Donald Trump has appeared to make a blunder after calling for White House nominees to undergo cognitive tests just moments before his own gaffe.The 78-year-old former President claimed he had “no cognitive problem” at a town hall event on Sunday but later suggested St Louis Cardinals star Stan Musial was in the audience.Trump said: “Stan Musial? Oh I see Dan Meuser. Is Dan here? I thought he said Stan Musial – Stan the Man, remember?”Musial died more than a decade ago, with Pennsylvania Representative Dan Meuser instead being referenced before taking to the stage.Trump also complained about his chair being uncomfortable, later describing his age of 78 as “not that close to 80”.Responding to Kamala Harris’ calls for Trump to complete a cognitive test, the ex-President said: “I have no cognitive – she may have a cognitive problem. But there’s no cognitive problem.”He added: “And I actually call for a cognitive test for all people wanting to run for President.“Not based on age. Some of the greatest leaders in the world – and I’m not 80 and I’m not that close to 80.”LATEST DEVELOPMENTS:Hilarious video shows Donald Trump working at McDonalds – ‘I would like to serve some french fries!’Donald Trump left red-faced as he’s forced to pace stage for 20-minutes in silence after rally blunderElon Musk vows to hand out $1 MILLION a day to registered US votersDiscussing a basic screening he has taken, Trump claimed: “I’ve done cognitive tests and I’ve aced both of them.”Age became a major issue in US politics after Joe Biden made a series of gaffes ahead of dropping out of the 2024 race.Trump came under fire from Democrats after footage circulated showing him dance to music for 40 minutes rather than take additional questions.During a rally over the weekend, Harris said: “Being President of the United States, is probably one of the hardest jobs in the world.“And so we really do need to ask if he’s exhausted being on the campaign trail, is he fit to do the job?”Trump’s allies have fired back by pointing to the ex-President’s busy weekend schedule in Pennsylvania.The 78-year-old worked a shift at a McDonald’s in Bucks County, held a town hall event in Lancaster and received a warm welcome at a Pittsburgh Steelers game.Asked about Harris’ 60th birthday, Trump said: “It’s Kamala’s birthday?“She’s 60 years old. I would say Happy Birthday, Kamala. She’s turning 60.“I think I’ll get her some flowers. Maybe I’ll get her some fries.“Give her some McDonald’s- I’ll get her a McDonald’s hamburger. Happy Birthday Kamala!”Opinion polls have nudged Trump ahead as Americans close in on Election Day.However, the knife-edge White House race remains too close to call.