If you’re pulled over and investigated for a DWI in Raleigh or anywhere else in Wake County, you’ll likely be asked to perform what’s called the Horizontal Gaze Nystagmus (HGN) test, which is one of three Standardized Field Sobriety Tests (SFSTs) promoted by the National Highway Traffic Safety Administration (NHTSA) to make it easier for cops and prosecutors to get convictions. This is a test in which the suspect is asked to follow an object from side to side with his or her eyes, and the theory is that an officer can detect alcohol intoxication by the manner in which the eyes track the object. Officers are trained to look for “jerkiness” in eye movements as the eyes track back and forth, and to conclude that jerkiness in eye movement is evidence of impairment.
The problem is, there are dozens of potential causes of the same symptoms, and officers have no idea how to discern the cause of their alleged observations. Other known causes of the same symptoms the HGN test identifies are: the flu, strep, MS, syphilis, vertigo, measles, muscular dystrophy, arteriosclerosis, Korsakoff’s Syndrome, hypertension, motion sickness, brain hemorrhage, eyestrain, sunstroke, eye muscle fatigue, glaucoma, changes in atmospheric pressure, as well as consumption of aspirin, caffeine, and nicotine. See Pangman. Horizontal Gaze Nystagmus: Voodoo Science. 2 DWI J. 1, 3-4 (1987), for more information.
Like many things used by cops and prosecutors to prosecute individuals, HGN is unreliable junk science that should never see the light of day in a criminal courtroom where people’s liberty is on the line. I hope to follow up on this with a more detailed analysis in the future.
Ben Hiltzheimer is a criminal defense lawyer in Raleigh, North Carolina, who represents individuals charged with DWIs and the full spectrum of misdemeanors and felonies. Contact us for a free, confidential consultation and case evaluation at (919) 727-9227.