For instance, Melissa can no longer do "times" tables. She was never a strong student, but these she knew by heart as a child. Asked to multiply 7 times 5, she counted out loud, "5, 10, 15 . . . ," and with each repetition held up another finger. When she got to her seventh finger and said, "35," she stopped.

She was far from confident of her answer.

Fried said concrete actions (making a sandwich, mopping a floor) are easier than abstract thought (multiplying in your head or creating a lesson plan).

Anjan Chatterjee, a neurologist and brain expert at the University of Pennsylvania, explained how short-term memory may be damaged.

The brain, he said, is the texture of firm Jell-O, and the skull in most places is smooth. When the brain is shaken, it can slide along this smooth surface and minimize injury.

But the bottom of the skull is scalloped and parts of the brain cradled there are often damaged when shaken in automobile accidents.

One such part is the temporal lobe, which includes the hippocampus, a sea horse-shaped structure that coordinates memories and dispatches them to other parts of the brain for storage.

When the hippocampus is injured, he said, the brain has difficulty creating new memories - a person can forget what happened 10 minutes earlier.

In addition, with a damaged hippocampus, a person can lose memories that had not already been completely stored in other parts of the brain - a process that can take months.

This, Chatterjee said, could explain why Melissa's recent memories of Jasta were lost.

One other area of the brain commonly damaged in automobile accidents is the orbito-frontal cortex. When this part of the brain is shaken, he said, a person can become "disinhibited, distractable, and judgments may be off."

A person may lack discipline, he said, seem immature.

Melissa's best friend, Erin Doyle, jokingly blames Melissa for making her gain weight, because Melissa is always wanting to go to Friendly's for ice cream - a place Melissa never went before the accident.

A crushing loss

Dan Jones was at the hospital every day with Melissa, then moved into her aunt's house with her. But a year after the accident, Jones ended the relationship.

"She was totally crushed," Melissa's mother said.

"He made it like he cared and loved me," Melissa said. "But he up and disappeared."

Jones said he never stopped loving Melissa. But she had changed and he couldn't deal with her family.

"I wanted something I wasn't going to get," he said. "I wanted my girlfriend back. She was like a little kid. Her family controlled her."