Chronic Traumatic Encephalopathy: Homing in on Specifics in Research

Researchers are still learning why it is that head trauma is the main factor for CTE, but not all people with head trauma develop CTE.

See more clips with Dr. Robert Cantu.

[Dr. Robert Cantu] Well I started working with CTE indirectly when I did a book called Boxing & Medicine a number of years ago in which we chronicled Martland's work and the work of Corsellis and others that took us through the clinical symptoms and signs of CTE and then the others that took us through the neuropathology of CTE, but I was writing a book. I was largely referencing other people's work. The actual work with CTE began when Sports Legacy became involved in looking at brains, and the first brain that we looked at was that of Andre Waters. Chris Nowinski, the CEO and co-founder of Sports Legacy, obtained that brain. Bennet Omalu and his team at the University of Pittsburgh studied it, and then shortly thereafter we moved the brain bank operation to Dr. Ann McKee in Boston University in the Boston VA Hospital. The subsequent studies have all been done there. I think seven or eight years ago certainly the entity of CTE was known. It was well-chronicled in boxers, but it wasn't well-chronicled in athletes in other sports. There were occasional case reports on a soccer player, and there were certainly occasional reports in other people that had repetitive brain injury but weren't even athletes, but the last seven years or so now where we have 35 brains from the National Football League, 34 of which have proven CTE, that's a huge change. Well I think the most important findings that we've seen with CTE over the last seven years or so is we certainly know where it is located in terms of it starts at the depths of sulci and around blood vessels in the superficial layers of the cortex. In the less severe early stages, it is also associated with significant axon disease. Axonopathy is what we call it. Then in the more severe degrees of it the medial temporal lobe is very much involved as is the amygdala in that area. So we know where the abnormal tau protein is being deposited. What we don't know very well is how much trauma's necessary to produce it, how important are the sub-concussive blows except we know that they're important. We don't know what are the other risk factors that seem to accelerate the disease in certain individuals and seem to protect other individuals. The one constant in all cases of Chronic Traumatic Encephalopathy is head trauma—almost always repetitive head trauma. But not everybody with repetitive head trauma comes up with CTE. So there obviously are protective factors, and there are also factors that make one prone to develop CTE.
Posted on BrainLine August 30, 2013.

Produced by Noel Gunther and Erica Queen, BrainLine.