A Comprehensive Study on the Etiology of Patients Receiving Cochlear Implantation With Special Emphasis on Genetic Epidemiology

Objective: Cochlear implantation is the most important treatment currently available for profound sensorineural hearing loss. The aim of this study was to investigate the etiology of hearing loss in patients with cochlear implantation, and to compare outcomes. Methods: Japanese hearing loss patients who received cochlear implants (CIs) or electric acoustic stimulation (EAS) in Shinshu University hospital (n = 173, prelingual onset: 92, postlingual onset: 81) participated in this study. Invader assay followed by the targeted exon-sequencing of 63 deafness genes using Massively parallel DNA sequencing (MPS) was applied. For prelingual patients, additional imaging examination, cCMV screening, and pediatric examination were performed for precise diagnosis. Results: Genetic screening successfully identified the causative mutation in 60% of patients with prelingual onset hearing loss and in 36% of those with postlingual hearing loss. Differences in the kinds of genes identified were observed between the two groups. Although there were marked variations in the outcome of cochlear implantation, patients with specific deafness gene mutations showed relatively good results. Conclusion: The present study showed genetic etiology is a major cause of hearing loss in CI/EAS patients. Patients possessing mutations in a number of deafness genes known to be expressed within inner ear have achieved satisfactory auditory performance, suggesting that the identification of the genetic background facilitates the prediction of post-CI performance. MPS is a powerful tool for the identification of causative deafness genes in patients receiving cochlear implantation. Therefore, determination of the involved region inside/outside of the cochlea by identification of the responsible gene is essential.

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American Neurotology Society Preliminary Program

No abstract available

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Initial Results With Image-guided Cochlear Implant Programming in Children

Hypothesis: Image-guided cochlear implant (CI) programming can improve hearing outcomes for pediatric CI recipients. Background: CIs have been highly successful for children with severe-to-profound hearing loss, offering potential for mainstreamed education and auditory-oral communication. Despite this, a significant number of recipients still experience poor speech understanding, language delay, and, even among the best performers, restoration to normal auditory fidelity is rare. Although significant research efforts have been devoted to improving stimulation strategies, few developments have led to significant hearing improvement over the past two decades. Recently introduced techniques for image-guided CI programming (IGCIP) permit creating patient-customized CI programs by making it possible, for the first time, to estimate the position of implanted CI electrodes relative to the nerves they stimulate using CT images. This approach permits identification of electrodes with high levels of stimulation overlap and to deactivate them from a patient's map. Previous studies have shown that IGCIP can significantly improve hearing outcomes for adults with CIs. Methods: The IGCIP technique was tested for 21 ears of 18 pediatric CI recipients. Participants had long-term experience with their CI (5 mo to 13 yr) and ranged in age from 5 to 17 years old. Speech understanding was assessed after approximately 4 weeks of experience with the IGCIP map. Results: Using a two-tailed Wilcoxon signed-rank test, statistically significant improvement (p 

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Effects of Intralabyrinthine Hemorrhage on the Cochlear Elements: A Human Temporal Bone Study

Hypothesis: To compare histopathologic findings in the cochlea of human temporal bones with versus without intralabyrinthine hemorrhage. Background: Hemorrhagic labyrinthitis can cause sensorineural damage, sudden hearing loss, and vertigo. Yet, to our knowledge, no studies have quantitatively described histopathologic effects of intralabyrinthine hemorrhage on the elements of the cochlea. Methods: We analyzed 46 human temporal bone samples from 23 patients with unilateral intralabyrinthine hemorrhage (23 samples from ears with intralabyrinthine hemorrhage and 23 samples from contralateral ears without). We noted the location of hemorrhage in the inner ear, the degree of endolymphatic hydrops, the number of spiral ganglion cells and hair cells, mean loss of fibrocytes in spiral ligament, and areas of the stria vascularis and spiral ligament. Results: Intralabyrinthine hemorrhage caused significant loss of outer hair cells in the lower basal (p = 0.001), upper basal (p = 0.005), and lower middle (p = 0.012) cochlear turns. The degree of endolymphatic hydrops was significantly different between the hemorrhagic and contralateral sides (p = 0.011). But we found no significant difference between the 2 sides in the number of inner hair cells, spiral ganglion cells, and fibrocytes, or in the areas of the stria vascularis and spiral ligament between the two groups (p > 0.05). Conclusion: These findings suggest that such patients could be good candidates for hearing aid or cochlear implant if they have profound sensorineural hearing loss.

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Does Bilateral Experience Lead to Improved Spatial Unmasking of Speech in Children Who Use Bilateral Cochlear Implants?

