Now does my MOM have ALZ?

I have reported here on my dad who is in advanced stages of ALZ and currently in a nursing home. But more and more signs my mom is losing it. We always passed these signs off as her general severe anxiety which prevents her from listening to anyone, or always asking the same question over and over for reassurance. And that indeed has been the case her whole life But her MD told me perhaps the anxiety is masking the memory issues. For about the third time in a month, she has forgot to hang up the phone, so now when we call to check up on her the line is busy all the time. Yesterday, she had to write a check to my brother and while she filled the numerals in correct, could not properly write the written portion stating the check amount. It took her eight tries. The SWs we have been working with for my dad have asked her if she has memory problems as she ask the same question over and over. I have explained this is the way she has always been. She is OCD, cannot take the time to listen to an answer to a question, and seems to ask it over and over when she does remember. e.g. She will ask me if my brothers car is blue, five times. (made up example). Finally I say it is green. She says, why did you say blue last time. So she did remember in that case. Nonetheless, worried I am entering second parent with ALZ. She has always been neurotic and therefore harder to deal with than my dad even while my dad has advanced stage ALZ. Her MD says she doesn't know how I do it. The MD says she is in a room for ten minutes with my mom and is worn out from the anxiety. She has always wanted to run a screening test for dementia, but is just happy to get out of the room after she has dealt with the issues my mom did come in for.