The surprise return of Rep. Gabrielle Giffords (D-Ariz.) to Congress to vote on the debt-ceiling bill offered the most public glimpse yet of how far she has come since being gravely wounded in a shooting in January.

Few details have been released about Giffords’s medical treatment and rehabilitation since she was shot in the left side of the brain, an injury that initially left her unable to speak and walk. She spent nearly five months at Houston’s TIRR Memorial Hermann rehabilitation hospital, then moved into the Houston home of her husband, astronaut Mark Kelly, but continued daily outpatient therapy.

In May, Giffords sat in a wheelchair at Cape Canaveral to watch Kelly and the rest of the crew of the space shuttle Endeavour launch its final mission.

On Monday night, her mere presence on Capitol Hill astounded people who saw it or learned of it.

“I think it’s safe to say that she’s had a remarkable recovery from the brain injury,” said Mark Hallett, a neurologist at the National Institute of Neurological Disorders and Stroke who heads the human motor control section. He is not involved in Giffords’s care.

“If she was able to really understand and cast a vote by her own decision,” Hallett said, “then it means that she has made a very substantial recovery in terms of her ability to think as well as communicate.”

This was not the first time someone with a debilitating brain injury cast a crucial vote.

Sen. Clair Engle (D-Cal.) voted on cloture for the civil rights act in 1964 while he was suffering from a brain tumor and was partially paralyzed. He was unable to speak but signaled his “aye” vote by pointing to his eye.

Engle died the next month.