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HGN and Head Trauma

If you have been pulled over in Georgia on suspicion of DUI, the investigating officer will probably ask you to perform a battery of standardized field sobriety tests. This request may take the form of any number of questions, such as “can we just check to see if you are safe to drive?” or “we want to perform some tests before we let you on your way, is that alright?”. These tests are not required, and declining to perform these tests cannot be used against you in a prosecution of DUI. For this reason, it is better to decline to perform any tests, no matter how much reassurance the police officer gives you that they are “just to make sure you are safe on the roads.”

Still, many people opt to perform the tests, either because they don’t see the harm, they wish to be congenial with the officer, or because they don’t know that they can decline to perform the tests. If you choose to perform the tests, the officer may ask you if he can “take a look at your eyes.” This is an indication that he is about to perform the first of three standardized field sobriety tests, the horizontal gaze nystagmus.

This test is considered to be a “scientific” test, and because of this, it is important that the officer comply with his training as exactly as possible. The test must begin with a number of questions designed to medically qualify the participant. The officer is trained that he must ask you whether or not you have recently had any head, neck, or brain injuries, as these kinds of trauma can affect whether someone exhibits nystagmus, even if not under the influence of alcohol. It is common practice to ask whether or not the subject has “any eye problems” or vision issues, but this is not enough. The officer must also determine that it is appropriate to use this test. If the subject has been in a recent accident, suffering from whiplash, a concussion, vertigo, or some other balance and coordination related condition, the HGN test may not be accurate or reliable.

If you have been in an accident at the time of your DUI investigation, the officer may have overlooked potential head trauma before administering this test. As a result, the “clues” of the test may be unreliable, and could be subject to suppression before trial.

It is important to understand your rights and protections when you are charged with DUI. If you want an attorney that is knowledgeable about DUI police training and procedure, call our office for a free consultation at 404-581-0999. Written by Attorney Katherine A. Edmonds.

VIDEO – Horizontal Gaze Nystagmus Test

You’ve been stopped for DUI and the officer asks you to follow their finger with your eyes? What is this horizontal gaze nystagmus field sobriety test? And can it even be passed? That is the subject of today’s Peach State Lawyer video blog.

Hello, I’m attorney Scott Smith and today I’m standing in our mock trial courtroom. We’re talking about being asked out of your car after only having two drinks. The officer asks you to face him and with your hands by your side, feet shoulder width apart to follow his pen with your eyes. He asks you if you wear glasses or contacts or if you’ve had any recent head injuries. You’re about to perform the horizontal gaze nystagmus field sobriety test. It’s commonly known as the HGN test, or in the DUI world, the “eye” test.

What is this test?

The horizontal gaze nystagmus field sobriety test was originally designed by optometrists to diagnose medical issues within your eyes. The test checks for the involuntary jerking of your eye as your eyes move side to side horizontal to the floor following an object. Researchers determined some substances, particularly ethyl alcohol, and other central nervous system depressants, inhalants, and the drug PCP can cause horizontal gaze nystagmus in your eyes after use.

The horizontal gaze nystagmus field sobriety test, when properly performed looks for six clues of impairment. In Georgia DUI investigations, this test is the first of the standardized field sobriety evaluations.

Before the test can be performed on anyone, the officer is supposed to make sure both of your pupils are of equal size and your eyes move together from side to side. If you are having eye issues, the officer is supposed to discontinue the test immediately.

The clues are established in pairs. There are three tests performed that look for clues of impairment. The first test, called lack of smooth pursuit, is performed by the officer moving his finger back and forth across your field of vision, checking for nystagmus in both eyes as his finger or pen light is moving.

Because your eyes work together, each clue will be present in both eyes. If the officer says they notice a clue in one eye but not the other, the test would not be valid.

The second test is called distinct and sustained nystagmus at maximum deviation. It is where the officer moves his finger to the edge of your field of vision and holds it there for a minimum of four seconds to determine if your eye continues to exhibit sustained jerking when it is fixed on his finger at the edge of your field of vision.

These tests are designed to build upon each other, so you should never see clues present for distinct and sustained nystagmus at maximum deviation unless clues are present for lack of smooth pursuit.

The third and final test is called onset of nystagmus prior to a forty-five degree angle. The test is performed by the officer moving his finger slowly from the center of your field of vision until they reach a forty-five degree angle. When the officer begins to see nystagmus they are supposed to stop their finger and hold it to confirm the sustained jerking of the eye.

That’s it. That’s the entire horizontal gaze nystagmus field sobriety test. There’s nothing you can do to pass it. It’s all about the involuntary jerking of the eye and trusting that the officer in his report has documented his observations accurately.

As you can imagine, there are things that an experienced attorney can look for to determine whether the tests are performed correctly. If the tests are not performed correctly, an experienced DUI attorney can ensure the test should not be admitted into evidence or at trial against you.

Have you been recently arrested for DUI and asked to take this eye test? Do you have questions about the test? We’re available twenty-four hours a day, seven days a week to talk to you. Call us today for a free consultation. Our telephone number is 404-581-0999.

Thank you.