Angular vestibulo-ocular reflex gains correlate with vertigo control after intratympanic gentamicin treatment for Meniere's disease

Objectives: The objective of our study was to determine whether angular vestibulo-ocular reflex (aVOR) gains correlated with vertigo control after intratympanic gentamicin treatment for Meniere's disease. Methods: We conducted a prospective study of 18 subjects with unilateral Meniere's disease treated with intratympanic gentamicin injection and followed all subjects for 1 year. We measured the gain of the aVOR elicited by rapid rotary head thrusts in each of the canal planes for each subject before and after treatment with intratympanic gentamicin by using magnetic search coils to record eye movements. Results: During the follow-up period, 11 subjects ("single-treatment group"; 61%) had control of their vertigo with a single gentamicin injection. The remaining 7 subjects ("multiple-treatment group"; 39%) experienced recurrent vertigo that required a second injection of gentamicin at a mean of 6 months after the first treatment. The 11 subjects in the single-treatment group had significantly greater reduction of labyrinthine function after the first treatment, as measured by change in ipsilateral horizontal canal gain, than did the 7 subjects with vertigo recurrence. Changes in caloric asymmetry did not correlate with vertigo control. Conclusions: Our results suggest that successful treatment of Meniere's disease is closely related to attenuation of semicircular canal function as measured by horizontal canal aVOR gains.