How do I know if my mother's memory loss is dementia?

Please aee someone who is knowldgeable in this area. SO many docs are throwing around this diagnosis so they don't have to do further investigation.
Alz symptoms mimic many others...ie: a result of a UTI infection, fever, drug interactions, etc. My Mom had a bad reaction to pain meds and the first thing out of the doc's mouth was "alzheimers." I told him that if she had Alz, then we all do.
Also, you are also the best guage of your Mom's behavior. Keep an anecdotal record. Occasional forgetfulness is common. If she is disoriented, forgets faces and events often, or seems unduly agitated...then something else is going on. Has she had a physical recently? I would recommend one with blood and UTI testing.

You should get her to a Neurologist as soon as you can for testing and diagnosis. I feel that Alzheimers/Dementia can be similar amongst individuals as well as completely different. The constant repeating is something that my grandfather did all the time in the early/mid stages of his dementia but my grandmother doesn't do this nearly as often as he did. My grandfather suffered from what I've recently learned as "sun downer's syndrome" and completely came alive at night when he should have been sound asleep. My grandmother, thankfully, sleeps through the night and only gets up once to use the bathroom and then back to bed she goes. No need to guess on this. You are better off getting an official diagnosis and potential treatment started. All the best.