burden of Injuries in the United States. New York (NY): Oxford University Press; 2006.
- Fung M, Willer B, Moreland D, Leddy J. A proposal for an evidence-based emergency department discharge form for mild traumatic brain injury. Brain Injury 2006;20(9):889-94.
- Alexander, Andrew L., Lee, Jee Eun, Lazar, Mariana, Field, Aaron, S.
Diffusion Tensor Imaging of the Brain. Neurotherapeutics. 2007 Jul; 4(3): 316–329.doi: 10.1016/j.nurt.2007.05.011
- Field M, Collins M, Lovell M, Maroon J. Does age play a role in recovery from sports-related concussion? A comparison of high school and collegiate athletes. The Journal of Pediatrics 2003;142(5):546-53.
- Bryan Kolb, PhDand Robbin Gibb, PhD: Brain Plasticity and Behaviour in the Developing Brain . J Can Acad Child Adolesc Psychiatry. 2011 Nov; 20(4): 265–276.
- Guskiewicz K, et al. Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA Concussion Study. JAMA 2003;290(19):2549-55.
- Pellman EJ, Lovell MR, Viano DC, Casson IR. Concussion in professional football: recovery of NFL and high school athletes assessed by computerized neuropsychological testing–Part 12. Neurosurgery 2006;58(2):263-74;discussion 263-74
- Kashluba S, Casey JE, Paniak C. Evaluating the utility of ICD-10 diagnostic criteria for postconcussion syndrome following mild traumatic brain injury. Journal of the International Neuropsychological Society 2006;12(1):111-8.
- Dean PJ, O’Neill D, Sterr A. Post-concussion syndrome: prevalence after mild traumatic brain injury in comparison with a sample without head injury. Brain Inj. 2012;26(1):14-26. doi: 10.3109/02699052.2011.635354.Epub 2011 Nov 22
- McManus, C. Stress-Induced Hyperalgesia: Clinical Implications for the Physical Therapist Orthopedic Physical Therapy Practice. 2012;24(3):165-168. (http://carolynmcmanus.com/publications/mcmanus-stress-induced-hyperalgesia.pdf)
- UPMC Sports Medicine Website
- Boston University CTE Center: http://www.bu.edu/cte/about/what-is-cte/
- Hart, J.J., JAMA Neurology 2013
- Mayo Clinic Press Release: Mayo Clinic: Evidence suggests contact sports played by amateurs increase risk of degenerative disorder http://newsletter.carehubs.com/t/ViewEmail/j/2B6E3073A3AD413C/59F3204D88C0AFA89A8E73400EDACAB4
- Aubry M, et al. Summary and agreement statement of the first International Conference on Concussion in Sport, Vienna 2001. Clinical Journal of Sports Medicine 2002 Jan;12(1):6-11