Thousands of Hoosiers may have brain damage they aren't aware of even if they were never diagnosed with a head injury.There are many ways to get a concussion, most commonly by playing football and other contact sports, but also by roughhousing or falling.Recent studies have shown that the number of children suffering brain bruises during organized sports has doubled in the last 15 years, and the damage can last for decades.Ian Berry's hockey career ended last October after another player hit him in the head and he fell to the ice, RTV6's Stacia Matthews reported."I couldn't walk off the ice. I had to be carried by my teammates," Berry said.At age 16, the big hit broke Berry's dream. He was diagnosed with a fourth concussion."I couldn't let Ian play hockey anymore because I was afraid he would damage his brain more," said Dr. Terry Horner, of Methodist Sports Medicine. "If I returned him to the sport and he got another concussion, he may never recover from that. It was tough to do that."Allie Coons is still playing lacrosse, but she knows one more concussion could bench her for good."The first time wasn't bad, but the second time, I don't remember anything," she said.Concussions are brain injuries, causing often mysterious damage that could permanently alter how the brain works. Doctors said children are especially vulnerable because their brains are still maturing."Even if you stop playing, there still could be long term effect if you've actually taken too much damage early on in life," said Dr. Tom Talavage, who leads a team of researchers at Purdue University working to find ways to protect children and adults from concussions.Scientists put sensors in the helmets of Lafayette Jefferson High School football team members, counting the hits.They then gathered MRI images of the players' brain activity over the course of two seasons. Researchers said they were troubled to find reduced brain activity on scans of players who were not diagnosed with a concussion.Joel Ripke took part in the study, enduring more than 3,000 hits to the head. His mother, Cheryl Ripke, wasn't too worried."Joel never seemed to have a headache or anything like that, but one morning they called to see if Joel was OK," she said. "'He suffered a huge hit last night and we want him to come in and have an MRI.' He doesn't seem any different, and he never did."Ripke now plays football in college, and his parents haven't noticed problems."What we ended up finding out is about 50 percent of our players who don't exhibit any external symptoms are, in fact, showing cognitive impairments," Talavage said. "That was a very big surprise and shock to us."All the hits add up over time, even if the player was never diagnosed with a concussion, especially if the brain isn't given time to fully heal between hits.Talavage and his team are trying to find ways to minimize brain injuries. They are developing a squishy new material that would allow the padding inside a helmet to absorb more energy.The technology is too late for Berry, who was wearing the best helmet money could buy when he was injured."It's not like a broken bone and you know how long it's going to take to heal," said Tim Berry, Ian's father. "I think that's also the hardest part for him, too."Six months after his last concussion, Berry, a former honors student, is having trouble in the classroom. Nothing is easy anymore."It's devastating to see him struggle so hard to recover, to catch up in school, and through all that, give up both of his passion," said Kim Berry, Ian's mother.Ian still frequents the rink, coaching his younger brother, Colin, but he misses the thrill of being in the game."The injury could have been a lot worse. I'm sitting here talking to you. All four limbs are working," he said. "I'm great. I'm lucky in that standpoint."Doctors urge someone who may have a concussion to visit an emergency room.Symptoms of a concussion vary among people. They can include headache, irritability, sluggishness and a general feeling that something isn't right. The most common symptom is a headache.Schools are putting more children on the sidelines, and coaches and teachers are being trained to ask specific questions to help diagnose a concussion.