How come my mother with dementia perks up when my sister comes by?

I find it so frustrating. I retired from my job to take care of her. I go crazy all day long with her and she is so different when my sister comes by or my brother phones her. She makes me look like I'm exaggerating all the time. It's like when my kids were little they would be so good at their friends house and be wild at home.

My mother does that when my brothers come. She doesn't see them often, so they're new and shiny to her. She sees me every day, so I'm old hat. No need for showtiming when I'm around.

It's called show-timing, and it's why they can fool doctors, friends and family who aren't with them for extended periods of time into believing they are just fine and caregivers like you are exaggerating!