Concentration-effect relationships of alcohol in a computerised psychometric test system.

The purpose of this study was to validate a computerised psychometric test system by demonstrating the change of the test variables of the Bochum Diagnostic System after administration of alcohol. Twenty-four healthy young male or female volunteers participated in a doubleblind, randomised, placebo-controlled study in a 3-way cross-over design. The volunteers took single doses of placebo, 0.4 and 0.7 g alcohol/kg body weight (females: 10% less) in a random sequence. Psychometric tests were performed before as well as 1 and 3 h after the administration of alcohol. The effects of alcohol on the psychometric performance were most pronounced 1 h after administration. At this time a significant dose-dependent impairment of performance in the concentration test, the simple and complex reaction tests, the vigilance test and the coordination test was observed. 3 h after administration, significant effects were only observed in the complex reaction test and the concentration test. Maximal alcohol serum concentrations of 0.47 +/- 0.05 % per thousand and of 0.90 +/- 0.15 % per thousand were reached after administration of 0.4 g/kg and 0.7 g/kg, respectively. The correlations between individual serum alcohol concentrations and differences of psychometric variables from baseline were significant. It is concluded that the tests of the Bochum Diagnostic System can quantitatively measure the effects of alcohol. The most sensitive tests are the complex reaction test and the concentration test.