What Is HGN?

Published On - October 30, 2014

If you are ever pulled over on suspicion of driving under the influence, or DUI, in Tennessee the stop will likely proceed through the same steps as most DUI stops. First, the officer will ask you a series of questions aimed at getting you to admit you have been drinking and/or as a way for the officer to observe you for sign of intoxication. Next, the officer will likely ask you to perform a series of field sobriety tests, or FSTs. While there are a number of FSTs that may be used, most officers stick to the standardized FSTs which will include the Horizontal Gaze Nystagmus, or HGN, test. The odds are good that you have seen this test performed on television before but may not know what the purpose of the test is and/or what the officer is actually looking for when administering the test.

Typically, the HGN test is performed using a pen light or other similar instrument. The officer will ask you to follow the instrument as it is moved from the center of your face to one side and then back again. You will then be told to follow the instrument with your eyes only. The officer is looking for “horizontal gaze nystagmus” which refers to a lateral or horizontal jerking when the eye gazes to the side. The way your system is wired, when alcohol or some central nervous system depressants enter your system it become harder and harder to control eye movement, hence the jerking and twitching when your eye tracks to the side. At about a 45 degree angle from your eye your peripheral vision is triggered. If your eyes show signs of HGN, it is considered to be a sign that you have been drinking and/or that you are under the influence of a controlled substance.

As with all FSTs, the results of the HGN test are subjective in nature, meaning that the officer conducting the test determines if you passed or failed the test. Moreover, there are a number of environmental and physiological factors that can directly impact the outcome of the test. AS with all FST results it is always best to discuss those results with an experienced criminal defense attorney to determine if errors were made in the administration or evaluation of the tests.

If you are currently facing charges of DUI, or another similar charge, in the State of Tennessee it is in your best interest to consult with the experienced Tennessee criminal defense attorneys at Bennett, Michael & Hornsby. Contact the team today by calling 615-898-1560 to schedule your appointment.

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Dinah Michael

Dinah’s practice at Bennett and Michael focuses on Family Law, Personal Injury Litigation, Insurance Defense, and General Civil Litigation. She has litigated cases in Tennessee’s trial courts, Court of Appeals, and the Tennessee Supreme Court. Dinah also maintains an active Family Law and Civil Mediation practice. She is a certified Rule 31 Family Law and Civil Law Mediator, handling matters ranging from divorce and custody to personal injury lawsuits.