Affiliations: [a] Department of Otorhinolaryngology, University Central Hospital of Helsinki, Finland | [b] Department of Otorhinolaryngology, Karolinska Hospital, Stockholm, Sweden | [c] Department of Computer Science, University of Tampere, Finland
Note: [*] Correspondence and reprint requests to: Dr. TP Hirvonen, Department of Otorhinolaryngology, University Central Hospital of Helsinki, P.O. Box 220, FIN-00029 HYKS, Finland. Tel. +358 9 4711; Fax: +358 9 47175010; E-mail: [email protected]
Abstract: The head autorotation test is a novel method for studying the high-frequency vestibuloocular reflex without heavy machinery to generate whole-body rotation. Despite many studies with the test, the method is far from standardized, and no comparison has been made of different versions of the test. The objective of this study was to compare the vestibuloocular reflex of 100 healthy subjects measured simultaneously with two versions of the head autorotation test. Gain, phase, asymmetry, and the frequency bands reached were determined in the frequency bands of 1, 2, 3, 4, and 5 Hz. The gain measured with both tests was close to unity (range 0.95–1.04) from 1 to 4 Hz and about 0.9 at 5 Hz. In the test developed by Vorteq the phase lagged (−7 to −21∘) in all the frequency bands, and it differed significantly from the phase lead of 2 to 5∘ that was measured by the other test. The asymmetry measured with the Vorteq test increased continuously from 1.5% variation, which was larger in the higher frequency bands. In conclusion, the high-frequency vestibuloocular reflex of healthy subjects can be quantified with active head oscillation. Both tests produced similar gain results, but the phase results differed systematically. Thus, the results of different head autorotation tests may not be directly comparable.
