In a letter, signed by 37 of his Republican colleagues in Congress, Texas Rep. Dr. Ronny Jackson warns that President Biden's "mental decline and forgetfulness have become more apparent over the past two years," and urges the 79-year-old to take a cognitive aptitude test (just as former President Trump did). “My colleagues and I are again asking President Biden to immediately undergo a formal cognitive screening exam, such as the Montreal Cognitive Assessment,” Jackson said. “As a former physician to three Presidents of the United States, I know what it takes mentally and physically to execute the duties of Commander-in-Chief and Head of State,” said Jackson, who served as a White House doctor to former Presidents George W. Bush, Barack Obama and Donald Trump.