AUTOROTATION TEST OF THE HORIZONTAL VESTIBULOOCULAR REFLEX IN MENIERES-DISEASE

Sixty-four patients with the diagnosis of Meniere's disease were teste d at the House Ear Clinic with an active head-rotation test system, th e Vestibular Autorotation Test (VAT). The VAT is a portable, computeri zed test that measures the horizontal vestibulo-ocular reflex (VOR) wi th the use of high-frequency (2 to 6 Hz) active head movements to obta in gain and phase. The purpose of this study was to characterize the h orizontal VOR at high frequencies in patients with Meniere's disease. At frequencies from 5 to 6 Hz, all patients demonstrated horizontal ph ase greater than 180 degrees and 85% showed abnormal VAT results. The most common patterns were decreased gain or increased phase values, or both, relative to normative data. No significant differences in the d egree of abnormality in gain and phase were noted among groups of pati ents when the patients were clinically staged. We conclude that, in ou r test population of patients with Meniere's disease, the VAT shows co mmon gain and phase patterns and abnormalities of the horizontal VOR. This may contribute to high retinal image velocities, which render the patient unable to stabilize retinal images during locomotion (visual field image slip), in as many as 85% of the patients tested, regardles s of clinical stage. Such high-frequency testing can reveal abnormalit ies of the horizontal VOR not apparent from conventional vestibular te sting. Thus VAT provides additional information about the functioning VOR when combined with the present vestibular test battery.