I've had 3 EEG's performed on me, so I think I could answer your question.
First of all, they want you to be sleep deprived because the test will be more accurate that way. The purpose of an EEG is to check for abnormal brain waves, such as seizure activity. Make sure you don't have any gel, mousse or hairspray in your hair. They will put some kind of gel on different spots of your head and attach wires to it. Your eyes will be closed for most of the test, they'll flash a strobe light in your face at different speeds (this is to check for photosensitive epilepsy), and they may ask you to hyperventilate yourself by breathing in and out really fast.
The test will be approximately 30-45 min.
Hope this helps.
What happened: I was randomly assaulted from behind in June of 2011. I was knocked unconscious for an unknown amount of time (less than 30 minutes) and have no memory of the event. CT scan showed contusion and hematoma of the left frontal lobe. I spent 3 days in the hospital. Diagnosed with Post-Concussion Syndrome in September 2011. Currently have Medicaid, Medicare and SSI.
Current symptoms: Brain fog, mild memory issues, problems with spontaneity, occasional spacing out, word finding difficulties, tinnitus in right ear and some other things that I can't explain.
Life after the brain injury: 4 years after the injury, I'm engaged to my beautiful girlfriend of 5 years, I'm the CEO of my own business, Notorious Labs, I've taught myself how to program complex games and apps which is a feat I never thought I'd accomplish and now live a semi-normal life with very mild PCS symptoms.
Slowly but surely regaining my life back.