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.
The moon visited by the Prometheus, called LV-223, is not the same planet visited by the Nostromo in Alien, which is called LV-426. I believe that the latter was not named on screen until the second film, Aliens. So they are two different Engineer ships and two different dead Engineers.