What does the acronym "HGN" stand for?

The acronym "HGN" stands for Horizontal Gaze Nystagmus. In the context of field sobriety testing, HGN refers to a specific eye movement phenomenon observed when a subject is under the influence of alcohol or drugs. During the HGN test, an officer assesses the movement of the eyes as they follow a target horizontally. The presence of nystagmus, or involuntary eye movement, particularly at certain angles, can indicate impairment. This test is part of standardized field sobriety tests and is widely used in law enforcement to help determine a driver’s level of impairment. Other options presented do not align with the established terminology in the field of sobriety testing and the understanding of eye movement assessments.