Its been a while since I took the exam. I used old EDXSAEs that I copied from one of my attendings. Found them quite useful. As far as content, I think really, really knowing your peripheral neuroanatomy will take you far. More uncommon stuff - rep stim, SSEPs, Blink reflexes, autonomic testing, SFEMG all are fair game. Each of these separately may be low yield but together they add up. Dont neglect the waveform part of the exam. Be able to recognize two different waveforms simultaneously. They may use gain or sweep speed settings that you dont normally use, so be aware that waveforms may look bigger/smaller than they actually are. The oral section IIRC consisted of two examiners (one neuro, one PM&R). 3 cases, each fairly straight forward. Recommend walking cases through from start (generating a DDx), to designing/performing the study (appropriate NCS, including electrode/stimulator placements), to finish (articulating a summary/impression on your EMG report based on the available data).
Good luck.