Diagnosis of Alcohol Intoxication: Effectiveness of Cognitive and Neurovestibular Field Sobriety Tests

Abstract

Tests from an automated performance test battery of cognitive tests and the standardized field sobriety tests (FST) used nationwide by law enforcement officers were administered in three experiments involving graded dosages of alcohol. In the first experiment, subjects were raised to one of four levels of alcohol dosage in four different sessions. In the second experiment, the descending branch of the blood alcohol level (BAL) curve was monitored from .15 BAL, and cognitive and motor performances were assessed by the Automated Performance Test System (APTS) and FST. In the third experiment, the ascending and descending limbs of the alcohol dosage curve were followed. Dose-response relationships were conducted and were statistically significant (p < .001) in all three studies for all but one test when evaluated singly. Using either test battery, composite scores could be employed to index degraded performance from elevated blood alcohol levels. The best single test was gaze nystagmus from the FST battery and the next best was code substitution from the cognitive battery. Taken singly, the individual tests ranged from 66% to 81% in terms of correctly detecting the dichotomous criterion of < 0.10 versus 0.10 BAC and above. These results are discussed in the context of standards setting for driving under the influence (DUI) and the use of behavioral tests to evaluate over-the-counter and prescription drugs.