Ups and Downs in 75 Years of Electrocochleography

Abstract

Before 1964, electrocochleography (ECochG) was a surgical procedure carried out in the operating theatre. Currently, the newest application is also an intra-operative one, often carried out in conjunction with cochlear implant surgery. Starting in 1967, the recording methods became either minimal- or not-invasive, i.e., trans-tympanic (TT) or extra tympanic (ET), and included extensive studies of the arguments pro and con. I will review several valuable applications of ECochG, from a historical point of view, but covering all 75 years if applicable. The main topics will be: (1) comparing human and animal cochlear electrophysiology; (2) the use in objective audiometry involving tone pip stimulation—currently mostly pre cochlear implantation but otherwise replaced by auditory brainstem response (ABR) recordings; (3) attempts to diagnose Ménière’s disease and the role of the summating potential (SP); (4) early use in diagnosing vestibular schwannomas—now taken over by ABR screening and MRI confirmation; (5) relating human electrophysiology to the effects of genes as in auditory neuropathy; and (6) intracochlear recording using the cochlear implant electrodes. The last two applications are the most recently added ones. The “historical aspects” of this review article will highlight the founding years prior to 1980 when relevant. A survey of articles on Pubmed shows several ups and downs in the clinical interest as reflected in the publication counts over the last 75 years.

Electrocochleography in Cochlear Implant Users with Residual Acoustic Hearing: A Systematic Review

“…For CI users with residual acoustic hearing, responses from the cochlea to acoustic stimuli can be recorded using the electrocochleography (ECoG) technique. Electrocochleography (ECoG) is a technique which has been used for decades to record responses from the cochlear hair cells and the auditory nerve [ 8 ]. The recording obtained using ECoG is a composite response that includes contributions from hair cells (i.e., the cochlear microphonic (CM), summating potential (SP)) and the auditory nerve (i.e., the compound action potential (CAP), auditory nerve neurophonic (ANN)).…”

“…The ECoG has been used in clinical settings to support the diagnosis and assessment of Meniere’s disease, to enhance the wave I of the auditory brainstem response (ABR), to assist with the diagnosis of auditory neuropathy spectrum disorders (ANSD), and to monitor cochlear and auditory nerve function during surgery [ 14 , 15 , 16 ]. Over the last 30 years, ECoG has been applied as an excellent tool for the diagnosis of patients with Meniere’s disease/endolympathic hydrops [ 8 , 17 ]. ECoG recordings from patients with Meniere’s disease are characterized by an enlarged SP and SP/Action potential (AP) ratio compared to normal hearing ears due to an increase in endolymphatic volume that creates mechanical biasing of vibration of the organ of Corti and amplifies the SP [ 14 , 15 ].…”

“…ECoG recordings from patients with Meniere’s disease are characterized by an enlarged SP and SP/Action potential (AP) ratio compared to normal hearing ears due to an increase in endolymphatic volume that creates mechanical biasing of vibration of the organ of Corti and amplifies the SP [ 14 , 15 ]. An interest in ECoG as a diagnostic tool has increased again since 2010 due to current attention on potential usefulness of ECoG in CI users with preserved hearing for intraoperative and postoperative monitoring purposes [ 8 ].…”

Techniques for Obtaining High-quality Recordings in Electrocochleography

“…Electrocochleography (ECochG) involves the measurement of stimulus-evoked potentials generated by cochlear hair cells and auditory nerve fibers (Eggermont, 2017). These potentials include cochlear responses to the onset and the steady-state portions of an acoustic stimulus.…”

Comparing the sensitivity and specificity of cervical vestibular-evoked myogenic potentials and electrocochleography in the diagnosis of Ménière’s disease

“…It is thought that elevation of SP amplitude compared with AP amplitude may be a positive indicator of EHs in patients with suspected MD. For details on the history of ECochG, see Eggermont (2017).…”