Background
Speech perception outcomes after cochlear implantation vary substantially across patients, and reliable predictors remain limited. Morphological changes in the brain during prolonged deafness have been shown to have predictive value and could help model long-term recovery in patients. Specifically, cortical thickness in auditory regions reportedly influences reacquisition of speech comprehension after implantation. Differences in cortical morphology may also exist between unilaterally and bilaterally deaf patients, as unilateral deafness preserves auditory input.
Objective
This study investigates whether cortical thickness in language-related brain regions predicts speech perception outcomes after cochlear implantation and whether these relationships differ between patients with unilateral and bilateral deafness. We also examine how aging affects cortical morphology in the two groups.
Methods
Cortical thickness was extracted from preoperative T1-weighted MRI scans obtained between 2021 and mid 2025, from the same scanner using identical acquisition parameters. Thickness values were derived for regions of the Desikan Killiany atlas using DL+DiReCT. Speech perception scores were obtained during routine postoperative audiological follow-up at multiple time points. Age-related changes in cortical thickness were assessed using regional correlation analyses. To examine associations between cortical morphology and speech outcomes over time, linear mixed effects models were applied with speech perception score as the dependent variable. Models included regional cortical thickness, time after implantation, and their interaction as fixed effects, with age at implantation, sex, and implanted ear as covariates. False discovery rate correction was used for multiple comparisons.
Preliminary Results
Unilaterally deaf patients show a strong negative correlation between age and cortical thickness across most cortical regions. In contrast, this relationship is limited to fewer regions in bilaterally deaf patients, implying differences in how auditory deprivation interacts with aging.
Associations between cortical thickness and outcomes also differ between groups. In unilateral deafness, significant effects are observed mainly in the temporal and frontal regions of both hemispheres. In bilaterally deaf patients, significant associations are predominantly located in the left hemisphere, with inferior frontal and parietal regions showing the strongest relationships.

Objective: To assess long-term structural changes of the primary auditory pathway in single-sided deafness (SSD) using diffusion tensor imaging (DTI). Fractional anisotropy (FA) was used to evaluate white matter integrity within the auditory pathway.
Methods: Five subjects with SSD for more than 10 years and five age- and sex-matched normal-hearing controls were included. DTI was performed on a 3T MRI scanner. The cochlear nucleus (CN) and inferior colliculus (IC) were defined as bilateral regions of interest. FA values were compared between deaf and normal-hearing ears and correlated with duration of deafness.
Results: Pronounced inter- and intraindividual variability in FA values was observed. Mean FA values in the ipsilateral CN were 0.58 ± 0.10 in deaf ears and 0.61 ± 0.14 in hearing ears of SSD subjects, compared with 0.53 ± 0.11 in controls. Mean FA values in the IC ranged from 0.25 to 0.33 across groups. No statistically significant differences in FA values were detected between sides or between deaf and normal-hearing ears, and differentiation using a median-splitting approach was not possible. FA values in the CN did not correlate with duration of deafness, whereas a strong positive correlation was observed in the contralateral IC (r² = 0.98, p = 0.001).
Conclusion: FA values reflect heterogeneous and highly individual microstructural alterations in the auditory pathway in long-term SSD. Although FA did not allow differentiation between deaf and normal-hearing ears, increasing FA values in the inferior colliculus with longer duration of deafness suggest time-dependent neural reorganization rather than uniform degeneration.

Background
Optimizing cochlear implant (CI) outcomes requires balancing effective neural stimulation with preservation of intracochlear structures. While pre-curved arrays aim for closer modiolar proximity, lateral wall positioning may better support structural and residual hearing preservation. However, the relationship between electrode position and outcomes remains unclear, partly due to limited routine use of post-operative imaging. Advanced software such as CImago enables detailed three-dimensional evaluation of electrode location. When combined with physiologic measures from the AIM system (real-time ECochG, automated audiometry, neural response metrics), a more comprehensive assessment of cochlear health is possible.
Aim
To evaluate whether electrode array position using CImago correlates with audiological outcomes and to explore predictors of cochlear health and hearing preservation via the AIM system in a pediatric cohort.
Methods
This predominantly retrospective, multi-center study includes 60 pediatric CI users implanted with Advanced Bionics devices using SlimJ or Mid-Scala electrode arrays. High-resolution pre- and post-operative CT/CBCT scans (≤0.5 mm) will be analyzed using CImago for cochlear dimensions, insertion depth, scalar position (including trans-scalar deviation), and electrode-to-modiolus distance with 3D reconstruction. Clinical measures include impedances, NRI, automated audiometry, M-levels, PTA, and bisyllabic speech discrimination up to 12 months. Intraoperative ECochG will be included where available. Correlation analyses will assess relationships between imaging metrics and clinical outcomes.
Results
Data collection is ongoing. Preliminary findings are expected to show a positive correlation between structural preservation-particularly lateral wall positioning without scalar deviation-and improved hearing preservation. Early trends may also suggest that CiMago-derived metrics help predict impedance patterns and speech outcomes.
Discussion
Integrating imaging with electrophysiology may clarify the clinical impact of electrode positioning. Findings could guide surgical approach, electrode selection, and prediction of hearing preservation, while assessing feasibility of incorporating CiMago into routine pediatric CI practice.
Conclusion
This study aims to establish imaging-based predictors of cochlear health and performance, supporting evidence-based surgical strategies and personalized CI care in a multi-center Indian setting

Objective: The present study sought to assess cortical plasticity with ongoing bilateral cochlear implant (BCI) use in children implanted as infants and to identify potential differences in this development from expected.

Background: Outcomes of BCI in children with congenital deafness are best when the hearing loss is identified and treated early. Yet, even when BCIs are provided at young ages, challenges to language and cognitive development remain, suggesting potential differences from typical auditory development.
This hypothesis was tested using cortical responses measured repeatedly in 35 children receiving BCIs simultaneously at ages under 12 months (mean 10.3 (SD 1.5)) from CI activation to < 72 months of BCI experience (mean 22 (SD 21)). Stimuli were biphasic pulse trains delivered from an apical electrode in 3 conditions: left, right, bilateral. Cortical responses, evoked by acoustic clicks in the same conditions, were also evoked in children with normal hearing aged 50 (SD 18) months. Responses in all children were measured at 62 cephalic sites and the ER-TRAC beamformer was used as in previous work to identify initial auditory detection in left and right auditory cortices.

Results: A significant peak at mean 114 (SD 25) ms was measured in all children and localized to auditory cortices (P1-AC). P1-AC peak latencies were similar in both groups (p=0.43). P1-AC latencies and dipole strength were stable across the age range of the young children with normal hearing (-0.09 ms/month (SE 0.13), p = 0.52; 0.12 (SE 0.10) nAm/month, p = 0.24, respectively). The children with BCI, in comparison, showed subtle decreases in P1-AC latency (-0.42 ms/month (SE 0.07), p < 0.0001) and significant increases in dipole strength (0.07 nAm/month (SE 0.02), p = 0.0002) with BCI use. Further, children with normal hearing showed an increase in ear-driven lateralization to the opposite cortex (left ear to right AC; right ear to left AC) which did not significantly change with age (0.21 %/month (SE 0.21), p = 0.34) whereas children with CIs showed an increase in activity lateralized to the right AC from both ears with BCI use (0.32 %/month (SE 0.15), p = 0.03).

Conclusions: The data reveal auditory plasticity in infants with ongoing BCI use as expected; however, these changes are marked by greater dominance of the right cortical hemisphere than in normal hearing peers. Effects of this unique pattern of cortical activity on functional hearing are being assessed.

Goals
To investigate the relationship between cortical auditory evoked potentials and speech and music perception abilities in pediatric cochlear implant (CI) users.

Material and Methods

Eighty pediatric CI users (mean age 7.27 ± 1.46 years; hearing age 4.36 ± 1.79 years) with prelingual hearing loss and ≥1 year of CI use were evaluated. Speech perception was assessed using the Early Speech Perception battery and Picture Speech Identification (PSI) test. Music perception was evaluated using the Montreal Battery of Evaluation of Musical Abilities (MBEMA). Cortical auditory evoked potentials (CAEP) and mismatch negativity (MMN) were recorded in a calibrated free-field setup. Latency and amplitude measures were analyzed, and regression models were used to identify predictors of perceptual outcomes.

Results

CI users demonstrated reduced speech perception (PSI: 63.68 %) compared to normal-hearing peers (~99 %). Music perception performance (MBEMA) was also reduced, with considerable inter-subject variability across melodic, rhythmic, and memory domains, particularly in melodic discrimination tasks.

Cortical electrophysiological measures showed significant abnormalities, with prolonged latencies and reduced amplitudes across CAEP and MMN components, indicating impaired higher-order auditory processing.

Regression analysis revealed strong predictive relationships between cortical measures and perceptual outcomes (adjusted R² up to 0.822, p < 0.001). N1 and P2 amplitudes of CAEP emerged as significant predictors of speech perception performance, with larger amplitudes associated with better outcomes.

Importantly, music perception abilities demonstrated similar associations with cortical responses, where children with more robust CAEP (N1–P2) amplitudes and shorter MMN latencies exhibited better performance on musical tasks, particularly in melodic discrimination, suggesting a shared neural basis for speech and music processing.

