Arizona Shooting: Will Gabrielle Giffords Ever Speak Again?

(CBS) If doctors' optimistic prognosis for Congresswoman Gabrielle Giffords holds, the question won't be "will she make it," but "how will she make it."

And that's a very big question.

For injuries like this, "recovery is on the order of weeks and months rather than days," says Dr. Shelly Timmons, neurotrauma director at Geisinger Health System in Pennsylvania.

Timmons is not working on Giffords' case but has seen many like it. People can get better or worse from this point out. "The next few days are critical," she says.

Giffords has not yet spoken since being shot in the head at a public appearance outside Tucson on January 8. But she was able to squeeze her doctor's hand in response to questions before surgery and extend her fingers afterward.

"She is able to process information that she hears and translate that into an executable action. That's a very good sign," says Timmons. "But it's also a good leap from there to a fully functionally walking, talking human being."

If Giffords pulls through and emerges from the medically induced coma, doctors will be looking carefully at her ability to speak, both in terms of having the motor skills to form words in the mouth and the cognitive ability to recognize words and their meaning, says Timmons.

Paralysis is also an issue. Unlike spinal injuries, which can paralyze from the neck or waist down, brain injuries can cause total or partial paralysis on one side, like a stroke. Long-term rehabilitation can be effective against this, although it's not yet clear if it will be a problem for Giffords.

Personality changes can occur too, says Timmons.

"Anything the brain does can be affected by an injury like this: memory, attention, concentration, behavior and personality are all possible changes," she says. "But with one-sided injuries, that's not as common."

"There are many cognitive skills that can be adversely impacted by traumatic brain injury," says Dr. Steven Flanagan, chair of the Rusk Institute of Rehabilitation Medicine at New York University. "Language is one skill. Often what we see, again this varies, are some combo of impairments in attention, concentration, solving problems, and processing information at various speeds. We see difficulty with remembering things from yesterday or years ago."

Giffords' doctors have said she was shot "through and through," meaning the bullet entered one side of the head and exited the other. That's important because it means some of the bullet's energy was spent outside of  Giffords' body rather than shattering inside her brain. And in this case, the bullet's path did not cross from one hemisphere of the brain to the other. Also, she received rapid care. Doctors had her on the operating table within 38 minutes of the attack.

Those are all good indicators for Giffords, but her doctors were cautious.

"She is still in critical condition. Brain swelling at any time can take a turn for the worse," Dr. Michael Lemole, chief of neurosurgery at University Medical Center in Tucson, where Giffords is being treated, told CBS News.

During surgery, doctors removed parts of her skull to allow room for brain swelling. They also removed bone fragments that shattered during the attack.

And despite the news media's hunger for a quick resolution to this story like a Hollywood movie, Giffords' potential recovery could be measured in months or even years.

"We don't close the book on recovery for years," said Lemole. "It will take as long as it takes."