ABSTRACT
BACKGROUND AND OBJECTIVES: The aim of this study was to analyze the summating potential (SP)/action potential (AP) ratio of electrocochleography (ECoG) recorded from the position of SP peak. We compared the SP/AP ratios of negative polarity and positive polarity graphs from the same ECoG of each patient by assuming different the position of SP peak. In addition, we attempted to evaluate the utility of two different manners of recording the ECoG graph in the diagnosis of Meniere's disease. SUBJECTS AND METHOD: Retrospectively, we analyzed the results of ECoG in 67 patients with unilateral definite Meniere's disease. ECoG was analyzed in two different manners. From the AP peak, the SP peak was determined close when positioned in the negative polarity; on the other hand, SP peak was considered distant when positioned in the positive polarity. The SP/AP ratio was interpreted with reference to the base line value. The ratio of two different ECoG values from each patient of Meniere's disease was calculated. RESULTS: In the abnormal side, the negative polarity ECoG showed significantly greater value of SP/AP ratio (mean: 0.334±0.10) than the positive polarity ECoG (mean: 0.283±0.09) (p<0.001). In the normal side, the negative polarity ECoG, showed significantly greater value of SP/AP ratio (mean: 0.250±0.09) than the positive polarity ECoG (mean: 0.204±0.06), as well as in the abnormal cases (p<0.001). CONCLUSION: The standard SP/AP ratio for the diagnosis of Meniere's disease can be variable according to the manner of determining the SP peak.