In an interview on MSNBC’s Morning Joe, Ramin Setoodeh, co-editor-in chief at Variety, said he did an hour long sit-down interview with Trump while researching for his book, "Apprentice in Wonderland: How Donald Trump and Mark Burnett Took America Through the Looking Glass." Via Salon:

A few months later, Setoodeh met with Trump again, this time at Trump Tower, to discuss his time in the White House. Trump had "no recollection of our lengthy interview," he said.

“Donald Trump had severe memory issues," Setoodeh said. "As the journalist who spent the most time with him, I have to say, he couldn’t remember things. He couldn’t even remember me.

[...] Setoodeh said the cognitive decline in the presumptive GOP candidate should not be ignored.

“I think that the American public really needs to see this portrait of Donald Trump," he said, "because this shows what he is like and who he is and who he has always been."