Extra-tympanic electrocochleography in a normal population. A descriptive study

Extra-tympanic electrocochleography is an electrophysiological register obtained after stimulating the cochlea with an audible stimulus. This stimulus is applied using an earphone over the external auditory canal, while the electrical activity is registered by surface electrodes. There are few studies that analyse normal electrocochleography in our environment. Thus, the main objective of our study was to regularize the values obtained with electrocochleography in ears without any otoneurological diseases. We explain in detail the process of obtaining the register.

Sixty healthy ears were studied by extratympanic electrocochleography. Statistical results were analysed. While 30 ears were studied with a stimulus at 90dB, another 30 ears were studied with a stimulus at 80dB.

Summating potential and action potential latencies and amplitudes were measured. Summating potential/action potential ratios were calculated. Wave I and wave II latencies were also determined. These results were analysed in function of stimulus intensity, patient gender, patient age group and ear side studied.

This study collected extra-tympanic electrocochleography data in a normal population and the results were in the range of other international studies obtained in other countries. These data can be used as a reference to evaluate illnesses that affect cochlear structure or functions.