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Implantable Hearing Devices (IHD)

RP209 - Role of Imaging in Cochlear Implant Mapping

Thursday, April 20, 2023
3:45 PM – 4:15 PM PDT
Location: Rooms 608-609 ** 705 Pike
Earn 0.05 CEUs

    Lead Presenter(s)

  • Margaret E. Richter, AuD (she/her/hers)

    Research Assistant Professor
    The University of North Carolina at Chapel Hill
    Raleigh, North Carolina

    Disclosure(s): MED-EL Corporation: Grant/Research Support (Ongoing)

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    • Contributor(s)

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    Kevin D. Brown, MD/PhD

    Associate Professor
    The University of North Carolina at Chapel Hill, Department of Otolaryngology

    Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
    Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

  • Nicholas Thompson, MD

    Neurotology Fellow
    University of North Carolina

    Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
    Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

  • AS

    A.Morgan Selleck

    Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
    Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

  • MD

    Matthew Dedmon

    Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
    Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

  • MD

    Margaret T. Dillon, AuD

    Research Associate Professor
    University of North Carolina at Chapel Hill
    Chapel Hill, North Carolina

    Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
    Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

Abstract:
Imaging (e.g., x-ray, computed tomography) is traditionally used in the management of cochlear implant (CI) patients. Imaging is used intraoperatively and/or postoperatively for the assessment of electrode array placement, such as identifying extracochlear electrode contacts or tip fold over. Audiologists use this information to determine channels that should be deactivated in order to improve the sound quality of the CI. More recently, imaging has been used to individualize the filter frequencies in order to match the frequency information with the specific cochlear place frequency. Individualizing the mapping with imaging findings may help CI recipients hear better faster with their device.

Summary:
Objective
This report summarizes the traditional use of intraoperative and postoperative imaging in the management of adult cochlear implant (CI) patients and investigates whether the use of imaging in the mapping of filter frequency information would support better outcomes for listeners of electric-acoustic stimulation (EAS).

Rational
CI recipients with hearing preservation experience improved speech recognition with EAS as compared to preoperative abilities, though outcomes are variable across individuals (Gantz et al 2016; Pillsbury et al 2018). The variability in outcomes with EAS may be due in part to differences in the filter frequency information and the cochlear place frequency for an electrode contact, known as frequency-to-place mismatch. Imaging can be used to identify the cochlear place frequency; this information can be used to individualize the filter frequencies to eliminate electric mismatches, known as place-based mapping. The present report investigated the influence of electric mismatches on performance with EAS and the effectiveness of place-based mapping for EAS users.

Design
Twenty-one adults were enrolled in the prospective study. The postoperative CT was used to calculate angular insertion depth and estimate the cochlear place frequency for each electrode contact. Participants were randomized to listen with a default or place-based map. Speech recognition was evaluated with tasks of vowel recognition and CNC word recognition at 1-, 3- and 6-months post-activation.

Results
Electric frequency-to-place mismatches varied for listeners of default maps, with a median of 5 semitones. Poorer speech recognition was observed over the study period for participants with larger magnitudes of electric mismatch.

Conclusion
Imaging has been used in the traditional management of CI recipients to confirm electrode array placement. There may also be utility of imaging in the individualization of the electric filter frequencies, such as with place-based mapping. Eliminating frequency-to-place mismatches with place-based mapping may support better outcomes faster for EAS users.

Learning Objectives:

  • Upon completion, participants will be able to define electric frequency-to-place mismatches and classify how mismatches influence the speech recognition of patients listening with electric stimulation only.
  • Upon completion, participants will be able to describe how electric frequency-to-place mismatches may influence the early speech recognition outcomes of adult EAS users.
  • Upon completion, participants will be able to evaluate the potential benefits of aligning filter frequencies to cochlear place frequency for EAS users.