What is Horizontal Gaze Nystagmus HGN?

Stephen H.: Hello, I’m Stephen Hamilton, board certified in criminal defense. I practice in Lubbock, Texas and the South Plains. Today’s video topic on DWI is what is HGN or horizontal gaze nystagmus.

Stephen H.: If you’ve been following some of the video clips that we’ve been talking about recently, we’ve talked about field sobriety testing and the different types, horizontal gaze nystagmus, walk and turn, one leg stand.

Stephen H.: Today I want to focus on what is horizontal gaze nystagmus. It’s the first, typically the first field sobriety test that the officer’s going to do and basically, it is a involuntary jerking of the eye.

Stephen H.: You’ll see an officer use a pencil or a stim, what they call a stimulus pin, and he’ll put it in front of your face at a certain length and he’ll begin to move it in certain directions.

Stephen H.: Oftentimes, I’ll have a client who says, “Well, Steve, I did really well on that test because I could follow the pen every time that he moved it.” But that’s really not what the officer’s looking for.

Stephen H.: What he’s doing is looking at your eye to see if he sees a twitch, a bounce, and at certain angles at certain limits that they have to hold it, then they’re going to say that’s a clue.

Stephen H.: A clue to what? A clue that you’re intoxicated. There are some real problems with this. First, the officer. I mean, the officer typically has gone through a three-day class. 24 hours, that’s it.

Stephen H.: 24 hours of field sobriety training and he’s coming into a courtroom and he’s saying he’s an expert in the case. Now, in a DWI case, that’s about the only time that I could imagine the trial court letting an officer do that. This was a civil case. It wouldn’t be admissible.

Stephen H.: Imagine going to the doctor and the doctor wants to do heart surgery on you and he says, “Well, I’ve had a 24-hour class on heart surgery.” Are you really going to trust that officer?

Stephen H.: So, that’s one of the problems. The second is the administration. One of the things we’re going to do in your case when you come in and sit down, we’re going to get your video because we want to look and see if we can see how the officer conducted the test.

Stephen H.: There are certain points that he has to stop, certain timeframes that he has to do and if he’s not doing those correctly, then we want to file a motion in the court to try to keep out that evidence.

Stephen H.: So, what if it comes in? Well, all he’s really telling you is that there’s an nystagmus or a twitching of the eye. But you know there are dozens of types of nystagmus.

Stephen H.: Only one, horizontal gaze nystagmus, the officer will say is caused by alcohol. But they don’t know all the other types of nystagmus, so how is it that an officer can say that he sees alcohol induced horizontal gaze nystagmus and not some other medical type of nystagmus, for example, Bruns nystagmus?

Stephen H.: Well, what is Bruns nystagmus? The officer doesn’t have a clue, so how can he tell a jury that what he sees is because of alcohol and not because of a medical condition or because of other issues?

Stephen H.: Smoke, nicotine, caffeine, many things affect the ability of the eye to track equally and that’s what the officer’s looking at.

Stephen H.: The other thing that really concerns us when we’re talking about it is even if the officer says that there’s nystagmus in the eye, at best it shows that there’s alcohol in your system.

Stephen H.: As long as you’re above 21 it’s not illegal in the state of Texas to have alcohol in your system and operate a motor vehicle unless you’re intoxicated.

Stephen H.: So, he spends all this time doing the test to say there’s alcohol in your system and yet it doesn’t mean that you’re intoxicated. That’s some of the areas of big concerns that we have, that I have when an officer says, “I’m qualified to administer this horizontal gaze nystagmus test.”

Stephen H.: There are a lot of areas that’ll affect the case. One of the things is we want to delve down into the science, okay? Just because the officer says it, doesn’t mean it’s so.

Stephen H.: Pick up the phone. Call me. Come in today. My office number is 806-794-0394. We can spend some time talking about what is nystagmus, how does it affect, and really, what does it mean in your case. I’m Stephen Hamilton. That’s it for today. Have a great day.

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