Congresswoman Gabrielle Giffords who was shot in the head remained in critical condition as of Monday morning, with little change in her condition, doctors said.

"No change is good. She is still following basic commands. The CAT scan is showing there is no progressive swelling," said Dr. G. Michael Lemole, Jr, chief of neurosurgery at the University Medical Center.

"But every day that goes by and we don't see an increase (in swelling), we're slightly more optimistic," he told a press conference

Giffords was able to perform some of the same basic responses to her doctors' commands, which included raising her thumb, showing two fingers and wiggling her toes, Lemole said.

It was still too early for any long-term prognosis, meaning Giffords' recovery probably would take a long time, said Lemole.

Along with Giffords, seven other patients wounded in Saturday's mass shooting north of Tucson remain hospitalized, with five in serious condition and another two in intensive care, said Dr. Pete Rhee, the medical director of the University Medical Center.

Rhee said the other victims faced a variety of medical procedures.

"We have had people who have had an operation in an abdomen. We had to make sure a heart wasn't injured as well," he said. "We've had vascular injuries, orthopedic injuries, and extremity injuries as well."

Rhee said he is confident the other patients will survive from "a physical standpoint," but doctors need to concentrate on the "whole human being."

Rhee said doctors remain positive about Giffords despite the severity of her wounds.

"At this point, things are going really well," Rhee said. "Typically about four or five days is when the worry about the swelling is gone."

The shooting, which presumably targeted Giffords, killed six people and wounded 13 others.

The motive for the killing remains unknown. The 22-year-old gunman, Jared Loughner, has been charged with five federal felonies: the attempted murders of U.S. Rep. Gabrielle Giffords and two of her staffers, and the murders of U.S. District Judge John Roll and Giffords aide Gabriel Zimmerman.

"Additional charges could be brought under domestic terrorism statutes as the investigation continues," FBI Director Robert Muellers said earlier.

A hearing is scheduled for later Monday.

Loughner could face the death penalty, although that decision has not yet been reached, court sources said.