Conclusion

Cortical auditory processing plays a critical role in determining both speech and music perception outcomes in pediatric CI users. CAEP components, particularly N1–P2 amplitudes, serve as sensitive objective markers of higher-order auditory function. These findings support the integration of cortical electrophysiological measures into routine CI evaluation and individualized rehabilitation strategies.

Background: Electrically evoked cortical auditory evoked potential (eCAEPs) offers an objective measure of auditory cortical function, reflecting neural responses in the auditory cortex following electric stimulation. Recently it has been demonstrated that eCAEPs can be measured directly using the Advanced Bionics cochlear implant system itself via back telemetry (CI-eCAEPs), providing a much easier, faster and clinically applicable methodology to obtain eCAEP measurements without the need for a traditional EEG system (1-3). However, the studies so far have been limited to a few research groups using slightly different experiment procedures and data were collected from limited number of patients with substantial inter-subject variability.
Goals: The goal of this multicenter observational study is to use a common experiment setup to collect a significant number of patient data (>100) across multiple CI centers or research sites (>10), globally. This will 1) provide a foundation for a standardized paradigm for potential CI clinical practices 2) generate substantial patient data to assess signal quality and inter-patient variability, and 3) provide access to longitudinal data points to better understand CI-eCAEPs morphology changes as function of CI use over time.
Material and Methods: CI-eCAEP responses will be recorded using BEEP (Bionic Ear Evoked Potential) research system from Advanced Bionics cochlear implant users, including pediatric and adult users. Various stimulation levels will be used (e.g., Sub-threshold level, M level, etc.) to demonstrate response repeatability and statistical significance of the recorded data. For CI recipients undergoing initial implantation, the same recordings will be conducted at multiple time points following CI activation (e.g., 1 month, 3 months, and 6 months). Demographic clinical information such as age, duration of deafness, duration of CI use, speech performance data etc. will also be collected to support post-hoc analysis.
Results: Some preliminary results may be shown at the time of the presentation.
Discussion: The results of this multicenter study will provide first large-scale evaluation of the CI-eCAEP measurements across multiple international sites. These findings will help establish a common framework for measurement procedure; provide insights into signal validity, quality, and repeatability; and contribute to development of characteristic signatures for patients with diverse backgrounds and CI usage.

Measurement of bone conduction hearing remains challenging because the effective excitation of the basilar membrane within the cochlea is not directly accessible in humans. Each of the existing approaches have limitations: human measurements, whether subjective or objective, are time-consuming and offer limited frequency and magnitude resolution; cadaver studies require complex and costly setups and are difficult to obtain; and computational models demand substantial technical expertise and computational resources.
An alternative approach is the use of anatomically realistic, 3D printed head phantoms. A recent model proposed by Irwansyah et al. (2025) incorporates both bone and soft tissue structures and was primarily developed for crosstalk investigations. However, its ability to replicate absolute bone conduction responses has not been systematically evaluated.
In the present study, we assessed the suitability of such a 3D printed head by comparing its 3D vibration patterns at the cochlear location and ear canal pressure with previously reported human data from experimental studies. The analysis revealed that the artificial skin layer in the phantom exhibits lower stiffness than human soft tissue, resulting in reduced low-frequency mechanical impedance. In addition, the phantom demonstrated an occlusion effect peak around 1 kHz that is not observed in human measurements. In contrast, vibration transmission through the artificial skull showed closer agreement with human data, indicating that the bone-like material more accurately replicates human mechanical behavior than the soft tissue analogue.
These findings suggest that while 3D printed head phantoms represent a promising, low-cost and accessible platform for bone conduction research, their current implementation is limited by inaccuracies in soft tissue mechanics. Further refinement of material properties, particularly for skin and soft tissue layers, is necessary before such models can be used for quantitative assessment of bone conduction stimulation in humans.

Introduction: Bone Conduction Hearing Aids (BAHA) are a well-established approach for addressing various hearing pathologies. Motion measurements at the promontory bone are widely considered a good indicator of the actual perceived sound and are therefore a standard reference in bone conduction research. While the directional motion sensitivity of the cochlea is still unclear, certain stimulation locations have been shown to induce motion directionality in space. This study aims to decouple the relationship between stimulation location and promontory motion directionality by introducing stimulation direction as an additional variable in the analysis.
Methods: A customized stimulation technique was developed to independently apply motion into specific anatomical directions, regardless of the location of stimulation. Motion is induced by pressure contact at fixed screw implants placed at several locations over the outer skull bone. The resulting motion response of the promontory bone was recorded using a three-dimensional Laser Doppler Vibrometer (LDV) on ipsilateral and contralateral sides.
Results: Our results demonstrate that altering the direction of stimulation significantly influences the motion pattern of the promontory bone. Although changes in stimulation direction modify the observed motion vector, the resulting motion does not always align with the applied direction. Furthermore, the motion observed at the implant locations also deviate from the stimulation direction and strongly depend on the implant’s location.
Conclusions: These findings suggest that both stimulation direction and location play a critical role in shaping promontory motion characteristics. Incorporating directional control in BAHA design and placement may improve device efficiency and optimize hearing outcomes.
Key words: Bone conduction, skull surface motion, Laser Doppler Vibrometry (LDV), Bone conduction hearing aid (BCHA), motion directionality.

Goals:
Cortical auditory evoked potentials (CAEPs) reflect cortical processing of auditory stimuli and allow objective evaluation of central auditory processing. This study aimed to assess whether CAEPs can be reliably recorded via bone conduction devices and whether responses are sufficient for objective verification of device fitting.

Materials and Methods:
Measurements were performed with the Ponto 5 SP (Oticon Medical). Acoustic stimulation and CAEP recording used the Eclipse system with frequency-specific, speech-like stimuli (ManU-IRU; Manchester University, Interacoustics, Denmark). Stimuli were presented in the free sound field via a loudspeaker. Cortical responses of awake, attentive participants were recorded using scalp electrodes. P1–N1–P2 complex was analyzed for latency and amplitude.

Results:
Twenty participants with sensorineural hearing loss (mean age 49.5 years) were included. Grand average CAEPs showed larger response amplitudes in the aided condition across low, middle, and high narrowband stimuli. The P1–N1–P2 complex was identifiable in 27.8% (not identifiable 72.2%) of unaided recordings, versus 90.3% (not identifiable only 9.7%) in aided recordings. High-frequency detectability was particularly low unaided but high across all frequencies with amplification. Amplitude differences (P1–P2, P1–N1, N1–P2) were significantly larger in the aided condition, latency differences also significant.

Conclusion:
CAEPs can be reliably recorded via the Ponto 5 SP during first-fit without additional adjustments. ManU-IRU stimuli allow clear representation of speech-relevant frequencies. CAEPs are a valuable objective tool for verifying bone conduction hearing devices, especially when subjective testing is uncertain or not feasible.

Hearing impairment represents a major global health burden, affecting over 1.5 billion individuals worldwide, of whom approximately 700 million require intervention (WHO, 2025). Current screening and diagnostic approaches rely heavily on subjective cooperation, limiting their applicability in pediatric, non-cooperative, or cognitively impaired populations.
We introduce a new objective hearing screening methodology that utilizes bone conduction devices as direct stimulation units. This approach enables frequency-specific and intensity-controlled auditory assessment without requiring active patient participation.
The method builds upon existing objective audiological techniques while introducing a key innovation: the integration of bone conduction stimulation directly into the measurement system. This allows standard screening protocols to be adapted for use with hearing assistive devices, including implantable systems.
Compared to current methods such as aided BERA and ASSR, the proposed technique provides frequency-specific information while maintaining compatibility with bone conduction devices—an area where existing methods are limited or unavailable. Furthermore, it enables repeated and reliable measurements without learning effects or patient-dependent variability.
The method can be applied in audiological centers, hearing aid clinics, and screening programs, offering a scalable solution for early detection and monitoring of hearing rehabilitation outcomes. Its implementation could significantly improve diagnostic accuracy and enable personalized treatment pathways, particularly in populations where subjective testing is unreliable.

Objective evaluation of hearing implant performance remains a critical challenge, particularly in patients who cannot provide reliable behavioral feedback. This study presents a novel in situ objective hearing assessment method using bone conduction implants as direct stimulation sources.
The proposed technique enables frequency- and intensity-specific measurements by integrating the implant into standard objective audiological testing frameworks. Unlike traditional approaches, the stimulus is delivered directly through the implanted device, establishing a direct link between the assistive technology and the measured auditory response.
A pilot study was conducted on a cohort of 10 patients implanted with bone conduction devices. Measurements were performed under controlled conditions, assessing the feasibility, reproducibility, and clinical relevance of the method. Preliminary results demonstrate that the approach provides consistent, frequency-specific responses and allows objective evaluation of implant performance both intraoperatively and postoperatively.
Compared to conventional methods such as Bone Conductive ASSR, the new technique offers improved specificity for bone conduction systems and eliminates uncertainties related to external signal transmission. It also enables assessment in non-cooperative patients, including children, under sedation or anesthesia.
The findings support the feasibility of this in situ measurement approach and highlight its potential as a standardized objective tool for implant verification and follow-up. Further studies with larger cohorts are planned to validate clinical applicability and establish normative data.

