How many observable clues can be seen during the HGN test?

The Horizontal Gaze Nystagmus (HGN) test is an important field sobriety test used by law enforcement to assess if a person is impaired, especially by alcohol. During this test, an officer looks for specific observable clues that indicate the presence of nystagmus, which is an involuntary movement of the eye.

There are a total of six observable clues during the HGN test. These clues involve evaluating the eyes for nystagmus as the officer moves a stimulus horizontally, such as a pen or a finger, in front of the subject. The specific clues include:

1. The onset of nystagmus prior to a 45-degree angle when following the stimulus.

2. The distinct nystagmus at maximum deviation, where the eye is held at the extreme lateral position.

3. The ability to smoothly pursue the moving object without abrupt changes in movement.

Each of these clues helps indicate whether a person may be under the influence of alcohol or other substances, as nystagmus tends to be exacerbated by such impairments. Thus, recognizing all six clues during the HGN test is crucial for making an accurate evaluation of sobriety.