It's estimated only one-third of patients return to work after a stroke, said Dr. Elliot Roth, medical director of the Rehabilitation Institute of Chicago's New Patient Recovery Unit and AbilityLab, where Kirk recovered.
The 53-year-old Republican will return to the high-profile, demanding life of a Washington lawmaker after an experimental rehabilitation so intense it's often compared to boot camp, Roth said. Patients keep grueling schedules, often spending eight hours a day or more re-learning how to walk, talk and do other tasks.
Because there are risks to going back to work unprepared, patients do "practice runs" of what it will be like to be back on the job. If and when they successfully return to work, Roth added, "It's like having a great symphony play and recognizing it's all the practice beforehand that went into it."
Kirk will walk back into a Congress that has grappled for weeks over how to avoid going over the "fiscal cliff," a series of across-the-board tax increases and spending cuts due to take effect Tuesday. President Barack Obama indicated Monday afternoon that a deal was in sight, but not yet finalized. But House Republicans said they will not vote on the issue Monday night, and it remained unclear whether the Senate would vote Monday.
The Illinois senator's return will be inspiring to fellow stroke patients, said Frank Watson, the former Republican leader of the Illinois Senate who resigned from office after his 2008 stroke.
"For us in the stroke fraternity, we're very happy to see this occur, to see somebody taking their life back," Watson said. "There are so many people who don't make it back."
Kirk, who won President Barack Obama's former Senate seat in 2010, checked himself into a hospital in January 2012 after feeling dizzy. Tests revealed that the avid swimmer had suffered a major stroke. Surgeons had to remove two small pieces of destroyed brain tissue, and temporarily removed a 4-inch by 8-inch portion of his skull to allow for swelling.
Doctors said movement in Kirk's left side was severely limited. He was in intensive care and would need speech therapy, but they expected he would make a full mental recovery.
Within days, they said Kirk was asking for his Blackberry. In May, Kirk released a video updating his progress and showing footage of him walking with the help of a harness, a cane and Rehabilitation Institute of Chicago staff. It also included clips of Kirk speaking while sitting in a chair, his left shoulder lower than his right and the left side of his face still largely paralyzed.
Kirk said in the video that his staff had counted the steps from the parking lot to the front door of the Senate. It was his hope to climb all 45 of them someday, "to fight for the people of Illinois."
In a separate video released three months later, Kirk was shown climbing stairs at the RIC and working in his home office. He said he had moved back to his home in the north Chicago suburbs, and that he was talking to his staff several times a day and keeping up with business in Washington via email. He also touted the experimental therapy, through which he had logged almost 15 miles and 145 flights of stairs.
Roth said the study represents a new approach to stroke rehabilitation, which has traditionally been slower and more cautious. In the study, one group—which included Kirk—was pushed harder and walked more, in an effort to see if it led to a quicker recovery.
In November, Kirk climbed 37 floors of stairs inside Chicago's Willis Tower as part of an RIC fundraiser. One of his therapists called it "remarkable progress."
Kirk has said little to the media throughout his rehabilitation. Through his staff, he declined to comment about his return to Washington. They have said he'll walk the steps Jan. 3, when the new Congress convenes.
Watson, who was in a wheelchair for months after his stroke, said it will be important for Kirk to take it slow and make time for continued rehabilitation, noting "it's not over."
Watson's stroke affected his emotions, prompting him to break down in tears at times he previously would not have. It's something that still happens a little, he said.
Moments later, talking about the significance of Kirk's return, Watson began to cry.
"We need success stories," he said, "and Mark's one of them."