Chronic traumatic encephalopathy

Chronic traumatic encephalopathy (CTE) is a progressive degenerative disease found in individuals who have been subjected to multiple concussions and other forms of head injury. A variant of the condition, dementia pugilistica, is primarily associated with boxing. CTE has been most commonly found in professional athletes participating in gridiron football, ice hockey, professional wrestling and other contact sports, who have experienced head trauma, resulting in characteristic degeneration of brain tissue and the accumulation of tau protein. Individuals with Chronic Traumatic Encephalopathy may show symptoms of dementia such as memory loss, aggression, confusion and depression which may appear within months of the trauma or many decades later.

Several former NFL players have been diagnosed post-mortem with chronic traumatic encephalopathy. Former Detroit Lions lineman and eight-time Pro Bowler Lou Creekmur, former Houston Oilers and Miami Dolphins linebacker John Grimsley, former Tampa Bay Buccaneers guard Tom McHale, former Cincinnati Bengals wide receiver Chris Henry, and former Chicago Bears safety Dave Duerson, have all been diagnosed with post-mortem CTE. Athletes from other sports have also been identified as having CTE, such as hockey players Reggie Fleming and Bob Probert.

An autopsy conducted in 2010 on the brain of Owen Thomas, a 21-year-old junior lineman at the University of Pennsylvania who committed suicide by hanging himself, showed early stages of chronic traumatic encephalopathy, making him the youngest person — and the second amateur player — to be diagnosed with the condition. The doctors who performed the autopsy indicated that they found no causal connection between the nascent CTE and Thomas's suicide. There were no records of Thomas missing any playing time due to concussion, but as a player who played hard and "loved to hit people," he may have played through concussions and received thousands of subconcussive impacts on the brain.

Study and developments
In 2002, Dr. Bennet Omalu, a forensic pathologist and neuropathologist in Pittsburgh, Pennsylvania found Chronic Traumatic Encephalopathy (CTE) in the brains of Mike Webster, Terry Long, Andre Waters, Justin Strzelczyk and Tom McHale. Repeated concussions and sub-concussions incurred during the play of football over a long period can result in CTE. The brain changes in CTE and DP are similar and are delayed sequelae of repeated concussions and sub-concussions of the brain. In 2009, Omalu discovered the same condition in recently retired wrestler Andrew "Test" Martin, who died aged 33 from a drug overdose.

In 2007, neuropathologists from the Sports Legacy Institute examined the brain of Chris Benoit, a professional wrestler with the WWE, and identified pathognomonic brain tissue changes of CTE. Chris Benoit had killed his wife and son before committing suicide by hanging at age 40. In 2008, the Sports Legacy Institute joined with the Boston University School of Medicine (BUSM) to form the Center for the Study of Traumatic Encephalopathy (CSTE). Since then, autopsies of eleven professional American football players by neuropathologist Dr. Ann McKee found CTE in all cases. BU researchers also found CTE in an amateur football player, 21-year old University of Pennsylvania lineman Owen Thomas, following his suicide. Thomas was the second amateur football player diagnosed with CTE, after Mike Borich, who died at 42. Neuropathologists at Boston University also diagnosed Reg Fleming as the first hockey player known to have the disease. This discovery was announced in December 2009, six months after Fleming's death.

On December 21, 2009, the National Football League Players Association announced that it would collaborate with the CSTE at the Boston University School of Medicine to support the Center's study of repetitive brain trauma in athletes. Additionally, in 2010 the National Football League gave the CSTE a $1 million grant with no strings attached. In 2008, twelve living athletes (active and retired), including hockey players Pat LaFontaine and Noah Welch as well as former NFL star Ted Johnson, committed to donate their brains to CSTE after their deaths. In 2009, NFL Pro Bowlers Matt Birk, Lofa Tatupu, and Sean Morey pledged to donate their brains to the CSTE. In 2010, 20 more NFL players pledged to join the CSTE Brain Donation Registry, including Chicago Bears linebacker Hunter Hillenmeyer, Hall of Famer Mike Haynes, Pro Bowlers Zach Thomas, Kyle Turley, and Conrad Dobler, and Super Bowl Champion Don Hasselbeck. In 2010, Professional Wrestlers Mick Foley and Matt Morgan also agreed to donate their brains upon their deaths. As of 2010, the CSTE Brain Donation Registry consists of over 250 current and former athletes.

The Center for the Study of Retired Athletes is also conducting a research study to learn if the dietary supplement Docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, affects signs and symptoms associated with cognitive impairment such as changes in brain function, memory and mental status, quality of life, and depression in retired NFL players aged 50 and older.

In February 2011, Dave Duerson committed suicide leaving text messages to loved ones asking that his brain be donated to research for CTE. The family got in touch with representatives of the Boston University center studying the condition, said Dr. Robert Stern, a co-director of the research group. Dr. Stern said Duerson's was the first time he was aware of that such a request had been left by a suicide potentially linked to CTE. Stern and his colleagues found high levels of the protein tau in Duerson's brain. These elevated levels are indicative of CTE.

In July 2010, NHL enforcer Bob Probert died of heart failure. Before his death, he asked his wife to donate his brain to CTE research because it was noticed that Probert experienced a mental decline in his 40s. In March 2011, researchers at Boston University concluded that Probert had CTE upon analysis of the brain tissue he donated. He is the second NHL player from the program at the Center for the Study of Traumatic Encephalopathy to be diagnosed with CTE postmortem.

In July, 2011, Colt tight end John Mackey died after several years of deepening symptoms of frontotemporal dementia. BUSM was reported to be planning to examine his brain for signs of CTE. Also within a few months in 2011, the deaths of three hockey "enforcers" -- Derek Boogaard from a combination of too many painkillers and alcohol, Rick Rypien, an apparent suicide, and Wade Belak, who, as Rypien, had reportedly suffered from depression; and all with a record of fighting, blows to the head and concussions -- led to more concerns about CTE. Boogaard's brain was being examined by BUSM but no results had yet been released. One National Hockey League player known in part for leading "the thump parade", Shawn Thornton of the Boston Bruins, mulled the "tragic coincidence" of the three recent league deaths and said their concurrence was just that, while defending the role of fighting on the rink.

Rick Martin, best known for being part of the Buffalo Sabres' French Connection, was diagnosed with CTE after his brain was posthumously analyzed. Martin was the first documented case of an ice hockey player not known as an enforcer to have developed CTE; Martin was believed to have developed the disease primarily as a result of a severe concussion he suffered in 1977 while not wearing a helmet. The disease was low-grade and asymptomatic in his case, not affecting Martin's cognitive abilities; Martin died of unrelated causes in March 2011 at the age of 59.

BUSM has also found indications of links between ALS and CTE in athletes who've participated in contact sports. Tissue for the study was donated by twelve athletes and their families to the CSTE Brain Bank at the Bedford, Massachusetts VA Medical Center.

American football

 * Mike Borich
 * Lou Creekmur
 * Dave Duerson
 * Shane Dronett
 * John Grimsley
 * Chris Henry
 * Wally Hilgenberg
 * Terry Long
 * Tom McHale
 * Justin Strzelczyk
 * Owen Thomas
 * Andre Waters
 * Mike Webster

Hockey

 * Reg Fleming
 * Rick Martin
 * Bob Probert