Since she only is really present in the 'presence' why not just make sure you spend time with her? Just being there with her and accepting her as she is ... Or helping her do something that she can still enjoy? Whatever that is. Something not requiring words. Finger paint with her, let her express herself in a way she hasn't in the past?
Just thoughts, hope they help.

I have taken two items to my mother that really went over well. I bought a giggle bear. You push his tummy and he giggles. She laughs every time the bear giggles. I have to push the tummy, she can't handle that. The other item she really enjoyed was a large calendar of cats. She would reach to touch each kitty like it was really there. Every sunday I take her a messy taco and a donut. It is food she does not get at the nursing home. She has a friend that takes her a mcdonald's shake once in awhile. I also made an album of photos from 1915 to present. And I have three of her favorite poems, that we read over and over. The duel, lucy gray and I wondered lonely as a cloud. Hope this helps.