The health news website Stat asked psychologists, psychiatrists, and experts in neurolinguistics to compare President Trump's way of speaking in 2017 to interviews he gave decades ago. "They all agreed there had been a deterioration," Stat reports, "and some said it could reflect changes in the health of Trump's brain."
Some of the experts noted that linguistic decline can result not just from neurodegenerative disease but also "stress, frustration, anger, or just plain fatigue." "In fairness to Trump, he's 70, so some decline in his cognitive functioning over time would be expected," pointed out New York City psychologist Ben Michaelis.
But others found the stark differences in Trump's way of speaking to be concerning:
In interviews Trump gave in the 1980s and 1990s (with Tom Brokaw, David Letterman, Oprah Winfrey, Charlie Rose, and others), he spoke articulately, used sophisticated vocabulary, inserted dependent clauses into his sentences without losing his train of thought, and strung together sentences into a polished paragraph, which — and this is no mean feat — would have scanned just fine in print […] Now, Trump's vocabulary is simpler. He repeats himself over and over, and lurches from one subject to an unrelated one … [Stat]
"It's hard to say definitively without rigorous testing," said another New York City psychologist, John Montgomery, "but I think it's pretty safe to say that Trump has had significant cognitive decline over the years."
Dr. Robert Pyles of suburban Boston, who supports President Trump, said: "I can see what people are responding to" when they suggest there has been a decline. He added: "[Trump's] language difficulties could be due to the immense pressure he's under, or to annoyance that things aren't going right and that there are all these scandals. It could also be due to a neurodegenerative disease or the normal cognitive decline that comes with aging."