Spencer Jean is a hockey player who had his career cut short by concussions — 15 of them. Now his brain is degenerating.

He's been diagnosed with chronic traumatic encephalopathy, a degenerative brain disease.

"My symptoms will just continually get worse over the years. It’ll mock symptoms of dementia," Jean said. "I want to get things accomplished before those symptoms come about."

'It was for the love of the game. That's the athlete's mentality.'- Spencer Jean

The 23-year-old former former collegiate and professional hockey player has written a book detailing his injuries.

The Untold Truth examines his first and last concussions, and everything in between.

Jean, who is from LaSalle, Ont., near Windsor, explains how he hid most of his concussions — and their symptoms — from his coaches, teammates, parents and even doctors.

“It was for the love of the game. It’s as simple as that,” he said. “That’s the athlete’s mentality.”

A lifetime of concussions

Jean said he suffered his first concussion on the playground as a kid. His last happened while playing hockey for Gulf Coast University in November 2011.

He suffered the injury on a Friday night, played through it and spent the night awake and throwing up. It still wasn’t enough to keep him off the ice the next day.

Untold Truth Spencer Jean

Spencer Jean wants to raise concussion awareness through his book The Untold Truth. (AuthorHouse)

“I don’t remember that game at all,” he said.

His injury came to light early in the third period when he was “unresponsive” to his coach’s instructions.

He left the bench, passed out in the locker-room, and woke up surrounded by EMS staff. He was rushed to hospital and his hockey-playing days were over.

“No doctor would give me clearance to play again,” he said.

His book includes some stories he's never told anyone before. Part of the reason he wanted to write it all down was so he can remember his life when his mind starts to go.

“I went through some dark times,” he said. “What happened to me happens to many, many professional athletes.

“I know so many other athletes are going through these dark times … and playing with concussions for so long.”

Jean said with education, support and encouragement, his injuries could have been prevented.

“It upsets me to this day to think about it,” he said.

He hopes his book will raise awareness about concussions.

“When you’re writing this type of book, you’re not thinking about yourself. The whole motivation about the book is to help others and spread the word,” he said. “Something needs to be done to help the athletes of today and tomorrow.”

Jean is the co-founder and medical director of the Concussion Education and Prevention Agency, Inc. He is also a certified brain injury specialist.

He wants governments at all levels to study concussions more closely and help implement more measures to decrease the chances of and number of concussions in sport.

Jean will be signing copies of his book at Chapters at Devonshire Mall in Windsor at 1 p.m. Saturday.