My mom has mid-stage dementia and can't live on her own, but she still knows our names. At what point are memory loss drugs effective?

Most of the time it's best to start the drugs early. There is controversy about the drugs as some people find them wonderful, and others say the side effects are bad and the good they do isn't worth it. Working closely with the doctor is the only way to go at it. If you aren't sure the doctor is able to detect the type of dementia with a PET scan or other methods, you should look for a specialist who can. One problem is mixed dementias, which researchers are finding very common. Many people have more than one type. It's never an easy road.
Carol

My mom was diagnosed by her Dr with "borderline sever" Alzheimer's. After that she started on medication specific to Alz and we definitely saw an improvement. More importantly, her rapid decline stopped. In the 5 months since she started the meds, she has declined some more, but very little compared to what was happening previously.

Not all dementia drugs are created equal. The ones that help one type of dementia can make another type worse. So it is important for the Dr to determine (as best they can) what type of dementia your mom has.

And pray tell how is he going to find out what type your mom has? In order to do that the doctors would have to go inside the brain, I have the same problem with my wife with memory drugs.

Thank you for your input. Mom has been going through this for over 10 years and refused she had a problem and wouldn't take the drugs. Now she is in an assisted living but the memory in the last 2 years is going a bit faster. She sounds like hers is a mixed dementia. What is a PET and what does it show.