October 29, 2015

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
8-18
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
8-19
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

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