What did Donald Trump do today?

He confused a dementia test with an intelligence test.

During his physical exam last week, Trump reportedly made an unusual request: that he be given a standard screening test for pre-dementia. The Montreal Cognitive Assessment Test (MoCA) is a quick screen for memory and cognitive impairment that allows physicians to determine if a patient may be suffering from incipient dementia. 

Notably, while many details about what the physical examination would involve were revealed before it took place, Trump did not reveal that he had asked for the MoCA until after he'd passed it. 

The test does not measure intelligence, learning disabilities, or the cognitive effects of personality disorders. By design, any person not suffering from dementia or a severe intellectual disability will get a very high or perfect score--as Trump did. Trump's physician, Navy Rear Adm. Ronny Jackson, explained as much during his press conference on Tuesday.

But by today, Trump already seemed to have started conflating a "perfect" score on a dementia screening with a perfect score on an intelligence test. He told Reuters in all apparent seriousness that he would solve the North Korean crisis where Presidents Clinton, George W. Bush, and Obama had not because it required a "president that scored the highest on tests."

It's not known if any of Trump's immediate predecessors had the MoCA or other dementia screenings done, but if so, none of them felt the need to remind people that they'd passed them.

Why is this a problem?

• It's bad if a president isn't intelligent enough to understand the difference between dementia and stupidity.

• A desperate need for validation is not evidence of dementia, but it's not a sign of good mental health either.