Pittsburgh Penguins captain Sidney Crosby will be missing Game 4 in his team鈥檚 semifinal series against the Washington Capitals due to yet another concussion -- at least the fourth in the 29-year-old鈥檚 nearly 12-year NHL career.

Receiving multiple concussions, experts warn, can lead to severe consequences.

鈥淲e鈥檙e getting more and more concerned about the relationship between multiple concussions and later degenerative diseases,鈥 neurologist Dr. Carmela Tartaglia of the at Toronto鈥檚 University Health Network told 麻豆影视 Channel. Those can include chronic traumatic encephalopathy and Alzheimer鈥檚 disease, Tartaglia said.

Multiple concussions, Tartaglia added, are the biggest risk factor for post-concussion syndrome, which counts headaches, nausea, blurred vision, memory loss and trouble concentrating as its symptoms.

鈥淲e don鈥檛 have any cures for concussions,鈥 Tartaglia said. Only symptoms, she said, can be treated. 鈥淪o we ask people to really put themselves out of harm鈥檚 way.鈥

On Monday, in the first period of Game 3 of the series, Crosby suffered a concussion after being cross-checked in the head by Washington defenseman Matt Niskanen. Niskanen was given a five minute major and a game misconduct. Crosby missed the rest of the game.

This is not the first time the star centre has been floored by a concussion. Since 2011, multiple concussions have seen Crosby miss dozens of games, including much of the 2011-2012 season.

Tartaglia鈥檚 advice for Crosby is simple.

鈥淎void any situation that could put you at risk for other concussions,鈥 she said. 鈥淗e needs to be sufficiently better so that he doesn鈥檛 place himself at risk of having another brain injury on top of the one that he鈥檚 just suffered.鈥