Although she had been told countless times that Jasta was dead, Melissa fully expected Jasta to run into her arms when she walked through her aunt's front door.

No Jasta.

"I thought they were so cruel, playing a horrible joke on me," recalled Melissa. That day she remembers.

Everyone - Melissa's mother, sisters, aunt and boyfriend - helped care for her.

"She was like a 2-year-old child," her aunt recalled. "She was in diapers. I would have to sit on the toilet and tell her what to wash in the shower. She got better at doing things for herself little by little, but she had to be constantly reminded."

To convince her that her daughter had died, and to get her to remember permanently, Daubenspeck asked Melissa if she wanted to watch the video of Jasta's funeral, which Melissa - in a coma - had missed. Jasta was buried in a Cinderella dress.

Melissa watched repeatedly.

At first, said her mother, Melissa seemed detached, watching the minister tell everyone how Jasta loved to dress up in long dresses and high heels, how she brought her blankie to school, loved her pop-pop's French toast.

"Maybe it was so hard for her to believe. Or to process and comprehend," Daubenspeck said.

But the more she watched the video, the more emotional Melissa got. She would see teachers from her preschool, her sisters, touching the casket on the snowy ground and she'd weep.

And forget.

"To go through a death is bad enough," said her mother, "but to go through it over and over is, like, unbelievable. . . . I guess what happened as the time went on, and her brain was getting a little better, she could grasp a little of it."

By summer, Melissa Sweeney understood that her daughter was dead.

Medical explanations

Guy W. Fried, chief medical officer at Magee and a specialist in rehabilitation medicine, said half a million Americans suffer traumatic brain injuries every year, and 50,000 die from them - often the result of car accidents.

Few are as lucky as Melissa. "Most people don't do that well when they come from such devastation," he said.

The brain, Fried said, "has nerves connecting all over the place, millions of connections . . . smaller than spiderwebs, connecting one thought to another."

Melissa's brain was shaken so violently by the crash that many of these connections were destroyed "in tiny areas diffusely throughout her brain."

"The blessing," he said, "was that she was 27, so her brain is going to have more plasticity, the ability to recover or form a new pathway."