INDEXING COGNITIVE TESTS TO ALCOHOL DOSAGE AND COMPARISON TO STANDARDIZED FIELD SOBRIETY TESTS

Cognitive tests from a computerized battery of mental tests and standa rdized roadside field sobriety tests (FST) were administered in three experiments involving graded dosages of alcohol but different administ ration schedules. In the first experiment, subjects were raised to one of four levels of alcohol dosage in four sessions 1 week apart. In th e second experiment, the descending branch of the blood alcohol concen tration (BAC) curve was monitored from 150 mg/dl BAC in a single sessi on. In the third experiment, the ascending and descending limbs of the alcohol dosage curve were followed over a single session. Dose respon se relationships were observed for all tests, and the changes were sta tistically significant (p < .001) in all three studies for all tests w hen evaluated singly, except for grammatical reasoning. When cognitive and FST tests were combined into a single multiple regression analysi s, Gaze Nystagmus consistently accounted for the most variance in BAC, followed by code substitution. While multiple regression analyses rev eal that tests from the two batteries can be combined to improve overa ll prediction of alcohol concentration, it is also true that the two b atteries share considerable variance (i.e., > 30%). This suggests that , while the two batteries may not be substitutable, they are measuring different aspects of the same thing.