Evaluation of an integrated electrocochleography function for the monitoring of residual hearing

A cochlear implant (CI) is a neural prosthesis that can restore hearing
function in the profoundly deaf. Preserving residual hearing in the implanted
ear is desirable to maximize auditory functions. During surgery, the implant
must be inserted carefully to spare the residual hearing. To this purpose, we
propose to monitor the auditory response of the inner ear intraoperatively via
electrocochleography (ECoG).

This is an exploratory validation study in a small group of subjects receiving
a CI to verify if ECoG measurements with AB*s novel ECoG system are useful as
an intra-operative tool for soft surgical techniques to spare residual hearing.
This trial may serve as a startup study to establish a standard clinical
practice during CI surgery.

Postoperative ECoG recordings and standard audiometric recordings will be
obtained to assess the stability of residual hearing postoperatively to
validate that intraoperative ECoG is a valid predictor of postoperative
residual hearing function.

Secondarily, benchmark comparisons for ECoG and eCAP recordings can be
performed between standard clinical equipment (BERA machine) and the AB device.

This is an unmasked, exploratory, descriptive-observational validation study
with a longitudinal component in a relatively small group of subjects.

There is minimal burden and negligible risk to subjects. All subjects are
adults and scheduled for standard CI implantation. The audiometry data
collected is also largely standard clinical practice. The longitudinal ECoG
recordings will be confined to during regular clinical visits and will add
approximately 15 minutes to the normal visit. The risks of the ECoG recordings
are negligible post-operatively. During surgery, the ECoG machine needs to be
brought into the OR (but will be kept away from the patient, alongside the
normal clinically used eCAP equipment). An additional electrode needs to be
placed in vicinity of the inner ear, i.e., in the operating area.
Intraoperatively, a mere ~15 minutes of recording will be added to a 4-hour
surgery. The added risk is considered negligible. Importantly, extra care will
be taken to spare residual hearing in the implanted ear, which can promote
beneficial outcomes postoperatively in terms of residual hearing function for
the individual patient.