Electrophysiological-based Estimation of Cochlear Implant Fitting (ENPICME)

Estimation of Perceptual Levels Used in Cochlear Implant Fitting Based on Electrophysiological Measures

The primary objective of this research is to evaluate the relationships between multiple data from cochlear implant (CI) adult users to and to estimate predictive models of their fitting parameters. In a group of patients, the Electrically-evoked Compound Action Potentials (ECAP) will be collected intra-operatively and the correlation with demographic data (deafness duration, age deafness onset, etiology, duration of cochlear implant use of CI), auditory performances and subjective measures used for implant fitting (hearing threshold and most comfortable level) will be calculated. In a second group of experienced users (more than 9months of use of their CI), ECAP and Electrically-evoked Auditory Brainstem Response (EABR) will be collected after 9 months of CI experience and after 12 months or more of use. Correlation analyzes with demographic data, performance and fitting parameters will be performed as well. Statistical predictive models for both fitting at the activation or in experienced users should be developed according to the correlation analysis. The secondary objective is to evaluate the effects of simultaneous stimulation on hearing performances. Simultaneous stimulations will be delivered in one ear (bimodal condition) in patients using an Electro-Acoustic Stimulation device (EAS) or in the two ears (binaural condition) for bilateral CI users. ECAP, EABR and speech perception will be measured and compared in the different conditions.

All patients using cochlear implants included in the study will take electrophysiological and psychoacoustic tests to measure auditive parameters regarding the study objectives : ECAP, EABR, speech recognition and MCL.

Patients using EAS device for more than 11 months will take electrophysiological and psychoacoustic tests with the implant functioning only with electrical pulses or in bimodal mode to measure ECAP, EABR, speech recognition and MCL ; this will allow to perform bimodal comparison.

Patients with bilateral cochlear implant for more than 11 months will take electrophysiological and psychoacoustic tests to measure ECAP, EABR, speech recognition, and MCL. The binaural interaction component will also be measured ; this will allow to perform binaural comparison.

ECAP amplitude growth function (AGF) will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. ECAP thresholds (in current unit) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to ECAP AGF recorded in clinical routine/during control visit before these 11 months that includes intra-operative records when available. The ECAP threshold recorded with and without acoustic stimulations will be compared in patients using EAS devices.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. ECAP thresholds (in current unit) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. ECAP maximal amplitudes (in µV) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to ECAP AGF recorded in clinical routine/during control visit before these 11 months that includes intra-operative records when available. The ECAP amplitude recorded with and without acoustic stimulations will be compared in patients using EAS devices.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. ECAP maximal amplitudes (in µV) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. ECAP latencies (in µs) of the ECAP recorded with the highest stimulation level will be determine , compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to ECAP AGF recorded in clinical routine/during control visit before these 11 months that includes intra-operative records when available. The ECAP latencies recorded with and without acoustic stimulations will be compared in patients using EAS devices.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. ECAP latencies (in µs) of the ECAP recorded with the highest stimulation level will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. ECAP AGF slopes (µV/qu) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to ECAP AGF recorded in clinical routine/during control visit before these 11 months that includes intra-operative records when available. The ECAP AGF slopes recorded with and without acoustic stimulations will be compared in patients using EAS devices.

ECAP AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. ECAP AGF slopes (µV/qu) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. EABR wave V maximal amplitudes (µV) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to EABR AGF recorded in clinical routine/during control visit before these 11 months.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. EABR wave V maximal amplitudes (µV) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. EABR wave V latencies (ms) recorded with the highest stimulation level will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to EABR AGF recorded in clinical routine/during control visit before these 11 months.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. EABR wave V latencies (ms) recorded with the highest stimulation level will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. EABR wave V thresholds (current unit) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to EABR AGF recorded in clinical routine/during control visit before these 11 months.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. EABR wave V thresholds (current unit) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for more than 11 months. EABR wave V AGF slopes (µV/qu) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed. These records could also be compared to EABR AGF recorded in clinical routine/during control visit before these 11 months.

EABR AGF will be recorded on three cochlear sites (basal, medial, apical) in all patients using their implants for 9 months. EABR wave V AGF slopes (µV/qu) will be determined, compared according to the stimulation sites and correlation tests with the other measures will be performed.

In bilaterally implanted patients using both of their implants for more than 11 months, EABR BIC will be recorded with a reference electrode of either the older implant or the one associated with the best hearing performances and all the electrodes of the second implant. EABR BIC amplitude (µV) will be determined, compared according to the electrode pairing and correlation tests with the other measures will be performed.

The MCL (current unit) will be evaluated for each electrode/cochlear site tested during the same recording session than the ECAP threshold evaluated after 11 months. These subjective limits will be compared according to the stimulation sites and correlated to ECAP and/or EABR characteristics.

The MCL (current unit) will be evaluated for each electrode/cochlear site tested during the same recording session than the ECAP threshold evaluated at 9 months. These subjective limits will be compared according to the stimulation sites and correlated to ECAP and/or EABR characteristics.

The percentage of speech recognition will be measured at 60 decibels (dB) in open space with implant(s) well fitted during the same recording session than the ECAP threshold evaluated after 11 months. This performance level will be correlated to the ECAP and/or EABR characteristics. In the bimodal and binaural groups, performances will be compared between hearing conditions (monaural = 1 implant vs. bimodal or binaural hearing). During these audiometry tests, the recognition score will be also measured at 40 and 50 dB and a pure tone audiometry will be performed.

The percentage of speech recognition will be measured at 60 dB in open space with implant(s) well fitted during the same recording session than the ECAP threshold evaluated at 9 months. This performance level will be correlated to the ECAP and/or EABR characteristics. During these audiometry tests, the recognition score will be also measured at 40 and 50 dB and a pure tone audiometry will be performed.

Inclusion Criteria: Good general health status including no neuropsychological diseases affecting intellectual capacities Users of cochlear implant or electro-acoustic stimulation devices Normal otoscopy No excessive sound exposure within 48h before the measure Exclusion Criteria: For women, possibility of pregnancy (absence of effective contraception or confirmed menopause); Concomitant use of ototoxic or psychotropic treatment with anxiolytic and / or antipsychotic