DWI Detection and Standardized Field Sobriety Testing Lack of smooth pursuit Clue Number 1

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

DWI Detection and Standardized Field Sobriety Testing

Lack of smooth pursuit

Clue Number 1

8-41

Clue No. 1: Lack of Smooth Pursuit

The first clue requires that the subject move the eye to follow the motion of a smoothly

moving stimulus.

The stimulus may be the eraser on a pencil, the tip of a penlight, the tip of your finger, or

any similar small object.

Begin by holding the stimulus vertically approximately 12 - 15 inches (30 - 38 cm) in

front of the subject's nose, and slightly above eye level.

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

DWI Detection and Standardized Field Sobriety Testing

Lack of smooth pursuit

Clue Number 1 (Cont.)

8-42

Move the stimulus smoothly all the way out to the right (checking subject's left eye first)

then move the stimulus smoothly all the way across the subject's face to the left side

(checking the subject's right eye), then back to center.

Make at least two complete passes with the stimulus

If a person is not impaired by alcohol (or drugs that cause HGN), the eyes should move

smoothly as the object is moved back and forth.

Analogy: movement of the eyes of a person not impaired by alcohol (or drugs that

cause HGN) will be similar to the movement of windshield wipers across a wet

windshield versus a dry windshield.

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HS 178 R5/13 28 of 62

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

DWI Detection and Standardized Field Sobriety Testing

Mechanics of Clue Number 1

• Move object steadily at a speed that

takes approximately 2 seconds to bring

the eye from center to side

• Make at least two complete passes in

front of the eyes

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The Mechanics of Clue Number 1

It is necessary to move the object smoothly in order to check the eye’s ability to pursue

smoothly.

The stimulus should be moved from center position, all the way out to the right side

(checking subject's left eye) where the eye can go no further, and then all the way back

across subject's face all the way out to the left side where the eye can go no further

(checking subject's right eye) and then back to the center.

The object must be moved steadily, at a speed that takes approximately 2 seconds to

bring the eye from center to side.

In checking for this clue, make at least two complete passes in front of the eyes.

If you are still not able to determine whether or not the eye is jerking as it moves,

additional passes may be made in front of the eyes.

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

DWI Detection and Standardized Field Sobriety Testing

Live Demonstration

Clue Number 1

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Live Demonstration of the Mechanics of Clue No. 1

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HS 178 R5/13 29 of 62

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

DWI Detection and Standardized Field Sobriety Testing

Participant Practice

Clue Number 1

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Participant Practice of the Mechanics of Clue No. 1

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

DWI Detection and Standardized Field Sobriety Testing

Participant Led Demonstration

Clue Number 1

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Participant Led Demonstration

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HS 178 R5/13 30 of 62 Source: DWI Detection and

Standardized Field

Sobriety Testing

March 2013 Edition