Alzheimer's is a deterioration of the brain that usually occurs during middle to old age. Ronald Reagan was diagnosed in 1994 at the age of 83, although his speeches gave clues to Americans while he was still in office. Ten years later he died at the age of 93.
He forgot names and subjects that were often talked about by political adversaries. He showed common symptoms such as memory loss and confusion but while he was in office they were so inconsequential that it couldn't prove that he had the disease until five years later. He started to use words like "um", "like" and "well" a lot more often.
Ronald Reagan Inauguration 1981
There is no cure for Alzheimer's.... yet. Although there are medicines to slow/improve symptoms. The medicine is called Cognition Enhancing Medication, which lowers blood pressure and improves brain function.
The average life expectancy is four to eight years for a person diagnosed at 65 or older. Although Ronald Reagan exceeded the average by two years some people lived 20 years after first showing signs.