Examining the HGN Test in DWI and DUI Cases in Washington County: A Defense Perspective

By Sullivan Rice

When discussing DWI cases in Washington County, it’s important to understand that field sobriety tests, like the Horizontal Gaze Nystagmus (HGN) test, aren’t the same as regular tests with clear "pass or fail" results. These tests are really attention tasks meant to look for signs that a driver may be impaired, but they don’t give a simple yes or no answer about whether someone is drunk or high.

The HGN test is one of the most common tests used by police officers in Washington County to check if someone is under the influence. During the test, the officer asks the driver to follow an object, like a pen or flashlight, with their eyes. The officer watches to see if the driver's eyes jerk involuntarily (a condition called "nystagmus"), which can be a sign of impairment.

While this test is used to determine if someone may be impaired by alcohol or drugs, there are many factors that can affect its accuracy. Experienced DWI defense lawyers in Washington County can challenge the results of the HGN test in court. This article explains how the HGN test works and how a skilled attorney can protect your rights.

What is Horizontal Gaze Nystagmus?

Nystagmus refers to the involuntary jerking or twitching of the eyes, which can occur naturally or be exacerbated by alcohol or other substances. What’s important to know is that people who experience nystagmus are often unaware of it and cannot control it. The challenge in DWI cases, especially in Washington County, is that law enforcement officers may misinterpret these eye movements. There are different types of nystagmus that may confuse officers during the HGN test:

1. Vestibular Nystagmus occurs due to disturbances in the inner ear and can be triggered by rapid movements like spinning. If a driver has recently engaged in such movements, this type of nystagmus could explain any jerking observed during the HGN test.

2. Neural Nystagmus includes Optokinetic Nystagmus and Physiological Nystagmus, neither of which is related to alcohol or drug impairment. For example, watching rapidly moving objects or focusing on a distant object may cause these natural types of nystagmus, which have nothing to do with intoxication.

3. Pathological Nystagmus is caused by medical conditions such as neurological disorders or inner ear problems. Officers are trained to look for certain indicators, such as unequal pupil size, before administering the HGN test. If these protocols aren’t followed, the test results can be highly unreliable.

Administering the HGN Test in Washington County

The HGN test involves three specific exercises, each designed to identify certain signs of impairment. However, the accuracy of the test is highly dependent on the officer’s adherence to standardized procedures. In Washington County, as in other areas, failure to follow these procedures can significantly compromise the results.

-Lack of Smooth Pursuit: This exercise checks whether the subject’s eyes can follow a moving object smoothly. If the officer rushes the test or doesn’t give the driver enough time to track the object properly, the test becomes unreliable.

-Distinct Nystagmus at Maximum Deviation: Officers must hold the stimulus at the farthest point (maximum deviation) for at least four seconds to observe clear eye jerking. Rushed or improperly timed observations can lead to erroneous conclusions.

-Onset of Nystagmus Prior to 45 Degrees: This exercise checks if nystagmus occurs before the eye reaches 45 degrees from the center. Again, the speed and precision of the officer’s movements are crucial to ensuring the test’s validity.

While the HGN test can reveal up to six clues of impairment, it’s important to note that even with proper administration, the test is only 88% accurate. In Washington County, if the officer deviates from the required protocols or misinterprets the signs, the reliability of the test diminishes significantly.

Defense Strategies Against HGN Test Results in Washington County

If you’ve been arrested for a DWI in Washington County, an experienced defense attorney will thoroughly review the HGN test’s administration and explore every opportunity to challenge its results. Here are some of the most effective defense strategies:

1. Officer Training and Certification: A primary defense strategy involves scrutinizing whether the officer properly followed standardized testing procedures. If the officer rushed the test, failed to properly observe the subject, or deviated from the required protocol, it could raise significant doubts about the reliability of the results.

2. Medical Conditions: If the driver has a medical condition that could explain the appearance of nystagmus—such as an inner ear disorder, neurological condition, or certain medications—this can serve as an effective challenge to the test results. Medical conditions unrelated to impairment can cause involuntary eye jerking that would be misinterpreted as a sign of intoxication.

3. Environmental Factors: The test’s accuracy can also be compromised by external factors, like poor lighting, distractions, or even officer error. For example, if the test was conducted in a poorly lit area or under distracting conditions, the officer’s observations might not have been valid.

4. Questioning the Officer’s Observations: Even if the officer followed the correct protocol, their interpretation of the results could be flawed. Nystagmus may be present for reasons unrelated to impairment, and a skilled defense attorney will work to cast doubt on the officer’s interpretation of the evidence.

Conclusion

The Horizontal Gaze Nystagmus (HGN) test is often seen as a reliable tool for detecting impairment in DWI cases, but it is far from infallible. In Washington County, the success of the test depends on the officer’s ability to follow strict protocols, and even then, the test is only 88% accurate. If you are facing a DWI charge in Washington County and have been subjected to an HGN test, it’s crucial to understand how the test works and how it can be challenged in court.

An experienced DWI attorney will thoroughly review the circumstances surrounding your HGN test and explore every legal strategy to challenge its results. Jack Rice Defense specializes in defending clients against DWI charges, particularly those based on field sobriety tests like the HGN test. If you're facing DWI charges in Washington County or the surrounding Twin Cities metro area, contact Jack Rice today for a free consultation. We are committed to providing you with the best defense possible, ensuring your rights are protected every step of the way.