Researchers at a Canadian university are studying whether modern hockey helmets are built solidly enough to prevent concussions.

"We really don't know how successful or how safe the helmets being used today are," lead researcher Blaine Hoshizaki of the University of Ottawa said. "Even some of the low-velocity impacts are creating high-risk for concussions."

Scientists at the University of Ottawa's Neurotrauma Impact Science Laboratory are testing helmets used by many NHL stars, including star forward Sidney Crosby.

Concussions are a hot a topic in hockey circles this season, as hotly disputed as who is going to win the Stanley Cup.

The league has been without Crosby, widely acknowledged to be its best player, since January, when the Pittsburgh Penguins star went down with a concussion.

The University of Ottawa researchers looked specifically at the Crosby concussion, which occurred when he was hit in the back of the head by Washington Capital David Steckel.

Crosby was injured during a Jan. 1 game by a bodycheck deemed legal. Although he had concussion symptoms the next day, Crosby played on Jan. 5 and was sidelined after Tampa Bay's Victor Hedman boarded him from behind.

The hit happened at about 25 kilometres an hour, and the researchers believe that no hockey helmet currently on the market could have prevented the concussion.

"Manufacturers are going to have to build shells that are rounder," Evan Walsh, a PhD student said.

Former European pro Kerry Goulet says hockey players need to show a "new kind of courage" and speak up when they have symptoms of a concussion.

"That's what we need to teach our youth," he says.

The issue was again in the spotlight this week when Maple Leafs forward Mikhail Grabovski appeared to be stunned by two heavy hits during a game in Boston, only to take smelling salts on the bench and return to score the winning goal on a highlight-reel play.

Some observers argued he should never have been allowed to return after the hits.

Head injuries will be on top of the agenda when NHL's general managers sit down together next month.

Preliminary statistics released last month by league commissioner Gary Bettman show concussions on the rise so far this season.

Bettman said the increase appears to be the result of what he called "accidental and inadvertent" collisions. He also said there had been an increase in concussions from fighting.

Bettman would not give the number of concussions so far this season, citing confidentiality.

With a report by CTV's Daniele Hamamdjian