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People v. Berger: The Horizontal Gaze Nystagmus Test in Operating While Intoxicated Cases

January 18, 2018 DUI/OWI/DWI

The case of People v. Berger is about the horizontal gaze nystagmus test. This test is one of three standardized field sobriety tests given by officers to drivers suspected of being under the influence of alcohol or drugs.

What is Nystagmus?

Nystagmus is the involuntary twitching of the pupil in the eye. As the eye moves from side to side, the pupil will slightly twitch away from the direction of the eye’s gaze before getting back on track.

Nystagmus was first noted by Los Angeles police officers investigating drivers who had taken barbiturates. Nystagmus was first called the “barb bounce.” Later, nystagmus studies were performed with alcohol.

When a person is being investigated on suspicion of drinking and driving, or drugged driving, the officer will ask the person to take tests called field sobriety tests. These tests are designed to provide evidence of impairment. Any evidence of impairment will be used as probable cause to arrest the driver for operating while intoxicated. Signs of nystagmus will be considered signs of alcohol or drug consumption and will be used as a basis to make an arrest.

What Happened in the Case

The defendant in this case was convicted of operating a vehicle while under the influence of liquor-second offense. On appeal, the defendant argued that the trial court erred in allowing the arresting police officer to testify about the horizontal gaze nystagmus test.

What is the Horizontal Gaze Nystagmus Test?

There are three standardized field sobriety tests that officers ask suspected drunk drivers to perform. One of those tests is the horizontal gaze nystagmus test. The officer will ask the person to follow a stimulus, such as a flashlight, with their eye. The officer makes a series of swipes before the driver’s eye, while holding the stimulus at certain angles.

The officer must perform the test in the correct manner. Failure to perform the test in the correct manner could render the results of the test inaccurate. Many officers do not perform the test correctly. It is important for your lawyer to watch the test carefully to see how the officer performs the test. This is because juries often look at the HGN test as the most “scientific” of all the field sobriety tests. That is, the least subjective.

The Court’s Ruling

In this case, the Court ruled that the horizontal gaze nystagmus test could be introduced into evidence by the officer.

The Court ruled that there are only two requirements for the introduction of the horizontal gaze nystagmus test into evidence at trial. First, that the test was properly performed. And second, that the officer was trained to perform the test. All OWI attorneys must know this rule because it comes into play later.

What Does This Mean?

This case is important because it means the results of the horizontal gaze nystamgus test could be kept out of trial where the test was not performed correctly. It may be good trial strategy to keep it out because juries often believe the results of the test show intoxication. As a practical matter, almost all officers in DUI cases will say they saw nystagmus, and there’s no way to prove they didn’t see it because we have never have a camera angle of someone’s eyes. So defense counsel must look to see if the test was performed correctly.

If the test wasn’t performed correctly, then defense counsel can file a motion to exclude the test from evidence. However, there may be good reason to not move the exclusion of the test. For example, it may be good to show the officer doesn’t really know what he or she is doing. If the officer botches one part of the investigation, then we can say the whole investigation is suspect or they botched other parts as well. It’s all a matter of strategy to be determined on a case by case basis.

Call ArborYpsi Law

Call Sam Bernstein at 734-883-9584 or e-mail at

Sam Bernstein is a Criminal Defense Attorney in Ann Arbor.

ArborYpsi Law is located at 4158 Washtenaw Ave., Ann Arbor, MI 48108.

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