The Horizontal Gaze Nystagmus test is one of the three standardized field sobriety tests used in the investigation of both drunk and drugged driving cases. The word "nystagmus" refers to a phenomenon of human physiology whereby the specific gravity of the fluid inside an organ inside your ear called a cochlea. When the amount of alcohol in the cochlea gets out of whack with blood alcohol a curious thing tends to happen – the eyes wiggle back and forth really quickly as they travel across a plane. This wiggling is called nystagmus. It is this wiggling or twitching that the officer is looking for when he/she administers this test at the roadside. The standardized tests breaks this twitching and movement into three things called clues. The are inability to pursue the stimulus smoothly, wiggly eyes happen when eyes are at corner or at maximum deviation from nose, and the start of wiggly eyes before halfway, or 45 degrees.
Test AdministrationIf the test had been appropriately administered, the officer would have begun by asking you to stand with your feet together, and arms at your side. You should then have been instructed to "follow the stimulus (usually the officer's finger, a pen, or a flashlight) with your eyes only, keeping your head still". Before beginning the test, the officer should have confirmed that you understood the instructions by directly asking you "Do you understand"? The officer should also have asked you if you were wearing contact lenses.
Other Factors an Officer is Looking ForIn addition to the three clues listed above, the officer also wants to see if you can follow the instructions. One that is often missed is the “with your eyes only” part. Its not natural to only follow with the eyes, because usually where the eyes go the head goes. Often when watching videos of these tests being administered we can hear the officer repeating telling the subject to not follow with their head. Also, did you lose your balance, or use your arms for balance rather than keeping them at your sides? While these are observations are not standardized clues the police officer might add them while testifying to make you look more intoxicated.
Benefit of an AttorneyHaving evaluated hundreds of these cases it is evident that officers almost never administer this test properly. The most alarming thing about this fact is that administering this test incorrectly can cause the Nystagmus that the officer will later use against you to prove you were intoxicated! You Michigan DUI Lawyer at the Barone Defense Firm can review the video recording of this test being administered at the roadside to evaluate whether the officer in your case followed the appropriate standard of their training. If not then the prosecutor will be precluded from offering this test as evidence of your intoxication at trial.