[Measuring the subjective visual vertical using a portable system: a comparison with the standard darkroom method]

Abstract

Objective: Assessing otolithic functions in the case of vertigo, although significant, is challenging from a practical point of view. A tilt of the subjective visual vertical (SVV) is a very sensitive sign of vestibular tonus imbalance in the roll plane. The standard method, a light bar in the dark, requires expensive, stationary equipment. However, portable equipment has been developed. The patient, who is in complete darkness afforded by a cover, sits in front of a monitor that can be seen by him and the examiner. Results obtained with this system were validated and compared with the standard application.

Patients and methods: Measurements were taken in 100 unselected, consecutive patients suffering from dizziness treated at the Baumrain Klinik, Bad Berleburg as well as in 26 healthy volunteers. All were examined and diagnosed by an ENT physician. Measurements in all participants were taken first with the standard procedure (equipment Vertitest) followed by the portable procedure (Vertistar equipment). In each case the deviation of the absolute from the true vertical was measured and the mean differences between the two procedures calculated. These were then analyzed using a paired t-test with the help of the SPSS system.

Results: Comparative measurements in the dizziness group (n = 100), t(25) = 0.868, p = 0.394 and in the healthy control group (n = 26), t(99) = -0.192, p = 0.848 showed no significant differences in the distribution of SVV values while using the stationary or the portable version. Inter-test reliability was significantly positive (r = 0.852; p < 0.01, n = 126).

Conclusions: The portable method for measuring SVV is practical, flexible and cost-effective and demonstrates the same diagnostic accuracy as the stationary method.