gms | German Medical Science

76th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

04.05. - 08.05.2005, Erfurt

Tonic torsional deviation eliceted by caloric stimulation - an indicator for otolith function?

Meeting Abstract

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Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. 76. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e.V.. Erfurt, 04.-08.05.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05hno488

The electronic version of this article is the complete one and can be found online at:

Published: September 22, 2005

© 2005 Waltmann et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



In an investigation of the three-dimensional nature of the caloric nystagmus a novel aspect of this vestibule-oculomotor response was systematically observed, namely the tonic torsional deviation (TTD). This phenomenon manifests during standard caloric irrigation and involves a slow torsional rotation of the bulbus conjugate to the slow phase of the torsional nystagmus component.

36 subjects were examined using standard bithermal caloric irrigation (44°R - 44°L -30°L – 30°R) in the Hallpike position. The three-dimensional nature of the resultant caloric nystagmus was evaluated using state-of-the-art videooculography. In addition the clear horizontal and torsional nystagmus components, the tonic torsional deviation of the bulbus was observed in all subjects. This consists of deviation of 2° to 6° in magnitude, which is systematically altered by irrigation temperature and stimulated labyrinth. Additional comparative measurements on 5 subjects demonstrated that the TTD is inverted by turning the subject from supine to prone position.

It is argued that this response component is induced by stimulation of the utricle. This hypothesis is supported by the fact that stimulation of the semicircular canals does not induce static changes of eye position and by further experimental evidence that torsional rotation of the eye is produced, e.g. by direct electrical stimulation of the utricle.

The findings indicate that a three-dimensional evaluation of the caloric response, in particular of the torsional component permits a unilateral test of utricular function that is suitable for routine clinical diagnostics.