Dr. David Dodick of the Mayo Clinic talks concussions in sports

The issue of concussions in sports, or concussions in general has never been a hotter topic - fueled by some high profile tragedies in the NFL.

The new movie 'Concussion' in which Will Smith plays a pathologist whose work reveals a link between brain damage in football players and repeated blows to the head during normal play.

So what are the truths about concussions and sports? The Mayo Clinic, hoping to get some answers out there have made some of their experts available this morning.

Joining us from their facility in Phoenix was Dr. David Dodick - Medical Director of the Headache Program and the Sports Neurology and Concussion Program.

The Centers for Disease Control and Prevention estimates that as many as 3.9 sports-related and recreation-related concussions occur in the US each year. And that number may even be higher because many more concussions are not actually diagnosed correctly.

Even with all the recent attention on concussions, how much do people really know about how to spot a concussion, what to do about it and how they are treated? In fact, many people don't know how a concussion is caused!

What is a concussion? A concussion is a traumatic brain injury that alters the way your brain functions. Effects are usually temporary but can include headaches and problems with concentration, memory, balance and coordination. Although concussions are usually caused by a blow to the head, they can also occur when the head and upper body are violently shaken. These injuries can cause a loss of consciousness, but most concussions do not. Because of this, some people have concussions and don't realize it. Concussions are common, particularly if you play a contact sport.