Kyle Turley would like to say it was the worst night of his life. But the truth is, it probably won't be.

Since retiring from the National Football League in 2007, the former star offensive lineman from San Diego State had grown accustomed ---- or at least as accustomed as a person can be ---- to the punishing aftereffects of an eight-year career spent crashing into other men approximately his size: 6 feet, 5 inches, and more than 300 pounds.

Nothing, though, could have prepared him for the night in August when he passed out at a music club in his hometown of Nashville, Tenn., went into a seizure and, for almost four hours, drifted in and out of consciousness and vomited.

"I've had bouts of vertigo that were similar, but this was by far the worst," Turley said. "I couldn't control my body. It was flopping around like a fish on the table in the emergency room. My wife and a couple of interns had to hold me down to get a CT scan to make sure I didn't have bleeding on my brain.

"It was pretty horrific."

Turley had been examined over the previous year and a half by multiple brain specialists in Nashville to help him discover the cause of his deteriorating health. But the August episode prompted him to consult Dr. Robert Cantu, a prominent Boston neurosurgeon and one of America's foremost experts on concussions in sports.

"All the doctors are pretty consistent. There's no real explanation," Turley said. "But they've all come to the understanding that it has something to do with the concussions that I received in the NFL."

Specifically, Cantu and others raised a frightening possibility: that Turley has chronic traumatic encephalopathy, a progressive degenerative brain disease found in people with a history of repetitive concussions.

Commonly associated with boxers since the 1920s, CTE has more recently become known as the condition found in the brains of 11 former football players (all but one of whom reached the NFL) who died between the ages of 36 and 52 and had traces of neurological damage that doctors would expect to see in an elderly person with dementia.

Turley, 34, fears that he might someday join them. But he wants to ensure that his possible premature death has a larger purpose. He's one of 40 current or retired NFL players ---- and more than 175 athletes overall ---- who have pledged to donate their brains after death to a Boston University medical school program that's seeking to unlock the mystery of the long-term effects of sports concussions.

'Long overdue' research

In large part because of the work of the Center for the Study of Traumatic Encephalopathy, a collaboration between BU and the nonprofit Sports Legacy Institute, the NFL has come under heightened scrutiny over the problem of head injuries in the sport. Commissioner Roger Goodell was among those called to testify on the subject during a congressional hearing last month.

But the concern isn't limited to the professional level. The BU center revealed in January that early stages of CTE were found in the brain of a recently deceased 18-year-old high school player ---- a big red flag for participants in prep and college football.

Officials at schools in North San Diego County have become more cognizant of the problem, with an athletic trainer and doctor required to be present for every football game. For Southwest Riverside County schools, an emergency medical technician is required to be present, though a trainer is also recommended.

"I think it's long overdue," Turley said of the research being conducted at the center. "It's unfortunate that these people didn't come along sooner."

Thanks to the recruiting efforts of Chris Nowinski, a former Harvard football player and professional wrestler who founded the Sports Legacy Institute with Cantu in 2007, the BU center recently pulled off a coup when three active NFL Pro Bowlers agreed to add their names to the brain donor program: Baltimore Ravens offensive lineman Matt Birk, Arizona Cardinals special teams ace Sean Morey and Seattle Seahawks linebacker Lofa Tatupu.

They joined a list of retired players that includes former New England Patriots linebacker and Carlsbad High graduate Ted Johnson and ex-Chargers linebacker Billy Ray Smith, now a sports-talk radio host in San Diego.

"For all the people who have played football, including my dad and all the kids who are coming up, I want to help however I can," Smith said. "It was literally a no-brainer for me."

Among the prominent donor athletes from sports other than football is Cindy Parlow, who retired from the U.S. women's national soccer team three years ago, citing post-concussion syndrome.

"Concussions are definitely an issue in soccer," Parlow said. "But as far as having issues later in life beyond post-concussion syndrome, I don't know, and that's one reason why (the BU center is) trying to get athletes outside of football."

A quest for answers

The Center for the Study of Traumatic Encephalopathy was born out of the concussions ---- the term refers to impaired functioning of the brain as a result of a violent blow or impact ---- sustained by Nowinski on the football field and in the wrestling ring.

Forced to retire from athletic competition seven years ago at age 24 because the symptoms from his last concussion ---- most notably, severe headaches and sudden bursts of anger ---- didn't subside for a year, he embarked on a quest for answers that led him to Cantu in 2003. Three years later, he wrote a book titled "Head Games: Football's Concussion Crisis."

"I went to a ton of doctors before I found one who could help me understand why I had headaches," said Nowinski, 31. "When I looked into it further on my own, I realized it was all there in the medical literature but no one was talking about it. So my role became trying to synthesize and drawing attention to the problem."

Because CTE can't be detected by X-rays or MRI exams, donated brains are required for postmortem analysis. Living donors also agree to an annual assessment to discuss their concussion history and track their cognitive function.

