Question: When did the NHL implement a new protocol for detecting concussions during gameplay?
About the article "Ice hockey", section "Head injuries".

Candidate passages:
According to the Hughston Health Alert, "Lacerations to the head, scalp, and face are the most frequent types of injury hockey."
(Schmidt 6) Even a shallow cut to the head results in a loss of a large amount of blood.
Most concussions occur during player to player contact (49%) rather than when a player is checked into the boards (35%).
Not only are lacerations common, “it is estimated that direct trauma accounts for 80% of all injuries.
Most of these injuries are caused by player contact, falls and contact with a puck, high stick and occasionally, a skate blade.” (Schmidt 3) One of the causes of head injury is checking from behind.
Due to the danger of delivering a check from behind, many leagues, including the NHL have made this a major and gross misconduct penalty (called "boarding").
Another type of check that accounts for many of the player to player contact concussions is a check to the head.
A check to the head can be defined as delivering a hit while the receiving player’s head is down and their waist is bent and the aggressor is targeting the receiving player's head.
Checks to the head have accounted for nearly 50% of concussions that players in the National Hockey League have suffered.
Concussions that players suffer may go unreported because there are no obvious physical signs if a player is not knocked unconscious.
This can prove to be dangerous if a player decides to return to play without receiving proper medical attention.
In recent years there has been debate over whether or not a check to head should be deemed an acceptable hit in hockey.
In March 2011, the NHL instituted a new concussion testing protocol to help improve detection of concussions during gameplay
The National Hockey League's concussion policy began in 1997, and players who sustain concussions are evaluated by a team doctor in a quiet room.
In March 2011, the NHL adopted guidelines for the league's concussion policy.
Before the adoptions, examinations on the bench for concussions was the minimum requirement, but the new guidelines make it mandatory for players showing concussion-like symptoms to be examined by a doctor in the locker room. 
Lindros was drafted in the 1994 NHL Entry Draft, 1st round, 9th overall by the New York Islanders.
After suffering a series of concussions, he was forced to retire on May 1, 1996 due to post-concussion syndrome after playing only 51 NHL games.
Brett now works in Toronto for hedge fund Radiant Capital 
Prevention of undiagnosed and repeat injury is of importance in sports-related concussions.
Rapid sideline testing using short neuropsychological tests that assess attention and memory function have been proven useful and accurate.
The Maddocks questions and the Standardized Assessment of Concussion (SAC) are examples of validated sideline evaluation tools.
The Return To Play (RTP) protocol aims to decrease repeat concussions within a short time frame to minimize second impact syndrome.
It assures players who experience a concussion have complete cognitive and clinical recovery before returning to play.
Best practices of RTP involve graduated activity intensification with each step taking at least 24 hours to assure full rehabilitation within one week (includes asymptomatic at rest and during exercise).
In cases in which resources (i.e.
neurospychologists, neuroimaging) are available on-site, RTP may be more rapid.
Baseline assessments, performed before concussion occurs, provide a comparison from which to measure severity of post-concussive symptoms.
However, they have not been shown to decrease risk of injury.
Use of protective equipment such as headgear has been found to reduce the number of concussions in athletes.
Improvements in the design of protective athletic gear such as helmets may decrease the number and severity of such injuries.
New "Head Impact Telemetry System" technology is being placed in helmets to study injury mechanisms and potentially help reduce the risk of concussions among American Football players.
Wearing a helmet is associated with a decreased risk of head injury for skiers and snowboarders.
Changes to the rules or the practices of enforcing existing rules in sports, such as those against "head-down tackling", or "spearing", which is associated with a high injury rate, may also prevent concussions.
The National Football League (NFL) implemented the sideline concussion assessment protocol in 2011 which oversees the treatment of any possible concussions and ensures that the medical staff on each sideline are following proper league protocol and testing for any head trauma.
In 2011 the NFL enforced a kickoff rule change which moved football kickoffs five yards forward, resulting in reduced concussion incidence by 50%.
Rules aimed at promoting fair play, while minimizing outwardly aggressive behavior, should be encouraged in all sports.
Prevention could be helped by professional sports such as the National Hockey League pushing towards making hockey safer.
Concussions have become a more common injury in hockey today and are being critiqued under a microscope for both their immediate and long lasting effects.
Concussion symptoms can last for an undetermined amount of time depending on the player and the severity of the concussion.
There is also the potential of post-concussion syndrome, which can last for months after the concussion.
Concussions damage the brain of a person and the brain controls everything in the body so to limit this severe injury to the highest percentage possible would be in everybody’s best interest.
National Hockey League Commissioners have been pushing towards stricter rules and longer suspensions to crack down on concussions.
There have been great strides taken in changing the rules to help concussion prevention but officials still have to continue to look into this considering the game is evolving at an extremely fast pace.
Players also need to make it a responsibility within themselves to protect each other and not take runs at each other with a player with their head down.
Taking all these things into consideration, this could help the prevention of concussions in the National Hockey League considerably. 
 The kickoffs are now at the 35-yard line rather than the 30-yard line, to match the NFL's rule changing.
Onside kicks can be executed from standard kickoff formations.
Tuner or for developers to improve gameplay code without the distribution of official patches.
To support awareness for concussions, players who suffer a concussion during gameplay will no longer be allowed to return to the game.
A new collision system uses momentum to produce more authentic tackling and hits with 100 new tackle animations, including 40 gang tackles.
AI enhancements allow players in zone and man coverage to correctly recognize and react to plays with the capability to break out of assignments when necessary.
The custom playbooks feature allows the player to modify an existing playbook or create his or her own by selecting plays from 75 playbooks.
The opening presentation for games includes mascots and cheerleaders for all teams that have them.
Player traits change dynamically throughout a game based on his performance.
Quarterbacks have distinct throwing motions, making them look much more like their real-life counterparts.