NCS/EMG's are actually quite subjective and can vary widely from doctor to doctor, the eqipment they use, nerves & muscles tested. I've had several that say "normal," but I know this is not the case as I have long fiber axonal damage in both lower extremities, left greater than right. I've decided not to have another one of these in my lifetime unless some dramatic motor nerve changes show up.

The best advice I've heard is to use the same doctor/technician if you are going to do serial testing. Too much variation otherwise. And I would trust results more from a large teaching hospital with a neurodiagnostic dept.