Intracochlear Position of Cochlear Implants Determined Using CT Scanning versus Fitting Levels: Higher Threshold Levels at Basal Turn

Toward neural health measurements for cochlear implantation: The relationship among electrode positioning, the electrically evoked action potential, impedances and behavioral stimulation levels

Introduction

Estimating differences in neural health across different sites within the individual cochlea potentially enables clinical applications for subjects with a cochlear implant. The electrically evoked compound action potential (ECAP) is a measure of neural excitability that possibly provides an indication of a neural condition. There are many factors, however, that affect this measure and increase the uncertainty of its interpretation. To better characterize the ECAP response, its relationship with electrode positioning, impedances, and behavioral stimulation levels was explored.

Methods

A total of 14 adult subjects implanted with an Advanced Bionics cochlear electrode array were prospectively followed up from surgery to 6 months postoperative. Insertion depth, distance to the modiolus, and distance to the medial wall were assessed for each electrode by postoperative CT analysis. ECAPs were measured intraoperatively and at three visits postoperatively on all 16 electrodes using the NRI feature of clinical programming software and characterized using multiple parameters. Impedances and behavioral stimulation levels were measured at every fitting session.

Results

Patterns in ECAPs and impedances were consistent over time, but high variability existed among subjects and between different positions in the cochlea. Electrodes located closer to the apex of the cochlea and closer to the modiolus generally showed higher neural excitation and higher impedances. Maximum loudness comfort levels were correlated strongly with the level of current needed to elicit a response of 100 μV ECAP.

Conclusion

Multiple factors contribute to the ECAP response in subjects with a cochlear implant. Further research might address whether the ECAP parameters used in this study will benefit clinical electrode fitting or the assessment of auditory neuron integrity.

Comparisons of electrophysiological and psychophysical fitting methods for cochlear implants

OBJECTIVE

This study compared two different versions of an electrophysiology-based software-guided cochlear implant fitting method with a procedure employing standard clinical software. The two versions used electrically evoked compound action potential (ECAP) thresholds for either five or all twenty-two electrodes to determine sound processor stimulation level profiles. Objective and subjective performance results were compared between software-guided and clinical fittings.

DESIGN

Prospective, double-blind, single-subject repeated-measures with permuted ABCA sequences.

STUDY SAMPLE

48 post linguistically deafened adults with ≤15 years of severe-to-profound deafness who were newly unilaterally implanted with a Nucleus device.

RESULTS

Speech recognition in noise and quiet was not significantly different between software- guided and standard methods, but there was a visit/learning-effect. However, the 5-electrode method gave scores on the SSQ speech subscale 0.5 points lower than the standard method. Clinicians judged usability for all methods as acceptable, as did subjects for comfort. Analysis of stimulation levels and ECAP thresholds suggested that the 5-electrode method could be refined.

CONCLUSIONS

Speech recognition was not inferior using either version of the electrophysiology-based software-guided fitting method compared with the standard method. Subject-reported speech perception was slightly inferior with the five-electrode method. Software-guided methods saved about 10 min of clinician's time versus standard fittings.

Speech Recognition Performance Differences Between Precurved and Straight Electrode Arrays From a Single Manufacturer

OBJECTIVE

Precurved cochlear implant (CI) electrode arrays have demonstrated superior audiometric outcomes compared with straight electrodes in a handful of studies. However, previous comparisons have often failed to account for preoperative hearing and age. This study compares hearing outcomes for precurved and straight electrodes by a single manufacturer while controlling for these and other factors in a large cohort.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary academic medical center.

PATIENTS

Two hundred thirty-one adult CI recipients between 2015 and 2021 with cochlear (Sydney, Australia) 522/622 (straight) or 532/632 (precurved) electrode arrays.

INTERVENTIONS

Postactivation speech recognition and audiometric testing.

MAIN OUTCOME MEASURES

Speech recognition testing (consonant-nucleus-consonant word [CNCw] and AzBio) was collected at 6 and 12 months postactivation. Hearing preservation was characterized by a low-frequency pure-tone average shift, or the change between preoperative and postoperative low-frequency pure-tone average.

