By Eliana Mtanios Khalil, student of the Master in Clinical Audiology and Hearing Therapy

Abstract

This review synthesizes evidence on the sound processing strategies used by the three dominant cochlear implant (CI) manufacturers, Cochlear’s ACE, MED-EL’s FS4, and Advanced Bionics’ HiRes/Optima, focusing on their technical underpinnings and clinical outcomes in speech, music, and noise. A targeted narrative review was conducted using PubMed, Scopus, and Web of Science (2010–2025). Eligible studies included clinical trials, crossover studies, large prospective cohorts, and multicenter registries comparing CI coding strategies. Extracted data were organized and thematically analyzed for speech-in-noise, music/pitch, and long-term outcomes. ACE strategies produce robust and consistent outcomes across patient groups but offer limited fine-structure detail. FS4 coding improves low-frequency pitch and melodic perception but shows inconsistent benefits for speech-in-noise. HiRes/Optima strategies provide expanded spectral detail through current steering, but advantages in everyday noise are variable and may involve battery trade-offs. Importantly, patient- and surgery-related factors (age at implantation, duration of deafness, electrode placement) explain more outcome variation than brand-specific coding strategies. No coding strategy is universally superior. Clinical selection should align device-specific strengths with patient needs and auditory profiles. Future research should focus on hybrid coding strategies, advanced machine-learning scene analysis, and multicenter standardization of speech-in-noise testing.

Keywords: Comparative analysis, Sound-processing strategies, Cochlear implants, Signal processing, Auditory rehabilitation.

Download the full Research Work: Khalil, E. M. (2026). Comparative Sound-Processing Strategies in Cochlear Implants: Cochlear (ACE), MED-EL (FS4), and Advanced Bionics (HiRes/Optima). SAERA