Test-retest reliability of the VOR as measured via Vorteq in healthy subjects.

To determine the reliability of the vestibolo-ocular reflex test measured via Vorteq, 16 subjects underwent head-autorotation test at the frequencies 1-5 Hz. All patients underwent the re-test. No linear correlation was observed between the measurements, i.e., no repeatability of the same measurements at the various frequencies. The Head Auto-Rotation Test by Vorteq has demonstrated advantages: patients are not disturbed by the active head movements; the full test protocol, lasts only a few minutes; the method enables the vestibolo-ocular reflex to be evaluated at high head-rotation frequencies. However, the test has disadvantages: poor test-retest inter-individual repeatability, wide standard deviations of results with heterogeneous inter-individual spread with regard to phase and asymmetry values especially at high rotation frequencies. In the light of the above findings, it can be seen that the test-retest of the Vorteq system is not sufficiently reliable and hence cannot be used in clinical practice.