DWI Detection and Standardized Field Sobriety Testing Horizontal Gaze Nystagmus Test Demonstration

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Horizontal Gaze Nystagmus

Test Demonstration

8-61

Test Demonstration

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

• Check for eyeglasses

• Verbal instructions

• Position stimulus (12-15 inches and slightly above

eye level)

• Check for equal pupil size and resting nystagmus

• Check for equal tracking

Administrative Procedures

8-62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

• Lack of smooth pursuit

• Distinct and sustained nystagmus as maximum

deviation

• Onset of nystagmus prior to 45 degrees

• Total the clues

• Check for vertical nystagmus

Administrative Procedures (Cont.)

8-63

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 39 of 62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Vertical Gaze Nystagmus

8-64

D. Vertical Gaze Nystagmus

The Vertical Gaze Nystagmus test is simple to administer. During the Vertical Gaze

Nystagmus test, look for jerking as the eyes move up and are held for a minimum of

four seconds at maximum elevation.

• Position the stimulus horizontally, about 12 - 15 inches in front of the subject's nose.

• Instruct the subject to hold the head still, and follow the object with the eyes only.

• Raise the object until the subject's eyes are elevated as far as possible.

• Hold for a minimum of four seconds.

• Watch closely for evidence of the eyes jerking upward.

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Vertical Gaze Nystagmus

8-65

Participant led demonstration.

For VGN to be recorded, it must be distinct and sustained for a minimum of four

seconds at maximum elevation.

VGN may be present in subjects under the influence of high doses of alcohol for that

individual, and some other drugs.

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 40 of 62 Source: DWI Detection and

Standardized Field

Sobriety Testing

March 2013 Edition