The association between electrode impedance and short-term outcomes in cochlear implant recipients of slim modiolar and slim straight electrode arrays

Abstract

Objectives

Electrode impedance measurements from cochlear implants (CI) reflect the status of the electrode array as well as the surrounding cochlear environment, and could provide a clinical index of functional changes with the CI. The goals of this study were to examine (1) the impact of electrode array type on electrode impedance, and (2) the relationship between electrode impedance and short-term hearing preservation and speech recognition outcomes.

Methods

Retrospective study of 115 adult hearing preservation CI recipients of a slim modiolar or slim straight array. Common ground electrode impedances, pre- and post-operative hearing thresholds and CNC word recognition scores were retrieved.

Results

Electrode impedances were significantly higher for recipients of the straight electrode array. Within individuals, electrode impedances were stable after the first week post-activation. However, increased standard deviation of electrode impedances was associated with greater loss of low frequency hearing at initial activation, and with poorer speech recognition at 6 months post-implantation.

Conclusions

Results demonstrate that electrode impedances depend on the type of implanted array. Findings also suggest that there may be a role for the variability in electrode impedance across electrodes as an indicator of changes in the intracochlear environment that contribute to outcomes with a CI.

Keywords:

• Cochlear Implants
• Electrode Impedance
• Electrode Array
• Hearing Preservation
• Speech Perception

Acknowledgement

We would like to thank Kaitlyn Mazzola for assisting with data collection, and Jason Schenker for assisting with the statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Declaration of interest statement

S.S. is a consultant for Cochlear Corporation and an advisory board member for Envoy Medical. The remaining authors report there are no competing interests to declare.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Bruna S. Mussoi

Dr. Bruna S. Mussoi is an Assistant Professor at Kent State University. Her research focuses on the relative contributions of peripheral, central and cognitive mechanisms to age-related changes in speech perception, through a combination of electrophysiological and behavioral methods. She is particularly interested in how those factors impact speech perception in adults with cochlear implants.

Alex Meibos

Alex Meibos is an Associate Professor of Audiology at The University of Akron and Northeast Ohio AuD Consortium (NOAC). His research has been focused in the areas of audiologic counseling, audiological practices across the lifespan, hearing loss prevention, and investigating factors that influence effective partnerships between hearing health professionals and patients with hearing loss or other ear related disorders.

Erika Woodson

Dr. Erika Woodson is the principal skull base surgeon for Kaiser Permanente Southern California, based in San Diego. She has a neurotology/skull base surgery fellowship administered via University of California San Diego. Dr. Woodson is formerly of Cleveland Clinic where she was Medical Director of the Hearing Implant Program and Section Head of Otology/Neurotology. She has had numerous leadership roles within the American Academy of Otolaryngology/Head and Neck Surgery.

Sarah Sydlowski

Sarah Sydlowski, AuD, PhD, MBA is Audiology Director of the Hearing Implant Program, Director of Audiology Innovation and Strategic Partnerships, and Associate Chief Improvement Officer at the Cleveland Clinic in Cleveland, Ohio. Dr. Sydlowski is Board Certified in Cochlear Implants, earned the Cleveland Clinic Distinguished Educator Certificate and is adjunct faculty at the University of Akron. Dr. Sydlowski completed her clinical doctorate at the University of Louisville, externship at Mayo Clinic Arizona, and PhD at Gallaudet University. Most recently, she completed her executive MBA at the Weatherhead School of Management at Case Western Reserve University where she was the recipient of the EMBA Leadership Award. She is a Past President of the American Academy of Audiology and the Ohio Academy of Audiology. She was Co-Chair of the 2021 American Cochlear Implant Alliance Program Committee. She is currently Co-Chair of the Hearing Health Collaborative. In her role as Associate Chief Improvement Officer, Dr. Sydlowski works closely with CI specialists across the organization to develop a culture of improvement where every caregiver is capable, expected, and empowered to make improvements every day.