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.
It was also noted by the crew of the Prometheus that the Engineers on LV-223 had been dead for around 2,000 years. This has led fans to speculate that up until about 2,000 years ago Engineers were on good terms with humans, but a specific event occurred which caused them to become hostile towards humanity.