Towards quantifying cochlear implant localization performance in complex acoustic environments.

Area of Science:

• Audiology
• Neuroscience
• Speech and Hearing Science

Background:

• Cochlear implant (CI) users often report challenges in noisy environments.
• Binaural hearing is crucial for speech understanding in noise for normal-hearing individuals.
• Quantifying binaural hearing in CI users with multiple sound sources is underexplored.

Purpose of the Study:

• To measure the horizontal sound localization ability of a bilateral CI user.
• To compare the CI user's localization performance with normal-hearing listeners.
• To assess localization in quiet and in diffuse background noise.

Main Methods:

• A pointing task was employed to assess horizontal sound localization.
• Localization was tested in quiet and with a continuous diffuse noise interferer at 0 dB SNR.
• Performance was evaluated for one bilateral CI user and six normal-hearing listeners.

Main Results:

• Normal-hearing listeners showed a small increase in localization error (1.8°) in noise.
• The bilateral CI user exhibited a large localization error (22° in quiet, 31° in noise).
• Target sounds were inaudible for the CI user at frontal locations (-20° to +20°) in noise.

Conclusions:

• Bilateral CI users face substantial sound localization deficits compared to normal-hearing individuals.
• Background noise significantly exacerbates localization difficulties for CI users.
• Findings support CI user complaints and can inform the development of noise reduction algorithms for implant processors.