Mystery of Amnesia Is Fact of Daily Life for Teen

June 2, 2009 -- "Memory is the diary that we all carry about with us," Oscar Wilde wrote. But what about when that diary is inexplicably erased?

Amnesia, or memory loss, is a rare and little-understood medical condition that happens to have -- perhaps because it is so mysterious -- great imaginative appeal. What would it be like to wake up and not know who you are? To not be able to recognize friends and family?

Kayla Hutcheson, 19, knows the answer to those questions, although they are difficult for her to articulate. She was struck with amnesia after bumping heads with a teammate at basketball practice in late October 2008. Her memory loss, especially in the beginning, was nearly complete.

Family vacations, high school graduation, holidays were all gone. All the little memories that make each of us whole were deleted from her mind like from a ruined computer hard drive.

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"I wish it would all come back, actually," Hutcheson told "Nightline" during a recent visit to Washington's Walla Walla Community College, where she is a student. "When we'd be sitting around friends or something, be talking about what they did as a child -- I just sit there, 'cause I don't know."

The first day of kindergarten? Or elementary school?

She shakes her head.

Her family?

"I don't remember doing stuff with them, but I do remember them … well, just the ones I've met, my brother and sister and my parents -- I don't remember my real mom."

Like so many of life's tragedies, it happened out of the blue -- during a simple basketball practice.

She ran into her teammate Jeni Gabriel. The two banged heads.

"I looked at her right away, and I said, 'Are you OK?' and she said, 'Yeah, I'm fine,' and we continued playing," Gabriel recalled.

Apart from a bloody nose, Hutcheson seemed just fine.

But later that night, at home with her teammates, she started acting strange.

"When Jill finally started like, asking her questions, that's when we realized that she didn't know anything," said teammate Nancy Johnson, 18. "She didn't know our names, who we were, where she was, what her name was, how old she was, who her dad was. She didn't know anything."

They took Hutcheson to the emergency room, where she was X-rayed and examined. According to her roommates, she was told she had a concussion -- nothing more.