All Research Projects

Association between Intra-Operative Cochlear Response Telemetry and Hearing Preservation (CREST)

CLTD 5667


This research project is testing an experimental system for monitoring the cochlea during cochlear implant surgery. The type of monitoring is called electrocochleography, and the equipment used for the measurement is currently named Cochlear Response Telemetry.

This study will monitor the response from your cochlea as the electrode is inserted during your operation to receive a cochlear implant. The Cochlear Response Telemetry tool aims to measure the response from the cells within the cochlea and may be useful in future to help to improve the surgical technique and potentially assist surgeons to better preserve any natural hearing that is available. The measurements obtained using the cochlear implant while a sound is presented to your ear through an earphone (like an earplug) which is placed into your ear canal.

Cochlear Response Telemetry is an experimental tool. This means that it is not an approved device for clinical monitoring of the cochlea in Australia. However similar types of measurements have been used in a number of clinics worldwide and without any reported adverse effects.

This research is being conducted by Cochlear Limited and sponsored in Australia by that company.

Up to 125 people will participate in this project in up to 12 cochlear implant clinics worldwide.


What is involved? 

This protocol includes a pre-operative visit to establish audiometric  measures, an ECoG measurement during the operation, and again at one of two follow up visits within 3 months post implantation.



Inclusion Criteria

  • Candidate for first cochlear implantation (with CI522, CI532 or Hybrid-L24 according to local indications
  • 18 years of age or older at the time of enrolment
  • Pre-operative audiometric threshold in the implanted ear at 500 Hz of better than or equal to 80 dB HL
  • Willingness to participate in and to comply with all requirements of the protocol


 Exclusion Criteria

  • Prior cochlear implantation in the ear to be implanted
  • Ossification or any other cochlear anomaly that might prevent complete insertion of the electrode array
  • Abnormal cochlear/nerve anatomy on pre-operative CT or MRI imaging (excluding a mild Mondini malformation or Large Vestibular Aqueduct Syndrome)
  • Deafness due to lesions of the acoustic nerve or central auditory pathway
  • Diagnosis of auditory neuropathy
  • Active middle-ear infection
  • Additional handicaps that would prevent participation in evaluations
  • Unrealistic expectations on the part of the subject, regarding the possible benefits, risks and limitations that are inherent to the procedure and investigational device


For more Information on this study or to express interest in participating in this study, please feel free to contact