"It is our policy to not discuss any completed, ongoing or potential research cases unless at the specific request of family members," the center said in a statement Thursday. "Our primary goal is to learn more about the long-term effects of repetitive brain trauma by conducting meaningful scientific research. At this time our thoughts and prayers are with Mr. Seau's family, his many friends and former teammates."
Several former NFL players have committed suicide in recent years, and many experts believe the deaths could be related to repeated blows to the head. In addition to Duerson, ex-Pittsburgh Steelers offensive lineman Terry Long and Philadelphia Eagles defensive back Andre Waters took their own lives. Chronic traumatic encephalopathy, or CTE, a degenerative and progressive disease found in people who have experienced multiple blows to the head, has shown up in the brains of several former athletes who committed suicide, including Duerson.
The condition has brain characteristics that resemble those of Alzheimer's, Parkinson's and Lou Gehrig's disease.
As of October, more than 500 current and former professional athletes agreed to donate their brains to the VA Brain Bank, which works in affiliation with Boston University's Center for the Study of Traumatic Encephalopathy.
Annese said the Brain Observatory at UCSD has been in contact with several athletes who are considering participating in the brain donation program.
"Like Mr. Seau, they feel that they personally hold many of the answers needed to know how to make their sport safer for future generations," said Annese. "The examination of the brain is only the final and definitive chapter of a long narrative that we create working with our participants."
The average life expectancy of a retired football player is 58 years old, according to the NFL Players Association. That is a stark contrast to the average American man's life expectancy of 75 years, according to government data based in 2006.
While Seau was never listed on any NFL injury report as having a concussion, according to ESPN, his family tells a different story. When asked whether Seau had experienced any concussions in his career, his ex-wife, Deboer, said, "Of course he had," according to the Associated Press. "He always bounced back and kept on playing. He's a warrior. That didn't stop him. I don't know what football player hasn't. It's not ballet. It's part of the game."
Repeated blows to the head may disturb neurotransmitters that affect mood, and may also damage parts of the brain that have to do with impulse control and the ability to weigh the long-term consequences of decisions.
Nevertheless, until more research is done, experts caution against definitively linking the hits Seau experienced in his career and his suicide.
In 2009, the NFL instituted new rules that require clearance from independent neurologists to allow players who endured concussions to return to the field. The league also imposed stricter guidelines to reduce the number of helmet-to-helmet hits.
"What happened to Junior Seau is terribly sad," said Annese. "The least us scientists can do is to match his dedication to his sport and his community with our own dedication to research, finding the reasons for such tragedy, so that it does not have to happen again."