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Maryland DUI Horizontal Gaze Nystagmus Test

If you’ve ever been pulled over for drunk driving in Maryland, the officer who stopped you may have asked you to perform a series of exercises like walking an imaginary line or balancing on one foot.  While they may seem meaningless, these tasks help law enforcement officers determine a driver’s level of impairment, and are often referred to as field sobriety tests. Out of the many different tests officers use, there are only three field sobriety tests that have been approved by the National Highway Transportation Safety Administration (NHTSA)—and one of the most common of them all is the Maryland DUI horizontal gaze nystagmus (HGN) test.

You’re probably wondering what a horizontal gaze nystagmus test is. Also known as a DUI pen test, the HGN test involves watching an item—typically a pen or flashlight—as it is placed directly in front of your face and moved from one side to another. This test is designed to help the officer identify an involuntary jerking of the eyes called nystagmus (a common sign of intoxication).

As the officer performs the test, he or she will be watching your eyes closely to look for signs of nystagmus. If you are unable to follow the object, or your eyes begin to jerk before reaching 45 degrees, you may be arrested and charged with driving under the influence.

Unfortunately, many things besides alcohol can cause a person to display signs of nystagmus. Multiple sclerosis, vision disorders, and head injuries can trigger the phenomena, as can certain medications. In fact, scientists have identified over 100 conditions that are known to cause nystagmus.

Although HGN tests are based on science, they are still subject to error. If the test is not administered properly, for example, the results may be unreliable—and that means you could fail the test even if you are not impaired. As a result, it is important to discuss your test results with an experienced DUI defense attorney immediately after your arrest.

Remember, being charged with drunk driving does not mean that you will be found guilty of the offense in court. Countless Maryland drivers are able to avoid the life-altering consequences of a conviction—and often thanks to help from a professional legal representation. If you have questions about your case, call 1-877-472-0791 to get in touch with Bruce Robinson. He is available 24 hours a day, 7 days a week.

You can also fill out an online evaluation to download a free copy of The Maryland DUI Fact Book, which may answer many of your pressing legal questions.


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