Do dementia symptoms include multiple-personality traits?

It sounds like some kind of mental illness, but probably not dementia. Whatever it is, if/when she becomes incapacitated it is not your responsibility to become a full-time caregiver.

Thanks for your listening and support. I've already talked w/ a person in a counseling capacity who has noted my concerns. I think if I had to ask them to give inputs on my reasoning for keeping "arms length" they would.

If she has been doing this for many years, it is probably not an indicator of dementia. Has she ever seen any kind of medical professional about this behavior in the past?

Jeannegibbs, I know she's been seen by medical professions for mental health issues years before I was even born or was old enough to be part of discussions regarding diagnosis. The persons who "discussed" have all passed away. I wish I knew how to get her medical records from her prior doc of many years. When he retired and gave over his practice I guess her records are stored in an old file somewhere? There are things that I wish I'd spoken up about as a child. She talked in a different voice to herself when I was a child. The grossest thing is that she would "touch" me and be talking in this different voice when she thought I was asleep. I just pretended to be asleep and wished she'd go away. She had me so verbally beat down that I thought I caused all her woes and weirdness. I was afraid that if i spoke up to someone that they would yell at me -- I had enough of that going on as it was :-(

Ok, so now I am a "big girl" and she cannot touch me that way any more but her other segues into some other "person" -- especially to absolve guilt, make me wonder (and fear) if this is a dementia symptom that will get worse. I am fearful of that and especially fearful/resentful if I have to be full-time caregiver. We are not quite there -- yet.