Impact of Microphone Positioning on Auditory Performance in Cochlear Implant Users

Summary

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.

Conditions

• Cochlear Prosthesis Implantation

Interventions

DEVICE

Modification of active microphone positioning

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.

BEHAVIORAL

SPHERE protocol

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.

BEHAVIORAL

French Matrix Test

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

BEHAVIORAL

Quality of life questionnaire

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.

BEHAVIORAL

Likert scale

This subjective evaluation will be added to evaluate difficulties and self-confidence felt by participants during the SPHERE protocol and the French Matrix Test.

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Principal Investigators

• Eric TRUY, Professor · Hospices Civils de Lyon

Study Design

Allocation

NA

Purpose

OTHER

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2022-12-01

Primary Completion

2023-06-01

Completion

2023-06-01

Countries

• France

Study Locations