Amplitude and area ratios of summating potential/action potential (SP/AP) in Meniere's disease

Conclusions. Our results suggest that summating potential/action potential (SP/AP) area ratio may not necessarily have higher sensivity in the diagnosis of endolymphatic hydrops of Meniere's disease (MD) than SP/AP amplitude ratio in transtympanic electrocochleography (ECochG). Objective. Recent studies suggested that SP/AP area curve ratio was more sensitive to endolymphatic hydrops in comparison with SP/AP amplitude ratio in extratympanic ECochG. The purpose of the present study was to evaluate the utility of the SP/AP area curve ratio in transtympanic ECochG for the diagnosis of MD. Patients and methods. A retrospective chart review of 198 patients (209 ears) was conducted in cases of MD. Results. With regard to SP/AP amplitude ratio, 57.1% in definite cases of MD (group 1), 39.6% in probable cases of MD (group 2), and 50.0% in the cases who had transformed from probable MD to definite MD (group 3) showed abnormally high values, respectively. Abnormally high values were observed in 43.9%, 27.7%, and 30.0% in SP/AP area ratio in groups 1, 2, and 3, respectively, indicating that abnormal values were observed more frequently in the amplitude ratio than in the area ratio in all three groups.