Hi!
Is your EEG inpatient? If so, first they'll put an IV in your hand/arm (in case of emergency). Then they'll glue electrodes on your head and hook the wires into a machine that monitors your brainwaves. The machine isn't in the room, it's elsewhere, at least it was at my hospital. It was in a control room, of sorts. There will also be a box-thing that you either hang on your shoulder or fasten around your waist. It has a button to push if you feel a seizure event, so the techinician can mark it on your eeg record (for the doctor to look at extra closely). There are a lot of wires! A computer program analyzes all your wave patterns. It marks abnormal waves for the doctor, and a little alarm goes off and the nurses rush in to see if you are okay.
As for moving around... they'll put you in bed with extra-high padded rails, and you probably won't be able to get up except for using the bathroom. They do it for a couple of reasons - to ensure your safety in case you have a seizure, and to keep you on camera. I've heard a couple of people in here say their doc finally let them get up and walk up and down the hall a little, but mine didn't.
If your EEG is outpatient, they'll glue the electrodes on your head and then plug the wires into a box that is fastened around your waist. You can go where you want, do what you want (except shampoo your head!).
If inpatient, you may want to call the hospital ahead of time and see what kind of amenities they have. And ask your nurse about rules, like visiting hours, cell phones, etc.
My hospital did allow laptops and cellphones, but they couldn't be plugged in inside the room and had to be charged outside of the room to avoid interfering with the equipment. Had I known this I would have brought a power strip - there was only one plug in the bathroom (where i charged stuff overnight).
My hospital also had entertainment galore - cable tv, video games, netTV, music channels, etc. Also 24 hour food service you order off a menu, like a restaurant. I still would have brought my favorite snacks, had I thought of it. Take entertainment, like books, games, etc. Take slippers even though they won't let you out of bed much. You may want to take a knit hat to cover all your wires, if you are having lots of visitors and you are concerned about looks.
Take along about 1/3 cup oil, to help get the glue off your head. It can be any kind of oil - olive oil, mayonnaise, baby oil. When you are ready to go home, massage it into your scalp for about 20 minutes and the glue will come off. I did it at the hospital in their shower because it makes a slick, slimy mess on the tile! If you forget the oil you can ask the hospital kitchen for some.
I'd say have fun, but..... lol.... Nothing hurts or anything. It's just boring.