DR MARC SIEGEL: Presidential fitness and what we deserve to know

Concerns about President Biden's cognitive health raise questions about transparency in presidential fitness, focusing on memory loss and neurological evaluations.

Marc Siegel, M.D. is a professor of medicine and medical director of Doctor Radio at NYU Langone Medical Center. He is Fox News Channel's senior medical analyst and author of "COVID: The Politics of Fear and the Power of Science." Follow him on Twitter @drmarcsiegel.

But missing from this letter, as from previous letters on President Biden’s health, was any mention of an MRI of the brain or or neuro-cognitive testing. Peripheral neuropathy or sensory loss in his extremities would hardly be a cause for concern about fitness. Further, even if there was a discussion about possible use of a wheelchair among White House insiders, as a new book, "Original Sin," by CNN’s Jake Tapper and Axios’ Alex Thompson suggests, this would also not be a reason to question fitness. FDR famously served from a wheelchair during World War II, even if he tried to hide it so as not to show weakness to the Nazis.