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Original Investigation
November 21, 2018

Association Between Flat-Panel Computed Tomographic Imaging–Guided Place-Pitch Mapping and Speech and Pitch Perception in Cochlear Implant Users

Author Affiliations
  • 1Department of Otolaryngology–Head and Neck Surgery, School of Medicine, University of California, San Francisco
  • 2Department of Radiology and Biomedical Imaging, School of Medicine, University of California, San Francisco
  • 3School of Nursing, The Johns Hopkins University Baltimore, Maryland
JAMA Otolaryngol Head Neck Surg. Published online November 21, 2018. doi:10.1001/jamaoto.2018.3096
Key Points

Question  Is an individualized, image-guided approach to place-pitch cochlear implant programming associated with improved pitch-scaling performance without undermining speech perception accuracy?

Findings  In this interventional cohort study of 17 cochlear implant users, significant improvement in pitch-scaling performance with an image-guided approach to postimplantation programming was observed. The greatest association occurred with major pitch reversals (notes spaced 1.65 semitones or greater) in the low- and high-frequency ranges.

Meaning  An image-based approach toward cochlear implant mapping may improve pitch perception outcomes by reducing place-pitch mismatch.

Abstract

Importance  Cochlear implant users generally display poor pitch perception. Flat-panel computed tomography (FPCT) has recently emerged as a modality capable of localizing individual electrode contacts within the cochlea in vivo. Significant place-pitch mismatch between the clinical implant processing settings given to patients and the theoretical maps based on FPCT imaging has previously been noted.

Objective  To assess whether place-pitch mismatch is associated with poor cochlear implant–mediated pitch perception through evaluation of an individualized, image-guided approach toward cochlear implant programming on speech and music perception among cochlear implant users.

Design, Setting, and Participants  A prospective cohort study of 17 cochlear implant users with MED-EL electrode arrays was performed at a tertiary referral center. The study was conducted from June 2016 to July 2017.

Interventions  Theoretical place-pitch maps using FPCT secondary reconstructions and 3-dimensional curved planar re-formation software were developed. The clinical map settings (eg, strategy, rate, volume, frequency band range) were modified to keep factors constant between the 2 maps and minimize confounding. The acclimation period to the maps was 30 minutes.

Main Outcomes and Measures  Participants performed speech perception tasks (eg, consonant-nucleus-consonant, Bamford-Kowal-Bench Speech-in-Noise, vowel identification) and a pitch-scaling task while using the image-guided place-pitch map (intervention) and the modified clinical map (control). Performance scores between the 2 interventions were measured.

Results  Of the 17 participants, 10 (58.8%) were women; mean (SD) was 59 (11.3) years. A significant median increase in pitch scaling accuracy was noted when using the experimental map compared with the control map (4 more correct answers; 95% CI, 0-8). Specifically, the number of pitch-scaling reversals for notes spaced at 1.65 semitones or greater decreased when an image-based approach to cochlear implant programming was used vs the modified clinical map (4 mistakes; 95% CI, 0.5-7). Although there was no observable median improvement in speech perception during use of an image-based map, the acute changes in frequency allocation and electrode channel deactivations used with the image-guided maps did not worsen consonant-nucleus-consonant (−1% correct phonemes, 95% CI, −2.5% to 6%) and Bamford-Kowal-Bench Speech-in-Noise (0.5-dB difference; 95% CI, −0.75 to 2.25 dB) median performance results relative to the clinical maps used by the patients.

Conclusions and Relevance  An image-based approach toward ochlear implant mapping may improve pitch perception outcomes by reducing place-pitch mismatch. Studies using a longer acclimation period with chronic stimulation over months may help assess the full range of the benefits associated with personalized image-guided cochlear implant mapping.

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