Subjective visual vertical perception in patients with vestibular neuritis and sudden sensorineural hearing loss

Objective: To determine the subjective visual vertical (SVV) perception in patients with vestibular neuritis (VN) and sudden sensorineural hearing loss (SSHL) using the SVV test and other neuro-otological examinations, namely, the vestibular evoked myogenic potential (VEMP) and caloric tests, and to clarify which vestibular nerve function is associated with an SVV shift. Patients and methods: We performed the SVV test in 36 VN patients and 80 SSHL patients. Thereafter, we investigated directional changes in the SVV in the VN and SSHL patients, and compared the results of the SVV test with those of the VEMP and caloric tests. Results: Abnormal SVV (>2 degrees) was found at a rate of 69.4% in the VN patients and 26.3% in the SSHL patients. In all except 1 VN patient, the SVV tilted to the lesion side. The rate of abnormal SVV was significantly higher in patients with complete canal paresis (CP) than in patients with partial CP. There was no significant relationship between the rates of abnormal SVV and VEMP. In the SSHL patients, neither the SVV nor the VEMP affected the hearing outcome and patients with abnormal VEMP tended to show abnormal SVV. Conclusion: VN patients showed a higher rate of abnormal SVV than SSHL patients. From the results, it is speculated that the superior vestibular nerve function mainly affects the SVV tilt, although the inferior vestibular nerve function may also have an effect.