Traumatic brain injuries are among the most common serious brain disorders in the US.

More than 5 million Americans are living with a disability like memory loss, suffered after a brain injury.

In one study, the alzheimer's drug, Rivastigmine, helped 30 percent of patients recall additional words on a test.

That was compared to ten percent on a placebo.

The drug enhances a chemical involved in memory and learning. "They can focus their attention better. They can concentrate better. They can recall things more easily," says Dr. Douglas Katz of Boston University.

Ryevastigmeen is FDA approved to treat alzheimer's.

The drug will undergo more studies before it can be approved to treat memory loss.

The drug does not need to be given immediately after the accident