President Reagan suffered from Alzheimer's while in office

Ronald Reagan was showing signs of Alzheimer’s while still in office, according to his son Ron Reagan.

In his memoir “My Father at 100,” Reagan writes:

“Today we are aware that the psychological and neurological changes associated with Alzheimer’s can be in evidence years, even decades, before identifiable symptoms arise.
The question, then, of whether my father suffered from the beginning stages of Alzheimer’s while in office more of less answers itself.”

Ron Reagan recounts having concerns as far back as 1984.

"Watching the first of his two debates with 1984 Democratic presidential nominee Walter Mondale, I began to experience the nausea of a bad dream coming true. At 73, Ronald Reagan would be the oldest president ever reelected...[M]y father now seemed to be giving them legitimate reason for concern.
My heart sank as he floundered his way through his responses, fumbling with notes, uncharacteristically lost for words. He looked tired and bewildered."

Two years later the president expressed his own concern about his failing memory:

“My father might himself have suspected that all was not as it should be. As far back as August 1986 he had been alarmed to discover, while flying over the familiar canyons north of Los Angeles, that he could no longer summon their names.”

Ron Reagan writes that there is “no evidence that my father (or anyone else) was aware of his medical condition while he was in office.”

“Had the diagnosis been made in, say, 1987, would he have stepped down? I believe he would have.”

In 1994, President Reagan revealed to the nation that he had been diagnosed with Alzheimer’s. But earlier, in 1989, doctors operating on Reagan expressed their belief he was suffering from the degenerative disease.

Ron Reagan writes that in July 1989, his father was thrown off a horse while visiting friends in Mexico. He received medical attention at a hospital in San Diego.
When surgeons opened the president’s skull to relieve pressure they “detected what they took to be probable signs of Alzheimer’s disease.” But no formal diagnosis was given.

Ron Reagan says the doctors gossiped about the likelihood his father was suffering from Alzheimer's.

“I have since learned from a doctor who happened to be interning at the hospital when my father was brought in that surgeons involved in his care, in what my informant characterized as ‘shameful’ behavior, violated my father’s right to medical privacy by subsequently gossiping about his condition.”

President Reagan was taken to the Mayo Clinic the following year, where it was confirmed he was suffering from the disease. He died at the age of 93 in 2004.
This year marks the 100th anniversary of his birth.