Effect of glycerol test on audiovestibular tests in patients with Meniere’s disease

Abstract This stud to explore the effect of glycerol on audiovestibular tests in patients with Meniere’s disease (MD) and to reflect different pathologic states of endolymphatic hydrops (EH) in the inner ear and compare the results of glycerol on these results. Subjects Thirty patients and 15 normal volunteers. Methods Each subject of this study underwent pure tone audiometry testing, evoked vestibular evoked myogenic potential (VEMP) and Vidionystagmography (VNG) before G1 and 2 h after glycerol G2 administration (1.3 g/kg). Results Affected ears were 32 and unaffected ears were 28. The affected ears had higher hearing and SRT thresholds when compared to the unaffected ears and control group. VEMPs of the affected ears were normal in six ears (18.75%), absent in four ears (12.5%) and augmented amplitude in 22 (68.75%), their VNG results showed peripheral vestibular disorder. After oral administration of glycerol, the previous test battery was repeated and it’s result on PTA showed that 53.13% (17/32) of affected ears had positive glycerol test mainly in stage II and III. Ten of the 32 affected ears (31.26%) showed improvement of VEMPs after glycerol administration. Also, two (7.8%) of the unaffected ears showed positive glycerol. Latency of the VEMP had no significant changes after glycerol administration and there was no statistical correlation between the results of G-PTA and G-VEMP. There was statistical significant improvement of the slow peak velocity of caloric test in patient’s affected ears and insignificant improvement in control group and in unaffected ears after glycerol administration.