Is it common for dementia patients to talk to themselves whether they are awake or sleeping?

It is not unheard of. While your loved one is awake, are you sure they are talking to themselves? Could they be talking to someone only they can see? (Hallucinations)

In addition to the talking, what is their sleep pattern like? Restless? Moving arms and legs?

Does the talking bother your loved one? That is, are they agitated, frightened, angry, etc as they talk, or does it sound like the kinds of thoughts we all have, except they are stated out loud?

Whenever there is a new symptom in someone who has dementia, it is a good idea to let the clinic where they are being treated know.