Hypothesis: In children with bilateral cochlear implants (BiCIs), experience over a 1 to 3-year period can improve speech understanding and spatial unmasking of speech. Background: One reason for providing children with BiCIs is to improve spatial hearing abilities. Little is known about changes in performance with added bilateral experience, and the relation between sound localization and spatial unmasking of speech. Methods: Twenty children with BiCIs participated. Testing was conducted typically within a year of bilateral activation, and at 1, 2, or 3 follow-up annual intervals. All testing was done while children listened with both devices activated. Target speech was presented from front (co-located); interfering speech was from front, right (asymmetrical), or right and left (symmetrical). Speech reception thresholds (SRTs) were measured in each condition. Spatial release from masking (SRM) was quantified as the difference in SRTs between conditions with interferers at 0 degrees and 90 degrees. For 11 of the children, data are also compared with sound localization measures obtained on the same visit to the laboratory but published elsewhere. Results: Change in SRM with bilateral experience varied; some children showed improvement and others did not. Regression analyses identified relationships between SRTs and SRM. Comparison of the SRM with localization data suggests little evidence for correlations between the two spatial tasks. Conclusion: In children with BiCIs spatial hearing mechanisms involved in SRM and sound localization may be different. Reasons for reduced SRM include asymmetry between the ears, and individual differences in the ability to inhibit interfering information, switch and/or sustain attention.

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Results of Postoperative, CT-based, Electrode Deactivation on Hearing in Prelingually Deafened Adult Cochlear Implant Recipients

Objective: To test the use of a novel, image-guided cochlear implant (CI) programming (IGCIP) technique on prelingually deafened, adult CI recipients. Study Design: Prospective unblinded study. Setting: Tertiary referral center. Patients: Twenty-six prelingually deafened adult CI recipients with 29 CIs (3 bilateral). Intervention(s): Temporal-bone CT scans were used as input to a series of semiautomated computer algorithms which estimate the location of electrodes in reference to the modiolus. This information was used to selectively deactivate suboptimally located electrodes, i.e., those for which the distance from the electrode to the modiolus was further than a neighboring electrode to the same site. Patients used the new IGCIP program exclusively for 3–5 weeks. Main Outcome Measure(s): Minimum Speech Test Battery (MSTB), quality of life (QOL), and spectral modulation detection (SMD). Results: On average one-third of electrodes were deactivated. At the group level, no significant differences were noted for MSTB measures nor for QOL estimates. Average SMD significantly improved after IGCIP reprogramming, which is consistent with improved spatial selectivity. Using 95% confidence interval data for CNC, AzBio, and BKB-SIN at the individual level, 76 to 90% of subjects demonstrated equivocal or significant improvement. Ultimately 21 of 29 (72.41%) elected to keep the IGCIP map because of perceived benefit often substantiated by improvement on either MSTB, QOL, and/or SMD. Conclusions: Knowledge of the geometric relationship between CI electrodes and the modiolus appears to be useful in adjusting CI maps in prelingually deafened adults. Long-term improvements may be observed resulting from improved spatial selectivity and spectral resolution.

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Bilateral Sequential Cochlear Implantation in Patients With Enlarged Vestibular Aqueduct (EVA) Syndrome

Objectives: To analyze audiometric outcomes after bilateral cochlear implantation in patients with isolated enlarged vestibular aqueduct (EVA) syndrome and associated incomplete partition (IP) malformations. Secondary objective was to analyze rate of cerebrospinal fluid (CSF) gusher in patients with IP-EVA spectrum deformities and compare this with the existing literature. Study Design: Retrospective chart review. Methods: Thirty-two patients with EVA syndrome who received unilateral or bilateral cochlear implants between June 1999 and January 2014 were identified in the University Hospitals Case Medical Center cochlear implant database. Isolated EVA (IEVA) and Incomplete Partition Type II (IP-II) malformations were identified by reviewing high-resolution computed tomography (HRCT) imaging. Demographic information, age at implantation, surgical details, postimplantation audiometric data including speech reception thresholds (SRT), word, and sentence scores were reviewed and analyzed. Intra- and postoperative complications were analyzed as well and compared with the literature. Results: Seventeen patients (32 implanted ears) had pediatric cochlear implantation for EVA-associated hearing loss. Data from 16 controls (32 implanted ears) were used to compare audiometric and speech outcomes of EVA cohort. Mean age at implantation was 6.8 years for EVA cohort and 6.0 years for controls. There was no statistically significant difference in long-term postoperative SRT, monaurally aided word scores, and binaurally tested word scores between pediatric EVA group and controls. The EVA patients had a long-term mean sentence score of 85.92%. A subset of EVA patients implanted at mean age of 3.18 years (n = 15 ears) had similar audiometric outcomes to another control group with Connexin 26 mutations (n = 20 ears) implanted at a similar age. Further subset analysis revealed no significant differences in age at implantation, SRT, and word scores in patients with IEVA and IP-II malformation. There was no significant association between size of vestibular aqueduct and age at implantation. There was no CSF gusher or other intra- or postoperative complications reported in our series. Conclusion: Bilateral sequential cochlear implantation can be performed safely in patients with EVA. Audiometric outcomes are excellent and comparable to pediatric cochlear implant patients with no malformations. CSF gusher rates can be minimized by trans-round window approach. Further long-term studies are needed to identify differences within IP-EVA spectrum deformities, audiometric outcomes, and proportions of EVA patients who will need cochlear implantation for hearing rehabilitation.

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