MCOLES State Licensing Practice Exam

What does the phenomenon of Nystagmus indicate during an alcohol impairment assessment?

1. Dehydration

2. High BAC levels

3. Normal vision

4. Fatigue

The correct answer is: High BAC levels

Nystagmus is an involuntary eye movement characterized by oscillations of the eyes, which can be vertically or horizontally oriented. During an alcohol impairment assessment, the presence of nystagmus serves as an indicator of the effects alcohol has on the central nervous system, particularly as blood alcohol concentration (BAC) levels increase. The observations during an assessment can include signs of horizontal gaze nystagmus, which becomes more pronounced at higher BAC levels. As BAC rises, the ability of the body to maintain normal muscle control and coordination diminishes, which is reflected through the eye movements and varying degrees of nystagmus. Law enforcement officers use this specific sign as part of standardized field sobriety tests to assess whether an individual is impaired due to alcohol consumption. Therefore, the presence of nystagmus is a significant indicator of potential alcohol impairment, correlating with higher BAC levels.