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

Abstract

<p class="first" id="d695734e308">This cohort study evaluates the association between image-based place-pitch mapping using flat-panel computed tomography with speech and pitch perception in individuals with cochlear implants. </p><div class="section"> <a class="named-anchor" id="ab-ooi180092-1"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e314">Question</h5> <p id="d695734e316">Is an individualized, image-guided approach to place-pitch cochlear implant programming associated with improved pitch-scaling performance without undermining speech perception accuracy? </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-2"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e319">Findings</h5> <p id="d695734e321">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-3"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e324">Meaning</h5> <p id="d695734e326">An image-based approach toward cochlear implant mapping may improve pitch perception outcomes by reducing place-pitch mismatch. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-4"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e330">Importance</h5> <p id="d695734e332">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-5"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e335">Objective</h5> <p id="d695734e337">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-6"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e340">Design, Setting, and Participants</h5> <p id="d695734e342">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-7"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e345">Interventions</h5> <p id="d695734e347">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-8"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e350">Main Outcomes and Measures</h5> <p id="d695734e352">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-9"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e355">Results</h5> <p id="d695734e357">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. </p> </div><div class="section"> <a class="named-anchor" id="ab-ooi180092-10"> <!-- named anchor --> </a> <h5 class="section-title" id="d695734e360">Conclusions and Relevance</h5> <p id="d695734e362">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. </p> </div>