Alzheimer's or something else?

My gma is 56 years old. In a matter of 4 years, she has gone from a fully functioning, working woman to stage IV Dementia. Everything I have read says that Alzheimer's takes time to progress. She is so young and has gone downhill sooo fast. Now she is starting to shake and jerk, like she is losing muscle control. I don't know what to do. No one will do anymore tests or anything besides keep her on the stupid medicine that obviously isn't doing anything.