In the movie, Kyle (Bradley Cooper) says he's 30 when he enlists, but the American Sniper true story reveals that the real Chris Kyle reported to the Navy for basic training in February 1999 when he was 24-years-old. -American Sniper book.
ELECTRO/VIDEO-NYSTAGMOGRAPHY (ENG OR VNG) Electronystagmography (ENG) refers to a group of tests or test battery, and uses small electrodes placed over the skin around the eyes during testing. Videonystagmography (VNG) refers to the same test battery run using goggles with video cameras to monitor the eyes.
Like the ENG/VNG, rotation tests are performed in a room that is dark with the examiner asking random questions during testing. Rotation tests provide information beyond the ENG/ VNG about how well the balance organs are functioning. Not all people in the diagnosis phase will require rotation tests.