DWI Detection and Standardized Field Sobriety Testing Clue Number 2 Distinct and Sustained Nystagmus at Maximum Deviation

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

DWI Detection and Standardized Field Sobriety Testing

Clue Number 2

Distinct and Sustained Nystagmus

at Maximum Deviation

8-47

Clue No. 2: Distinct and Sustained Nystagmus at Maximum Deviation

Once you have completed the check for lack of smooth pursuit, you will check the eyes

for distinct and sustained nystagmus when the eye is held at maximum deviation,

beginning with the subject's left eye.

The Mechanics of Clue Number 2

Once again, position the stimulus approximately 12 - 15 inches (30 - 38 cm) in front of

subject's nose and slightly above eye level.

Move the stimulus off to the right side (checking subject's left eye) until the eye has

gone as far as possible.

Hold the stimulus steady at that position for a minimum of four (4) seconds, and

carefully watch the eye.

Then, move the stimulus back across the subject's face all the way out to the left side

(subject's right eye).

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HS 178 R5/13 31 of 62

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

DWI Detection and Standardized Field Sobriety Testing

Clue Number 2 (Cont.)

Distinct and Sustained Nystagmus

at Maximum Deviation

8-48

Four seconds will not cause fatigue nystagmus. This type of nystagmus may begin if a

subject’s eye is held at maximum deviation for more than 30 seconds.

Hold the stimulus steady and carefully watch the eye.

If the person is impaired, the eye is likely to exhibit definite, distinct and sustained

jerking when held at maximum deviation for a minimum of 4 seconds.

In order to "count" this clue as evidence of impairment, the nystagmus must be distinct

and sustained for a minimum of 4 seconds.

If you think you see only slight nystagmus at this stage of the test, or if you have to

convince yourself that nystagmus is present, then it isn't really there.

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

DWI Detection and Standardized Field Sobriety Testing

Live Demonstration

Clue Number 2

8-49

Live Demonstration of the Mechanics of Clue No. 2

Participant Led Demonstrations

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HS 178 R5/13 32 of 62 Source: DWI Detection and

Standardized Field

Sobriety Testing

March 2013 Edition