RESULTS

Two hundred thirty-one patients (253 ears) with 6-month and/or 12-month CNCw or AzBio testing were included. One hundred forty-nine (59%) and 104 (41%) ears were implanted with straight and precurved electrode arrays, respectively. Average age at implantation was 70 years (interquartile range [IQR], 58-77 y). There was no significant difference in mean age between groups. CNCw scores were significantly different ( p = 0.001) between straight (51%; IQR, 36-67%) and precurved arrays (64%; IQR, 48-72%). AzBio scores were not significantly different ( p = 0.081) between straight (72%; IQR, 51-87%) and precurved arrays (81%; IQR, 57-90%). Controlling for age, race, sex, preoperative hearing, and follow-up time, precurved electrode arrays performed significantly better on CNCw (b = 10.0; 95% confidence interval, 4.2-16.0; p < 0.001) and AzBio (b = 8.9; 95% confidence interval, 1.8-16.0;, p = 0.014) testing. Hearing preservation was not different between electrodes on adjusted models.

CONCLUSION

During the study period, patients undergoing placement of precurved electrode arrays had significantly higher CNC and AzBio scores than patients receiving straight electrodes, even after controlling for age, preoperative hearing, and follow-up time.

PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED

Understanding the difference in audiometric outcomes between precurved and straight electrode arrays will help to guide electrode selection.

LEARNING OBJECTIVE

To understand differences in speech recognition scores postoperatively by electrode array type (precurved versus straight).

DESIRED RESULT

To demonstrate a difference in hearing performance postoperatively by electrode type.

LEVEL OF EVIDENCE

III.

INDICATE IRB OR IACUC

Approved by the Institutional IRB (090155).

Model-based prediction of optogenetic sound encoding in the human cochlea by future optical cochlear implants

When hearing fails, electrical cochlear implants (eCIs) partially restore hearing by direct stimulation of spiral ganglion neurons (SGNs). As light can be better confined in space than electrical current, optical CIs (oCIs) provide more spectral information promising a fundamental improvement of hearing restoration by cochlear implants. Here, we turned to computer modelling for predicting the outcome of optogenetic hearing restoration by future oCIs in humans. We combined three-dimensional reconstruction of the human cochlea with ray-tracing simulation of emission from LED or laser-coupled waveguide emitters of the oCI. Irradiance was read out at the somata of SGNs. The irradiance values reached with waveguides were about 14 times higher than with LEDs, at the same radiant flux of the emitter. Moreover, waveguides outperformed LEDs regarding spectral selectivity. oCIs with either emitter type showed greater spectral selectivity when compared to eCI. In addition, modeling the effects of the source-to-SGN distance, orientation of the sources and impact of scar tissue further informs the development of optogenetic hearing restoration.

Investigating the association of electrically-evoked compound action potential thresholds with inner-ear dimensions in pediatric cochlear implantation

OBJECTIVES

A narrow bony cochlear nerve canal (BCNC), as well as a hypoplastic and aplastic cochlear nerve (CN) have been associated with increased electrically-evoked compound action potential (eCAP) thresholds in some studies, suggesting poorer neural excitability in cochlear implantation. Also, in large cochleae the extent of activated spiral ganglion neurons with electrical stimulation is less than in smaller ones. However, a detailed description of the relationship between eCAP thresholds for a lateral-wall electrode array and dimensions of the inner-ear structures and internal auditory canal (IAC) is missing.

DESIGN

The study subjects were 52 pediatric patients with congenital severe-to-profound hearing loss (27 females and 25 males; ages 0.7-2.0 years; 1.0 ± 0.3 years, mean ± SD) implanted bilaterally with Cochlear Nucleus CI422, CI522, or CI622 implants with full insertion of the Slim Straight electrode array. Diameters of the cochlea and the BCNC as well as the widths and heights of the IAC and the CN were evaluated from preoperative computed tomography and magnetic resonance images. These anatomical dimensions were compared with each other and with the patients' intraoperative eCAP thresholds.

RESULTS

The eCAP thresholds increased from the apical to basal direction (r = 0.89, p < 0.001). After sorting the cochleae into four size categories, higher eCAP thresholds were found in larger than in smaller cochleae (p < 0.001). With similar categorization, the eCAP thresholds were higher in cochleae with a larger BCNC than in cochleae with a smaller BCNC (p < 0.001). Neither IAC nor CN cross-sectional areas affected the eCAP thresholds. Correlations were found between cochlea and BCNC diameters and between IAC and CN cross-sectional areas (r = 0.39 and r = 0.48, respectively, p < 0.001 for both).

CONCLUSIONS

In the basal part of the electrode array, higher stimulation levels to elicit measurable neural responses (eCAP thresholds) were required than in the apical part. Increased eCAP thresholds associated with a larger cochlear diameter, but contrary to the earlier studies, not with a small size of the BCNC or the CN. Instead, the BCNC diameter correlated significantly with the cochlea diameter.

