Last updated on November 2, 2021

The Horizontal Gaze Nystagmus Test Has Been Proven to Demonstrate Whether Somebody is Impaired Due to Alcohol or Not

Interviewer: How is the horizontal gaze nystagmus test performed? What’s the idea behind that one?

Paul Tafelski: The nystagmus test is one of the National Highway Traffic Safety Administration tests that was studied. It has been proven to demonstrate whether somebody has actually used alcohol or not.

It’s not really proven to be determinative of whether or not they are intoxicated, and the other thing about this test is it’s many times performed improperly by the police officer, and therefore the results are questionable. I’ll give you a little bit of information about that test, but it’s fairly complicated.

A “Gaze Nystagmus” is a Jerking of the Eyes as they Gaze Side to Side

Basically, nystagmus means “a jerking of the eyes,” and a gaze nystagmus is a jerking of the eyes as they gaze side to side. A nystagmus is normal in people. However, if you do this test properly and you hold the object that the person is looking at still for four seconds at the end range and the jerking continues for that entire time, then it can be reliably considered to have been caused by alcohol.

However, for example in that situation, most officers will not hold the object still at the end of the range for a full four seconds, and that invalidates reliability of that test because some nystagmus at end range is normal, and so if you don’t hold it there long enough to see if it continues longer than it should, you’re not doing the test properly.

It’s kind of a complicated test in that it usually requires a couple minutes for the officer to properly perform that test and yet most of the time the officers will do it in 30 seconds or less.

A Horizontal Gaze Nystagmus Test May be Performed While Sitting down or Standing

Interviewer: Do they do it while the individual is standing or sitting down?

Paul Tafelski: I’m not aware that the standing or sitting really makes that much of a difference. I’ve seen it done both ways, but they’re supposed to do it in an area where there’s not light that is coming at the eyeball from different directions and where the person has an ability to focus without moving their head to follow the object, and so there can be situations where the place they administer it could also affect the reliability of the information they gather from that test.

If An Officer Determines in his Report that you’ve failed the Test, It Cannot be Refuted

That’s another test also that is hard to argue with if the officer did perform it properly because the cameras do not show what the officer is seeing. If the officer just happens to write down “Given nystagmus, clear nystagmus at maximum deviation” then there’s not much you can say about it because it’s your word against theirs again. You can’t see what they see, and so the only way we can attack that test is by watching what the officer did. If he doesn’t follow the protocol properly, then you can attack what he did, but if he does follow the protocol properly, now you’re kind of stuck with what he says because it’s your word against his. It’s just, again, another reason why taking those tests really doesn’t help you.

Posted in: DWI
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