Evaluation of speech perception and dislocation analysis in perimodiolar and straight electrode arrays

Objective The aim of this study is to examine scalar position in straight and perimodiolar electrode arrays (EA), to analyze the specific position of dislocation of EA depending on their design and to compare these results to postoperative speech perception.

Methods We conducted a comparative analysis of patients (n=548) (2013–2018) inserted with a perimodiolar or straight EA (Cochlear™ (N=360): Contour Advance^®, slim straight^® and slim modiolar^®, MED EL (n=188): Flex^Soft, Flex²⁴ and Flex²⁸ electrode array). Rotational tomography was used to determine EA position (scalar position, dislocation, angle of dislocation and insertion angle) and postoperative speech discrimination has been evaluated.

Results Perimodiolar electrode arrays showed significant shorter coverage than straight ones. The EA with the highest rate of scala vestibuli insertions was the Contour Advance; the highest dislocation rate showed the Flex^Soft EA (length: 31.5mm). The slim modiolar showed no dislocation. The angle of dislocation is EA design specific. Perimodiolar EA dislocate between 170 and 190°, whereas straight ones dislocate between 360 and 390°. A multivariate nonparametric analysis revealed that the dislocation of the electrode array has no significant influence on postoperative speech perception. Nevertheless, increasing cochlear coverage significantly reduced postoperative speech perception for monosyllables.

Conclusion EA position, dislocation rate and angle significantly depend on the EA design. Straight and perimodiolar electrode arrays differ from each other regarding both the rate and place of dislocation. Insertion via cochleostomy does not lead to increased dislocation rates in any of the included EA. Speech perception is significantly negatively influenced by cochlear coverage.

Poster-PDF A-1180.pdf

Publication History

Article published online:
13 May 2021