Glycerol affects vestibular evoked myogenic potentials andon the pure tone hearing in meniere's disease

GLYCEROL AFFECTS VESTIBULAR EVOKED MYOGENIC POTENTIALS ANDON THE PURE TONE HEARING IN MENIERE'S DISEASE Objective: To document changes in vestibular evoked myogenic potentials inpatients with Meniere's disease and normal volunteers before and after oral administration of glycerol. Design: Prospective and controlled clinical study. Settings: Baskent University Otorhinolaryngology Head and Surgery Department. Patients: Twenty-nine study group subjects, over 19 year-old were chosen amongpatients admitted to the clinic with complain of vertigo. Control group consisted of 10 healthy volunteers. Method: VEMP testing and the pure tone audiometry were performed before and 1, 2 and 3 hours following oral administration of 1 g/kg glycerol. Meniere's diseasegroup was compared with control group. Results: Mean of the latences and amplitudes in 20 normal subjects wasdetermined. On the basis of this value, 9 patients (31%) revealed unilateralabsence of VEMP. The results also yielded prolonged p13 latency in 5 patients(17.2%) and prolonged n23 latency in 8 patients (27.5%), decreased amplitude in2 patients (6.8%) in Meniere's group. The VEMP results recovered in 5 patiens(17.2%), 2 of the prolonged p13 latency and 5 of the prolonged n23 latencyshowed increase of the latences after glycerol administration. The difference between study and control groups was statistically significant. 20 patients showedpositive results on the effected ear side in Meniere's disease group, after glycerol administration. Conclusion: Results of audiologic data of glycerol test show positive association with cochlear endolymphatic hidrops. Glycerol test and VEMPs are both usefuland support saccular hydrops. VEMP results of glycerol test have positive association with audiological outcomes of glycerol test. iv Key Words: Meniere's disease, Glycerol test, Vestibular evoked myogenicresponse