I think there are two types of EMGs. One is invasive and painful while a newer version is non-invasive. On Loma Linda University Medical Center's patient teaching page, it states, "Impulses are recorded by attaching small disk electrodes to the skin surface over the muscle or by inserting needle electrodes into the muscle." So Kaplan must be testing to see if you know about the newer non-invasive test.
http://www.llu.edu/llumc/patvis/patedu.html
Thanks for posting. I learned something today.