Answer: The HGN test or the horizontal gaze nystagmus test in Maryland. The first thing you need to know is that is nothing more than an indicator of alcohol on board or alcohol in your system. There is case law in Maryland that does not let a judge or the jury go any further than the assumption that there is alcohol on board if you have HGN or horizontal gaze nystagmus. In Maryland, the HGN is considered a scientific test as opposed to, say, a layman’s test. And because it’s a scientific test, it requires an expert to come to court to testify. Now, the expert in that case would be the police officer. However, interestingly enough, because the police officer is being named as  an expert or utilized as an expert, he does have to properly be named as such in Maryland in discovery. So, when we at Robinson & Associates file our copious discovery on the State, one of the questions that we ask is, what experts will you be calling in court? And they have to properly designate the police officer as an expert. If they fail to do so, the HGN is not coming in to evidence.

Now, there are some other foundational requisites that the officer needs to get into on an HGN: he needs to check for equal pupil size, he needs to check for equal tracking, and he needs to check for resting nystagmus, according to Maryland law. And the officers typically don’t even know that these foundational things are supposed to be checked for. So, without that, often times we can also suppress the results of an HGN. Now, what is a horizontal gaze nystagmus test? The officer holds a pen or his finger 12 to 15 inches from your face, and he slowly takes it to the left, then he slowly takes it to the right and he checks for equal tracking. And then he’ll make four passes beyond that to check for if you actually have the nystagmus and you have early onset of nystagmus and how much nystagmus do you have at the maximum edge of your face.

What is nystagmus? Nystagmus is the involuntary eye movement when you’re tracking his finger in front of your face. That’s the nystagmus. And the assumption is that if your pupil involuntarily jumps or moves while it’s tracking, that you have nystagmus and then they make the leap of faith that that nystagmus is based on the consumption of alcohol. However, it’s sort of silly because according to Maryland case law and medical articles on the topic, you can have nystagmus from like 37 or 38 different causes such as caffeine, such as sugar, such as aspirin, such as a bump on the head or an accident of any kind, or any other large number of reasons why one may suffer or have a nystagmus condition. One of those reasons can be the consumption of alcohol. Therefore I would say, again, it’s a highly unreliable test but, nonetheless, it’s one that the officers are trained to use. But in the final analysis, it only means that you consumed alcohol.

Consequently, if you told the officer that you had one or two beers at the bar or the restaurant, well, you’ve just committed that you’ve consumed alcohol, and therefore having the signs up to six different signs or clues under HGN would be totally accountable should that come into evidence; it really doesn’t have a great impact. But that’s what HGN is in Maryland.