Oral Session A3 -VEMP A3-1 Ocular vestibular evoked potentials (oVEMPs) compared to the subjective visual vertical (SVV) during tilt and eccentric rotation -easier, cheaper and almost better Objective: We compared vibration-evoked oVEMPs with the SVV during whole-body roll tilt and eccentric rotation in healthy subjects and patients with unilateral vestibular loss, to determine which test was most sensitive in discriminating impaired utricle function. Methods: We measured oVEMPs and the visual

more »

... ertical in 11 patients and 11 healthy subjects. Visual vertical was measured during roll tilts between −9.6 and 9.6 • , and during rotation at 400 • /s with the head upright and the rotation axis located between ± 3.5 cm from the center of the head. Results: OVEMPs in patients were strikingly asymmetric, whereas they were approximately symmetric in healthy subjects. Patients showed reduced gain of the SVV during eccentric rotation, and increased errors for both tilt and eccentric rotation tests. OVEMPs were superior at discriminating between patients and healthy subjects, though eccentric rotation could perform nearly as well. Conclusions: Vibration induced oVEMPs provide a more powerful test for discriminating between healthy subjects and patients with chronic unilateral vestibular loss than visual vertical tests during either whole-body roll tilt or eccentric rotation. They are easier to administer, less demanding on patients, and most importantly, in general more effective at identifying chronic unilateral vestibular loss than visual vertical measurements. A3-2 Direction dependent excitatory and inhibitory ocular vestibular evoked myogenic potentials (oVEMPs) produced by oppositely directed accelerations along the antero-posterior mid-sagittal axis of the head References [1] B.L. Day and R.C. Fitzpatrick, Virtual head rotation reveals a process of route reconstruction from human vestibular signals.