Effects of Head Movements on Sound-Source Localization in Single-Sided Deaf Patients With Their Cochlear Implant On...

Area of Science:

• Auditory Neuroscience
• Audiology
• Biomedical Engineering

Background:

• Single-sided deafness (SSD) presents challenges in sound localization.
• Cochlear implants (CIs) aim to restore hearing but spatial perception can be complex.
• Understanding how SSD-CI listeners use head movements for localization is crucial for rehabilitation.

Purpose of the Study:

• To assess the sound source localization abilities of SSD-CI listeners.
• To investigate the impact of head rotations on localization performance.
• To explore the role of monaural spectral cues in front-back localization.

Main Methods:

• Tested SSD-CI patients with CI on and off, alongside normal-hearing (NH) listeners (unilaterally plugged and non-plugged).
• Presented band-pass filtered Gaussian noises (2-8 kHz) from loudspeakers surrounding the listeners.
• Evaluated localization with stationary heads and during voluntary head rotations.

Main Results:

• SSD-CI listeners and unilaterally-plugged NH listeners performed near chance for front-back localization with stationary heads.
• Head rotations improved both front-back and left-right localization for all participants.
• CI activation combined with head turns led to near-perfect front-back localization in SSD-CI patients.

Conclusions:

• Head movements are essential for SSD-CI listeners to overcome limitations in stationary sound localization.
• The non-implanted ear significantly contributes to localization improvements with head turns.
• SSD-CI listeners effectively utilize monaural level cues and head shadowing during rotations to enhance spatial awareness.