Teaching the ECochG New Tricks

By Bre Myers

This article is a part of the July/August 2021, Volume 33, Number 4, Audiology Today issue.

Electrocochleography (ECochG) has been used in clinical practices since the 1960s. Historically, it has been touted as helpful in the identification of Meniere’s disease (MD). However, differences in recording strategies significantly reduce its efficiency in this endeavor (Ho Oh et al, 2014). Moreover, consensus guidelines put forth by Lopez-Escamez et al (2015) use a set of specific symptomatic findings to classify MD as either definite or probable, leaving ECochG results out of the diagnostic picture. 

As our understanding and access to new tests of the  vestibular system grow, is there still a need to keep ECochGs in our toolbox? Perhaps, but we may need to repurpose the ECochG. Auditory neuropathy spectrum disorder (ANSD), compared to MD, is a fairly “young,” less familiar disorder. The ability of the ECochG to enhance the cochlear microphonic of the auditory brainstem response may be the right tool for the job when it comes to ANSD’s clinical diagnosis.

Historical Uses of ECochGs

You know the saying, “It’s hard to teach an old dog new tricks,” but that just may be what needs to happen to transition ECochG out of the vestibular toolbox and into the auditory one. Historically, ECochGs have been used in the hopes of identifying MD. The rationale for this assumption is derived from the suspected increased levels of endolymph in the MD-affected ear. This elevated level produces a larger-than-typical summating potential (SP), which may be visible in an ECochG recording (FIGURE 1).