My mother started acting strange on Tuesday. She suddenly didn't believe it was Christmas and thought we were all just puting on a show but she didn't know why. We took her to the ER on Christmas Eve and they found nothing live threatening. She is insisting that she has missed a year of her life, her grand children are a year older and all the TV shows are old. She is 65 years old. We will see a Dr next week but I am worried. She hasn't even for a moment came back to us since Tuesday. I just never thought dementia could happen so quick.