He scored a 30/30 on the test, Jackson said, and there was "no indication that he has cognitive issues".
"He's very sharp. He's very articulate when he speaks to me," Jackson said.
Based on the clinical information he has on Trump and his year of observing the president, Jackson said: "I feel very confident that he has a very strong and a very probable possibility of making it completely through his presidency with no medical issues."
Trump took office at age 70, making him the oldest incoming US president.
Trump took Propecia, an anti-baldness medication, daily and also took medicine to lower cholesterol along with a multivitamin and a pill for rosacea.
The President does not drink alcohol, he confirmed, and does not use tobacco products.
Trump is known to have indulged in McDonald's and other fast food on the campaign trail - but Jackson said he has changed his habits since becoming president.
On Air Force One, for instance, Jackson says he's watched Trump eat the meals that everyone else does on the plane, and they tend to be on the healthier side, with the exception of the desserts.
Jackson's stellar review of President Trump is likely to take his critics - who have been claiming he is mentally unfit for office - by surprise, particularly as they have pointed to signs of dementia, Alzheimers and other cognitive deterioration.
The White House physician said several times that there was nothing he was holding back, and that neither Trump nor his aides had coached him on what to say.
"I can promise you there's absolutely nothing that I'm withholding," he asserted.
An incident involving Trump urgently needing a glass of water and another one in which he slurred his speech are nothing to be alarmed by.
One working theory had been that Trump has dentures, but Jackson said that's not the case. Jackson said the water-gulping incident was a result of taking Sudafed, a decongestant medicine.
