Under certain circumstances, horizontal gaze nystagmus (HGN) sobriety tests can be considered "inadmissible" in court. According to the NHTSA, HNG testing can allow prosecutors to establish scientific evidence against a DUI suspect in court. However, HGN testing isn't always accurate. In fact, combined sobriety testing methods produce accurate results only 91% of the time. This means that 9% of sobriety test arrests may be the result of imprecise test results.
HGN testing must be performed by a qualified law enforcement officer. During the test, the officer holds a small flashlight, pen, or other object in front of the subject's eyes and slowly moves it back and forth. As he/she moves the object from side to side, the law enforcement officer watches for signs of intoxication. Generally speaking, nystagmus only occurs while the eyeball is rotated to the side, but an elevated BAC can result in involuntary eye movement at other times.
If the test is not performed by a qualified law enforcement officer, it may not be allowed as evidence against the DUI suspect in court. Additionally, the scientific validity of the test can be brought into question. While most courts consider HGN testing "scientific," others only accept the test as an observation. If the test was administered by a law enforcement officer but executed improperly, prosecution may not be able to hold it as evidence against the suspect.
Even a properly administered test can yield inaccurate results. According to the NHTSA, a variety of other facts can cause nystagmus. For instance, seizure medication, fatigue, inner ear disturbances, and pathological disorders can lead to eye tremors. If you were arrested for DUI because you failed HNG testing, contact an Atlanta DUI lawyer from the Law Offices of Howard J. Weintraub today. With more than 35 years of experience, our team has the skill and dedication to fight for the case results you need.