October 29, 2015

DWI Detection and Standardized Field Sobriety Testing • Rotational • Post Rotational • Caloric Vestibular Nystagmus

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)
DWI Detection and Standardized Field Sobriety Testing
Rotational
Post Rotational
Caloric
Vestibular Nystagmus
8-20
Vestibular Nystagmus is caused by movement or action to the vestibular system.
Types of vestibular nystagmus:
• Rotational Nystagmus occurs when the person is spun around or rotated rapidly,
causing the fluid in the inner ear to be disturbed. If it were possible to observe the
eyes of a rotating person, they would be seen to jerk noticeably.
• Post Rotational Nystagmus is closely related to rotational nystagmus: when the
person stops spinning, the fluid in the inner ear remains disturbed for a period of time,
and the eyes continue to jerk.
Neither Rotational nor Post Rotational Nystagmus will interfere with the Horizontal Gaze
Nystagmus test because of the conditions under which they occur.
• Caloric Nystagmus occurs when fluid motion in the canals of the vestibular system is
stimulated by temperature as by putting warm water in one ear and cold in the other.
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HS 178 R5/13 13 of 62 Source: DWI Detection and
Standardized Field
Sobriety Testing
March 2013 Edition

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