Quality-assured training in the evaluation of cochlear implant electrode position: a prospective experimental study

BACKGROUND

The objective of this study was to demonstrate the utility of an approach in training predoctoral medical students, to enable them to measure electrode-to-modiolus distances (EMDs) and insertion-depth angles (aDOIs) in cochlear implant (CI) imaging at the performance level of a single senior rater.

METHODS

This prospective experimental study was conducted on a clinical training dataset comprising patients undergoing cochlear implantation with a Nucleus® CI532 Slim Modiolar electrode (N = 20) or a CI512 Contour Advance electrode (N = 10). To assess the learning curves of a single medical student in measuring EMD and aDOI, interrater differences (senior-student) were compared with the intrarater differences of a single senior rater (test-retest). The interrater and intrarater range were both calculated as the distance between the 0.1th and 99.9th percentiles. A "deliberate practice" training approach was used to teach knowledge and skills, while correctives were applied to minimize faulty data-gathering and data synthesis.

RESULTS

Intrarater differences of the senior rater ranged from - 0.5 to 0.5 mm for EMD and - 14° to 16° for aDOI (respective medians: 0 mm and 0°). Use of the training approach led to interrater differences that matched this after the 4th (EMD) and 3rd (aDOI) feedback/measurement series had been provided to the student.

CONCLUSIONS

The training approach enabled the student to evaluate the CI electrode position at the performance level of a senior rater. This finding may offer a basis for ongoing clinical quality assurance for the assessment of CI electrode position.

Cochlear Implantation in NF2 Patients Without Intracochlear Schwannoma Removal

OBJECTIVE

To determine if cochlear implantation without removal of inner ear schwannomas (IES) is an effective treatment option for Neurofibromatosis 2 (NF2) patients. To determine how the presence of an intracochlear schwannoma might impact cochlear implant (CI) outcomes and programming parameters.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary center for cochlear and auditory brainstem implantation.

PATIENTS

Of 10 NF2 patients with IES, 8 are reported with no previous tumor removal on the implanted ear.

INTERVENTIONS

Cochlear implant without tumor removal.

MAIN OUTCOME MEASURES

Performance outcomes with CI at least 1-year post intervention. Programming parameters, including impedances, for patients with IES.

RESULTS

All patients had full insertion of the electrode arrays with round window approaches. Performance outcomes ranged from 0 to 100% for Bamford-Kowal-Bench sentences. Impedance measurements for active electrodes for patients with IES were comparable to those measured in patients without vestibular schwannoma (VS). Only patients who had radiation treatment before receiving their implant had elevated threshold requirements for CI programming compared with CI recipients without VS.

CONCLUSION

Cochlear implantation without tumor removal is an effective option for treating NF2 patients with IES. The presence of an intracochlear tumor did not have an impact on CI performance or programming requirements compared with patients without VS; however, previous treatment with radiation may be related to elevated current requirements in the CI settings.

On the Intracochlear Location of Straight Electrode Arrays After Cochlear Implantation: How Lateral Are Lateral Wall Electrodes?

OBJECTIVE

Cochlear implants are the gold standard for patients with severe sensorineural hearing loss. A focused electrical stimulation of individual spiral ganglion neurons has not been achieved yet because the scala tympani is a fluid-filled compartment and does not offer a matrix for neuritic outgrowth. Coating of the electrode contacts with swelling hydrogels could fill that gap between the electrode array and the medial wall of the cochlea. Therefore, the exact position of the electrode array within the scala tympani has to be known.

STUDY DESIGN

Retrospective analysis of patient data sets.

SETTING

Tertiary referral center. A total of 95 patients with cochlear implants from one manufacturer were included in this study. The lateral wall, the modiolar wall, and the cochlear implant electrode were segmented using OsiriX MD. For repositioning and reconstructing the respective contours and measuring distances, files were analyzed in MATLAB. The distances from the edge of each electrode contact to the cochlear walls showed no significant differences. But between the different contacts within each patient, there were significant differences. Around 180 degree insertion, electrodes start to get in contact with the lateral wall. The tip of the electrode array was always facing toward the modiolar wall independent of the length of the electrode. We established a method to analyze the position of electrodes within the cochlea.

