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The Impact of Electrode Array Length on Hearing Preservation in Cochlear Implantation

Suhling, Marie-Charlot; Majdani, Omid; Salcher, Rolf; Leifholz, Melanie; Büchner, Andreas; Lesinski-Schiedat, Anke; Lenarz, Thomas

doi: 10.1097/MAO.0000000000001110

Objective: The aim of the study was to determine the degree of hearing preservation (HP) and its relation to electrode array length after cochlear implantation using different thin flexible electrode arrays (TFEA).

Study Design: Retrospective analysis.

Intervention: One hundred twenty adult patients with preoperative residual hearing received a cochlear implant with a TFEA: 46 received a TFEA20, 34 a TFEA24, and 40 a TFEA28 mm.

Main Outcome Measures: Pure-tone audiometry (125–1500 Hz) was performed preoperatively, at initial fitting, and at 3, 6, and 12 months postoperatively. Median hearing loss (HL) was determined for each of the three array groups. The pre- to postoperative pure-tone average difference was scaled into three groups (≤15 dB, >15 to ≤30 dB, >30 dB) for array group.

Results: At initial fitting, median HL of 17.5 dB (TFEA20), 20 dB (TFEA24), and 24 dB (TFEA28) was observed. At 12 months, medial HL of 15 dB (TFEA20), 19.4 dB (TFEA24), and 32.5 dB (TFEA28) was observed. At initial fitting, a HL of ≤15 dB was achieved in 45.6% TFEA20 subjects, 29.4% TFEA24 subjects, and 15.0% TFEA28 subjects; compared with 48.8% TFEA20 subjects, 50.0% TFEA24 subjects, and 15.8% TFEA28 subjects at 12 months.

Conclusion: HP is possible in the majority of subjects who are implanted with a TFEA20, 24, or 28. Using shorter arrays led to greater HP and lower median HL.

Department of Otolaryngology, Medical University of Hanover, Hanover, Germany

Address correspondence and reprint requests to Marie-Charlot Suhling, M.D., Department of Otolaryngology, Medical University of Hanover, OE6500, Carl-Neuberg Street 1, 30625 Hannover, Germany; E-mail:

The authors disclose no conflicts of interest.

Copyright © 2016 by Otology & Neurotology, Inc. Image copyright © 2010 Wolters Kluwer Health/Anatomical Chart Company