Charles Bernik, MD of the Cleveland Clinic thinks that there may be a correlation to repeated head trauma and a threshold of when degenerative brain disease begins, like CTE. An article appearing in Science Daily last week discusses this;
A new study suggests there may be a starting point at which blows to the head or other head trauma suffered in combat sports start to affect memory and thinking abilities and can lead to chronic traumatic encephalopathy, or CTE, in the brain.
The study looked at 78 “fighters” and split them based on their years of experience, in this study the split was nine years. Those that had fought more than nine years showed significant changes in memory and the other areas being studied in the research;
“Our study shows there appears to be a threshold at which continued repetitive blows to the brain begin to cause measurable changes in memory and thinking, despite brain volume changes that can be found earlier,” said Bernick.
Not only is accurate identification of CTE prior to death important, but if research can find a time/injury threshold of degenerative diseases then perhaps a practical approach can be made to sports.
The Concussion Blog 
It’s always difficult for the layperson to fully understand complex medical and biomechanical issues. For instance, I don’t know if we can apply any of the information gained from this study to youth contact and collision sports. The study only involved 78 fighters with an average age of 29. What if anything does it say about the number of years children, teens and young adults should be allowed to participate in high contact and collision sports, especially sports such as football where there can be a high number of impacts at practice?
As a mom, I’ve read enough over the past few months to decide that my children won’t participate in certain sports. But, I’m not always sure what to say to other parents. In our school system, kids can participate in football and wrestling from first grade through high school (and some kids participate in both). That’s twelve years of potential exposure to concussive and subconcussive impacts (of course, there are limits to the number of months children participate in these sports). Do we really have any idea how many impacts or what magnitude of impacts kids are being exposed to? The recent youth football impact study gave us a limited amount of information, but I’m sure there are significant differences between various practice groups.
It seems as though we may be reaching a point where red flashing warning lights should be going off. The one analogy that came to mind after reading this post was to what happened to the “experts” who misread the warning signs before the last financial bubble popped. At one point Citigroup’s chief executive recognized there could be problems up ahead, and told the Financial Times “… as long as the music is playing, you’ve got to get up and dance. ” http://business.time.com/2007/07/10/citigroups_chuck_prince_wants/ I’m not sure if Prince was as prepared as he thought he was to get a chair when the music stopped. A humbled Greenspan had to admit he was wrong (see New York Times, “Greenspan Concedes Error on Regulation,” October 23, 2008 for details).
I hope the experts get it right with respect to what the CDC has referred to as a concussion epidemic among adolescents, and that parents are provided with enough information to make informed decisions. I realize kids have been participating in these sports for decades, but it does seem as though things have changed for there to be such an increase in concussions (I doubt if all of the increase can be attributed to greater awareness).
The other concern/question I have right at the outset is this: “How did the study arrive at nine years as the breakoff point? What made nine years better than, say, eight or ten?” Without being a scientist and without knowing all the details of the study itself, I wonder whether this data is empirical data or data that’s been massaged to meet a predetermined outcome or idea?
To Concerned Mom and Glenn
I have not read through this study, but what it is basically telling us is that the effects are cumulative and therefore, someday, we will be able to determine how much repeative subconcussive impact is too much. This sounds intuative, but without good data we do not know if this is true or if it is more random. This study will lead to other studies that might help determine that threshold. While I do believe that some fo the increased numbers we are seeing are due to the increase in size and speed of the athletes , as well coaching, the vast majority of it is recongnition.
Thanks for the feedback. I hope the grade school aged children who are currently participating in multiple collision/high contact sports are never told that they should discontinue playing in high school or college due to the number of years of exposure. I understand the need to not jump to far reaching conclusions after one limited study, yet still wonder if parents need to be warned about the potential need to limit years of exposure now – there was a comment on our bantam facebook page about a parent who allowed her sons to suit up at home for extra tackling practice. (I suspect doctors and athletic trainers come across many clueless parents – that results in a lot of guilt once you learn about the risks you were actually exposing your child to.)
http://www.nytimes.com/2012/04/25/health/research/study-shows-changes-in-fighters-brains-before-symptoms.html?_r=2
“In other words, “We may not need to focus so much on concussions,” Dr. Bernick said. “It could be that sustaining thousands of blows that don’t knock you out could be more important” to assessing the long-term health of your brain.”