Impact of Microphone Positioning on Auditory Performance in Cochlear Implant Users

Study Overview
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Brief Summary
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The construction of our auditory space requires several prerequisites, including localization abilities in 3D (azimuth, elevation and distance). These abilities rely on the proper development and functionality of the auditory system to extract various acoustic cues from our environment. Extraction and analysis of these auditory cues are based on the synchronous use of ears, called binaurality. Other natural behaviours are useful to precisely determine the location of a sound source: visual information and head movements. The slightest anatomical-functional change (e.g. unilateral hearing loss, malformation of the pinna) can disturb spatial hearing abilities. Many patients with hearing loss are fitted with a hearing aid (HA) or a cochlear implant (CI) to ensure the best speech understanding. However, this auditory rehabilitation remains insufficient to restore a good perception of spatial hearing. One of the key point to improve sound localization seems to be microphone positioning on hearing aids. Several questions remain on the optimal microphone positioning.

Official Title
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Impact of Microphone Positioning on Auditory Performance in Cochlear Implant Users

Conditions
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Cochlear Prosthesis Implantation

Intervention / Treatment
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* Device: Modification of active microphone positioning
* Behavioral: SPHERE protocol
* Behavioral: French Matrix Test
* Behavioral: Quality of life questionnaire
* Behavioral: Likert scale


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18 to 75 inclusive Regular follow-up in the Ear Nose and Throat department of the Edouard Herriot hospital in Lyon Post-lingual deafness Fitted with two Advanced Bionics (AB) cochlear implants (Naïda Q70 or Naïda Q90 processor) Or fitted with one AB cochlear implant and a contralateral hearing aid Fitted with the latest implant for more than 1 year Normal or corrected vision Able to understand experimental instructions Affiliated with a social security scheme Exclusion Criteria: Oculomotor disorder Bilateral vestibular areflexia Adult subject to a legal protection measure (guardianship, curatorship)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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 |
| --- | --- |
| Experimental: Implanted patients<br>All the participants are patients with post-lingual deafness and fitted with cochlear implants | Device: Modification of active microphone positioning<br>* Patient will pass the experimental tests described above with 3 different active microphone positions : on the cochlear implant processor; on the antenna in front of the external ear canal Patient will pass the tests 1 week after each microphone position change, so that they can get used to the new position in their everyday life.<br>Behavioral: SPHERE protocol<br>* Patient's 3D localization in noise will be assessed thnks to a 3D localization system called SPHERE based on virtual reality. Data from spatial hearing perception will be recorded in three-dimensional space (azimuth, elevation, and depth). First, the pointing error will be computed separately for azimuth, elevation, and depth, in terms of constant error (absolute and signed) and variable error. Then, these separate errors will be combined into a cumulative error 3d-D (the 3d-D value), hence summarizing all three space dimensions, and taking into account absolute and variable error in one measure.<br>Behavioral: French Matrix Test<br>* This test assesses the intelligibility threshold defined as the noise level (in decibels) for which the subject can repeat 50% of the words heard (in dichotic listening), resulting in an Speech Recognition Threshold (SRT) value<br>Behavioral: Quality of life questionnaire<br>* The Speech, Spatial and Qualities of Hearing Scale short-form with 15 items (SSQ15) questionnaire is performed in order to evaluate auditory abilities of patients in different daily life situations.<br>Behavioral: Likert scale<br>* This subjective evaluation will be added to evaluate difficulties and self-confidence felt by participants during the SPHERE protocol and the French Matrix Test.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in 3d-D value at day 7 | We will compare 3d-D values obtained with baseline microphone position (at day 0) and 1 week after the first microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in SRT values and SSQ15 scores, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 7 | 
| Change from baseline in 3d-D value at day 14 | We will compare 3d-D values obtained with baseline microphone position (at day 0) and 1 week after the second microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in SRT values and SSQ15 scores, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 14 | 
| Change from baseline in SRT value at day 7 | We will compare SRT values obtained with baseline microphone position (at day 0) and 1 week after the first microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in 3d-D values and SSQ15 scores, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 7 | 
| Change from baseline in SRT value at day 14 | We will compare SRT values obtained with baseline microphone position (at day 0) and 1 week after the second microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in 3d-D values and SSQ15 scores, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 14 | 
| Change from baseline in SSQ15 score at day 7 | We will compare SSQ15 scores obtained with baseline microphone position (at day 0) and 1 week after the first microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in 3d-D values and SRT values, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 7 | 
| Change from baseline in SSQ15 score at day 14 | We will compare SSQ15 scores obtained with baseline microphone position (at day 0) and 1 week after the second microphone positioning change. Baseline microphone position is defined as the usual position at inclusion and might vary from one patient to another. Combined with change in 3d-D values and SRT values, these results will allow us to assess the effect of microphones positioning on spatial auditory performance. | Baseline and day 14 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cochlear implants users, microphone, virtual reality, spatial hearing perception