How can perception of time affect HGN results?

The perception of time can significantly affect HGN results because impairment, such as that caused by alcohol or drugs, can hinder a person's ability to follow a moving stimulus smoothly. When an individual is under the influence, their neurological function is affected, often leading to a lack of coordination and impaired motor skills. This impairment can manifest as difficulty in tracking the moving object with their eyes, causing irregular eye movements that are characteristic of HGN.

Individuals who are impaired may have delays in response, making their eye movements less fluid and more jerky, which impacts the basic premise of the HGN test—evaluating the smooth pursuit of the stimulus. Therefore, a person's ability to track the stimulus smoothly will directly determine the outcomes of the test, and alterations in their perception of time can exacerbate these difficulties further.

This understanding underlines the importance of conducting the HGN test with a clear awareness of the individual's cognitive states and potential impairments, as these factors can directly influence the test's accuracy in assessing potential intoxication levels.