Accompany with mom for Green Card interview

[babydragon]

I'm the petitioner for my mom's GC. Her I-130 is approved and I'm waiting to pay the Visa fee. I've heard from may people that I can go with my mom to the interview as an US citizen. Is that true? Do I need to get a permit or anything before doing so? Can I be sitting next to her during the interview since she has really bad memory?

Thanks in advance.