HOUSTON — Rep. Gabrielle Giffords has begun what will likely be a months-long recovery at a Houston rehabilitation center two weeks after being shot in the head by an Arizona gunman, medical staff said on Saturday.
"She's doing very well," said Gerard Francisco, chief medical officer at the Institute for Rehabilitation and Research at Memorial Hermann, who is overseeing Giffords' months-long rehabilitation journey.
"We initiated therapy yesterday and had therapy today as well," Francisco told reporters on a tour of the rehab center. "She is responding very well."
Another of her doctors, trauma surgeon John Holcomb, said a buildup of fluid in her brain could keep her in intensive care until at least the end of the week, delaying the start of full-fledged rehab.
In a Twitter message sent at about 5 a.m. CST Saturday, Giffords' husband, Mark Kelly, said she was "all settled in" and was "doing great in her new room."
The 40-year-old Arizona congresswoman arrived Friday at the Texas Medical Center, where she was expected to spend days in intensive care before moving to TIRR Memorial Hermann rehab hospital.
Giffords, 40, suffered a gunshot wound to the head at close range on Jan. 8 when a gunman opened fire at an event where she was meeting with constituents. Doctors have described her progress so far as akin to a miracle.
Jared Lee Loughner, a 22-year-old college dropout, is charged with the shooting. Six bystanders including a federal judge and a 9-year-old girl were killed in the incident, and 13 others were wounded, Giffords among them.
Giffords remains in the intensive care unit because of a drain in place to remove a buildup of fluid in her skull, which puts her at higher risk for infection.
Even in the intensive care ward, Giffords could undergo some rehab activities, including moving in bed, sitting and standing, and other strengthening exercises, Francisco said.
Giffords will get more intensive rehabilitation at the Institute for Rehabilitation and Research, renowned for its treatment of brain and spinal cord injuries. Once she is out of the intensive care unit, doctors said, she faces at least four to six months of intensive therapy.Video: Mark Kelly: Wife's rapid recovery 'quite inspiring'
Rehabilitation center staff gave journalists a tour of their facilities — including a large gymnasium-like room full of exercise mats, weight machines and treadmills where brain-injury patients relearn the rudimentary movement skills.
"The biggest challenge is discipline — you have to repeat things so many times," said Lex Frieden, a rehabilitation expert at the hospital.
Giffords will likely have to relearn basic skills like tying her shoes, and "the repetition is boring and requires a lot of discipline," Frieden told reporters.
The rehabilitation center is decked out with specialized equipment, including a weight-assisted treadmill that suspends patients in a harness and allows them to relearn walking skills without bearing their full weight.Video: What will Giffords' rehab involve? (on this page)
Departure from Tucson
On Friday, a caravan carrying her swept past cheering crowds as she left the hospital in Tucson, Ariz., prompting tears to well up in Giffords' eyes and smiles.
Children sat on their parents' shoulders as the motorcade passed. Many waved. Others carried signs wishing "Gabby" well. "It was very emotional and very special," said Dr. Randall Friese, who traveled with Giffords.Video: Wounded survivor: 'Christina, don't you die on me' (on this page)
For some along the route to the airport in Tucson, the sight of her motorcade seemed like a prayer answered.
Bundled into an ambulance, Giffords slipped away from the hospital, leaving behind the grief and hope embodied in the cards, candles and carnations at a makeshift memorial on the front lawn.
Marine veteran Al Garcia waited anxiously along the route to the airport, his Harley Davidson motorcycle at his side. He wanted to join the back of the caravan to show support for the woman who visited his neighborhood to ask about residents' concerns.
"It's through all of these prayers that she's leaving in just two weeks," Garcia said.
"The community has just come together so much — all walks of life, no matter what party you belong to," he said. "They've all come together to show their support for her and the other victims of this tragedy."
Reuters, The Associated Press and msnbc.com staff contributed to this report.