NEW YORK -- In his first CNN special since stepping down from his nightly talk show, Larry King visits a Las Vegas clinic where Alzheimer's disease is studied. He is accompanied by former President Ronald Reagan's son Ron.
One of the men takes a brain scan to reveal whether he is at risk of developing Alzheimer's or other memory disorders. The other declines.
King, trying to pump up interest for the show, won't say in advance which is which. Reagan and King had visited the Lou Ruvo Center for Brain Health at the Cleveland Clinic to learn about advances in treating the incurable memory disorder.
King's special, "Unthinkable: The Alzheimer's Epidemic," airs Sunday at 8 p.m. EDT/PDT on CNN. It features interviews with several celebrities touched by the disease, including Maria Shriver, whose father Sargent Shriver had it, and actor Seth Rogen. The mother of Rogen's fiancée was diagnosed with Alzheimer's at age 55, and he wanted to talk about it to make clear that not only old people are affected.
King chose the topic for his first CNN special because "the disease has always fascinated me," he said.
King, who is 77, said he is healthy but, like many older people, Alzheimer's is something he's kept in the back of his mind. King is close with former first lady Nancy Reagan, who took care of her husband during his battle with Alzheimer's before dying in 2004.
"Every time I can't think of something, I get scared," said King, who urged people to seek medical attention if they suspect someone they know is showing symptoms.
People shouldn't necessarily be worried if they lose their keys occasionally. "We all lose our keys," he said. "It's if you don't know what the key is for once you find it" that a concern should be raised, he said.
King said he had future CNN specials planned with Johnny Depp and on baseball. King, who has been replaced by Piers Morgan, said he misses his nightly platform – sometimes. He would have liked to have been involved in big stories like the Japanese earthquake and Egyptian political uprising, he said.
"But I don't miss the Kardashians," he said.
"It's mixed emotions," he said. "It's like watching your mother-in-law go over the cliff in your new car."
Mother-in-law jokes play into another facet of King's post-show career. He's going on a concert tour telling jokes and old stories, starting May 14 in Atlantic City, N.J.
Seth Rogen and his fiancée talk about her mother's struggle with Alzheimer's
Maria Shriver goes public about her father's death from Alzheimer's
Ron Reagan talks about his father, President Ronald Reagan's, struggle with Alzheimer's:
Watch more clips on CNN Health.