Probation Officer Certification Academy Practice Exam 2025 – All-in-One Guide to Exam Success!

The correct response indicates that none of the substances listed—cannabis, stimulants, or narcotics—typically exhibit Horizontal Gaze Nystagmus (HGN) or Vertical Gaze Nystagmus (VGN).

HGN is a particular type of involuntary eye movement that is often used in field sobriety tests to indicate impairment due to the consumption of certain substances, most commonly alcohol. It involves the eyes exhibiting an abnormal rhythm as they follow a moving object. VGN similarly involves abnormal eye movements, typically indicating a higher level of impairment.

In practice, while alcohol use is associated with both HGN and VGN, the other substance categories often do not produce these eye movement effects in the same way. For example, cannabis may impair cognitive and motor functions, but it does not typically lead to the same ocular signs as alcohol. Stimulants, like amphetamines, cause heightened alertness and energy but do not generally produce significant eye movement disturbances. Narcotics, on the other hand, often lead to sedation rather than pronounced nystagmus, which is more characteristic of depressants like alcohol.

This understanding helps clarify why none of the mentioned categories typically exhibit HGN or VGN, thus making "