The grilling came during an annual hearing with the House Financial Services Committee on the international financial system on Tuesday.
Rep. Mike Lawler (R-N.Y.) asked Yellen at the time if she had “noticed any mental or cognitive decline” in any of her meetings with Biden.
“The president is extremely effective in the meetings I’ve been in with him. That includes many international meetings that are multi-hour — like his meetings with President Xi [Jinping of China],” Yellen said.
The Treasury secretary declined to answer Lawler’s question about the last time she met with the president.
“I’m not going to comment on my meetings with the president. Those are private,” Yellen said.
Yellen also offered a single “no” when Lawler asked if there had been any discussion among Biden’s cabinet about invoking the 25th Amendment, which would allow a majority of the Cabinet to transfer powers from the president to the vice president if they believe they are unable to perform their duty.
Biden sparked alarm among Democratic lawmakers, allies and donors when he fumbled his words and struggled to string together responses at points during the first presidential debate of the 2024 cycle nearly two weeks ago.
Trump currently has a 58 percent chance of winning the presidency, according to a forecast by The Hill and Decision Desk HQ.
The incumbent has also been struggling to buck negative perceptions of his handling of the economy and win over voters who are upset about how he has handled the humanitarian crisis from the war between Israel and Hamas.
The Hill’s Taylor Giorno has more here.