Dr. Ruben Echemendia, the NHL's leading voice in the research, data collection and analysis of concussions, outlined the protocol that a player suspected of having a concussion must go through in order to return to the ice.

Echemendia said the process starts the moment the suspected player comes to the bench and continues until he proves through an extensive series of testing that he is symptom-free "both at rest and on exertion."

When a player comes off the ice and is suspected of having a concussion ("a big hit might have happened, the player might look a bit stunned") the team athletic trainer typically on the bench will do an initial evaluation, said Echemendia. Some of the questions: What just happened? What do you remember before the hit? Where are we know? Who are we playing? What was the score of the last game?

If the on-the-bench evaluation raises concern in regard to concussion symptoms, then the player is taken to the dressing room, where a more extensive evaluation is conducted by the team physician and the team athletic trainer. The tests in the dressing room assess the player for attention and concentration, short-term learning and memory, balance and "motor coordination," said Echemendia.

"If at that time the player is determined to have had a concussion than that triggers the concussion protocol, which means the player must be kept out of play until they are symptom-free both at rest and on exertion," he said

Notably, the player is held out of practices, workouts and games. Additionally, "strenuous cognitive activity," such as video games, prolonged reading, working at a computer monitor -- activities that all "tax the brain and increase symptoms" -- are avoided.

Echemendia said the player will have to pass "a fairly extensive neuropsychological test battery conducted by the consulting neuropsychologist [who works closely with NHL/NHLPA Concussion Working group] for each team."

The data from those tests goes to the team physician, who ultimately makes the decision on when the player can return.

"Throughout that process we put the player through a gradual increasing intensity of physical exercise to see whether the physical provocation brings about any symptoms," Echemendia said, adding the physical exercise tests begin with trials on a stationary bike.

Echemendia said the player's history of injury and the timing of the current injury is significant in the overall evaluation and ultimate decision to allow him back on the ice.

"Are there two concussions within a space of a two-week period or a two-month period or within a 10-year period?" he said. "All of these variables are important in how the injury manifests itself in the brain. Not only that, but where the blow is affecting the brain affects what the type of injury it is. When you take all of that, the complexity of the brain and then you add on the complexity of culture, you begin to understand how difficult a task this really is."

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