Eighteen-year old Dana Kiger is happiest chasing down balls on the soccer field.
But not long ago, she couldn't remember her love of the game, her parents faces or even her name.
At 16, the Tennessee honor student and star athlete was hit from behind while playing in a routine soccer game. She fell to the ground, her head striking the hard turf. The blow knocked out just about all of Kiger's memories.
"My husband and I were standing at her bedside, and the physician pointed at me and pointed to my husband and said, 'Do you know who these people are?'" her mom, Jill Kiger, said on "Good Morning America." "And Dana said no."
With no physical trauma or swelling in her brain, doctors were positive Kiger's memory would return in a few days.
But it did not. And 2½ years later, it still hasn't. Kiger -- who has no memory of her family, her childhood or her life before her injury -- has had to create new memories, rekindle relationships and relearn old skills.
"The only thing I had … I could walk, write, but I didn't know what to write," Kiger said of the days after the accident. "Physically, I was OK, I guess, but mentally was a struggle."
Doctors say long-term amnesia brought on by a moderate brain injury like Kiger's is unusual.
"It's very rare for people to have this persistent problem with memory going back into their autobiography and into their past," said Dr. Roger Hartl, assistant professor of neurosurgery at Weill Cornell Medical College.
Kiger's parents tried to help their daughter assimilate into the life she once loved.
"She didn't know what food was," Kiger's mom said. "She said, 'What is that?' I said, 'Lettuce." She said, 'Do I like it?' I said, 'That's up to you to decide.'"
Remarkably, Kiger's natural ability on the soccer field was the one part of her previous life that kicked in immediately. And soon, she'll begin a new chapter at Slippery Rock University, where she plans to study physical therapy.
Kiger said that while parts of her past still remain a mystery, she's focused on what's to come.
"It is about my future," she said.