At the end of the procedure a flashing light may be placed nearby to see if this affects your brain activity. Sleep EEG or sleep-deprived EEG. A sleep EEG is carried out while you're asleep. It may be used if a routine EEG doesn't give enough information, or to test for sleep disorders.
This is all I could find on years...Prometheus was originally intended as a direct prequel to the 1979 science fiction horror film Alien, set approximately 30 years before the events depicted in the film. Alien supposedly takes place around 2122. Prometheus had a date of 2093 according to the intro.
No date is given in Alien for the action, save that it happens in the 22nd Century (due to the presence of a crew uniform patch that says, 'Flag of the United Americas 2104 to present'). In Aliens Carter Burke orders the colonists to investigate the crashed Engineer ship on 12 June '79. Assuming Aliens happens in 2179, then Alien takes place 57 years earlier, in 2122 (and this was later confirmed in featurettes in the Alien Legacy boxed set). From a computer display at the start of Alien, the movie starts on 3 June. Thus, Prometheus concludes 28 years, 5 months and 2 days before the start of Alien.