Robustness of the Horizontal Gaze Test (Report)

These series of studies examined the effect of procedural variations in administration of the Horizontal Gaze Nystagmus (HGN) test of the Standardized Field Sobriety Tests (SFST).  In the first experiment, stimulus speed, elevation and distance were varied from the participants' faces.  In the second experiment, participants received the HGN test in a standing, seated or lying position.  The third experiment investigated the occurrence of HGN signs in people with monocular vision.  The overall results reveal that the HGN test is valid in both standard and varied testing procedures.