Across Massachusetts, as part of roadside field sobriety testing, police officers routinely administer the Horizontal Gaze Nystagmus test to those suspected of driving under the influence. The Horizontal Gaze Nystagmus field sobriety test involves the officer moving a pen in front of the defendant’s eyes to determine if the defendant can follow the path, or if unusual eye movements occur. A strong correlation between intoxication and nystagmus has been demonstrated and DUI prosecutors may attempt to introduce HGN related evidence in Massachusetts DUI cases.
However, courts have repeatedly ruled that testimony about this science-based DUI sobriety test requires an accompanying expert witness. Without such an expert, courts will exclude a police officer’s testimony regarding HGN, because the correlation between nystagmus, the involuntary jerking of the eyeball, and intoxication is beyond the common knowledge and experience of jurors. Massachusetts courts routinely require this foundational testimony even in light of a resolution which the American Optometric Association passed in 2003 endorsing the use of horizontal gaze nystagmus by police officers in drunk driving cases.
When administering the test in a DUI case, the person suspected of DUI is told to follow an object to the peripherals of his sight, and if his eyeball twitches the officer is trained to associate that twitching, nsytagmus, with drunkenness. However, it is a sign of number of ailments which have absolutely nothing to do with alcohol intoxication. As with the other field sobriety tests, there are numerous innocent explanations for what might be characterized as a field sobriety test “failure.” For HGN evidence to be admitted, the prosecution must lay a proper foundation through the use of a properly qualified expert witness such as an ophthalmologist, who can adequately explain, to the jury, the relationship between nystagmus and alcohol intoxication.
The best Massachusetts DUI Lawyers file motions, in advance of the drunk driving trial, to exclude any HGN related testimony and evidence. This is a sound practice because there have been cases where no motion has been filed and the jury hears some mention of the HGN field sobriety test. DUI defense lawyers will usually object at the first mention of HGN. However, it is too late by then. The jury has usually already heard that the test was, at least, offered. Therefore, the best practice is to file a motion in advance of the trial.
