Effect of cochlear implant processing, interaural place mismatch, and spread of excitation on interaural coherence of speech signals and its implications on binaural fusion

Binaural fusion - the ability to perceptually group signals presented to the two ears into a single auditory percept - can be challenging for some cochlear implant (CI) users. Binaural fusion relies, in part, on interaural coherence, or the statistical similarity of the signal across the two ears....

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Findings highlight that interaural place mismatch and CI processing strategy both degrade binaural coherence; however, specific fitting protocol changes require validation in larger clinical trials before practice change is warranted.

Understanding how CI signal processing disrupts binaural fusion may guide future fitting and electrode design strategies to improve hearing in noise for bilateral CI users.

1. 01CI signal processing, electrode place mismatch, and spread of excitation each independently reduce interaural coherence of speech.
2. 02Reduced interaural coherence is linked to poorer binaural fusion, affecting speech intelligibility in bilateral CI users.
3. 03Findings have implications for bilateral CI fitting strategies aimed at maximizing binaural benefit.
4. 04Study provides a mechanistic account of why bilateral CI users often struggle with spatial hearing tasks.
5. 05Results may inform electrode design and mapping approaches intended to reduce place mismatch.

PMID

42613684

DOI

10.1080/14670100.2026.2714656.

Journal

Cochlear Implants International

Publication type

research_article

Evidence level

2b

Population

Cochlear implant users with bilateral implants or bimodal fitting

Intervention

Analysis of CI signal processing, interaural place mismatch, and spread of excitation on interaural coherence