this reference http://emedicine.medscape.com/article/1832855-treatment does a very nice job showing the actual trace differences of the AP (action potential) recorded during the test.I plan on asking if i can review them with the dr while the testing is happening. my neuro was kind enough to do this. What I dont know if they will let me do if record pics of the trace on the equipment with my cell phone camera. Should have thought of that the first time...