can anyone explain this to me??

on my son's 2nd EEG report it says "poorly developed anterior to posterior gradient appreciated during study". What does that mean?? It also says he had epileptiform discharges of small amplitude 50 to 75 microvolts occuring at a frequency of 1 Hz for up to 5 seconds. It says "ictal EEG, no electrographic seizures captured".  He has only had two seizures that we know of, tonic-clonic seizures(hope I got the name right), but lately after researching other different types of seizures, I am wondering if he has had more. He has this hand tremor that comes and goes, it makes him spill his drinks and drop his fork. Hoping someone could explain this a little better than the doctor has. He is currently taking depakote for the seizures. Any thoughts would be appreciated!