Feinstein's return prompts renewed scrutiny over her fitness for office

Just a week after her return to the United States Senate after a roughly three month absence, questions continue to swirl around Sen. Dianne Feinstein and her mental capacity to serve in the world's greatest deliberative body.

The 89-year-old Democrat had been recovering from shingles at home in California, and had been absent from the Hill since February.

Her long-awaited return on May 10 not only meant that the Senate Democratic Caucus would be at full attendance - since both Feinstein and Pennsylvania Sen. John Fetterman had been absent for much of the spring - but that the one-seat margin Democrats held on the powerful Judiciary Committee would be reconstituted to help advance President Joe Biden's judicial nominations.

Senate Majority Leader Chuck Schumer greeted the frail Feinstein personally upon her return, when she was wheeled into the Capitol for a vote accompanied by staff on and off the floor. Schumer said Feinstein was "exactly where she wants to be, ready to do the things she loves the most - serving the people of California." First elected to the Senate in 1992, she is the longest-serving woman senator in US history.

But questions quickly sprang up on whether Feinstein, though present, would really be able to resume her demanding job. In a statement released by her office last week, Feinstein said that she is still "experiencing some side effects" from shingles and her doctors have advised her to "work a lighter schedule" as she returned to the Senate. During her arrival at the Capitol for votes, she appeared confused and was heard asking staff, "Where am I going?"

And in an interaction with reporters Tuesday, as reported by the Los Angeles Times and Slate, Feinstein appeared confused by questions about her absence, saying, "I haven't been gone. I've been here, I've been voting. Please, either know or don't know." It is not clear if Feinstein was referring to just the past week since her return or referring to the past several months while she was recovering at home.

CNN has reached out to Feinstein's office to request comment.