"He has not let up for a minute, that's the secret," said Paul Rao, Johnson's primary speech therapist and vice president of the National Rehabilitation Hospital in Washington.
"Like you, the care was great, and I was at the right spot at the right time, in that my hospital … the doctors were around, and the hospital was nearby," Johnson told Woodruff in August.
By last week, the results were clear.
"He's ready to return to the Senate," Rao told Woodruff definitively.
"There's no question that he could be a functional senator?" Woodruff asked.
"He is a functional senator," Rao said.
"I see him every week or two, sometimes every week, and we send memos back and forth and he's — cognitively, he's just fine," said Drey Samuelson, Johnson's chief of staff.
Rao said: "His comprehension is virtually intact. When he has complex sentences or paragraphs, sometimes a challenge. But in terms of day-to-day conversation and communication, he's 100 percent. When you speak to Sen. Johnson and he makes a statement and he listens to what you have to say, I think you can take that to the bank."
Woodruff told Johnson last week, "I think people will be shocked at how well you move and speak."
Johnson said, "Yeah, but I'll be getting better as time goes on."
"What do they tell you — how many years will you be improving?" Woodruff asked.
"Forever," Johnson said with a laugh. "You constantly improve. Bit by bit, but constantly improve."
Johnson plans to run for re-election in 2008.
"I expect to run and to win," he said.
This weekend and on the eve of Johnson's return to public life, Barbara and Tim returned to their home in Sioux Falls for the first time since he became ill. Their three children, two daughters-in-law and five grandchildren were there to greet them.
The senator stood before his constituents today, back from the fight of his life, and told them he is ready to serve.
"Never in my life have I been so grateful that you have been standing by my side as well. From the bottom of my heart, thank you South Dakota."