S233 – Diagnostic Role of Electrocochleography after Glycerol Test

Abstract

Objectives Response to dehydrating agents such as glycerol in Meniere's disease is evaluated by audiometric shifts after substance administration. Since the major pathogenic event in this disease is endolymphatic hydrops, evidenced by elevated SP/AP ratio, this study was conducted to determine the value of electrochochleography in assessment of response to glycerol administration in patients with definite Meniere's disease. Methods Between October 2006 and December 2007, 12 women and 10 men with definite Meniere's disease, based on AAO-HNS guidelines during acute phase, were included in this study. Pure tone audiometry (before and 1,2,3 hours after glycerol administration) and extratympanic electrocochleography (before and 3 hours after test) were performed; improvement in tinnitus, aural fullness, and vertigo symptoms were recorded after glycerol administration. Chi-square test was used to compare the sensitivity of electrocochleography and pure tone audiometry for detection of response to glycerol test. Results 22 patients, mean age of 40.18±8.8 years, were included in this study. Of 16 patients with tinnitus complaint, 9 patients reported significant improvement after glycerol test. Of 22 patients with vertigo and aural fullness symptoms, 19 reported significant clinical improvement. The SP/AP ratio was significantly reduced and reached to less than 80% of pretest values in 17 of these patients, but improvement in pure tone thresholds was observed in 8 patients. The difference between 2 methods was significant (p<0.05). Conclusions It seems that significant reduction in SP/AP ratio in patients with Meniere's disease might be a more sensitive indicator of the response to glycerol test than pure tone threshold shifts.