President Donald Trump has been touting his mental stamina for years. Even before his 2016 election, Trump played up his intellectual acuity while downplaying that of his opponents, including former Secretary of State Hillary Clinton.

On a number of occasions, Trump questioned Clinton’s “stamina” on the campaign trail in 2016—an innuendo that led Clinton’s operation to assert her mental fitness. Clinton “lacks the mental and physical stamina to take on ISIS, and all the many adversaries we face,” he said at one point.

He’s used the same line of attack against presumptive Democratic nominee Joe Biden in this year’s race—most prominently in an interview this past weekend in a lengthy interview with Fox News host Chris Wallace. Trump said he “aced” his most recent cognitive test and left his own doctors surprised by his mental capacity.

Wallace pushed back by pointing out that commonly available versions of these cognitive tests are not all that difficult to pass. Trump said that the final questions on the test are more complicated than the ostensibly simple ones at the beginning, and that Biden or Wallace would struggle to answer them. Wallace noted that the final questions on the test he himself took included correctly identifying a picture of an elephant and counting backward from 100 by seven.

It’s unclear exactly which test Trump took. But an assortment of cognitive exams including the Standardized Mini-Mental State Examination (SMMSE), a test for those with Alzheimer’s disease; the Montreal Cognitive Assessment (MOCA) test, which Wallace referenced in his interview and follow-up segment on Fox News; and other common mini–mental status examinations are not particularly complicated.

That’s not to say they aren’t important when determining cognitive abilities. Questions range from redrawing shapes, remembering the order of numbers, and doing basic mental math on the spot, among other skills. These questions can help physicians determine if a patient is falling behind on a specific cognitive skill set and are commonly administered to people who may be at risk for, or show signs of, mental decline.

The situation is a bit more complicated for politicians, especially older ones. There’s no requirement for presidential candidates to release their medical records or take tests. That’s a voluntary task—but it becomes an issue when you have the two of the oldest presidential candidates sparring against each other. If elected again, Trump would be 74 years old on Inauguration Day; Biden would be 78. The risk of dementia increases dramatically with age, especially for people over the age of 65, according to the Mayo Clinic.

But it’s a sensitive issue from a medical ethics standpoint. Psychiatrists and other mental-health experts, who examine everything from depression to cognitive decline, have been wary about expressing opinions on politicians’ mental and cognitive health if they haven’t treated them personally. The American Psychiatric Association (APA) even issued an official statement about speculation on then-candidate Trump’s mental acuity in 2016, asserting that it would be unethical.

Trump, however, has played up the issue on multiple occasions by attacking his political opponents and touting his own mental faculties. The testing metrics he’s using, though? Acing them is impressive mostly for patients in active cognitive decline.