What is the first step in the HGN test process?

Positioning the stimulus is indeed the first step in the Horizontal Gaze Nystagmus (HGN) test process. This step is crucial because it sets the proper environment for conducting the test. It involves the officer ensuring that the stimulus, often a pen or a similar object, is placed approximately 12 to 15 inches in front of the subject's eyes and at eye level. This position is necessary to allow for the most accurate assessment of the subject’s eye movement, as it is at this distance that the eyes can best follow the stimulus and any signs of nystagmus can be observed effectively.

By properly positioning the stimulus, the officer can effectively assess the side-to-side movements of the subject's eyes, a key indicator in determining impairments related to alcohol or drugs. It's essential that this step is executed correctly before any verbal instructions or any other evaluations occur, as it sets the stage for the rest of the test.