What's it like for them?

As you all know ( as I have complained and ranted and gone on and on about it as well) I work in a nursing home with old people.
I've got those who are bedridden but still clear-minded, those who only need minimal assistance with their daily needs, those who are fuzzy-minded and demented, and worst of all, those who are both demented and bed-ridden.
Whenever I'm attending to them, I'm always wondering ( I even drift off on my thoughts sometimes and forget what I'm doing with them but that's not the point), what's it like for them?
Well not the lucid ones so much, it's easier to understand how they feel. Frustration, helplessness, hopelessness, anger, fear, confusion, depression. Its easy to feel that way in their situation when they find out they can't do what used to be easy for them. Not being able to drive, not being able to shower oneself, not being able to go out whenever and with whomever they please, it's no suprise some old people who live long enough in nursing homes try to commit suicide, no matter how good the quality of care is.
But I often wonder about the demented patients.
What do they see?
What do they feel?
How does the world look like from their eyes?
Do they see the world as a baby might see it? With many foreign and strange things they have never seen before, with many things they have yet to learn about yet?
Do they see the world through their past? Do they actually see their family walking around them and talking to them like in the past even though there's no one there? Or do they just lose touch with the surroundings and imagine themselves in situations from the past?
I see them sitting there sometimes, in that same seat sometimes for the whole day. Only getting up for meals and toileting sessions. And I wonder what goes on in their heads all day long because they seem so lost in thought.
Do they spend the whole day wondering what they're doing there, what they're names are, and how old they are?
Do they just go blank and think about nothing at all?
I wouldn't want to be them, no sir, but I'd just like to know what it's like for them. Maybe take a quick little peek into their thoughts like Harry Potter did with Dumbledore's memories. Then maybe I could understand better, and know what it's like for them.