It's one of the hottest topics in the NHL — concussions.  Why are so many happening, what are the effects, and what can be done to curtail them?

All those questions will be addressed on Saturday night, starting with the Inside Hockey segment on Scotiabank Hockey Tonight and continuing throughout Hockey Night in Canda with opinions and information from our various reporters and analysts.

On Inside Hockey, Elliotte Freidman explores the root causes of concussions and what the NHL is doing to protect its players. For the first time, the league has agreed to allow an interview with Dr. Ruben Echemendia, the league's neuropsychologist, who explains the NHL's position on head shots and puts Elliotte through the tests that determine if a player is ready to return to the ice.