It hurt when she overheard me talking with relatives for a few minutes and asked me smiling and friendly, "And you are?" The relatives attributed it to the vision impairment. I would be able to recognize my close family members voices by phone without them identifying themselves. Who is in denial? Any reality checks for me out there, please. The families denial is frustrating. I wish there was compassion when I expressed my dismay with them privately. It's hard to have my mother ask who I am. My sister her POA will not answer my voice mail when I asked if my mother has been diagnosed with A or D.
As a kind of old person, even without dementia, my abilities are getting worse. Sometimes I don't recognize people by sight, never mind by voice.
It sounds like your family is difficult, but please try not to take this too much to heart. It could be due to dementia, but it could just be a "mistake" that your mother didn't know you by voice. Best wishes.