Goals: The primary objective of this study was to evaluate the objective audiometric performance in noise, simulating real life acoustic environments as well as subjective patient-reported quality-of-life outcomes, in patients with single-sided deafness (SSD) using Baha Connect and Osia piezoelectric systems. We also aimed to assess the correlation between user satisfaction and objective speech recognition measures.
Materials and methods: This monocentric, prospective, cross-sectional study analysed 35 patients (Baha Connect: n = 21; Osia: n = 14). Objective performance was assessed using the Digits-in-Noise (DIN) test to determine speech-in-noise thresholds (SNR50) in front and side listening conditions. Subjective quality of life (QoL) and hearing benefit were evaluated using three standardised questionnaires: The Glasgow Benefit Inventory (GBI), the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing Scale (SSQ).
Results: No significant differences were found between device types for objective SNR50 thresholds or subjective quality of life (QoL) outcomes. A linear mixed-effects model revealed a significant interaction between listening condition and presentation side (p = 0.023). Both groups reported significant subjective QoL improvements (GBI: median 19.4 [13.9–36.1]–18.1 [8.3–35.4]; APHAB benefit: median 5.6 [1.8–18.3]–19.1 [5.4–25.4]; SSQ: median 6.9 [5.9–7.4]–6.3 [5.1–7.3]). No statistically significant differences were found in any of the questionnaires. However, the SSQ spatial subscale remained the lowest-rated domain for both devices (4.0–5.1). Spearman's analysis revealed an absence of correlation between objective SNR50 improvements and subjective questionnaire scores (ρ < 0.20, p > 0.29).
Conclusion: Both systems achieve comparable rehabilitative success for SSD patients and generate high levels of subjective satisfaction, despite minimal objective shifts in speech-in-noise thresholds. The 'clinical disconnect' between objective and subjective measures indicates that bone-conduction hearing implants (BCHIs) provide comprehensive advantages, including reduced listening effort and enhanced social participation, which are not fully captured by standard audiometric tests. While both devices effectively mitigate the head-shadow effect, true spatial hearing remains challenging, underlining the importance o

Goals:
Building on previous work demonstrating that remote impedance measurements can be reliably performed over extended postoperative periods, allowing detailed characterization of impedance dynamics and revealing systematic daily fluctuations with lower evening values as soon as electrical stimulation is present, this study aimed to assess whether dexamethasone reduces mean postoperative impedance and eliminates intra‑day fluctuations compared with conventional FLEX28 electrodes.
Material and Methods:
Participants were assigned to a dexamethasone‑eluting (DEX) or non‑dexamethasone (NoDEX) group based on the cochlear implant electrode type. Impedance was measured twice daily (morning and evening) over four months following surgery using a smartphone application. Primary outcomes were mean impedance levels and intra‑day fluctuations, quantified as the morning‑to‑evening difference (MED). Analyses were descriptive and comparative, using the start of electrical stimulation (t0) as reference. Four postoperative phases were defined: early postoperative (days 1-10), late postoperative (day 11-t0), intensive fitting (t0-day 21), and regular hearing phase (day 22-4 months).
Results:
The DEX group exhibited consistently low and stable impedance values across all phases, without observable effects of t0. Mean impedance was lower in DEX than in NoDEX, reaching high statistical significance from the late postoperative phase onward (p < 0.0001). Intra‑day fluctuations were abolished in the DEX group (MED ≈ 0). In contrast, the NoDEX group showed measurable fluctuations during intensive fitting (DEX: 0.0 kΩ, n = 7 vs. NoDEX: 0.75 kΩ, n = 11, p < 0.001) and the regular hearing phase (DEX: 0.0 kΩ, n = 8 vs. NoDEX: 0.56 kΩ, n = 11, p = 0.02).
Conclusion:
Dexamethasone‑eluting FLEX28 electrodes reduce mean postoperative impedance, ensure stable longitudinal impedance profiles, and eliminate intra‑day fluctuations. These findings indicate a clear stabilizing effect of dexamethasone on early and mid‑term electrophysiological behavior after cochlear implantation.

Goals:
To evaluate postoperative changes in access and polarization impedance in MED-EL cochlear implant users and to assess their clinical usefulness as indicators of the electrode-tissue interface condition.

Material and Methods:
The study included 47 adult cochlear implant users (mean age: 51 years; 30 females, 17 males), with 27 right-ear and 20 left-ear implantations. All patients were implanted with MED-EL cochlear implants from the Mi12xx series. Impedance components were measured using MED-EL research software at four postoperative time points: 3 days, 1 month, 5 months, and 9 months after surgery. Access impedance and polarization impedance were analysed to assess postoperative changes at the electrode-tissue interface.

Results:
Access impedance increased significantly during the early postoperative period, from (2987.5 ± 2365.5 Ω) at 3rd day after implantation to (3953.3 ± 848.0 Ω) at 1 month and (4455.1 ± 1451.5 Ω) at 5 months, with stabilization at 9 months after implantation (4581.5 ± 1743.3 Ω). Significant differences were observed between 3rd day and 1 month (p = 0.007), between 1 and 5 months (p = 0.009), and between 3rd day and 9 months (p < 0.001), while no significant change was found between 5 and 9 months (p = 0.187).
Polarization impedance showed a different pattern, with a marked increase at 1 month (2586.0 ± 1079.9 Ω) compared to 3 days (1445.7 ± 653.9 Ω), followed by a decrease and stabilization at 5 months (1753.7 ± 582.5 Ω) and 9 months (1669.5 ± 664.1 Ω). Significant differences were found between 3 days and 1 month (p < 0.001) and between 1 and 5 months (p < 0.001), while no significant change was observed between 5 and 9 months (p = 0.183).

Conclusion:
Access impedance and polarization impedance show different postoperative dynamics, suggesting distinct biological mechanisms at the electrode-tissue interface. The gradual increase in access impedance may reflect changes in intracochlear conductivity related to healing and fibrous tissue formation, whereas the early peak and later stabilization of polarization impedance may be associated with surface phenomena and foreign body response. Analysis of impedance components may provide clinically relevant information beyond clinical impedance and may serve as a non-invasive biomarker of intracochlear tissue response, potentially improving postoperative monitoring and follow-up in cochlear implant patients.

Goals:
Cochlear implant (CI) candidacy increasingly includes patients with residual hearing, making atraumatic electrode insertion essential. Motorized insertion tools (MITs) aim to standardize electrode insertion and reduce mechanical stress, but their effects compared with manual insertion remain insufficiently understood. We hypothesized that MIT-assisted insertion results in lower postoperative impedance values and improved hearing preservation.

Material and Methods:
In this matched cohort study, 56 adult CI recipients (28 MIT, 28 manual) were analyzed. Patients were matched based on demographic and clinical characteristics including age, preoperative low-frequency pure-tone average, cochlear duct length, and angular insertion depth. CI electrode impedance measurements were obtained intraoperatively and at 1, 3, and 6 months postoperatively. Associations between insertion technique, impedance values, and hearing outcomes were analyzed using a linear mixed-effects model.

Results:
Impedance values showed a characteristic postoperative course with an early peak followed by stabilization over time. MIT-assisted CI insertion was associated with consistently lower postoperative impedance values in the basal cochlear region than manual insertion (median difference -0.7 kΩ to -1.5 kΩ, p ≤ 0.004). Lower impedance values were associated with better residual hearing (p < 0.001). Insertion technique was not significantly associated with hearing preservation (p = 0.69). In patients with substantial preoperative residual hearing, thresholds remained more stable in the MIT cohort at 6 months.

Conclusion:
MIT-assisted CI insertion was associated with lower postoperative impedance values in the basal cochlear region, suggesting a reduced insertion-related intracochlear tissue response. These findings indicate that insertion technique primarily affects the basal cochlea, where mechanical stresses during electrode advancement are greatest. Spatially resolved impedance measurements may provide a clinically accessible biomarker to characterize intracochlear responses to different surgical insertion techniques.

Goals: Electrode impedance telemetry is widely used to monitor the electrode–tissue interface (ETI) in cochlear implant (CI) users. This metric can reveal important biological processes following implantation when analyzed longitudinally and spatially along the cochlear tonotopic axis (Parreño et al., 2020). It has been shown that topic dexamethasone application modulates impedance dynamics, particularly near the basal turn of the cochlea (Ausili et al., 2022). The goal of this study was to investigate longitudinal and spatial impedance patterns along the cochlea over time and to compare the effects of dexamethasone delivery using different electrode designs.
Material and Methods: Impedance measurements were analyzed across CI electrode arrays at multiple postoperative time points. Tonotopic impedance gradients were evaluated along the electrode array. Measurements included clinical monopolar impedance as well as localized four-point configurations designed to probe more spatially restricted regions of the ETI. Impedance was further decomposed into subcomponents associated with access resistance and polarization effects. Comparisons were performed between conventional electrodes and dexamethasone-eluting electrode arrays.
Results: Topical dexamethasone exposure reduced impedance values predominantly in the basal region and modified the spatial impedance gradient along the cochlea. Four-point measurements revealed greater spatial variability across patients. Dexamethasone-eluting electrodes showed more homogeneous impedance patterns along the array. A spatial gradient in impedance suggests that the pharmacokinetic effect of the drug-eluting electrode evolves over time, with the strongest impact initially localized near the drug reservoirs and progressively spreading along the cochlea toward both basal and apical regions. This pattern is consistent with localized pharmacological effects followed by diffusion of the drug along the cochlear length.
Conclusion: Combined spatial and temporal analysis of impedance telemetry reveals tonotopic patterns of electrode–tissue interface dynamics after cochlear implantation. Differences between electrode technologies and stimulation configurations suggest that impedance measurements can provide indirect insights into pharmacological effects and drug dispersion within the cochlea. Spatial impedance analysis may therefore serve as an objective tool for evaluating drug-eluting electrode technologies and cochlear health.

