Optimized cochlear coverage to improve cochlear implant outcome

Introduction Despite the general success of treatment with cochlear implants (CIs) there is still a high variability in individual hearing success. Among other things hearing success can be affected by the position of the electrode array in the cochlea. In the present study the effect of proportional coverage of the cochlea by lateral wall electrode arrays on postoperative speech understanding was analyzed and evaluated in a larger cohort.

Methods In a retrospective study a cohort of N  = 156 ears implanted with a CI of the FLEX series (MED-EL, Innsbruck, Austria) was analyzed. Cochlear coverage (CC) and insertion angle were derived from pre- and postoperative CBCT scans. The impact of these parameters on hearing success was then examined using results in the Freiburger monosyllabic word test (FMWT) in quiet and in the HSM sentence test in noise.

Results A significant linear correlation was observed between results in the FMWT and CC (r=0.237, p<0.01) and IA (r=0.226, p<0.01) respectively, but not between results in the HSM sentence test and either CC or IA. A significant correlation was however also found between the difference between post- and preoperative FMWT scores and CC (r=0.292, p=0.001).

Discussion: For the electrode arrays included in this study it could be shown that the position of the electrode array has an effect on postoperative speech understanding. It can be derived from the results that insertion should aim at a cochlear coverage between 70% and 82% to ensure optimal chances for treatment success.

Exzellenzcluster Hearing4All, Oldenburg, Deutschland

Publication History

Article published online:
24 May 2022