"No two brain injuries are alike," said Dr. Steve Flanagan, chair of the Rusk Institute for Rehabilitation at NYU Langone Medical Center. "She has received some of the best rehab anyone can conceive -- a lot longer than a lot of folks because of her status.
"A brain injury that's as severe as hers is not measured in days or weeks or sometimes even months, but many years," Flanagan said. "It could well be very hard for her and would not be unusual for severe disability that will require some rehab for years."
Typically, injuries such as Giffords' create a host of cognitive and behavioral problems, from impairing walking, to washing and dressing, language, attention span and memory.
"Sometimes there is a change in behavior or mood and there is a worsening of irritability and they are anxious or agitated," he said.
Brain injuries can also add stress to the family.
"Oftentimes roles change and the impact isn't just on the patient," Flanagan said. "It changes the family dynamics."
Doctors also report marital break-ups, depression and even suicide among those with brain injuries.
Patients often tell their doctors, "I am completely different," according to Dr. Brian Greenwald, medical director of brain injury rehabilitation at Mt. Sinai Medical Center.
"Although we think of ourselves as our car or our house or what dress we like, what we are is our brain -- the mush in the head that is the same consistency as Jell-o," he said. "It's our thoughts and our emotions and our moods."
The challenges are enormous, say doctors, who point to the 30-year struggle of Jim Brady, the former press secretary to President Ronald Reagan, who was shot in the head during the 1981 assassination attempt outside the Washington Hilton.
His injuries were more serious than Giffords because he had been shot in both hemispheres of the brain.
In a March editorial in the Washington Post on the anniversary of his shooting, Brady's wife Sarah lamented how the "vivacious life" she and husband shared before his life was shattered in a "few seconds" by a bullet to the head.
Today, at 70, Brady is partially paralyzed, confined to a wheelchair, and undergoes physical therapy several times a week. Though his speech is sometimes slurred, he has full cognitive function.
His neurosurgeon, Arthur Kobrine, said in a January article in the journal Nature right after Gifford's shooting, Brady would "kind of cry-talk for a while," and had difficulty controlling his emotion and didn't recognize loved ones.
"It's a constant battle," said Paul Helmke, president of the Brady Center to Prevent Gun Violence, who worked with the Bradys to pass the 1993 Brady bill. "You want to encourage the patient and hold out and be positive with great progress, and the family and friends want them to be up. But it's a real challenge to the body.
"He tires quickly and has trouble with his eyesight as a result of his brain injury," he said. "There are so many things. Traveling is tough for him. The pain comes and goes."
Helmke said the Bradys were rooting for Giffords, knowing she will be an advocate for their cause, strengthening gun control laws.
"Our dream is that she recovers quickly, gets back to Congress and asks why no one has done anything about this issue," he said.
But medical experts like Greenwald say this is an unrealistic scenario.
"It's still early on and I think there is still reason to be optimistic overall," Greenwald said. "But being able to speak again and rejoining Congress are two different issues."