Background & Objective
Cochlear implant electrode status is typically checked infrequently using impedance measurements during scheduled sessions at the clinic or remotely via mobile applications. Little is known about daily impedance variations at home. Understanding these daily changes is key to using impedance as a potential biomarker of cochlear health and detecting clinical events such as altered sound quality, vertigo, tinnitus, or worsening residual hearing levels.
This study tracked daily impedance fluctuations and examined relationships between these fluctuations and contemporaneous clinical data collected from experienced adult CI users.
Methods
Data was collected using a newly developed wireless measurement system operated via a mobile application in the recipient’s home. The mobile app measured total electrode impedance at different time points during the stimulation pulse, enabling separation into access resistance and polarization impedance. It also measured transimpedance matrices and bipolar 4-point impedances to examine near-field and far-field effects around the electrodes and tissue.
Forty-five experienced Nucleus CI users performed impedance and transimpedance measurements five times daily for two weeks and then two times daily for an additional six weeks. Clinical parameters were assessed with a Digit-Triplet speech perception test and device usage logs. Additional data on medication, medical and hearing conditions, and clinically relevant health-related events were collected via questionnaires.
Results
Results showed daily total impedance fluctuations exceeding 2 kOhm in 11 out of 45 participants. Access resistance and polarization impedance displayed different cyclic daily patterns and periods of stronger fluctuation, with some changes correlated with device use, particularly overnight for polarization impedance. Tissue (far-field) impedance changed more slowly and steadily. Speech test results and questionnaires did not reveal significant clinical or perceptual impacts during the study; most reported events were mild or unrelated to the ear.
Conclusion
This study demonstrates that electrode impedance fluctuations can occur without clinical symptoms and that patterns are patient specific. Characterizing these fluctuations helps to define normal ranges for individuals and supports clinicians in interpreting impedance data, as well as providing a baseline for developing detection and prediction models for impedance as a biomarker.

Goals: In the clinic, cochlear implant (CI) electrode impedances help guide electrical stimulation parameters. Electrode impedances directly impact the maximum current amplitude that can be delivered to a given electrode without exceeding the voltage compliance limit; higher impedances reduce the maximum current amplitude allowed. The present study aimed to characterize changes in electrode impedances obtained at multiple pulse durations across patients with either perimodiolar or lateral wall electrode arrays.

Materials and Methods: Electrode impedance was measured at 25, 50, 75, 100, and 150 µs at a fixed current level for 38 CI patients: 21 with perimodiolar (632) and with 17 lateral wall (622) electrode arrays. Impedances were consistently recorded at the end of the first phase of the cathodic-leading biphasic pulse. Analysis was performed on impedance subcomponents including access resistance, Warburg capacitance, and Faradaic resistance in order to better characterize the underlying mechanisms for impedance changes.

Results: Total impedance significantly increased with larger pulse durations across all patients (p < 0.001). Impedances were similar between the 632 and 622 electrode arrays. Warburg capacitance decreased with increases in electrode impedances as a function of pulse duration.

Conclusion: Wider pulse durations lead to higher total impedances. Thus, increasing pulse duration restricts the maximum current amplitude that can be delivered without exceeding compliance limits of the device. This relationship between pulse duration, electrode impedance, and voltage compliance must be considered when attempting to provide increased electrical stimulation on channels nearing the compliance limit.

Introduction: In cochlear implantation (CI), intraoperative measurements of electrically evoked auditory brainstem responses (eABR) are often limited due to time constraints during surgery. Instead, the electrically evoked compound action potential (eCAP) is commonly recorded because it can be obtained rapidly via the electrode array and reflects spiral ganglion cell function and the electrode–nerve interface. However, eABR provides additional information on neural transmission along the auditory pathway, which can be particularly relevant in cases of complications or in patients with limited subjective feedback. The aim of this study was to develop and evaluate a measurement setup for the simultaneous acquisition of eCAP and eABR.
Methods: During CI implantation with the FLEXsoft electrode array (MED-EL), intraoperative eCAP and eABR measurements were performed simultaneously at the apical electrode pair (E2–E3). Twenty-one stimulation levels (0–25 qu, 500 repetitions each) were presented, and an additional AutoART control measurement (up to 40 qu) was obtained. eCAP responses were analyzed using the N1–P2 complex, while eABR responses were evaluated based on the ej5 component. Amplitude growth functions (AGFs) were derived to determine response thresholds, and correlations between eCAP- and eABR-derived parameters were analyzed.
Results: Seventeen implanted ears were included (mean age 62.2 ± 18.6 years). eCAP responses were detectable in 94.1% of cases, whereas eABR responses were measurable in 76.5%. Mean AGF thresholds were 13.9 ± 3.4 qu for eCAP and 12.2 ± 2.0 qu for ej5. eCAP thresholds obtained with ART correlated significantly with AutoART thresholds (R = 0.66, p = 0.014). Strong correlations were observed between eCAP thresholds and ej5 thresholds (ART–ej5: R = 0.75, p = 0.0047; AutoART–ej5: R = 0.78, p = 0.004).
Conclusion: Simultaneous acquisition of eCAP and eABR during cochlear implantation is technically feasible and allows assessment of neural responses at both the peripheral and brainstem levels within a single stimulation paradigm. Thresholds derived from amplitude growth functions proved to be robust and physiologically meaningful parameters, showing strong correlations between eCAP and ej5 responses. Combining both electrophysiological measures may therefore improve the objective evaluation of auditory pathway function and support clinical CI fitting and neural monitoring.

Abstract
Background: Electrically evoked auditory brainstem responses (eABRs) offer an objective measure of auditory pathway function, reflecting neural activity in the auditory nerve and brainstem structures. To date, eABRs have been predominantly acquired using external, conventional electrophysiological (EP) recording systems in conjunction with intracochlear electrical stimulation. While this approach is well established in research and has demonstrated clinical utility, it relies on separate recording hardware and far-field scalp electrodes, which may limit its clinical application. An integrated recording framework capable of acquiring eABRs directly through the cochlear implant system may overcome this limitation and enable robust and streamlined objective auditory assessments.
Goals: This study evaluates the clinical feasibility and neurophysiological validity of direct cochlear implant-based eABR recording (CI-eABR) using Advanced Bionics cochlear implant system.
Material and Methods: CI-eABR responses were obtained from two setups: 1) test bench with simulated response, and 2) cochlear implant users. Responses were recorded directly via intracochlear electrodes. CI-eABR responses were also compared with conventional eABR recordings obtained using an EP system in a subset of cochlear implant users.
Results: Bench testing confirmed stable acquisition, appropriate artifact rejection, and reliable waveform extraction under controlled conditions bilaterally. In human cochlear implant users, robust CI-eABR responses were successfully recorded on the ipsilateral side, with peak latencies falling within established ranges for eABRs. In the subset of subjects with concurrent scalp recordings, strong concordance in waveform morphology and latency was observed. Additionally, CI-eABR recordings demonstrated substantially larger amplitudes consistent with near-field recording characteristics.
Conclusion: These findings support the feasibility of direct eABR recording through the cochlear implant platform and, to our knowledge, represent the first demonstration of a fully implant-based approach for rapid, objective auditory assessment in clinical applicable settings.

