We’ve only known about the devastating realties of CTE — chronic traumatic encephalopathy — for about 15 years. And yet in that relatively short period, those three letters have threatened the future of contact sports like nothing before.

The disease is believed to have a variety of critical symptoms that are still being studied — it can affect behaviour and mood, and can create cognitive and motor problems. It has been discovered in the brains of deceased football and hockey players at an alarming rate. Bob Probert had it. As did both Derek Boogaard and Steve Montador. So too, one might guess, do many current and retired NHL players.
http://www.sportsnet.ca/hockey/nhl/q...-means-hockey/