Which statement best summarizes the impairment clues?

• A. There are three impairment clues: Lack of smooth pursuit; Distinct and Sustained nystagmus at maximum deviation; Onset of nystagmus prior to 45 degrees.
• B. There are four impairment clues.
• C. Impairment clues are based on pupil size only.
• D. Impairment clues are used to diagnose medical conditions unrelated to impairment.

Answer: (A)

The main concept here is understanding how impairment clues are identified during the horizontal gaze nystagmus portion of the Standardized Field Sobriety Test. There are three impairment clues you look for: lack of smooth pursuit, distinct and sustained nystagmus at maximum deviation, and onset of nystagmus prior to 45 degrees. This combination is what the test uses to flag potential impairment.

So the best statement is the one that says there are three impairment clues and lists exactly those three clues. The other options are inaccurate because there aren’t four clues, the clues aren’t based on pupil size alone, and impairment clues aren’t used to diagnose unrelated medical conditions.