GOAL Objective measures of neural responsiveness can help the setting of thresholds and most-comfortable loudness (MCL) levels for individual cochlear-implant (CI) users. ALternating-Frequency Interleaved Electrical Stimulation (ALFIES) is a method for recording cortical responses to sustained fast-rate electrical stimuli in CI users. It uses 2 high-rate, interleaved, amplitude-modulated (AM) pulse trains that, when recorded with an EEG system, contain electrical artefacts at the AM frequencies but, importantly, not at their distortion product. It successfully extracts neural responses from these electrical artefacts while using stimulation parameters broadly similar to clinical coding strategies. We investigated recording ALFIES using the CI electrodes and embedded telemetry system.
METHODS Ten ears with Cochlear CIs (8 users, 2 bilateral) were stimulated at MCL with 2 interleaved AM high-rate pulse trains (respectively modulated at F1=76/82/88 & F2=111/120/129Hz). We simultaneously recorded the responses from the CI itself (NIC4.3 research platform, recording in gaps between pulses) and a custom-designed 264-kHz EEG. The NIC4.3 and 264kHz-EEG data were investigated for significance of power at the frequencies of the quadratic (QDP: F2-F1=35/38/41Hz) and cubic (CDP: 2F1-F2=41/44/47Hz) distortion products between the 2 AM rates. The group delay of the distortion products was then calculated using their frequency-to-place functions to distinguish between neural and artefactual responses and to estimate the locus of any neural generator.
RESULTS Two of ten ears showed significant CDPs with group delays consistent with thalamic/cortical generators (16.9–54.1ms), and two others showed significant QDPs, one with a long group delay (34.1–42.1ms) and one with a short group delay (1.1-4.0ms). The responses recorded with CI telemetry were partially consistent with the simultaneous measurements from the EEG system.
CONCLUSION It’s possible to record neural responses to ALFIES stimuli using the hardware of the CI itself, although these aren’t always consistent with EEG measurements, and may reflect different neural generators. It’s also not possible to record in all CI users, and may be limited by the area covered by the dipole between the CI recording electrodes. We have recently optimised the stimulus parameters so as to maximise the neural response measured using the EEG system, and it is possible that this may also optimise responses measured via CI telemetry.

Goals
Electrically evoked stapedius reflex (ESR) measurements provide objective means for fitting the cochlear implant (CI) recipient’s audio processor (Spivak LG. & Chute PM. Ear Hear 1994:15(2):184). Post-operative ESRs are measured as changes in the middle-ear admittance using probe tones. Typically, a 226 Hz probe tone is used. However, the ESR threshold (ESRT) values can be better measurable at higher frequencies (Wolfe J. et al. Ear Hear:2017:38:255). Here, we compare ESR amplitude growth functions (AGFs) and ESRTs measured simultaneously at four probe tone frequencies.
Material and Methods
ESRs were measured on 22 ears of 16 experienced CI users. All of them implanted with MED-EL devices. 300-ms-long bursts of biphasic pulses were presented from electrode contacts #2, #6 and #10 using the MAESTRO software. Responses for four probe tones (226, 678, 904 and 1130 Hz) were recorded simultaneously using a Sentiero Desktop hardware. The ESRT level was defined as the smallest stimulus strength required to elicit a deflection of 0.02 cc (or higher). The slope of the ESR AGF was characterized with an analytical method (Skidmore J. et al. Ear Hear:2022:43(1):150).
Results
In agreement with (Wolfe J. et al. Ear Hear:2017:38:255), the success rate of the ESRT measurement depended on the frequency (p < 0.01): the three higher probe tones achieving, on average, 26.3 percentage unit higher success rate than 226 Hz. ESRTs were, on average, approximately 3.3-qu (charge unit) lower at higher probe tone frequencies (p < 0.001). Steeper lopes of the ESR AGF were observed with the higher probe tone frequencies (p < 0.01). In addition, on average, 2 times larger response amplitudes could be observed with other probe tones at the threshold level for 226 Hz (p < 0.01). The ESRTs were found to correlate with the MCL values, with all probe tone frequencies (p < 0.01, for all), despite that the audio processors of the participants had been adjusted based on subjective feedback.
Conclusion
The findings of this study bolster the idea of recording ESRs simultaneously with multiple probe tone frequencies in clinical practice. When doing so, ESRTs can be obtained at lower stimulus strength and the success rate is less dependent on the admittance of the middle ear at a single probe tone frequency. The steeper ESR AGF slopes and the larger response amplitudes ease reliable detection of the reflex.

Goals
The primary objective of this study was to evaluate the clinical utility and feasibility of measuring Electrically Evoked Stapedius Reflex Thresholds (eSRT) across a diverse population of cochlear implant (CI) users. Specifically, the study aimed to identify electrode-specific response rates and determine the impact of eSRT based programming on clinical maps.
Material and Methods
We conducted a retrospective analysis of 99 ears from 85 CI users, ranging in age from 6 to 82 years. Length of implant use varied from 1 month to 26 years (average=9, SD=7.5), with many long-term users. The users were from all three cochlear implant manufacturers: The number of ears were Cochlear -59, Advanced Bionics – 26, Medel -14. Those tested included people with one implanted ear (72) and bilateral implant users (13). In 37 of the ears tested, the eSRT was elicited ipsilaterally with the probe in an ear with an implant. For each subject, the reflex was tested on a range of 2 to 15 electrodes (mean = 9, SD=2.86). Measurements were used to adjust programming levels. To assess the influence of the eSRT on the mapping we compared the maximum values of the behavioral maps the subjects arrived with to the new maps that were adjusted using the eSRT values.
Results
The eSRT was successfully elicited across most of the electrodes tested (mean – 87%). While the overall average rate of no response was only 13%, there was a much higher percentage of no response (27 % of the electrodes tested) in the basal end. In 85 ears a new map was created based on the eSRT measurement. Comparison between the pre-test and post-test maps revealed that eSRT guided adjustments resulted in a significant difference in mapping levels for a high percentage of the users.
Conclusion
This study provides clinical evidence supporting the significant role of the eSRT as a powerful tool in the mapping procedure, identifying cases of under and over stimulation even in long term cochlear implant users. The significant differences found between behavioral and eSRT based maps highlight the importance of incorporating objective measures to optimize CI fitting even in experienced users.

Goals:
Cochlear implants (CIs) are a recommended intervention for individuals who derive minimal to no benefit from conventional hearing aids (USFDA, 2021). Despite extensive CI research, discontinuities remain in evidence-based guidance for programming. Manufacturer training and recommendations exist, but there are no widely accepted benchmarks to guide clinical management. Unlike the American Academy of Audiology (AAA) guidelines for hearing aid fitting, CI programming lacks consistent high-level evidence. Following a scoping review identifying seven relevant studies, we leveraged expert experience to contextualize findings through structured discussion and voting. Our goals were to identify knowledge gaps, define clinical programming approaches, and establish best-practice recommendations for a standardized programming protocol.

Material and Methods:
A mixed model exploratory sequential design was used for the study. Six experts were recruited to represent and balance the panel with those who used primarily objective approaches and those who used primarily subjective approaches. The Nominal Group Technique (NGT) was used in two 1.5-hour online meetings for reaching consensus on comfort (C/M/MCLs) and threshold levels (T/THRs). Discussions allowed peers to expand on their technique(s) and clarify any unclear concepts. Panelists then voted for their top programming approaches, based on the literature review, expertise, and discussions.

Results:
The panel reached consensus on best practice recommendations for C/M/MCLs and T/THRs. The standardized protocol outlined using the electrical stapedial reflex (eSRT) in conjunction with subjective measurements for C/M/MCLs across the electrode array for all three manufacturers. T/THRs, however, are to be optimized by measuring every other electrode for Cochlear Limited, select electrodes for Advanced Bionics, and using a hard set of 10% of C/M/MCL for MED-EL devices.

Conclusion:
Our study represents an initial step towards developing a standardized CI programming protocol using an evidence-based approach. By using the Nominal Group Technique (NGT), we established a framework that centered on eSRT-based objective programming while integrating subjective cross-checks. The resulting protocol provides a practical roadmap for clinical implementation, offers a standardized pathway to improve patient outcomes, and serves as a foundation for future CI programming research.

Goals: Existing Nucleus devices use monopolar stimulation (MP) that recruits neurons up to some distance on either side of the stimulating electrode. The new CochlearTM Nucleus® NexaTM implant uses simultaneous multipolar stimulation to focus the current field, allowing the spread of current to adjacent sites to be controlled or eliminated. However, there are additional parameters to tune in comparison to MP modes of stimulation. Our experience with behavioural fitting of focused multipolar stimulation (FMS) indicates that threshold (T) and comfortable levels (C) are more variable across electrodes for MP, such that standard interpolation techniques cannot be successfully applied.

Materials and Methods: This study investigated three different methods of fitting experimental sound processor programs using FMS with the Nexa smart implant research system. A behavioural single-channel T profile was obtained using an automated Von Bekesy method, while ECAP thresholds (tNRT) were used to create two objective profiles employing different focusing levels. T and C profiles were then adjusted using six channel groups to account for loudness summation. Fourteen new CI recipients used the behavioural fitting for three months, then trialled the new programs in a balanced cross-over design. Outcomes included Spanish HINT (SNR50), word recognition in quiet, SSQ12 questionnaires, and clinician fitting experience.

Results: Objective profile-based programs were simpler to fit than behavioural profile programs, with less time spent adjusting T and C levels. Final profiles were quite similar between behaviourally and objectively derived programs. There were often large variations in FMS T and C levels across channels (~80 CL) unlike for MP (~30 CL), and these were captured in tNRT profiles. Further analyses of the relationships between the tNRT, and T and C profiles will be provided at the time of presentation.

Speech recognition in noise was not significantly different between programs (with < 1 dB mean differences). Word scores in quiet and SSQ12 scores were also not significantly different between programs.
Conclusions: These preliminary results demonstrate that simpler objective-measure based fittings may produce equivalent performance to behavioural profile fittings for FMS in cochlear implants. The time taken to perform ECAP measurements can be optimised such that the total time taken to fit would be shorter for objective versus behaviourally fit programs.

