Electrocochleography: using extratympanic or transtympanic methods?

The advantages and disadvantages of the transtympanic and extratympanic methods for recording electrocochleographic potentials (ECochG) are discussed. Our extra-tympanic method (adapted from Coats) and some results are presented. We conclude that for broad clinical application an ear canal surface electrode is the method of choice for recording ECochG, unless the primary question is one of threshold measurement. If the registration of brainstem potentials from the vertex does not show a potential I, we recommend simultaneous recording of ECochG by an extratympanic method with earphones.