HORIZONTAL GAZE NYSTAGMUS TESTING FOR DUI - DON'T DO IT!
National Highway Traffic Safety Administration (NHTSA) studies pertaining to Horizontal Gaze Nystagmus (HGN) suggest flaws suggesting they are not reliable indicators of a level of intoxication.
LAW ENFORCEMENT RELIANCE AND ERRORSLaw Enforcement believe Horizontal Nystagmus, or the horizontal jerking of the eyes, is considered to be an indicator that a person is under the influence of alcohol or drugs.
ISSUES AND FLAWS WITH HGN TESTINGIn addition to poor training in the administration of the test, as well as a myriad of environmental factors that can affect results, a large number of conditions unrelated to alcohol which can cause Horizontal Nystagmus. These conditions included:
problems with the inner ear labyrinth; irrigating the ears with warm or cold water under peculiar weather conditions; influenza; streptococcus infection; vertigo; measles; syphilis; arteriosclerosis; muscular dystrophy; multiple sclerosis; Korchaff's syndrome; brain hemorrhage; epilepsy; hypertension; motion sickness; sunstroke; eyestrain; eye muscle fatigue; glaucoma; changes in atmospheric pressure; consumption of excessive amounts of caffeine; excessive exposure to nicotine; aspirin; circadian rhythms; acute trauma to the head; chronic trauma to the head; some prescription drugs, tranquilizers, pain medications, anti-convulsants; barbiturates; disorders of the vestibular apparatus and brain stem; cerebellum dysfunction; heredity; diet; toxins; exposure to solvents, PCBs, dry-cleaning fumes, carbon monoxide; extreme chilling; lesions; continuous movement of the visual field past the eyes; and antihistamine use.
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