Check out this fascinating interview between Eric Topol and Bennet Omalu, the pathologist who made the connection between football and brain damage in the Mike Webster case. This is the story that forms the basis for the new movie Concussion. It's worth watching the interview before you see the movie.
(Note: The combination of poor Skype fidelity and Dr. Omalu's Nigerian accent may make it hard for some to understand the audio. Just read along with the text as the interview proceeds if you need help.)