Chronic Traumatic Encephalopathy (CTE) among former American football players: Study

By Dr. Ananya Mandal, MDJul 25 2017

A new study involved 202 deceased players of American football players’ brains. It was found that Chronic Traumatic Encephalopathy (CTE) could be neuropathologically diagnosed in 177 players. Of the sample of players who developed CTE, 110 of 111 former National Football League players were found to have CTE in their brains. Researchers connected the presence of CTE in the brains of the dead players to the participation in football.

Image Credit: Herbert Kratky

Study researchers believe that these players of American football may be at an increased risk of long term neurological conditions especially CTE. The brains of the 202 players studied in this work were donated for research at the Boston brain bank by the players and their families. The brains were examined neuropathologically. A detailed history of their exposure to trauma and head injury was taken using telephonic interviews and questionnaires. Online questionnaires were also sent to the families of the players and their military and athletic history was evaluated. Participation of American football at any level of play was considered as exposure.

Results showed that the brains of the players showed varying degrees of CTE. The definitive diagnostic criteria for CTE included CTE neuropathological severity (stages I to IV). Of these CTE I and II were considered mild and stages III and IV were considered severe. Players who died in 2014 or later were also examined using informant questionnaires looking at their behavioural symptoms, mood changes, dementia and symptoms affecting cognition.

Of the 202 players whose brains were examined, the median age of death was found to be 66 years. CTE was diagnosed in 177 players (87%). Average age of football playing by the study subjects was 15.1 years which included 21% or 3 of 14 played in high school, 91% or 48 of 53 in college and 64% or 9 of 14 played as semiprofessonals. It was found that 7 of 8 (88%) played Canadian Football League 110 of 111 (99%) National Football League players. The severity of the CTE was most with high level of players. It was seen that 86% of the former professional players had severe CTE. Of the 27 with mild CTE in the study, history showed that 26 or 96% had mood swings or behavioural symptoms. Cognitive symptoms affected 23 of 27 (85%) and dementia was seen in 9 of 27 (33%) individuals. Of the 84 detected with severe CTE, mood swings and behavioural issues had plagued 75 (89%), cognitive decline was seen in 80 of 84 (95%) and dementia was seen in 71 of 84 (85%).

Researchers concluded that participation in football was linked to CTE in almost all players. This is the largest update on CTE among football players.

CTE leads to a wide range of neurological symptoms including memory loss or dementia, cognitive decline as well as behavioural symptoms. Lead author Dr. Ann McKee, a Boston University neuroscientist believes that this still leaves many questions that could not be addressed. This includes factors like genetic predisposition to this condition, the number of years that can be said to raise the risk definitively and the exact incidence of CTE among football players she explained. It is important to note that not all players develop CTe despite long years of playing football. Other lifestyle factors such as alcohol, steroids, smoking, diet and drugs may also play a role.

The report was published yesterday in the Journal of the American Medical Association.

Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy is considered to be a neurodegenerative disease with progressive decline in brain functions. It is cause by repeated brain injuries as seen in athletes and soldiers who suffer from repeated concussions or head injuries. The actual incidence of the condition is as yet not known. It is commonly suspected due to the symptoms before death and confirmed on neuropathological examination of the brain after death. The brain is found to have a specific protein called Tau that is present in clumps. Symptoms of the condition include decline of memory, cognitive functions and behavioural changes. There is progression of dementia, irritability, mood swings and suicidal tendencies as well. The symptoms may appear decades after the initial injuries.

Reference

1. https://www.cdc.gov/
2. http://www.mayoclinic.org/diseases-conditions/chronic-traumatic-encephalopathy/basics/definition/con-20113581