Is REM necessary with hearing test conducted with hearing aids?

[Adrian]

And here:

REM - Real Ear Measurement ... what is it?

Since I wrote about having trouble with the adjustment of a new aid, someone asked me if I have had REM done, they said it was Real Ear Measurement. I asked my audi and she didn’t feel it was necessary with the new type of aids, but said in the future she could try it. I’ve tried a search, but nothing comes up that explains it. What exactly is REM, how is it done and would it help with the newer aids or someone with my loss?