EFFECT OF ALCOHOL ON THE THRESHOLD FOR DETECTING ANGULAR-ACCELERATION

We investigated the effects of a low blood alcohol level (mean BAC = 0 .037%) on subjects' ability to detect acceleration and deceleration of angular motion. The angular motion thresholds of six alcohol and six placebo subjects, all of whom had private pilot certificates, were tes ted under double-blind conditions in an enclosed simulator apparatus p rior to drinking, after drinking, and at a time when the BAC's of alco hol subjects had reached zero. Mean threshold values for the th ree th reshold determination sessions were 0.282, 0.376, and 0.343 degrees . s(-2) respectively for the alcohol subjects, and 0.263, 0.262, and 0.2 62 degrees . s(-2) for placebo subjects. A significant alcohol x test- session interaction (p < 0.005) reflected the elevated thresholds show n by all alcohol subjects after consuming alcohol (p < 0.001). Of the six alcohol subjects, four continued to have elevated thresholds after their BAC's reached zero (p < 0.001). Alcohol and placebo subjects sh owed similar performance on the ancillary tasks of maintaining altitud e and reporting a specified number when it appeared on a digital displ ay. Both groups also reported that they had experienced similar levels of discomfort symptoms before and after drinking. The results indicat e that a pilot's ability to detect angular motion can be compromised b y low BAC levels, and this effect may continue for same pilots after t heir BAC reaches zero.