On Wednesday night, along with some friends, I went to the Mazet bar in the 6th Arrondissement of Paris to watch some soccer.
It was the night of Europa League final and two rivalries from London, Arsenal and Chelsea were facing each other. Being a huge Arsenal fan since middle school, I was very nervous about the game. Olivier Giroud, a French footballer who plays as a forward for Chelsea broke the deadlock after half time by scoring a header that ultimately led to Chelsea winning the Europa League this season. At the end of the game, I felt disappointed and miserable looking at the scoreboard, Chelsea 4 – 1 Arsenal.Embed from Getty Images
As an amateur soccer player myself, I know in order to score such a header, both power and precision during the impact with the ball are crucial. Though it may seem effortless when a professional footballer heads the ball, it is in fact quite painful for a non-athlete like me who do not know how to control a header well. Being a neuroscience student, this got me thinking that perhaps there are some negative consequences to the brains as these professional soccer players head the ball almost every single day, both on-pitch and off-pitch.
I first heard about Chronic Traumatic Encephalopathy (CTE) in the 2015 movie starring Will Smith as Dr. Bennet Omalu. Dr. Omalu first found CTE in American football players when he performed an autopsy on former Pittsburgh Steelers center Mike Webster in 2002 (Omalu et al., 2005).
This disease has been observed in athletes with a history of repetitive brain trauma and symptoms include memory disturbances, behavioral and personality changes, parkinsonism and speech and gait abnormalities (McKee et al., 2009). Currently, CTE has been associated with several pathological hallmarks. One of them is neurofibrillary tangles of tau deposition, which is as a marker of Alzheimer’s Disease (McKee et al., 2009). In other words, the protein tau becomes abnormal and is now unable to carry out its normal job to facilitate forming microtubules (Kadavath et al., 2015), the “conveyor belt” of nerve cells.
So, does heading in soccer lead to this disease? This is a tough question to answer. The main reason is that CTE does not have a definite diagnosis prior to autopsy. Therefore, there is a very limited study sample to test this question and we have to rely heavily on case studies. One famous case was Brazilian captain and two-times FIFA world cup winner, Hilderaldo Bellini. With no history of concussion, he died at the age of 83 and examination by the doctor revealed widespread CTE (Grinberg et al., 2016).
One neuroimaging study has identified thinning of the cerebral cortex in former professional soccer players when compared against former non-contact athletes. The cerebral cortex is the outer layer of neural tissue of our brain and is involved heavily in memory, attention, perception, etc. (Penfield & Rasmussen, 1950). The authors have also found that thinning of the cortex was tied to how many times the players have headed the ball in their career. Cortical thinning was also related to a decrease in cognitive performance and hence concluded that maybe these “sub-concussive head impact” of headings in soccer are not so good at all (Koerte et al., 2016). However, one thing to note is that a self-report survey was used to obtain a rough estimate of how many times the players headed the ball in their career. As a result, the exact forces and the exact frequency of heading the ball were not considered (Koerte et al., 2016).
Prof Henrik Zetterberg is a world-leading expert in developing biomarkers for Alzheimer’s disease and whom my lab at Emory had the honor to collaborate in several studies. He did a study to look at the evidence in neurochemical fluctuations immediately after study participants head the balls. Results demonstrate that headings in soccer do not have a short-term biochemical sign of neuronal injury. They have further suggested that the effect of heading in soccer seems to be quite different from that caused by head punches in boxing (Zetterberg et al., 2007).
After looking at a case study, an imaging study, and a neurochemical study, it seems that both positive and negative findings exist. A review of the current scientific literature demonstrates that the effects of heading the ball and connection to CTE remain inconclusive (Grinberg et al., 2016). Though there is evidence of a relationship between heading and abnormal brain structure, most data is still preliminary (Rodrigues, Lasmar, & Caramelli, 2016). As for now, it is not yet the right time to think about banning heading the ball completely in soccer. It’s a great part of this sport that as soccer fans we all love. However, I think the recommendation by the U.S. Youth Soccer is very valid. Only kids after age 10 should be taught heading and heading in game should be delayed until they have both the skill and physical maturity (Nitrini, 2017). If you are a parent ready to take your child to their soccer game this weekend, maybe consider this advice.
Grinberg, L. T., Anghinah, R., Nascimento, C. F., Amaro, E., Leite, R. P., Martin, M. d. G. M., . . . Nitrini, R. (2016). Chronic Traumatic Encephalopathy Presenting as Alzheimer’s Disease in a Retired Soccer Player. Journal of Alzheimer’s disease : JAD, 54(1), 169-174. doi:10.3233/JAD-160312
Kadavath, H., Hofele, R. V., Biernat, J., Kumar, S., Tepper, K., Urlaub, H., . . . Zweckstetter, M. (2015). Tau stabilizes microtubules by binding at the interface between tubulin heterodimers. 112(24), 7501-7506. doi:10.1073/pnas.1504081112 %J Proceedings of the National Academy of Sciences
Koerte, I. K., Mayinger, M., Muehlmann, M., Kaufmann, D., Lin, A. P., Steffinger, D., . . . Behavior. (2016). Cortical thinning in former professional soccer players. 10(3), 792-798. doi:10.1007/s11682-015-9442-0
McKee, A. C., Cantu, R. C., Nowinski, C. J., Hedley-Whyte, E. T., Gavett, B. E., Budson, A. E., . . . Stern, R. A. (2009). Chronic Traumatic Encephalopathy in Athletes: Progressive Tauopathy After Repetitive Head Injury. Journal of Neuropathology & Experimental Neurology, 68(7), 709-735. doi:10.1097/NEN.0b013e3181a9d503 %J Journal of Neuropathology & Experimental Neurology
Nitrini, R. (2017). Soccer (Football Association) and chronic traumatic encephalopathy: A short review and recommendation. Dementia & neuropsychologia, 11(3), 218-220. doi:10.1590/1980-57642016dn11-030002
Omalu, B. I., DeKosky, S. T., Minster, R. L., Kamboh, M. I., Hamilton, R. L., & Wecht, C. H. (2005). Chronic Traumatic Encephalopathy in a National Football League Player. Neurosurgery, 57(1), 128-134. doi:10.1227/01.NEU.0000163407.92769.ED %J Neurosurgery
Penfield, W., & Rasmussen, T. (1950). The cerebral cortex of man; a clinical study of localization of function. Oxford, England: Macmillan.
Rodrigues, A. C., Lasmar, R. P., & Caramelli, P. (2016). Effects of Soccer Heading on Brain Structure and Function. 7(38). doi:10.3389/fneur.2016.00038
Zetterberg, H., Jonsson, M., Rasulzada, A., Popa, C., Styrud, E., Hietala, M. A., . . . Blennow, K. (2007). No neurochemical evidence for brain injury caused by heading in soccer. British journal of sports medicine, 41(9), 574-577. doi:10.1136/bjsm.2007.037143
Regan, Michael (2019). Olivier Giroud of Chelsea scores his team’s first goal. [Photograph], Retrieved 21:08, June 4, 2019, from https://www.gettyimages.com/detail/news-photo/olivier-giroud-of-chelsea-scores-his-teams-first-goal-as-he-news-photo/1152484213
File:Estátua do Bellini2.jpg. (2017, December 31). Wikimedia Commons, the free media repository. Retrieved 21:08, June 4, 2019 from https://commons.wikimedia.org/w/index.php?title=File:Est%C3%A1tua_do_Bellini2.jpg&oldid=275670697.