Ronald Reagan had Alzheimer's while President? Surely Not?

An early picture of Reagan
feeding George W. Bush

I see that Ronald Reagan's son says that the former president of the US had Alzheimer's Disease while he was president. That come's as a bit of a surprise to us all.  We never would have guessed.......

"How are you, Mr. Mayor? I'm glad to meet you. How are things in your city?" - Ronald Reagan greeting Samual Pierce, his secretary of Housing and Urban Development, during a White House reception for Mayors"

"My name is Ronald Reagan. What's yours?" -introducing himself after delivering a prep school commencement address. The individual responded, "I'm your son, Mike," to which Reagan replied, "Oh, I didn't recognize you."

"Reagan's only contribution throughout the entire hour and a half was to interrupt somewhere at midpoint to tell us he'd watched a movie the night before, and he gave us the plot from War Games, the movie. That was his only contribution."   Lee Hamilton (Representative from Indiana)

"Poor dear, there's nothing between his ears." British Prime Minister Margaret Thatcher

"This President is treated by both the press and foreign leaders as if he were a child.... It is major news when he honors a political or economic discussion with a germane remark and not an anecdote about his Hollywood days." Columnist Richard Cohen

"They told stories about how inattentive and inept the President was.... They said he wouldn't come to work--all he wanted to do was to watch movies and television at the residence." Jim Cannon (an aide to Howard Baker) reporting what Reagan's underlings told him, Landslide: The Unmaking of the President.

"What planet is he living on?" President Mitterand of France poses this question about Reagan to Canadian Prime Minister Trudeau. 

"During Mr. Reagan's trip to Europe...members of the traveling press corps watched him doze off so many times--during speeches by French President Francois Mitterrand and Italian President Alessandro Pertini, as well as during a one-on-one audience with the Pope--that they privately christened the trip 'The Big Sleep.'" Mark Hertsgaard, On Bended Knee: The Press and the Reagan Presidency 

"...like reinventing the wheel." --Larry Speakes (Reagan's former press secretary) describing what it was like preparing the President for a press conference, Speaking Out: The Reagan Presidency from Inside the White House 

"His errors glide past unchallenged. At one point...he alleged that almost half the population gets a free meal from the government each day. No one told him he was crazy. The general message of the American press is that, yes, while it is perfectly true that the emperor has no clothes, nudity is actually very acceptable this year." Simon Hoggart, in The Observer (London), 1986