Experts on aging caution against concluding that U.S. President Joe Biden and his Republican rival Donald Trump are suffering from cognitive decline based on their verbal slip-ups‚ saying that mixing up names or dates does not necessarily mean a deterioration in mental acuity. Biden‚ 81‚ a Democrat running for re-election in November‚ and former President Trump‚ 77‚ his likely challenger‚ have accused each other of mental decline. Trump's last rival for the Republican nomination‚ 52-year-old...