Delayed Effect and Gain Restoration After Intratympanic Gentamicin for Meniere's Disease
Objective: This study aimed to evaluate the changes in the VOR gain after intratympanic gentamicin therapy and to correlate them with the mid-term effects on the control of vertigo, in a population of Meniere's disease patients. Study Design: The study design was a prospective "Outcomes research." Setting: Tertiary referral center. Patients: This study included 20 patients with unilateral Meniere's disease refractory to medical therapy for at least 1 year, and treated with an on demand intratympanic gentamicin protocol. Intervention: Therapeutic. Main Outcome Measure: Audiometry, caloric testing, and a vHIT before beginning the protocol were performed. Patients underwent weekly vHIT assessments until a significant gain reduction was observed. Subsequently we performed vHIT tests 1 month after the therapy completion, and then every 3 months for at least 1 year. Results: Complete vertigo control (class A) was achieved in 14 patients at the 12-month follow-up assessment. We observed a significant reduction in VOR gain values at the 3-week follow-up assessment. We found a significant correlation between the 1-month posttreatment ipsilateral hVOR gain and the rate of vertigo recurrence after the first IT gentamicin treatment (p = 0.012; r(2) = 0.400). At the mid-term assessment, 10 patients exhibited a significant partial recovery of the hVOR gain. Conclusions: The delayed effect of intratympanic gentamicin and the subsequent gain restoration are factors that may influence the patients' outcome. The feasibility of the vHIT system makes it a useful tool to monitorize the VOR changes.