Relations Between Scalar Shift and Insertion Depth in Human Cochlear Implantation

OBJECTIVE

The intracochlear position of an electrode array may influence the outcome after cochlear implantation. The design of the electrode array can increase the risk of trauma causing penetration of the basilar membrane or shift of the electrode array into the scala vestibuli. The aim of the present study was to identify a scalar shift after implantation of two different electrode arrays developed by one manufacturer.

STUDY DESIGN

Retrospective analysis.

SETTING

Tertiary referral center.

PATIENTS AND INTERVENTION

Cochlear implant recipients implanted between 2010 and 2014 and receiving either a mid-scala (n = 30) or a perimodiolar (n = 30) electrode array.

MAIN OUTCOME MEASURE

Occurrence of scalar shift in association with the electrode type.

RESULTS

Scalar shift occurred in 26.7% (8 of 30) of the patients implanted with a perimodiolar electrode array and in 6.7% (2 of 30) of the patients implanted with the mid-scala electrode array. The mean insertion depth in the patients experiencing scalar shift after implantation of the mid-scala electrode was much deeper (21.59 ± 0.34 mm) when compared with the mean insertion depth of the patients with scalar shift after implantation with a perimodiolar electrode array (17.85 ± 2.19 mm). There tends to be a correlation between the cochlear length and the occurrence of a scalar shift. However, the number of patients with scalar shift in the mid-scala group is rather small.

CONCLUSION

Based on the presented data, more patients implanted with a perimodiolar electrode array have a scalar shift when compared with the midscalar electrode array.

Intraoperative Impedance-Based Estimation of Cochlear Implant Electrode Array Insertion Depth

OBJECTIVE

Cochlear implant impedances are influenced by the intracochlear position of the electrodes. Herein, we present an intuitive approach to calculate tissue resistances from transimpedance recordings, ultimately enabling to estimate the insertion depth of cochlear implant electrodes.

METHODS

Electrode positions were measured in computed-tomography images of 20 subjects implanted with the same lateral wall cochlear implant model. The tissue resistances were estimated from intraoperative telemetry data using bivariate spline extrapolation from the transimpedance recordings. Using a phenomenological model, the electrode insertion depths were estimated.

RESULTS

The proposed method enabled the linear insertion depth of all electrodes to be estimated with an average error of 0.76 ± 0.53 mm.

CONCLUSION

Intraoperative telemetry recordings correlate with the linear and angular depth of electrode insertion, enabling estimations with an accuracy that can be useful for clinical applications.

SIGNIFICANCE

The proposed method can be used to objectively assess surgical outcomes during and after cochlear implantation based on non-invasive and readily available telemetry recordings.

Angular Electrode Insertion Depth and Speech Perception in Adults With a Cochlear Implant: A Systematic Review

Objective:

By discussing the design, findings, strengths, and weaknesses of available studies investigating the influence of angular insertion depth on speech perception, we intend to summarize the current status of evidence; and using evidence based conclusions, possibly contribute to the determination of the optimal cochlear implant (CI) electrode position.

Data Sources:

Our search strategy yielded 10,877 papers. PubMed, Ovid EMBASE, Web of Science, and the Cochrane Library were searched up to June 1, 2018. Both keywords and free-text terms, related to patient population, predictive factor, and outcome measurements were used. There were no restrictions in languages or year of publication.

Study Selection:

Seven articles were included in this systematic review. Articles eligible for inclusion: (a) investigated cochlear implantation of any CI system in adults with post-lingual onset of deafness and normal cochlear anatomy; (b) investigated the relationship between angular insertion depth and speech perception; (c) measured angular insertion depth on imaging; and (d) measured speech perception at, or beyond 1-year post-activation.

Data Extraction and Synthesis:

In included studies; quality was judged low-to-moderate and risk of bias, evaluated using a Quality-in-Prognostic-Studies-tool (QUIPS), was high. Included studies were too heterogeneous to perform meta-analyses, therefore, effect estimates of the individual studies are presented. Six out of seven included studies found no effect of angular insertion depth on speech perception.

Conclusion:

All included studies are characterized by methodological flaws, and therefore, evidence-based conclusions regarding the influence of angular insertion depth cannot be drawn to date.

Shape of the Cochlear Basal Turn: An Indicator for an Optimal Electrode-to-Modiolus Proximity With Precurved Electrode Type

OBJECTIVE

The objective of this study was to determine the shape of cochlear basal turn through basic cochlear parameters measurement. The secondary aim was to overlay an image of the precurved electrode array on top of the three-dimensional (3D) image of the cochlea to determine which shape of the cochlear basal turn gives optimal electrode-to-modiolus proximity.

