The effect of G-LOC on psychomotor performance and behavior.

Acceleration (+Gz) induced loss of consciousness (G-LOC) and its effect upon cognitive and motor performance were evaluated in seven male volunteers who were exposed to closed-loop acceleration exposures at the Naval Air Warfare Center--Aircraft Division, Warminster (NAWCADWAR) human centrifuge (DFS). The +Gz profile consisted of several aerial combat environment simulations (ACES) of up to +12 Gz. In the event of G-LOC, the DFS was brought down to a base +Gz level. As the subject recovered consciousness, he was required to complete various tasks to regain control of the aircraft. Psychomotor performance was measured before, immediately after, and 20-40 min post-G-LOC. These tasks included: 1) extinguishing master caution signals initiated upon G-LOC by an observer; 2) entering a control code on a head-down display to initiate DFS trim mode; and 3) matching own aircraft altitude, airspeed and heading to that of a displayed target. Absolute (6 +/- 2 s), relative (5 +/- 3 s) and total (12 +/- 3 s) incapacitations were briefer than those reported in the literature. The time intervals to execute the performance tasks tended to be longer for post-G-LOC than for pre-G-LOC. Recovery of psychomotor performance, as measured in this study, occurred approximately 60 s post G-LOC. There were no performance decrements during those tasks assigned 20-40 min after G-LOC.