Comparison in New Cochlear Implanted Subjects of a Tonotopy-based Bimodal Fitting With or Without Synchronization

Comparison in New Cochlear Implanted Subjects of a Tonotopy-based Bimodal Fitting With or Without Synchronization

Comparison of a Bimodal Fitting With Synchronization and a Conventional Bimodal Fitting in Newly Implanted Cochlear Patient. Prospective Monocentric Randomized Double-blind Crossover Study.

Main objective: For a bimodal fitting (hearing aid (HA) + cochlear implant (CI)): Comparison of a tonotopy based fitting strategy with synchronization between HA and CI (ABFS) to a tonotopy based fitting strategy without synchronization (ABFnoS) for the accuracy of sound localization. Secondary objectives: Comparison of ABFS to ABFnoS for the bias of sound localization. Comparison of ABFS to ABFnoS for speech perception in noise. Comparison of ABFS to ABFnoS for the auditory skills experienced by the subject.

Introduction: Cochlear implantation allows the rehabilitation of profound bilateral deafness, restoring speech perception and verbal communication when the traditional hearing aid no longer provides satisfactory hearing gain. A cochlear implant includes an electrode array and its functioning is based on the principle of cochlear tonotopy: Each electrode encodes a frequency spectrum according to its position in the cochlea (high frequencies are assigned to the basal electrodes and low frequencies to the apical electrodes). The cochlear implant thus breaks down the frequency spectrum into a number of frequency bands via bandpass filters corresponding to the number of electrodes in the implant. During the fitting these bands can be modified by the audiologist. MED-EL has developed a fitting strategy (ABF) that allows, from a post-operative scanner, to calculate the theoretical characteristic frequency of neurons stimulated by each electrode contact and to transmit this information to the fitting software of the CI. Bimodal hearing refers to the use of a CI in one ear with a HA on the contralateral side. This association allows for adults and children a better perception of speech in quiet and in noise, a better perception of music, hearing comfort, better sound quality, better localization of sound and, consequently, a better quality of life compared to unilateral CI alone. However, there is great variability in the integration process; while some bimodal users show substantial benefits, others receive little or no benefit. This variability could be due to different processing times between CI and contralateral HA. Recently, MED-EL (Austria) has developed a new approach to synchronize the treatment time of the CI with that of the contralateral HA via the fitting software. This new approach takes into account the different treatment times between CI and contralateral HA and allows synchronization between the 2 systems (CI and HA). This strategy (ABFS) could therefore allow a better integration of information in bimodal hearing and in particular improve the sound localization compare to a strategy without synchronization (ABFnoS). Main objective: For a bimodal fitting (hearing aid (HA) + cochlear implant (CI)): Comparison of a tonotopy based fitting strategy with synchronization between HA and CI (ABFS) to a tonotopy based fitting strategy without synchronization (ABFnoS) for the accuracy of sound localization. Secondary objectives: Comparison of ABFS to ABFnoS for the bias of sound localization. Comparison of ABFS to ABFnoS for speech perception in noise. Comparison of ABFS to ABFnoS for the auditory skills experienced by the subject. Plan of the study: It is a prospective open monocentric randomized crossover study: Measures will be done on the patient at 6 weeks and 12 weeks post-activation.

Two arms A and B: Arm A: Bimodal patient's fitting with tonotopy-based fitting without synchronization (ABFnoS) --> 6 weeks use --> tests and bimodal patient's fitting with tonotopy-based fitting with synchronization (ABFS) --> 6 weeks use --> tests; Arm B: Bimodal patient's fitting with ABFS --> 6 weeks use --> tests and bimodal patient's fitting with ABFnoS --> 6 weeks use --> tests

Cochlear implant with tonotopy-based fitting without synchronization with the contralateral hearing-aid then with synchronization with the contralateral hearing-aid

Cochlear implant with tonotopy-based fitting with synchronization with the contralateral hearing-aid then without synchronization with the contralateral hearing-aid

The accuracy of sound localization will be achieved with a sound localization test in the horizontal plane with 7 loudspeakers (HP) spaced 30° apart and arranged in a ½ circle from -90° to +90° at 1m around the patient.

The accuracy of sound localization will be achieved with a sound localization test in the horizontal plane with 7 loudspeakers (HP) spaced 30° apart and arranged in a ½ circle from -90° to +90° at 1m around the patient.

The bias of sound localization will be achieved with a sound localization test in the horizontal plane with 7 loudspeakers (HP) spaced 30° apart and arranged in a ½ circle from -90° to +90° at 1m around the patient.

The bias of sound localization will be achieved with a sound localization test in the horizontal plane with 7 loudspeakers (HP) spaced 30° apart and arranged in a ½ circle from -90° to +90° at 1m around the patient.

The speech recognition in noise is evaluated with the French-language VRB (vocale rapide dans le bruit) test [Leclerc et al., Eur Ann Otorhinolaryngol Head Neck Dis . 2018 Oct;135(5):315-319.]. It is a sentence test with target words. The speech level is at 65 dB sound pressure level (SPL) and the signal-to-noise ratio varies from 18 dB to -3 dB by 3 dB step.

The speech recognition in noise is evaluated with the French-language VRB (vocale rapide dans le bruit) test [Leclerc et al., Eur Ann Otorhinolaryngol Head Neck Dis . 2018 Oct;135(5):315-319.]. It is a sentence test with target words. The speech level is at 65 dB SPL and the signal-to-noise ratio varies from 18 dB to -3 dB by 3 dB step.

Auditory skills experienced by the patient are evaluated with the French version of the speech spatial qualities scale (SSQ) with of 49 questions describing various real-world auditory situations..

Auditory skills experienced by the patient are evaluated with the French version of the speech spatial qualities scale (SSQ) with of 49 questions describing various real-world auditory situations..

Inclusion Criteria: Adult patient (>= 18 years old) speaking French Patient who fulfils the criteria for cochlear implantation Total hearing loss for less than 5 years Exclusion Criteria: retro-cochlear pathology: auditory neuropathy, vestibular schwannoma patient with residual hearing < 70 dB hearing level (HL) at 250 Hz and 500 Hz and < 80 dB HL at 1000 Hz on the contralateral ear