The first brain examined by BU researchers belonged to John Grimsley, a former Houston Oilers and Miami Dolphins linebacker who died of an accidental gunshot wound in February 2008 at age 45. Grimsley was found to have excessive buildup of an abnormal protein called tau, indicating CTE.

Add to that the research performed by Dr. Bennet Omalu, a neuropathologist from the University of Pittsburgh, and the total is now 11 football players who died after age 25 whose brains have been examined for CTE. Evidence of the disease was discovered in all 11, most recently in Western Illinois wide receiver Mike Borich ---- representing the first CTE case involving a football player whose career stopped at the college level.

"One for one, two for two could be an aberration," Nowinski said. "But 11 for 11 should scare the hell out of anyone who played more than eight years of football."

In particular, the findings are alarming because CTE is exceedingly rare in the general population. Cantu emphasized that the sample size isn't representative because the condition was discovered in people who had shown symptoms of it before their death. But that doesn't mean he isn't concerned.

"We don't have our hands around what the prevalence of this is, but I suspect that it's higher than people might think," he said.

Higher rate of dementia

The NFL is conducting its own study on the long-term effects of concussions in football players. League spokesman Greg Aiello said results are expected by the end of next year.

In the meantime, the NFL sponsored a study by University of Michigan researchers suggesting that retired pro football players could have a higher-than-normal rate of Alzheimer's disease or other brain afflictions. While criticizing the methodology of that study because it was based on phone surveys, Cantu noted that it found "exactly what we would have expected: namely, a much higher incidence of dementia in the NFL group as compared with the expected incidence in the population at large."

In response to the troubling findings of the BU center, Aiello said: "We have an ongoing dialogue with Chris and his group, including Dr. Cantu. We are interested in any research that furthers the understanding of concussions. ... (But) we are not waiting on science in order to continue to take steps to aggressively address the issue of concussions. Our focus is on prevention and treatment.

"There is no question that there has been a culture change in football and other sports in the way concussions are managed now."

Before the 2007 season, the NFL sent a memo to all players and team personnel outlining steps taken to address concussions. They included establishing a confidential hotline to report information about any player being forced to practice or play against medical advice; a summary of recommendations governing when a player who has had a concussion can safely return to a game or practice; and the expansion of neuropsychological testing for all NFL players.

Last spring, the league approved three new rules specifically designed to reduce the frequency and severity of head injuries: making illegal blindside blocks above an opponent's shoulder pads, contact to the head of a defenseless receiver and wedge blocking of more than two players on kickoffs. And last month, the NFL Players Association formed a committee on concussions and traumatic brain injuries.

"I think people now identify that it is a serious health concern and people need to take concussions seriously," said the Cardinals' Morey, the co-chairman of the NFLPA committee. "I think there needs to be a standardized leaguewide protocol that every team follows. Each team sort of handles it in their own way. We can improve the way we prevent, diagnose and manage concussions in the NFL."

Playing hurt

But as if to underscore how difficult it will be to solve the concussion problem in football, Morey ---- perhaps the NFL player most knowledgeable about and committed to the cause ---- admitted two weeks ago that he played with a concussion against the Chicago Bears on Nov. 8. And he's not alone. In a recent survey conducted by the Associated Press, 30 of 160 NFL players acknowledged that they have hidden or downplayed the effects of a concussion.

"There's such a high competitive interest to stay in the game once you get concussed," Morey said in an earlier interview. "When I've suffered a concussive episode, the first thing I've always done in my career is avoid the trainers like the plague. I go to the opposite end of the sideline and just roll right through it, and I think a lot of players have done that for a number of years.

"That's sort of the mentality and the code that you play by. There's such a deep loyalty to your teammates and coaches to finish a game and do your job."

Turley felt that same tug to set aside bodily concerns for the good of the team. But he also faults the NFL for not properly educating him on head injuries or looking out for his well-being.

He relates the story of a particularly nasty concussion sustained when he played for the St. Louis Rams in 2003. After an opposing player's knee collided with the back of his helmet, Turley said, he was unconscious on the field for more than a minute. He eventually went to the hospital, but only at the recommendation of a former teammate who noticed his dazed appearance as Turley left the stadium with his wife. Four days later, he returned to practice, still suffering from headaches and nausea.

"You fight through it because you want to play," he said. "I shouldn't have been allowed to play, though. Who knows what damage it did?"

Turley is beginning to find out. Since his collapse at the bar, he has been plagued by extreme light sensitivity, forcing him to wear sunglasses almost constantly (even at night) and causing migraine headaches if he watches TV or looks at a computer screen for too long. He said he once had vertigo every day for a month, during which time he could do little but sleep.

He also is stricken with bouts of depression and anger that he said harm his relationship with his wife, Stacy, and affect his ability to enjoy time with his 7-month-old son, Dean.

"I shouldn't have these things going on at such a young age," Turley said. "I had a great career, beautiful wife, new child ---- everything is going for me. ...

"It's such a badge of honor to be a tough guy. But when you're in a situation where you're trying to figure out why you hate life at 34 ---- not every day, but some days, to the extent of putting a gun in your mouth ---- there needs to be some rethinking there."