The Relation of Cochlear Implant Electrode Array Type and Position on Continued Hearing Preservation

Area of Science:

• Otolaryngology
• Neurosurgery
• Biomedical Engineering

Background:

• Cochlear implantation aims to restore hearing in severe to profound sensorineural hearing loss.
• Preserving residual hearing is a key goal in modern cochlear implant surgery.
• Electrode array (EA) design and placement may influence hearing preservation outcomes.

Purpose of the Study:

• To investigate the relationship between electrode array (EA) type and position and the longevity of hearing preservation after cochlear implantation.
• To identify factors predicting short-term and long-term hearing preservation.

Main Methods:

• Retrospective chart review of adult cochlear implant recipients (2013-2019) with preserved hearing and postoperative CT scans.
• CT scan analysis assessed EA position, including angular and base insertion depth, and scalar position.
• Stepwise regression analyzed the influence of EA type, position, and patient demographics on low-frequency hearing preservation.

Main Results:

• No statistically significant difference in low-frequency pure tone average (LFPTA) shift was found based on EA type (straight, precurved styletted, precurved nonstyletted).
• Preoperative LFPTA and age predicted LFPTA shift at activation.
• LFPTA shift at activation, scalar position, and base insertion depth predicted 6-month LFPTA shift.
• 12-month LFPTA shift was the strongest predictor of long-term hearing preservation.

Conclusions:

• Excellent long-term residual hearing was achieved regardless of electrode array type.
• Age, preoperative hearing, and insertion depth are potential short-term predictors.
• 12-month hearing preservation outcomes significantly predict long-term hearing preservation success.