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Report No: DOT/FAA/AM-95/3

Title and Subtitle: Effects of Age and Low Doses of Alcohol on Compensatory Tracking During Angular Acceleration, N95-23934

Report Date: January 1995

Authors: Harris, H. C. Jr., Schroeder, D. J., and Collins, W. E.

Abstract: Heightened interest in existing FAA regulations regarding alcohol and flying, with emphasis on the potential effects of low blood alcohol levels on performance, indicated a need for research to help define effects of low doses of alcohol on performance. This study was designed to assess the effects of age and three breath alcohol levels (0.04, 0.027, and 0.014%). Performance was assessed while subjects experienced mild angular stimulation. On the day prior to drinking, 48 subjects drawn from three age categories (27-32, 42-47, and 57-62 years) completed four training sessions on a compensatory tracking task (a localizer/glide slope instrument that required compensatory tracking of both a horizontal and a vertical needle) with and without a secondary auditory recognition task, under 1.0 ft L. and 0.1 ft L. illumination conditions.

The test day consisted of a pre-drinking session and three experimental sessions conducted at the appropriate times on the descending limb of the alcohol curve, as indicated by breath alcohol measurements. Mean performance scores for the three age groups were compared across the four sessions, (pre-drinking and three levels of alcohol). A Multivariate Analysis of Variance (MANOVA) test yielded a significant interaction and a significant main effect (age and sessions) for the combined needle errors under the 0.1 ft L. illumination level with the secondary task.

The resulting simple effects tests revealed age differences at all post-drinking sessions favoring younger over older subjects, and poorer performance for the older age subjects at the 0.04% BrAC level. When testing individual needle errors, MANOVA tests yielded a significant interaction and main effects in the high illumination condition both with and without the secondary task for vertical needle errors. Resulting simple effects Analysis of Variance tests yielded significant age and alcohol effects for the older age subjects. The 0.04% level accounted for the alcohol effect. The alcohol and age interaction was accounted for by the older age group at the 0.04% BrAC level. This study showed no evidence of performance decrement associated with BrACs below 0.04%.

Key Words: Alcohol, Angular acceleration, Aviation Compensatory tracking, Performance Age

No. of Pages: 22