Background: In the 21th century, medicine in total is rapidly moving towards the direction of personalized and individualized treatment options. According to the broad variety of sensorineural hearing loss there are new technologies (due to artificial intelligence) for providing patients with severe to profound inner ear hearing loss with cochlear implants and speech processors on an individually anatomy-based fitting strategy (ABF).
The aim of this study is to evaluate the influence of personalized anatomy-based fitting strategies on the outcome of cochlear implanted (CI) patients regarding audiological aspects like speech recognition, music perception and sound quality in comparison to non ABF fitting procedures.

Methods: A cohort of cochlear implanted patients with either single sided deafness or asymmetrical sensorineural hearing loss is included. Two strategies of CI fitting – ABF (according to digital radiological imaging and frequency channel detection) and non ABF (with standardized logarithmic frequency mapping) starting with the initial activation of the cochlear implant system are implemented in two study comparison groups. Outcome in speech recognition (number and CVC monosyllables), music perception tests and questionnaires including sound quality were evaluated 3 months and 6 months post first CI fitting.
Digital radiological imaging was also used for preoperative planning and the decision of CI electrode length.

Results: Preliminary evaluation shows comparable audiological results in speech recognition but better outcomes in music perception.

Conclusion:
Anatomy-based frequency fitting (ABF) may provide speech and music reception in a more natural way than the common used CI fitting procedures.

Objective. The aim of this study was to evaluate whether the SOE width is a marker capable of identifying cochlear dead zones and deleterious channel interaction, proposing a cut-off point to predict electrodes to be deactivated and observe the impact on speech recognition. Methods. Prospective, cross-sectional study, approved by the ethics committee of a tertiary care hospital, under protocol 3.974.822. Adult patients with post-lingual hearing loss, CI users for more than 1 year with stable stimulation levels, and speech recognition outcomes higher than 50% were included. Patients with absent neural responses, double-peak SOE function, or incomplete insertion of the electrode array were excluded. The SOE width in millimeters was measured on electrodes e16, e11 and e6 at 75% transection level of the function. Four maps were programmed and saved in the sound processor: program in use (PU), and programs with the deactivation of e6 (PD6), e11 (PD11), and e16 (PD16). Recorded lists of 25 monosyllables in silence presented at 0° azimuth at 65 dBSPL were used to assess recognition in each program. The position of each map in the processor and the order of presentation of the monosyllables lists were randomized. Analyzes were performed using SPSS 21 software for Windows and the significance level used was p < 0.05. Results. Ten patients were recruited and accepted to participate in the study, signing the free and informed consent form, with two bilateral participants, totaling twelve evaluated ears, 6 ears implanted with straight arrays and 6 with perimodiolar arrays. Using the ROC curve (p < 0.05), the cutoff point of 3 mm was found as the best point of specificity and sensitivity for electrode deactivation. 100% of patients who had SOE equal or greater than 3 mm on e16 and e11, when deactivated, improved in monosyllable recognition (p < 0.05). The improvement ranged from 4 to 12%. The basal region of the cochlea (e6) has a higher Neural Response Telemety Threshold and SOE. Conclusion. The SOE width from 3 mm was efficient to identify the deleterious channel interaction in the apical and medial region of the cochlea (e16 and e11), guiding the deactivation to improve monosyllabic recognition in quiet.

Goals: Following the introduction of the new NEXA cochlear implant, the default stimulation parameters have been updated. The Slim Modiolar (CI1032) electrode now uses a pulse width (PW) of 45.6 µs, rather than the standard 25 µs (e.g. CI632). Electrically evoked compound action potential thresholds (T-ECAPs) using AutoNRT with NEXA implants have so far been measured using a pulse width of 24.8 µs. The most recent version of the Custom Sound Fitting Software (v7.1.270.128) now uses a PW of 45.6 µs for NEXA users in AutoNRT.
Since the stimulation pattern of the hearing nerve is changed, ECAP thresholds should also differ. The aim of the study is to investigate the effect of the two different PWs on the T-ECAPs.

Materials and methods: So far, we have retrospectively analyzed 20 adult cochlear implant users with CI1032, correct cochlear electrode placement, and no other known pathological findings. Measurements with PW 24.8 µs and 45.6 µs were taken during routine postoperative checks.

Results: Preliminary results show a success rate of 96% (PW 45.6 µs) and 98% (PW 24.8 µs) in finding T-ECAPs. In average T-ECAPs with PW 45.6 µs are 33.0 (STD 5.4, range: 19-45) current levels (CL) lower than with PW 24.8 µs. The mean absolute T-ECAPs are 136.8 (STD 16.9, range: 120-169) CL and 169.5 (STD 16.6, range: 151-200) CL with PW 45.6 µs and PW 24.8 µs, respectively. Patients reported fewer “too loud” stimulations with the new PW 45.6 µs.

Conclusion: Using a pulse width of 45.6 µs results in lower T-EACPs. Although early data suggests that the both T-ECAP profiles follow a similar course from apical to basal, further data is required to confirm that individual electrodes do not exhibit additional effects. The higher pulse width may also be more acceptable in terms of loudness during AutoNRT for some subjects. However, the longer pulse width also affects comfort and threshold level adjustments. Therefore, correlation between comfort levels and T-ECAPs needs to be reconsidered.

Background
Despite advances in cochlear implant (CI) technology, understanding speech in noisy environments continues to be a persistent difficulty for users. This challenge is particularly relevant in densely populated and acoustically complex settings, including tier-3 cities in India where traffic, crowd activity, and enclosed public spaces generate high and fluctuating background noise levels. Even with optimized CI programming, speech perception (SP) often declines significantly as signal-to-noise ratio (SNR) worsens. Adaptive digital modulation (DM) systems, such as Roger technology, are designed to enhance the speech signal relative to background noise and may offer meaningful improvements in both controlled and everyday listening situations.
Objective
This multicentric Indian study examined the effectiveness of Roger adaptive DM technology on speech perception in unilateral CI users across clinical and real-world environments.
Methods
Thirty unilateral CI users (aged 13–58 years) were evaluated using 13 different combinations of CI program settings and Roger microphone configurations. Assessments were conducted in a two-room audiology setup and in real-world environments including a hospital waiting area, cafeteria, and programming room. In the audiology setting, speech-in-noise (65 dB HL) was delivered at 90° azimuth on the CI side, while recorded sentences were presented from 0° azimuth at a 1.5 m distance. Mean ambient noise levels in real-world settings were 59 dB SPL (waiting area), 69 dB SPL (cafeteria), and 43 dB SPL (programming room).
Results
All Roger configurations significantly enhanced speech recognition scores (SRS). The most effective setup-Roger Select-IN in lanyard beamformer mode positioned 6 inches from the speaker-achieved 50% SRS at −20.3 dB SNR (±2.06), compared to −12.9 dB in SIN mode (UltraZoom + SNR Boost) (p=0.0001). In real-world conditions, SRS improved by 38% (SD 0.98) in the waiting area, 48% (SD 1.04) in the cafeteria, and 16% (SD 0.66) in the programming room.
Conclusion
Roger technology significantly enhances speech perception, particularly in noisy environments, supporting its application in varied real-life listening scenarios and complex auditory conditions.

Objectives
Prolonged high frequency deprivation may hinder cochlear implant (CI) adaptation in adults with sensorineural ski slope hearing loss, yet implantation is often delayed because of high preoperative low frequency thresholds and large variability in CI outcomes. This study examined whether preoperative audiogram characteristics, residual hearing loss, and duration of hearing loss relate to one year postoperative speech recognition in quiet and noise, and quality of life, in adults with ski slope hearing loss. We hypothesized that timely implantation—reflected by better preoperative thresholds and shorter hearing loss duration—leads to better CI outcomes.

Design
A retrospective review included 166 Dutch speaking adults with ski slope hearing loss who received a unilateral CI or electric acoustic stimulation (EAS). One year outcomes included speech recognition in quiet (Dutch NVA test) and noise (Dutch Digits in Noise test), and quality of life (Nijmegen Cochlear Implant Questionnaire, NCIQ). Associations between preoperative audiogram characteristics, residual hearing loss, and duration of hearing loss with postoperative outcomes were assessed using correlation analysis. Linear regression evaluated individual and interactive effects of preoperative low frequency thresholds and slope steepness on postoperative speech recognition in quiet.

Results
One year after implantation, aided speech recognition in quiet and quality of life improved significantly. The mean postoperative speech reception threshold in noise was −2.5 ± 2.4 dB SNR. Correlation analysis showed that (1) a higher frequency corresponding to the maximum slope, (2) lower (better) preoperative 1 kHz threshold, and (3) shorter duration of hearing loss predicted better postoperative speech recognition. Loss of residual hearing and thresholds at 250–500 Hz and 2–4 kHz did not. A lower 1 kHz threshold unexpectedly predicted worse postoperative NCIQ Activity scores. Linear regression showed that poorer low frequency hearing and steeper slopes predicted worse outcomes, although the negative effect of a steep slope diminished as low frequency hearing worsened.

