Correlation of Electrocochleography SP/AP With Endolymphatic Hydrops in Unilateral Ménières Disease

OBJECTIVE: To determine the optimal cut-off value of the electrocochleography (ECochG) SP/AP ratio and evaluate its correlation with endolymphatic hydrops (EH) in patients with unilateral Ménière's disease (MD). STUDY DESIGN: Retrospective study. SETTING: Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University. METHODS: This retrospective study enrolled 162 patients with unilateral MD. EH was assessed using gadolinium-enhanced MRI, and ECochG was performed to measure the SP/AP ratio. The correlation between SP/AP and EH severity was analyzed. RESULTS: The mean pure-tone average (PTA) threshold was significantly higher in affected ears than in unaffected ears (51.0 ± 17.9 dB vs 21.4 ± 10.6 dB, P < .001). The ECochG SP/AP ratio was also elevated in affected ears (0.41 ± 0.17 vs 0.24 ± 0.12, P < .001) and showed significant correlations with cochlear (r = 0.483, P < .001) and vestibular EH (r = 0.476, P < .001). Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.79 for distinguishing affected ears, with an optimal SP/AP cut-off value of 0.305 (sensitivity = 83.33%, specificity = 72.22%). CONCLUSION: The ECochG SP/AP ratio demonstrates strong diagnostic utility for MD and correlates significantly with EH severity. A cut-off value of 0.305 provides a reliable objective marker for early MD diagnosis and EH assessment, particularly in settings where MRI is unavailable. ECochG serves as a valuable adjunctive tool for clinical decision-making in MD management.