Electroaudiometry is a method of determining if the cochlear nerve is working. It is a subjective test method, similar to audiometry itself. (Liard et al, 1988)
The stimulating electrode is placed in the external ear canal prefilled with saline. The patient determines the electrical current that causes a sensation of hearing. This technique is generally proposed as being less painful for potential cochlear implant users than promentory electrodes. (Takanami et al, 2009; Spies et al, 1993). A potential drawback is that it may produce a "vibrotactile" type response -- in other words, people can feel the shock in their ear.
A variant is to use the electrical current to detect a brainstem potential (Gaddam et al, 2008; Knaus, C., et al. 2000; Hartman et al, 1994). This is of course technically more challenging due to artifact.
This technique also may be useful in the future to help select patients for hair cell regeneration treatment. One would not want a patient whose auditory nerve was not working.