MATERIALS AND METHODS

Computed tomography (CT) preoperative image-data sets of 117 ears were made available for the measurements of cochlear parameters retrospectively. Three-dimensional slicer was used in the visualization and measurement of cochlear parameters from both 3D and 2D (2-dimensional) images of the inner ear. Cochlear parameters including basal turn diameter (A), width of the basal turn (B), and cochlear height (H) were measured from the appropriate planes. B/A ratio was made to investigate which ratios correspond to round and elliptical shape of the cochlear basal turn.

RESULTS

The cochlear size as measured by A value ranged between 7.4 mm and 10 mm. The B value and the cochlear height (H) showed a weak positive linear relation with A value. The ratio between the B and A values anything above or below 0.75 could be an indicator for a more round- or elliptical shaped cochlear basal turn, respectively. One sized/shaped commercially available precurved electrode array would not offer a tight electrode-to-modiolus in the cochlea that has an elliptical shaped basal turn as identified by the B/A ratio of <0.75.

CONCLUSION

Accurate measurement of cochlear parameters adds value to the overall understanding of the cochlear geometry before a cochlear implantation procedure. The shape of cochlear basal turn could have clinical implications when comes to electrode-to-modiolus proximity.

Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports

OBJECTIVE

To quantify and compare the number of cochlear implant (CI) electrodes found to be extracochlear on postoperative computerized tomography (CT) scans, the number of basal electrodes deactivated during standard CI mapping (without knowledge of the postoperative CT scan), and the extent of electrode insertion noted by the surgeon.

STUDY DESIGN

Retrospective.

SETTING

Academic Medical Center.

METHODS

Two hundred sixty-two patients underwent standard cochlear implantation and postoperative temporal bone CT scanning. Scans were analyzed to determine the number of extracochlear electrodes. Standard CI programming had been completed without knowledge of the extracochlear electrodes identified on the CT. These standard CI maps were reviewed to record the number of deactivated basal electrodes. Lastly, each operative report was reviewed to record the extent of reported electrode insertion.

RESULTS

13.4% (n = 35) of CIs were found to have at least one electrode outside of the cochlea on the CT scan. Review of CI mapping indicated that audiologists had deactivated extracochlear electrodes in 60% (21) of these cases. Review of operative reports revealed that surgeons correctly indicated the number of extracochlear electrodes in 6% (2) of these cases.

CONCLUSIONS

Extracochlear electrodes were correctly identified audiologically in 60% of cases and in surgical reports in 6% of cases; however, it is possible that at least a portion of these cases involved postoperative electrode migration. Given these findings, postoperative CT scans can provide information regarding basal electrode location, which could help improve programming accuracy, associated frequency allocation, and audibility with appropriate deactivation of extracochlear electrodes.

Computational Evaluation of Cochlear Implant Surgery Outcomes Accounting for Uncertainty and Parameter Variability

Cochlear implantation (CI) is a complex surgical procedure that restores hearing in patients with severe deafness. The successful outcome of the implanted device relies on a group of factors, some of them unpredictable or difficult to control. Uncertainties on the electrode array position and the electrical properties of the bone make it difficult to accurately compute the current propagation delivered by the implant and the resulting neural activation. In this context, we use uncertainty quantification methods to explore how these uncertainties propagate through all the stages of CI computational simulations. To this end, we employ an automatic framework, encompassing from the finite element generation of CI models to the assessment of the neural response induced by the implant stimulation. To estimate the confidence intervals of the simulated neural response, we propose two approaches. First, we encode the variability of the cochlear morphology among the population through a statistical shape model. This allows us to generate a population of virtual patients using Monte Carlo sampling and to assign to each of them a set of parameter values according to a statistical distribution. The framework is implemented and parallelized in a High Throughput Computing environment that enables to maximize the available computing resources. Secondly, we perform a patient-specific study to evaluate the computed neural response to seek the optimal post-implantation stimulus levels. Considering a single cochlear morphology, the uncertainty in tissue electrical resistivity and surgical insertion parameters is propagated using the Probabilistic Collocation method, which reduces the number of samples to evaluate. Results show that bone resistivity has the highest influence on CI outcomes. In conjunction with the variability of the cochlear length, worst outcomes are obtained for small cochleae with high resistivity values. However, the effect of the surgical insertion length on the CI outcomes could not be clearly observed, since its impact may be concealed by the other considered parameters. Whereas the Monte Carlo approach implies a high computational cost, Probabilistic Collocation presents a suitable trade-off between precision and computational time. Results suggest that the proposed framework has a great potential to help in both surgical planning decisions and in the audiological setting process.

