My grandma has alzheimers!?

My grandmas been in a nursing home for a couple years now.She didnt ever want to be in a nursing home and we promised her wed never put her into one.My grandpa died in 1998 and my Grandma slowly lost her mind after losing him.We had to put her into a home because she was walking around in a bad neighborhood at 3 am every night giving her money to strangers and knocking on peoples doors calling the police and pulling knives on people.We lied to her and told her she was in a hospital.She knows who she is but thinks shes still 25 years old.Im 27 and she has 16 other grandkids that she doesnt even know.My Grandma was like a mother to me but now she has no idea who I am.No clue.My question is how can I make her remember me?I went through this with my great grandma too but it wasnt the same because my grandma pretty much raised me and now she doesnt know me.What can I do to make her remember me again?