The use of electrocochleography (EcoG) is considered to be of clinical value in otological diagnosis. Non-invasive ear canal (EC) and tympanic membrane (TM) EcoG recording techniques, and invasive transtympanic (TT) technique are the methods used for objective assessment of cochlear function. In this study, eight adults (16 ears) with suspected
Meniere's disease were examined using a newly designed, disposable tympanic
electrode and a traditional, thin transtympanic needle. The amplitudes of the TT
electrode responses were 4-6-fold larger than those produced by the TM
electrode. The morphology of the waveforms for the two recording techniques was nearly identical. The mean amplitudes of the action potential (AP) obtained with the TM
electrode were 2.39-3.73 microV, and with the TT
electrode 14.08-19.60 microV, depending on the stimulus intensity. For the summating potential (SP), the TM and TT
electrodes had mean amplitudes of 0.82-1.60 microV and 3.53-5.81 microV respectively. The SP/AP ratios were larger with the TM
electrode than with the TT
electrode. They were inconsistent in four ears (25%) when measured with the TM and TT
electrodes. All patients were more satisfied with the TT examination, since it was quite painless, unlike the TM examination. The authors recommend the use of the TT recording technique as a painless examination in which the
electrode is close to the inner ear, allowing a good signal-to-noise ratio and large amplitudes. Diagnostic interpretations are easier and more reliable with the TT
electrode than with the TM
electrode.