4th Afghan exchange student reported missing in US

Rep. Gabrielle Giffords has been told that she was shot. Her ability to walk and talk is improving. And doctors say there's a good chance she'll be able to attend her husband's space shuttle launch next month.

Doctors provided the new details about Giffords' condition Friday, describing several milestones in her recovery in recent weeks. The developments include the removal of her breathing tube and her improving ability to walk with assistance and talk in complete sentences such as "I'm tired and want to go to bed."

Dr. Imoigele Aisiku called the breathing tube removal a "fist-pump" moment.

"I'm very happy to report that she's making leaps and bounds in terms of neurological recovery," Dr. Dong Kim added.

Her memory is also improving, although she does not recall the tragic event in Tucson that wounded her and 12 others and killed six people.

"She has been told both by her husband and by us, and I think she understands," Kim said. However, it's still not clear if Giffords knows if people were killed at the event.

Doctors also said she is showing emotion at times, including smiles when she makes key progress.

"She has a personality that's already showing through," Kim said. "She's very upbeat, focused on getting better. She hasn't shown us depression, and she's just been very forward-looking and even with the speech she's not showing much frustration."

Kim said it's a good possibility Giffords will be able to attend her husband Mark Kelly's space shuttle launch in April. He said doctors expect to reattach a piece of skull at some point in May but she can travel before that happens.

Part of her skull was removed to allow for brain swelling after she was shot in the head; she now wears a helmet to protect her head.

The news of her progress has been welcomed in her hometown of Tucson, where her supporters held a benefit concert on Thursday night to raise money for a fund created by a survivor of the attack. Rockers Alice Cooper and Jackson Browne were among the headline acts.

The suspect, 22-year-old Jared Loughner, has pleaded not guilty in federal court. Authorities described him as a mentally unstable college dropout who became obsessed with carrying out violence against Giffords.

He appeared in court this week in Tucson at a hearing attended by at least three survivors of the attack.