First, I've had 3 of the 4 tests.
EEG ~ I've had this many many times as I used to have Epilepsy. Let me tell you, this is a BREEZE. They will measure and mark your head with a waxy pencil. Then they will "glue" electrodes onto the places they marked on your head. This process if easy. Then depending on the neurologist performing .. you may have to do things (like blow out on a pin wheel for 30 seconds) and they may do flashing lights ... something to show whether there is seizure activity or any other abnormalities. The test is simple. I recommend not sleeping well the night before b.c they typically want you to go to sleep.
EMG/ENG ~ If i'm not mistaken, these tests can be quite painful. I've experience worse pain, but I wasn't given a chance to look up these tests prior to the test. It was an "hey you need to get these tests" ... then the receptionist called up stairs and found out that they happened to have appointments available that same day. One is a needle probing test and the other is a muscle test. It's not pleasant, but I made it through it without XanaX and I used to have a precription for XanaX to take in emergencies.
I'm not sure about the PET scan. I've never had that.