Cochlear Response Telemetry and Hearing Preservation

Study Overview
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Brief Summary
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The main purpose of this study is to monitor the response from the cochlea as the electrode is inserted during the 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 the future to help to improve the surgical technique and potentially help surgeons better preserve any natural hearing that is available. The measurements are obtained using the cochlear implant and sound processor while a sound is presented to the ear through an earphone (like an earplug) placed into the ear canal.

Official Title
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Association Between Intra-Operative Cochlear Response Telemetry and Hearing Preservation

Conditions
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Hearing Impairment, Sensorineural

Intervention / Treatment
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* Device: Cochlear implant


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Candidate for cochlear implantation (with CI522, CI532, CI622, CI632 or Hybrid-L24 (US only) 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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Cochlear implant recipients<br>Study group is comprised of cochlear implant patients already identified as candidates and undergoing surgery. | Device: Cochlear implant<br>* Study involves measuring using Electrocochleography to measure the CM response in patients undergoing cochlear implant surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Low-frequency Hearing Thresholds Assessed Audiometrically Pre- and Post-operatively. | Average low-frequency (LF) hearing thresholds (average thresholds at 500, 750, and 1000 Hz) will be measured for the implanted ear 4 to 6 weeks following surgery and compared with average LF hearing thresholds measured relative to the pre-operative baseline measured within 90 days of CI surgery. The outcome measure of interest is the change in average LF hearing thresholds pre- to postoperative for each subject. The average change observed for individual subjects will then be compared with individual electrophysiological cochlear microphonic (CM) measures made during the surgery using the Cochlear Response Telemetry System. Of specific interest is whether or not compromised CM measures relate to pre-to-postoperative changes in low-frequency hearing. In other words, are larger changes in average LF hearing thresholds observed in subjects with compromised CM measures made intraoperative versus those with uncompromised CM response? | Baseline measurement (pre-operatively) compared to 4 to 6 weeks post-surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Low-frequency Hearing Thresholds Assessed Audiometrically Pre- and Post-operatively. | Average low-frequency (LF) hearing thresholds (average thresholds at 500, 750, and 1000 Hz) will be measured for the implanted ear 3 months following cochlear implant activation and compared with average LF hearing thresholds measured preoperatively. The outcome measure of interest is the change in average LF hearing thresholds pre- to postoperative for each subject. The average change observed for individual subjects will then be compared with individual electrophysiological cochlear microphonic (CM) measures made during the surgery using the Cochlear Response Telemetry System. Of specific interest is whether or not compromised CM measures relate to pre-to-postoperative changes in low-frequency hearing. In other words, are larger changes in average LF hearing thresholds observed in subjects with compromised CM measures made intraoperative versus those with uncompromised CM response. | Baseline (pre-operative) compared to 3 months post cochlear implant activation | 
| Correlation of Preoperative High-frequency Hearing Thresholds and Cochlear Microphonic Response (Number of Electrodes Inserted When CM Detected). | The onset of the cochlear microphonic (CM) response will be measured intraoperative to determine if there is a relationship between the onset of the CM response during electrode insertion and the preoperative high-frequency acoustic hearing thresholds. The onset of the CM response will be tracked by impedance measures that are interleaved with the CM recordings. As each electrode in the array enters the perilymph in the cochlea there will be a measured reduction in impedance. CM onset will be defined in terms of the nth electrode (out of the 22 electrodes) to enter the cochlea. Preoperative high-frequency hearing will be defined as the average of preoperative thresholds at frequencies of 2 kHz, 3 kHz and 4 kHz for each individual subject. | Intraoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cochlear implantation, electrocochleography