What are the stages of alzheimer's disease?

There's a New One. Besides the expected mild, moderate, & severe very nicely described by dr. Nash, there is now officially a 4th category --- mild cognitive impairment (mci). This is a stage before mild & the thinking is that here would lie your best bet at preventative strategies (if & when we find some of those).
Depends. There are many different systems used for different purposes: researchers or placement needs or hospice qualification.... Clinically, it can be helpful to use a simpler way of looking at it: mild illness is when a person has problems but can function with minimal supports, moderate disease leads to a need for major support and severe disease requires 24 hour care in a secure setting.
Mild Moderate Sever. There several different ways of classifying Alzheimer's disease the simplest way to think about it in three stages: mild /moderate /and severe. Each stage has associated with it changes in activities, behaviors and cognition. https://www.youtube.com/watch?v=nFTQ-76-CtI.