INCIDENCE OF ENDOLYMPHATIC HYDROPS IN ASYMPTOMATIC EARS OF UNILATERAL MENIERE PATIENTS
GATA KBB, KBB Anabilim Dalı, Ankara, Türkiye Objective: Although Meniere's disease usually affects one ear at the beginning, incidence of bilateral involvement increase after 5 year-follow-up. The aim of our study is to investigate the incidence of endolymphatic hydrops in the asymptomatic contralateral ears of the patients with unilateral Meniere's disease.Materials and methods:The study included 55 patients with definite Meniere's disease considering the criteria recommended by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head&Neck Surgery (1995), another group of asymptomatic 25 ears with unilateral Meniere's disease, a group of 10 patients with non- Meniere-cochlear hearing loss and 15 healthy volunteers with no balance and hearing disorders. The parameter investigated in diagnosis of endolymphatic hydrops and bilateral involvement is the summation potential (SP) / action potential (AP) amplitude ratio obtained through tympanic membrane electrocochleography (TM ECoG). Upper limit of SP/AP ratio based on the control group data was 0,32 (0,20 (mean) ± 2 X 0.06 (standard deviation)=0,32).
Results:Mean SP/AP ratio was 0,35±0,15 in the definite Meniere group (in comparison with control group p=0,001), 0,29±0,12 in asymptomatic ears (in comparison with symptomatic ears of unilateral Meniere's disease p>0,05, control group p=0,011), 0,27±0,10 in cochlear hearing loss group (in comparison with control group p=0,03). Abnormal SP/AP ratio was obtained in % 58,2 of Meniere patients, %44 in asymptomatic ears and %28,6 of cochlear hearing loss patients.
Conclusion: Even though there is a possibility of abnormal SP/AP ratio in non-Meniere-cochlear hearing loss group which might decrease the specificity of the test, diagnosing an increased SP/AP ratio in the asymptomatic ear of Meniere patients might be a sign of bilateral involvement. Long-term follow-up can highlight bilaterality of the disease for these patients.
Keywords : Electrocochleography, endolymphatic hydrops, vertigo, hearing loss