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Hearing preservation potential of different cochlear implant electrodes: Perimodiolar versus Lateral-Wall
18 April 2018 (online)
The postoperative hearing- and structure preservation after a cochlear implantation has been successfully established for patients with residual hearing in recent years with the help of lateral-wall electrodes. Nevertheless, the perimodiolar electrodes have electrophysiological advantages, which are to be achieved with the development of a thin perimodiolar electrode (Nucleus Profile 532 Cochlear (MRA)). Despite the proximity to the modiolus, the mechanical properties should secure the structures of the cochlea. Our goal is to analyze the potential of the MRA electrode based on the degree of postoperative hearing preservation in comparison to the lateral wall electrode (Nucleus SRA 522 Cochlear (SRA)).
2017 adult patients were implanted with 84 MRA and 427 SRA at the Medical School of Hanover and wer retrospectively analyzed. Pre- and postoperative pure tone audiometry was performed at the initial fitting and after 12 months.
Preliminary evaluations show a median hearing loss of 29 dB for the MRA and 14 dB for the SRA at the initial fitting. After 12 months, a median hearing loss of 36 dB was observed for the MRA and 18 dB could be analyzed for the SRA electrode. Good hearing preservation (hearing loss < 15 dB between 500 – 1500 Hz) was achieved at 21% of MRA and 49% of SRA patients.
Hearing preservation is possible with the the perimodiolar electrode MRA. Compared to the lateral wall electrode SRA, however, it is smaller. Further studies and a longer observation period are necessary to show whether the results are stable in the long term and whether the hearing can contribute to a better hearing outcome.