A longtime aide toJoe Bidensat for a transcribed interview in House Republicans' probe of the former president's potential cognitive decline and possible efforts to conceal it from the public. Bruce Reed, the former White House deputy chief of staff for policy, appeared before the House Oversight Committee Tuesday as part of the Republican-led panel's investigation. He's just the latest Biden White House official to do so, and the first of two top former White House aides scheduled to appear this week. Former senior adviser to the president for communications Anita Dunn is set to appear Thursday, and the committee is expected to hold more voluntary interviews in the coming weeks. During the Biden administration, Reed oversaw much of the domestic policy agenda in the White House. He had also played a role inpreparing Bidenfor his presidential debate against Donald Trump – adisastrous eventfor Biden that eventually led to his exit from the race altogether. The panel has conducted a number of interviews with former Biden officials in recent weeks, with varying degrees of cooperation. Former Biden counselorSteve Ricchettiand onetime senior adviserMike Donilonvoluntarily sat for transcribed interviews last week. Others have been subpoenaed to appear. Compelled to testify, White House physicianDr. Kevin O'Connor, former assistant to the president and senior adviser to the first ladyAnthony Bernaland former assistant to the president and deputy chief of staffAnnie Tomasiniall invoked their Fifth Amendment right against self-incrimination. This headline and story have been updated with additional developments. For more CNN news and newsletters create an account atCNN.com