Electrocochleography in Cochlear Implant Patients

Electrocochleography measures the function of the hair cells and the peripheral auditory nerve. It’s role has been intensively discussed during new applications in cochlear implant patients. The EcochG is used mainly for two applications

1) Preoperative check of inner ear functions and function of auditory nerve
2) Intraoperative use for cochlear monitoring

Ad 1)
Patients with severe to profound sensorineural hearing loss are candidates for cochlear implants. The main prerequisite is besides a present cochlear a function of the auditory nerve. Electrocochleography has a different shape together with the recording of optoacoustic emissions and auditory brainstem responses between pure damage of the outer hair cells, the perisynaptic complex, transition of inner hair cells and the synapse and dendrites and the auditory nerve in terms of lesion. Perisynaptic audiopathy can be treated with cochlear implants. True auditory neuropathy is a contraindication

Ad 2)
An increasing number of patients with residual hearing is undergoing cochlear implantation. Hearing preservation is crucial in order to use the acoustic hearing postimplantation. Monitoring of cochlear function using electrocochleography with recording of cochlear microphonics is the new promising tool to improve the hearing preservation wave. It helps to modify the surgical insertion process.

For both applications patient data will be presented and the results in terms of cochlear implantation are discussed.

Overall electrocochleography is a very useful and not to neglected diagnostic and monitoring tool in cochlear implantation.