Dr Alan Pearce reveals to Peter FitzSimons the price of playing the game.
As an international rugby union player, Peter FitzSimons knows a thing or two about head injuries while playing elite sport.
He raced head-first into any number of rucks and mauls during a career with the Wallabies, and also in French rugby union, where he once "had my eye balls turned around so much I could look into my brain".
As a journalist, FitzSimons has reached deep into the ramifications of those continuous bashings taken by the noggins of sports people in any number of sports, including VFL and AFL champion, Greg "Diesel" Williams.
Williams claimed when interviewed by FitzSimons on Channel 7's Sunday Night program not to remember vast chunks of his career because of the damage he sustained.
Williams, a Brownlow Medallist, has taken part in a research program undertaken by Deakin University's Dr Alan Pearce.
The research looks at Chronic Traumatic Encephalopathy (CTE) in elite athletes. CTE is a form of encephalopathy that is a progressive degenerative disease often associated with people who have a history of multiple concussions.