Gigi and Hazel hit in on the head. The stage theory was set up more for our benefit than for the medical world. They use a whole different set-up....when you look at the stages bear in mind that when some of us speak in reference to those it is to let the others know how far we have gone.
Medical issues can also cloud where someone is at. Today your mother may be a stage 3 but next week seem to have skipped to 5 simply because of a urinary tract infection, allergies or what-not. A person can also be pushed past a few stages because a health concern has happened an example would be someone having a stroke, which effects the brain.
Don't let the stages alarm you, they are examples. I know I would refer to stage 7 ...mom was at the point she was fetal (her arms and legs were contracting from lack of use) was doubly incontinent, had a catheter, had to be fed baby food and sipped only her drinks, her breathing was loud....all very graphic and a stage I can honestly say I do not wish on anyone.
Julieann, the best way to approach this disease is to learn everything you can about it...make yourself the the expert, your dr. won't be and when you can challenge him with your knowledge your patient will get better care.