Amplitude Effects on Electrocochleography Outcomes

OBJECTIVE: Electrocochleography measures in humans were examined to determine factors affecting results. STUDY DESIGN: Retrospective study. METHODS: Analysis was performed on data from 479 patients seen from 1998 to 2002 who underwent electrocochleography with a tympanic membrane electrode. Measures from click evoked electrocochleography (the summating potential to action potential ratio [SP/AP]) were compared with tone evoked electrocochleography (the SP amplitude). RESULTS: Findings indicate a strong correlation between click and tone measures if the AP from click measures was over 1 microV (P <.001), but no significant correlation between these measures if the AP was under 1 microV. Results were also analyzed with respect to patient hearing sensitivity and final diagnosis. CONCLUSION: Tympanic membrane electrocochleography is more efficacious when the AP from click stimulation is over 1 microV.