OBJECTIVES: By assessing unilateral utricular function at the acute and subacute stages, we sought to determine the ability of the subjective visual vertical (SVV) during eccentric rotation (dynamic SVV) in detecting latent abnormality of otolith dysfunction in unilateral vestibular neuritis. In addition, we compared the validity of the dynamic SVV with static SVV during the compensated recovery phase.
METHODS: The static SVV and dynamic SVV of 19 patients diagnosed with acute unilateral vestibular neuritis and 31 patients diagnosed with the subacute stage of vestibular neuritis were determined in this study. First, the static SVV was measured in a dark booth without rotation. The dynamic SVV was measured during rotation with an eccentric displacement of the head to 3.5cm from the vertical rotation axis during a constant velocity of 300 degrees /s.
RESULTS: In the acute stage of vestibular neuritis, the static SVV showed an increase in deviation to the side of the lesion compared to findings in normal subjects. In the subacute stage, it did not differ significantly from that of the normal subjects. The dynamic SVV, however, had a statistically significant increase in deviation to the side of the lesion compared to normal subjects in both the acute and subacute stages.
CONCLUSION: The dynamic SVV would be an effective method in detecting latent abnormality of otolith dysfunction in unilateral vestibular neuritis, compared to static SVV, especially compensated unilateral vestibular neuritis.