Stephen Colbert isn’t sure that President Donald Trump’s brain is working at full capacity.

Trump revealed Monday that he’d taken an MRI scan during his Oct. 10 trip to Walter Reed Medical Center. Trump claimed his results were “perfect,” and White House Press Secretary Karoline Leavitt claimed the scan was simply a routine part of his regular health check-ups.

“Quick reminder,” Colbert responded in his Tuesday monologue, “People don’t just get an MRI.”

Colbert explained, “It’s usually something you only get when the doctors think something’s wrong with you. Scans are typically ordered for disease detection and monitoring, or to detect bone or joint abnormalities.”

“Even though Donald Trump bragged to reporters about his perfect MRI, the White House declined to say why doctors had ordered the scan,” The Late Show host continued. “That’s not comforting. What were they looking for?”

Colbert’s point echoes concerns raised by Dr. Jonathan Reiner, who served as cardiologist to former Vice President Dick Cheney.

Reiner told CNN Monday, “An MRI is never part of a routine evaluation, whether you’re President of the United States or whether you’re just a civilian.”

The news of Trump’s MRI scan comes amid growing concerns about the president’s cognitive health. These concerns weren’t helped by Trump bragging on Monday about passing a “very hard” test in April 2025 that screened for signs of cognitive decline.

Colbert showed a clip of Trump bragging about passing the test and challenging “low IQ” Democrats Alexandria Ocasio-Cortez and Jasmine Crockett to attempt it.

“As a reminder, the cognitive test Trump took is not designed as a measure of intelligence or IQ,” Colbert said. “And not knowing the difference between those two things is one of the reasons they make you take a cognitive test.”

Colbert quipped further, “The test Trump took is just a set of simple tasks such as identifying animals, and Trump crushed it!”