Assessment of vestibulo-oculomotor reflex in ménière's disease: Defining an instrumental profile

Objectives: To analyze and compare, in two groups of patients affected by definite Ménière's disease (MD) but treated differently, the Video Head Impulse Test findings especially by putting them in relationship with canal paresis, hearing loss, and duration of the disease. Study Design: Retrospective chart review. Patients: Seventy patients affected by unilateral definite MD (16 in Group 1 and 54 in Group 2) observed between March 2014 and May 2015 in a tertiary referral center were retrospectively studied and then divided into two groups: Group 1 was previously treated with intratympanic gentamicin, whereas Group 2 underwent only a conservative therapy. Instrumental tests included audiometry, caloric test, and Video Head Impulse Test. All the findings were statistically analyzed; significance was set at p=0.005. Intervention: Diagnostic. Main Outcomes Measures: If MD is treated conservatively the high-frequency vestibulo-oculomotor reflex gain determined with Video Head Impulse Test is normal; it is pathological if MD is treated with gentamicin. Results: High-frequency vestibulo-oculomotor reflex gain showed a statistically significant reduction in Group 1; at the same time, it showed no correlation in both groups with hearing loss, duration of disease or canal paresis. Conclusion: High-frequency vestibulo-oculomotor reflex is naturally preserved even in late stage MD if the patient has been treated conservatively; the dissociation between Caloric Test and Video Head Impulse Test findings could be considered an instrumental hallmark of MD. Gentamicin significantly reduces high-frequency vestibulo-oculomotor reflex gain: This reduction can be taken into account when determining the effectiveness of an ablative treatment.