Democratic Sen. Tim Johnson, whose emergency brain surgery this week raised the prospect of a shift in power in the Senate, showed signs of recovery Friday, his office said.
Considering the seriousness of the medical problem found in Johnson's brain, "his progress is encouraging," Dr. Anthony Caputy said in a statement released by the lawmaker's staff.
Caputy was a member of the team that operated on the 59-year-old South Dakotan on Wednesday night.
Johnson was experiencing post-surgery swelling in his brain, but that was considered routine. "Much like a bruise, it takes time to heal," Caputy said.
With Democrats having captured a 51-49 majority in the Senate that convenes in January, Johnson's condition has riveted Washington's political community.
Should Johnson die or resign from office, South Dakota's Republican governor has the authority to replace him. If he chose a Republican as a replacement, the Senate would be knotted at 50-50. Vice President Dick Cheney, the Senate's presiding officer, would break the tie, returning the chamber to Republican control. But news of Johnson's increasing alertness substantially quelled such speculation.
After becoming disoriented Wednesday, Johnson was rushed to George Washington University Hospital, where doctors performed emergency surgery to relieve bleeding in his head stemming from the congenital defect arteriovenous malformation.
AVM, as the condition is called, can lead to speech problems, paralysis or, in rare cases, death.
A CT scan performed on Johnson early Friday showed "that the pressure has been relieved from his brain, and there is no further bleeding," Dr. Vivek Deshmukh, the lead surgeon, said in the statement from the senator's office. "Currently, his brain pressures are normal," Deshmukh said.
Johnson's office has not disclosed the precise location of the tangle of arteries and veins that caused the bleeding, a critical factor in determining what kind of long-term effects he may suffer.
Johnson was complaining of weakness on his right side when he arrived at the hospital. Doctors said they anticipated that physical therapy would be part of his recovery process.