Clinical investigation of the Nucleus Slim Modiolar Electrode

AIMS

The Nucleus CI532 cochlear implant incorporates a new precurved electrode array, i.e., the Slim Modiolar electrode (SME), which is designed to bring electrode contacts close to the medial wall of the cochlea while avoiding trauma due to scalar dislocation or contact with the lateral wall during insertion. The primary aim of this prospective study was to determine the final position of the electrode array in clinical cases as evaluated using flat-panel volume computed tomography.

METHODS

Forty-five adult candidates for unilateral cochlear implantation were recruited from 8 centers. Eleven surgeons attended a temporal bone workshop and received further training with a transparent plastic cochlear model just prior to the first surgery. Feedback on the surgical approach and use of the SME was collected via a questionnaire for each case. Computed tomography of the temporal bone was performed postoperatively using flat-panel digital volume tomography or cone beam systems. The primary measure was the final scalar position of the SME (completely in scala tympani or not). Secondly, medial-lateral position and insertion depth were evaluated.

RESULTS

Forty-four subjects received a CI532. The SME was located completely in scala tympani for all subjects. Pure round window (44% of the cases), extended round window (22%), and inferior and/or anterior cochleostomy (34%) approaches were successful across surgeons and cases. The SME was generally positioned close to the modiolus. Overinsertion of the array past the first marker tended to push the basal contacts towards the lateral wall and served only to increase the insertion depth of the first electrode contact without increasing the insertion depth of the most apical electrode. Complications were limited to tip fold-overs encountered in 2 subjects; both were attributed to surgical error, with both reimplanted successfully.

CONCLUSIONS

The new Nucleus CI532 cochlear implant with SME achieved the design goal of producing little or no trauma as indicated by consistent scala tympani placement. Surgeons should be carefully trained to use the new deployment method such that tip fold-overs and over insertion may be avoided.

Towards a Complete In Silico Assessment of the Outcome of Cochlear Implantation Surgery

Cochlear implantation (CI) surgery is a very successful technique, performed on more than 300,000 people worldwide. However, since the challenge resides in obtaining an accurate surgical planning, computational models are considered to provide such accurate tools. They allow us to plan and simulate beforehand surgical procedures in order to maximally optimize surgery outcomes, and consequently provide valuable information to guide pre-operative decisions. The aim of this work is to develop and validate computational tools to completely assess the patient-specific functional outcome of the CI surgery. A complete automatic framework was developed to create and assess computationally CI models, focusing on the neural response of the auditory nerve fibers (ANF) induced by the electrical stimulation of the implant. The framework was applied to evaluate the effects of ANF degeneration and electrode intra-cochlear position on nerve activation. Results indicate that the intra-cochlear positioning of the electrode has a strong effect on the global performance of the CI. Lateral insertion provides better neural responses in case of peripheral process degeneration, and it is recommended, together with optimized intensity levels, in order to preserve the internal structures. Overall, the developed automatic framework provides an insight into the global performance of the implant in a patient-specific way. This enables to further optimize the functional performance and helps to select the best CI configuration and treatment strategy for a given patient.

Music perception improves in children with bilateral cochlear implants or bimodal devices

The objectives of this study were to determine if music perception by pediatric cochlear implant users can be improved by (1) providing access to bilateral hearing through two cochlear implants or a cochlear implant and a contralateral hearing aid (bimodal users) and (2) any history of music training. The Montreal Battery of Evaluation of Musical Ability test was presented via soundfield to 26 bilateral cochlear implant users, 8 bimodal users and 16 children with normal hearing. Response accuracy and reaction time were recorded via an iPad application. Bilateral cochlear implant and bimodal users perceived musical characteristics less accurately and more slowly than children with normal hearing. Children who had music training were faster and more accurate, regardless of their hearing status. Reaction time on specific subtests decreased with age, years of musical training and, for implant users, better residual hearing. Despite effects of these factors on reaction time, bimodal and bilateral cochlear implant users' responses were less accurate than those of their normal hearing peers. This means children using bilateral cochlear implants and bimodal devices continue to experience challenges perceiving music that are related to hearing impairment and/or device limitations during development.