Effect of Glycerol Administration on ECochG and VEMP Findings in Individual with Meniere's Disease

The present study aimed to find the effect of glycerol administration on Electrocochleography (ECochG), cervical and ocular Vestibular Evoked Myogenic Potential (c-VEMP, o-VEMP) findings in individual with Meniere's disease. Sixteen participants (32 ears) diagnosed with Meniere's disease underwent ECochG, c-VEMP and o-VEMP for both pre and 1 h post-glycerol administration. Paired t-test indicated that the SP/AP ratio of ECochG measures was significantly improved with post-glycerol administration. There was no significant difference in the mean amplitude of o-VEMP and c-VEMP between pre and post-glycerol administration. However, while individual differences were compared, 75% of the participants reported either improvement in c-VEMP amplitude or newly emerging c-VEMP& o-VEMP. Based on the recommendation by Adams et al. (Otolaryngol Clin North Am 43(5):995-1009, 2010), the improvement on these tests results with post glycerol administration were considered as a significant indicator for the presence of Meniere's disease.With post glycerol administration, the present study found that 84%of participants were found to have an improvement in the amplitude for ECochG measures. There was an improvement in the amplitude measures of o-VEMP and c-VEMP, which were observed in 75% and 68%of participants respectively with post-glycerol administration. Improvement in the amplitude of test measures with post-glycerol administration were observed to be more for cochlear potentials of ECochG followed by vestibular potentials of c-VEMP and o-VEMP. Thus, improvement of ECochG amplitude with post-glycerol administration might serve as an additional indicator for the presence of Meniere's disease.