For me as a brain specialist, it was concerning to watch President Joe Biden, and it quickly became clear that I was not alone in my reaction. Over the past week, I received more than a dozen calls, texts and emails from medical colleagues who, like me, specialize in the brain. It wasn’t that what we noticed was necessarily new but that it was particularly pronounced, and right from the start of the debate.

From a neurological standpoint, we were concerned with his confused rambling; sudden loss of concentration in the middle of a sentence; halting speech and absence of facial animation, resulting at times in a flat, open-mouthed expression. To be clear, these are only observations, not in any way diagnostic of something deeper, and none of these doctors wished to suggest that was the case.

The consensus from the doctors reaching out to me, however, was that the president should be encouraged to undergo detailed cognitive and movement disorder testing, and those results should be made available to the public.