List of NFL players with chronic traumatic encephalopathy
A large number of former National Football League (NFL) players have been diagnosed with or have had chronic traumatic encephalopathy, or CTE. A definitive diagnosis so far can be made only post-mortem. However, an increasing number of former players are reporting symptoms of CTE. According to 2017 study on brains of deceased gridiron football players, 99% of tested brains of NFL players, 88% of Canadian Football League (CFL) players, 64% of semi-professional players, 91% of college football players, and 21% of high school football players had various stages of CTE . However, this study had several limitations, including possible selection bias as families of players with symptoms of CTE are far more likely to donate brains to research than those without signs of the disease. Despite the limitations, the study still showed that CTE is far more common than once believed. Other common injuries include injuries of legs, arms, and lower back. Players affected. Many football players affected by CTE have played professionally, but others have also been affected by or live with the possibility of having CTE. In July 2011, Colts tight end John Mackey died after several years of  deepening symptoms of frontotemporal dementia. The Boston University School of Medicine (BUSM) was reported to be planning to examine his brain for signs of CTE. The Brain Bank found CTE in his brain post-mortem. On July 27, 2012, an autopsy report concluded that the former Atlanta Falcons safety Ray Easterling, who died from suicide in April 2012, had CTE. On February 4, 2016, an autopsy report from Massachusetts confirmed CTE in Ken Stabler's brain after his death. Stabler, an NFL MVP and Hall of Famer, was diagnosed with high Stage 3 CTE. Stage 4 is the most aggressive  stage of the disease. Heisman Trophy winner and former NFL All-Pro Bo Jackson said in a 2017 interview with "USA Today" that if he had known about the risks associated with CTE, he would never have played football, and he discourages his children from doing so. In late 2017, former Kansas City Chiefs running back Larry Johnson reported having symptoms akin to Aaron Hernandez, including memory blanks, suicidal thoughts and thoughts of committing violent acts. Although there is no way to positively diagnose CTE before death, Johnson believes he is living with the disease. Former players with CTE confirmed  post-mortem. A common definitive test currently can be made only by examining the brain tissue of a deceased victim. As the families of many deceased players wish to keep their medical information private, the following list is incomplete. A brain injury study conducted at the Boston University School of Medicine showed that 33 of 34 players tested post-mortem showed clear signs of CTE, and additional players have so far been confirmed with CTE separately. A new list released in November 2016 mentions CTE in 90 of 94 brains of former and deceased NFL players. In July 2017, a  new study showed that 110 of 111 brains examined showed signs of CTE. Deceased players suspected of having had CTE. Included in the list are players diagnosed with amyotrophic lateral sclerosis (ALS) who were never tested "post-mortem" for CTE but whose history appears consistent with CTE. A typical diagnosis of ALS has primarily been based on the symptoms and signs the physician observes in the patient and a series of tests to rule out other diseases and therefore, prior to the discovery of CTE as a phenomenon in ex-American football players, many CTE cases were diagnosed as ALS . The testing of CTE in deceased ex-NFL players began only after the disease was first diagnosed, in 2002, in the brain tissue of Mike Webster. After then, testing became common practice only gradually. A cohort mortality study run by the National Institute for Occupational Safety and Health (NIOSH) examined 3,349 NFL players who played at least five full seasons from 1959 to 1988. Findings showed that while NFL players lived longer than the average American male, the risk of death associated with neurodegenerative disorders was about three times higher among the NFL cohort. The risk for death from Alzheimer 's disease and ALS were about four times higher among the NFL cohort. Some on this list may have had dementia not related to ALS or CTE. Living former players diagnosed with CTE or ALS or reporting symptoms consistent with CTE or ALS. These players have publicly acknowledged either having been diagnosed with likely CTE or having experienced symptoms, such as dementia or unusual memory loss, consistent with CTE. In some cases, the player has received a diagnosis of ALS but symptoms are consistent with CTE. There are at least two dozen former players who were diagnosed as part of  a UCLA study but have not come forward publicly. There are also around 4,500 former players who joined a class action lawsuit against the NFL alleging that it had covered up a growing body of medical evidence about the preponderance of head-trauma related CTE in ex-NFL players. Some of these ex-players may have medical conditions other than CTE or ALS. For example, ex-players that have presented with symptoms late in life may have other forms of age-related dementia. Some of the former players on this list came forward only in the context of the class  action lawsuit versus the NFL. At present, there is no definitive CTE test available for living persons. Their average age is 51. Former players listed as plaintiffs in lawsuits against the NFL for concussion-related injuries received after playing. This list is incomplete. The NFL reportedly reached a settlement in 2013 with around 4,500 former players (or their estates). This list currently contains fewer than half that number.