Psychomotor performance after forward-facing impact.

An experiment to assess psychomotor performance before and after forward-facing (-Gx) impact was conducted using the AFAMRL Horizontal Decelerator Facility. There were 10 volunteer subjects who participated in 50 tests at 4 impact levels (0 G or sham, 8 G, 10 G, and 12 G). Two initial head positions were explored at the highest impact level. The manikin psychomotor task, a complex reaction time and accuracy task, was used to evaluate performance. Linear and angular accelerations were measured at the head. Although there was a weak correlation between angular head acceleration and prolonged post-impact reaction time, no compelling statistical evidence was found to support the hypothesis that psychomotor performance is degraded with increasing impact severity at these test levels. The highest test level explored in this study may not have been sufficient to produce a change in performance or, alternatively, the manikin task may not have been sufficiently sensitive to measure a change in performance if one was present. In addition, significantly lower angular head acceleration was observed at the 12-G test level when the head was rotated forward initially rather than prepositioned upright against the headrest. The potential for temporary stunning of aircrew members during operational crash landings or ditchings may be reduced by rotating the head forward prior to an imminent crash if time permits.