Abstract
Auditory nerve action potentials (APs) were recorded by four kinds of electrodes from the external ear canals of 91 ears. Silver small ball electrodes made by 200μ enamelled silver wire, were fixed by narrow adhesive tape on the external canals. On 41 ears, clear APs were recorded on 36 ears, on 15 ears recording was not succeeded by failure of fixation of the electrode on ear canals. Silver foil electrodes were made by a 5mm×10mm rectoangular silver foil solderd on the top of silver wire, also fixed on ear canal. This electrode technique was very easy and pain-less procedure. Tube electrode made by pen-shaped soft rubber or silicon tube, was fitted the ear canals of patients. On the top of pen-shaped tube a small silver ball electrodes or looped silver wire was placed as a inducing electrode. Eartip electrodes were made by hearing aid-tips. Silver wire was bended over an umbrella of eartip. The fixation of the tube and eartip electrodes was easier than the other procedure. Clear APs were recorded by four kind of electrodes. Those extratympanic procedure was very usefull for the recording of APs as an office procedure. This extratympanic procedure was also applicable as a training technique of the recordings of APs and ECochG for beginners or non-otologist doctors.