Conclusions
Cochlear implantation in adults with ski slope hearing loss improves speech recognition in quiet and quality of life. Preoperative audiogram characteristics and hearing loss duration meaningfully relate to CI outcomes, emphasizing the importance of timely referral for this population.

Background and Objectives

Optimizing auditory brainstem implant (ABI) programming in children requires precise and individualized parameter adjustment. In very young patients, reliable behavioral feedback regarding auditory perception and speech understanding is often limited or unavailable. As a result, clinicians frequently lack objective indicators of whether auditory input reaches and is processed at higher neural levels.
This study investigates the feasibility of implementing the CORGEE system—an electroencephalography (EEG)-based method originally developed for hearing aid users—within routine pediatric ABI care. The primary aim of this study is to assess the feasibility of integrating EEG recordings into the routine clinical workflow of pediatric ABI care. Specifically, this investigation evaluates whether EEG can reliably provide clinically applicable, real-time objective measures of auditory perception and early speech-related neural processing in pediatric ABI users under everyday clinical conditions.

Materials and Methods

Pediatric ABI users undergo EEG recordings during auditory stimulation with natural, continuous speech using a child-adapted EEG protocol (CORGEE, Brainphonics) integrated into routine ABI appointments.
Neural speech envelope tracking during continuous speech stimulation serves as the primary electrophysiological marker. This approach quantifies the synchronization between cortical activity and the temporal envelope of speech and is considered an early neural correlate of speech processing.

Results

Data collection is ongoing. Preliminary analyses currently include a preliminary number of 5 pediatric ABI users. EEG recordings were successfully implemented during routine ABI appointments, demonstrating practical feasibility within the clinical setting. Cortical responses to continuous speech stimulation were measurable in some participants. Interindividual variability in neural tracking strength was observed, which may reflect differences in auditory performance, neural development, or variability in ABI-mediated auditory input.

Conclusions

The integration of EEG-based neural speech tracking into routine pediatric ABI care appears feasible and provides objective information about early neural speech processing. This approach may support clinical decision-making during ABI programming when behavioral feedback is limited and could enable objective monitoring of auditory development during early rehabilitation.

Goals: Cortical auditory evoked potentials (CAEPs) have proven effective in optimizing cochlear implant (CI) fitting (Távora‑Vieira et al., PLOS ONE 2022:17:10), yet their applicability for active middle ear implants (aMEIs) and bone conduction implants (BCIs) remains unclear. This study investigated whether CAEP‑guided fitting could enhance hearing outcomes in adult aMEI and BCI users. Materials and Methods: CAEPs were recorded with a 32‑channel EEG system in response to LING sounds /OO/, /AH/, and /SH/, covering low-, mid-, and high-frequency regions, presented at 55 dB SPL in sound field. If robust CAEPs were observed for all stimuli, no adjustments were made. When responses were absent, map parameters in the corresponding frequency regions were optimized in 5–10 dB steps until a cortical response was elicited or loudness tolerance was reached. Functional benefit was assessed via pre‑ vs post‑optimization adaptive speech-in-noise performance (BKB‑SIN), and subjective feedback was collected. Results: Fifteen participants were enrolled; one was excluded. Three required no optimization, nine were successfully optimized using CAEPs, and two could not be optimized. Univariate analyses of CAEP responses showed significant pre‑ vs post‑optimization differences for the /AH/ sound in the N1-P2 time windows; multivariate pattern analysis (MVPA) additionally identified differences for the /SH/ sound in the P2 time window. The optimized subgroup (N = 9) showed a significant ~9.4 dB SNR improvement in pre‑ to post‑optimization speech-in-noise performance (overall effect of condition: F(2,21) = 60.69, p < 0.001). Participants were generally satisfied with the procedure. Conclusion: These findings demonstrated that middle- and high-frequency tokens could be successfully optimized using CAEPs, resulting in significant improvements in hearing performance and subjective benefit. Our results support the use of CAEPs for the optimization of aMEI and BCI adult users' fitting.

Relationship Between Electrically Evoked Compound Action Potential and Behavioural Responses in Subjects with Auditory Brainstem Implants
Background: Auditory Brainstem Implant (ABI) is indicated for individuals who cannot benefit from cochlear implantation due to cochlear nerve deficiency or severe cochlear malformations. Programming and electrode mapping in ABI users, especially pediatric recipients, is challenging because behavioural responses may be inconsistent and non-auditory stimulation is frequently reported. Objective electrophysiological measures such as Electrically Evoked Compound Action Potential (eCAP) and Electrically Evoked Auditory Brainstem Response (eABR) are therefore used to support clinical decision-making during device programming. However, the relationship between these objective measures and behavioural auditory outcomes in ABI users remains unclear.
Aim: To evaluate the relationship between eCAP characteristics, eABR responses, and behavioural outcomes in pediatric ABI recipients.
Methods: Five pediatric non-NF2 ABI recipients were included. eCAP responses were recorded using Automated and Manual Auditory Response Telemetry and analysed for waveform morphology, latency, and amplitude growth function (AGF). eABR recordings were analysed retrospectively for waveform morphology and peak identification. Behavioural responses were assessed electrode-wise during programming sessions and classified as auditory or non-auditory. Associations between electrophysiological responses and behavioural outcomes were analysed across electrodes.
Results: eCAP morphology showed inter-subject variability and was categorised into four patterns ranging from absent responses to well-defined waveforms at higher charge levels. AGF slopes were present in several electrodes but varied across subjects. eABR responses were obtained in most electrodes with variable waveform patterns. Behavioural auditory responses showed partial correspondence with objective measures, while non-auditory responses were observed at higher stimulation levels. No consistent one-to-one correlation was identified.
Conclusion: eCAP and eABR provide useful supplementary information for ABI programming but cannot independently predict behavioural outcomes. A combined approach integrating objective measures with behavioural observation is essential for effective and safe ABI mapping in pediatric populations.
Keywords: ABI, eCAP, eABR, Pediatric Audiology, Objective Measures

Goal
The study examined the relationship between electrically evoked auditory brainstem response (EABR) characteristics, mapping parameters, and functional listening outcomes in children with Auditory Brainstem Implants (ABI). It also investigated how findings relate to auditory perception, listening abilities, and speech–language development.
Method
A cross-sectional correlational case study was conducted with four pediatric ABI users (Participants A, B, C, and D) who had at least six months of device experience. Participants A, B, and C received primary ABI implantation due to cochlear aplasia, while Participant D received an ABI after CI explantation. All participants had unilateral implantation with MED-EL Synchrony devices. Electrophysiological assessment included intraoperative and postoperative recording of EABR, analyzing waveform morphology, Wave III and Wave V latencies, and amplitude. Mapping data included active electrodes, stimulation thresholds, M-levels, and electrodes causing non-auditory stimulation. Functional listening outcomes were measured using caregiver questionnaires and clinical auditory tests such as aided audiometry, Ling Six Sound Test, CAP, MAIS, MUSS and LIP. Speech and language outcomes were assessed using REELS and SIR.
Results:
The age at implantation ranged from 1.8 to 4 years, device use ranging from 6 months to nearly 6 years. EABR Wave III and Wave V responses were observed in Participants B and C, indicating effective brainstem activation, while no responses were identified in Participant A and data were unavailable for Participant D. Participant A showed minimal auditory benefit (CAP score 0) and no awareness of Ling sounds. Participants B and D demonstrated aided thresholds within the speech range, consistent identification of all Ling sounds, and CAP score of 5 and 6 respectively. Participant C showed emerging auditory awareness. Participants with measurable EABR responses tolerated more active electrodes and stable stimulation levels. Participant A required conservative programming. Participant D’s programming relied on behavioral responses and gradual mapping adjustments. Participants B and D were enrolled in mainstream schools with functional communication abilities, whereas Participant A primarily relied on visual communication.
Conclusion: The present study highlights the importance of EABR, individualized mapping, continuous rehabilitation, and multidisciplinary support for optimal functional development

Goals
Predicting individual speech outcomes after cochlear implantation remains unsolved, complicating patient expectation management. Explained variances typically range from R2 = 0.07 to 0.27. Prediction errors remain too large for precise medical counselling, even using powerful statistical models. It is unclear if this reflects insufficient model capability or a fundamental limit in the available predictor space. We compare statistical models across prediction tasks and discuss their clinical relevance.

Material and Methods
We retrospectively analysed a large single-centre (Zurich) adult cohort from the Swiss National Cochlear Implant Database. Using cross-validation, we compared linear models, ensemble methods, and a tabular transformer foundation model across varying feature sets and imputation strategies. Tasks evaluated included continuous outcome prediction, binary risk classification (performance decline, poor outcome), and unsupervised phenotyping of post-operative speech profiles.

Results
No model achieved clinically useful prediction of individual post-operative scores. Pre- and post-operative score distributions showed patients across hearing-loss severities converging to overlapping outcome ranges, limiting variance for regression. Reframing as binary risk classification—identifying likely performance decliners or poor performers—was substantially more successful. Onset type, contralateral hearing, and hearing loss duration emerged as consistent risk factors. Unsupervised clustering of post-operative speech profiles revealed distinct subgroups, including atypical multidimensional patterns, but these could not be predicted from pre-operative data alone.

