My 9 year old son will be getting an EEG next month. What can I expect?

During interviews with psychologists recently, they noticed that my son would stare off in the middle of the interview. He did this several times and it has raised questions in their minds about the possibility he has epilepsy. As his mother and someone who spends 24/7 with him, I am very doubtful and I think it is simply him daydreaming and getting bored with the conversation with a grown up. He is booked for this EEG next month and I have talked a bit to him about how it will map brain waves and, without mentioning the suspected epilepsy, I explained that the doctors just want to get a better picture of what is going on. I don’t know what else to say. Will there be needles? I’m thinking not, but I want to be sure before I make any promises. How long will it take? I received some very, very basic information and this letter came out of left field for me as we never discussed the possibility of epilepsy before. (And of course everything is in Norwegian so there are loads of terms I don’t understand.) Any enlightenment would be greatly appreciated.