Assessing the stage of Menieres disease using vestibular evoked myogenic potentials

Background: The staging of Menieres disease that was proposed by the American Academy of Otolaryngology-Head and Neck Surgery in 1995 was based on the arithmetic mean of the pure-tone thresholds at 0.5, 1.0, 2.0 and 3.0 kHz using the worst audiogram during the 6-month interval before treatment. The stages were classified as follows: stage I, a 4-tone average of less than 26 dB; stage 11, 26 to 40 dB; stage 111, 41 to 70 dB; and stage IV, more than 70 dB. Objective: Because the saccule, next to the cochlea, is the second most frequent site of hydrops formation, we wanted to find out whether vestibular evoked myogenic potential (VEMP) responses can reflect the stage of Menieres disease. Design: Prospective study. Setting: Tertiary university hospital. Patients: Forty patients (23 men and 17 women; mean +/- SD age, 43 12 years) with unilateral definite Menieres disease were enrolled in the study. Main Outcome Measures: The interaural amplitude difference (IAD) ratio, which was defined as the difference of the amplitudes of peak p13 to peak n23 (p13-n23) in the right (R) and left (L) ears divided by the sum of p13-n23 in both ears (R-L/R+L), was measured, and the stages of the disease were compared with the types of hearing loss, the percentage of unilateral weakness of caloric response, and the IAD ratio, respectively. Results: Six ears were classified as stage 1: the VEMPs were normal in 5 and augmented in 1, with a mean SD IAD ratio of -0.02 +/- 0.20. Twelve ears were classified as stage 11: the VEMPs were normal in 7, augmented in 2, depressed in 1, and absent in 2, with an IAD ratio of -0.12 +/- 0.39. Seventeen ears were classified as stage III: the VEMPs were normal in 10, depressed in 4, and absent in 3, with an IAD ratio of -0.30 +/- 0.30. Five ears were classified as stage IV: the VEMPs were normal in 2, depressed in 1, and absent in 2, with an IAD ratio of -0.54 +/- 0.43. A comparison of the IAD ratio and the stage of Menieres disease demonstrated a significant relationship (P<.05, 1-way analysis of variance test), whereas there was no significant relationship noted between the percentage of unilateral weakness of caloric response and the stage of disease. Conclusion: The IAD ratio of VEMPs correlates with the stage of Menieres disease and can be used as another aid to assess the stage of Menieres disease.