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DUI Field Sobriety Tests - HGN

Today's topic of discussion concerns the most important of all the standardized field sobriety tests, the Horizontal Gaze Nystagmus test. Nystagmus is defined as the involuntary jerking of the eyes. Horizontal Gaze Nystagmus is defined as the involuntary jerking of the eyes as they gaze to the side. Now, what we mean by Nystagmus in Horizontal Gaze Nystagmus is this: Think of a set of windshield washers or excuse me, windshield wipers. As the windshield wipers go across a wet windshield, they go across in a very smooth manner. If the windshield is dry and you turn on your windshield wipers, they stutter, they skip. That is what your eyes do when the police officer is checking them for Horizontal Gaze Nystagmus.

There are many different causes of Nystagmus including the flu, inner ear disorders, eye strain, sleep deprivation, consumption of caffeine or nicotine and neurological issues. These are just a few causes, only one of which is alcohol. I strongly disagree with the lack of scientific principles behind this battery of test. However, it is an accepted standardized field sobriety test as used here in Maine and the prosecutor can argue that the evidence of Horizontal Gaze Nystagmus is indicative of someone who is under the influence of alcohol. Most people think, “well I think I did fine on that test”. Unfortunately, you have no idea how well you did or how poorly you did on that test because HGN doesn't test your balance; you can't know subjectively how you did. You can't practice for Horizontal Gaze Nystagmus. It's literally looking for the involuntary jerking of the eyes.

Now, according to NHTSA (National Highway Transportation Safety Administration), 4 or more clues means a 77 percent probability that the person being tested is a 0.10 or greater. Now that sounds all fine and dandy; but that's only a 3 out of 4 chance that you are in fact impaired. What if you fall into that 1 out of 4 category? Just importantly, or perhaps more importantly, what if the officer administers the test improperly or evaluates what he sees incorrectly? Is that a fair result?

It's extremely important to get somebody involved who truly understands the in's and out's behind standardized field sobriety testing. Because in the state of Maine, the police use Horizontal Gaze Nystagmus to determine impairment, as well as the walk and turn and the one-leg stand tests. And the prosecutor will use the results of these tests against you. If you have questions or if you've been arrested for OUI, please do not hesitate to pick up the phone and call my office. I look forward to speaking with you soon. Thank you.

Categories: DUI


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