Personally, I think this website has the very best explanation of the 7 Stages:
https://www.dementiacarecentral.com/aboutdement...

Hi Cynthia! If you go to the resources section of this site, you can look for an article on the Stages of Alzheimer’s. There are three, five and seven stage models for tracking the disease. No one person follows it completely in order, but it is good for helping us understand what might be happening and look in to the future a bit.