Sen. Johnson's Condition Slowly Improving

Democratic U.S. Sen. Tim Johnson of South Dakota has shown steady improvement following brain surgery last month, but still faces a long recuperation and has been on a ventilator, aides said Wednesday.

"The next phase of his recovery is expected to take several months and focus upon rehabilitation and physical therapy," the aides said in a written statement. They did not estimate when the 60-year-old senator might be able to return to Capitol Hill.

Democrats will hold a narrow 51-49 majority in the Senate when the 110th Congress convenes Thursday. If Johnson had to leave the Senate, a Republican likely would be appointed to finish the last two years of his term. That would make for an evenly split chamber, with Vice President Dick Cheney, the president of the Senate, able to cast tie-breaking votes.

Johnson could be out for months, but still hold his seat. A Senate seat becomes vacant through death or resignation.

Johnson's wife, Barb, said she expects a long recovery. "We know there is a long road in front of us, but Tim's determination will make all the difference and he'll be at back at work as soon as he can be," she said in a statement.

On Dec. 13, Johnson was admitted to George Washington University Hospital, where doctors performed emergency surgery to stop a brain hemorrhage caused by malformed blood vessels.

Dr. Vivek Deshmukh said tests were performed Wednesday that showed no evidence of residual malformation of blood vessels following the surgery.

Doctors also said Johnson developed fluid in his lungs as a result of the initial hemorrhage and was placed on a ventilator to help him breathe.

"His breathing has steadily improved and now he only requires assistance at night," Deshmukh said.

Deshmukh said Johnson continues to be responsive to family and doctors, "following commands, squeezing his wife's hand and understanding speech."