DWI Detection and Standardized Field Sobriety Testing Involuntary jerking of the eyes, occurring as the eyes gaze to the side Horizontal Gaze Nystagmus

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

DWI Detection and Standardized Field Sobriety Testing

Involuntary jerking of the eyes,

occurring as the eyes gaze to the side

Horizontal Gaze Nystagmus

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C. Horizontal Gaze Nystagmus

Definition Review: Involuntary jerking of the eyes, occurring as the eyes gaze to the

side.

In addition to being involuntary:

• Person is usually unaware that it is happening.

• Person is powerless to stop it or control it.

Key Summary Point: Alcohol and certain other drugs cause Horizontal Gaze

Nystagmus.

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

DWI Detection and Standardized Field Sobriety Testing

• Vestibular

• Neural

• Pathological Disorders and Diseases

Categories of Nystagmus

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Categories of Nystagmus

Horizontal Gaze Nystagmus is not the only kind of nystagmus. There are other

circumstances under which the eyes will jerk involuntarily.

It is important to know some of the other common types of nystagmus, to be aware of

their potential impact on our field sobriety tests.

Nystagmus of several different origins may be seen. The three general categories of

nystagmus are:

• Vestibular

• Neural

• Pathological Disorders and Diseases

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HS 178 R5/13 12 of 62 Source: DWI Detection and

Standardized Field

Sobriety Testing

March 2013 Edition