Longterm Outcome of Electric-Acoustic Stimulation with Nucleus Hybrid-L24

Introduction Cochlear implants (CIs) have been highly successful in restoring speech understanding not only in deaf individuals but also in patients with residual hearing at low frequencies by combination of electric and acoustic stimulation (EAS) in the same ear. Additional acoustic stimulation improves speech intelligibility, especially in difficult situations like noisy environments. However, progressing hearing loss might lead to a reduction of the EAS benefits and the patients might switch to electric only stimulation after some time. In the presented study, the long term outcome regarding air conduction pure tone thresholds and speech intelligibility in quiet and noise was evaluated. Patients: 115 Nucleus Hybrid L-24 implants in 102 patients implanted at MHH between 2005 and 2017. These patients continued to visit the implanting center yearly for the CI aftercare.

Methods Retrospective analysis of EAS usage, air conduction thresholds and speech intelligibility in sound field with Freiburg monosyllable test in quiet and HSM Sentence Test at 10 dB SNR in S₀N₀ condition.

Results Kaplan-Meyer evaluation indicated that Nucleus Hybrid-L24 patients used the additional acoustic stimulation on median for 14.5 years before switching to electrical only stimulation with their CI. The average hearing loss at 500 Hz between first fit and the deactivation of the acoustical component was 45 +/- 23 dB HL.

Conclusion CI patients with residual hearing at low frequency can profit from combination of acoustical and electrical stimulation for years after implantation.

Cochlear Deutschland GmbH

Publication History

Article published online:
12 May 2023