My Dad has dementia and now its what they think ( but cannot be truly dx'd till they can do an autopsy) as early onset of alzheimers now. I havn't the heart to tell him this yet. Dementia can also lead to Parkinsons from what I hear. Not sure quite how. But you might want to look into that as that could be something that starts up for her earlier . Just a suggestiom. I am sorry to hear this . As it can be frustrating to loved ones and the person themselves. You'll be in my thoughts.
Ohh btw .. a good thing to have them do is to make lists .. thats something they can always count on having near by . Hope that helps.

Hugz~
Beth