Conclusion
The limit to predicting CI outcomes appears informational rather than algorithmic due to strongly overlapping variance. Key variables likely explaining individual differences (e.g., neural survival, cognition) are absent from current clinical databases. We propose alternatives to score prediction, specifically pre-operative risk screening and post-operative profiling, to guide rehabilitation and improve CI outcomes.

Introduction
IFT Heat map is a colour coded and numerical visualization that of the impedance status of the electrode array. It allows a visual evaluation of the impedance status of the entire electrode array, enabling in idenfying the problem channels (short circuit, high impedance, extra cochlear electrodes, high ground path impedance etc). Lighter colors indicate higher current flow and the Darker colors represent lower current flow. A consistent transition from light to dark with increasing distance from the stimulated electrode suggests optimal electrode performance.
Aim
The aim of this study is to identify possible impedance heat map patterns for various electrode array status.
Method
Impedances from 500 patients using MED-EL implants were studied. A total of 14 patients with various problems in the impendence like high impedances,high ground path impedance, incomplete insertion, short circuit were taken up for this study. Additional information like case history, AutoART and post- op X-Ray was taken to analyze.
Result
The heatmap changed with the change in the impedances. Lighter colour in heatmap indicate higher impedance value and darker colour in heatmap indicate lower impedance values.
In 4 patients with higher impedance, the colour was darker on the channels with high impedance, which is possibly because channels with high impedance have lower voltages across all measuring channel.
In 3 patients with high ground path impedance, the colour representation on heatmap is abnormal. Generally categorized as random colours in random places possibly because overall impedance gets affected since the reference electrode itself id high.
In 5 patients with incomplete insertion, the impedances of the electrodes that are extra cochlear are higher or normal, however are represented by darker color in basal channels even if impedance was normal or high.
2 patients had short circuit on some channels. The impedance and field telemetry flagged them as short circuit and the heat map indicated those channel with lighter colour.
Conclusion
To conclude the heatmap is a useful visual tool for assisting the audiologist for identifying patterns and area of concern in deciding the further action needed.

Goals: Despite cochlear implants (CI) being the most successful neural prosthetic device to-date1,2, damage to residual hearing still occurs in approximately 30% of patients3,4. Insertion force (IF) is a physical mechanism by which damage to residual hearing may occur and can vary based on patient factors, surgical approach and CI selection5. Individual temporal bone anatomy, particularly mastoidectomy shape and posterior tympanotomy (PT) alignment, can constrain the operative approach during CI insertion and coiling. Despite significant research efforts into “soft surgery” techniques, lead coiling in the mastoid cavity following implantation has been largely overlooked in terms of its potential impact on insertion trauma6. This study aims to investigate how intracochlear IF may vary during implantation by mastoid anatomy and coiling technique using 3D printed cochlea models in a high-fidelity surgical simulation.

Methods: Mastoidectomy and PT were performed on four cadaveric temporal bones. Micro-CT scans of specimens were then obtained and segmented to produce surface reconstructions. A custom MATLAB script was used to characterise cochlea anatomy and align mastoid cavities to a representative scala tympani model. One cochlea and four interchangeable mastoidectomy models were then fabricated using high-resolution 3D printers and integrated into a CI simulation platform enabling continuous single- and six-axis force sensor measurements and video recordings during manual cochlear implantation.

Results: Mean mastoid cavity volume lateral to PT was 3.93ml (standard deviation (SD) 0.57) and mean facial nerve-chorda tympani angle was 35.35 (SD 15.33). Mean PT width and length, at an angle with adequate visualisation of the RW, were 2.45mm (SD 0.38) and 8.38mm (SD 0.57). During intracochlear CI insertion, IF peaked highest in the axis of electrode advancement with smaller peaks in the vertical axis. However, during CI coiling in the mastoid cavity IF peaked in the vertical axis.

Conclusion: This study demonstrated variations in peak and axial IFs at different stages of CI insertion and coiling. Higher IFs in the vertical axis during coiling may indicate an increased risk of damage to the basilar membrane and result in poorer hearing outcomes based on the patient’s remaining frequencies of residual hearing. These findings may help to inform surgical decision-making during lead coiling to further optimise hearing preservation and CI performance in patients.

Goals:
The aim of this study was to establish a standardised protocol for measuring the postauricular muscle reflex (PAMR), and to characterise short- and mid-latency responses in adults with normal hearing under controlled conditions. The long-term goal is to evaluate the potential of the PAMR as an objective measure of auditory function, particularly in populations where behavioural feedback is limited, such as cochlear implant users.

Material and Methods:
Electromyographic recordings of PAMR were obtained from 43 normal-hearing adults using surface electrodes placed over the postauricular muscle. Auditory stimuli (50 ms tone bursts at 500, 1000, 2000, and 4000 Hz; 80–100 dB SPL) were presented monaurally under varying conditions of stimulation side (ipsilateral/contralateral) and eye position (forward/rotated). Data were processed to extract reflex amplitude and latency, and analyzed using linear mixed-effects models to assess the influence of experimental variables.

Results:
Short-latency PAMRs (10–25 ms) were observed in 98% of participants, with contralateral stimulation producing significantly stronger responses and lower thresholds (p < 0.001). A novel mid-latency PAMR (37–50 ms) was identified in 91% of participants, exhibiting lower amplitude and higher thresholds. Both reflex types were significantly modulated by stimulation side, eye position, frequency, and intensity (all p < 0.001). Gender had a moderate effect (p = 0.044), while age was not significant for short-latency responses.

Conclusion:
This study demonstrates that PAMR is a robust and modifiable reflex in normal-hearing adults, with consistent detection across participants. The identification of a mid-latency component expands the understanding of PAMR physiology. These findings support PAMR’s potential as an objective auditory measure, with promising implications for CI users, particularly in the context of closed-loop calibration and maximum comfort level estimation.

Goals:
This international multicenter study evaluated whether objective, context-aware analysis of cochlear microphonic (CM) amplitude decreases (events) from electrocochleography (ECochG) can predict hearing preservation during cochlear implantation. The secondary goal was to determine whether additional ECochG features, such as CM phase and the auditory nerve neurophonic (ANN), enhance the predictive value of CM events.

Material and Methods:
In 112 cochlear implantations performed at tertiary referral centers in Melbourne, Bern, and Zurich, real-time ECochG and electrode impedance were recorded via the implant’s telemetry system. Objective algorithms automatically extracted CM amplitude, CM phase, and ANN amplitude from the ECochG recordings, as well as CM events from the resulting continuous CM amplitude. The approximate location of each CM event was derived from the impedance measurements.
Inclusion criteria were a preoperative hearing threshold not greater than 85 dB HL at 0.5 kHz, and CM amplitudes exceeding 5 μV. Univariate and multivariable logistic regression assessed CM events distinguished on location and persistence (non-recovery of CM amplitude) with hearing preservation at 3 months after surgery (≤25% loss in the 0.25–1.0 kHz pure-tone average). A post hoc analysis examined the ANN:CM amplitude ratio and CM phase stability as additional predictors.

Results:
Persistent CM events and those occurring near the end of electrode insertion were strongly associated with loss of residual hearing (adjusted OR 31.6 [95% CI 6.4–205.4] and 53.0 [95% CI 8.0–472.6], respectively). Events accompanied by an increasing ANN:CM ratio or stable CM phase were associated with better hearing preservation (mean differences 24.4% [95% CI 7.3–41.5%] and 20.9% [95% CI 2.9–38.9%], respectively). Confounders such as age, preoperative hearing, and implantation center had no significant influence.

Conclusion:
Automated analysis of real-time ECochG can be used to objectively predict residual hearing during cochlear implantation. Persistent CM events and those occurring near the end of electrode insertion are strong predictors of hearing loss. The ANN:CM amplitude ratio and CM phase can potentially be used to distinguish negligible CM events from those related to loss of residual hearing. These findings motivate the development of automated intraoperative feedback systems to guide cochlear implantation and improve hearing preservation outcomes.

Background
One method for assessing the integrity of hair cells during CI insertion is recording the cochlear microphone potentials (CMP). When measuring CMPs before the round window membrane (RWM), its opening results in a doubling of amplitudes (+6 dB increase). Reasons could be an electric phenomenon due to the isolation of the RWM, or a hydromechanic phenomenon of the cochlea, where pressure and vibration are changed. Measurement of CMPs at an unaltered point outside the cochlea during insertion in parallel to the one over the CI could contribute to clarifying the mechanisms involved.

Materials and methods
In three patients we recorded CMPs using the apicalmost electrode contact (1) of the CI before and after opening the RWM and continuously during robotic electrode insertion. Simultaneously, we recorded the CMPs with a J-shaped electrode at the promontory outside the cochlea (2) through a clinical ECochG system. The CMPs’ evolution was measured from two different sites in parallel.

Results
With closed RWM the CMPs outside the cochlea were larger than those over the electrode array’s tip. Fundamentally different measurement devices and amplifying methods (CI vs. ECochG system) are sufficient explanations for this observation. When opening the RWM, the CMP measured at (2) were stable compared to (1) where the amplitude about doubled, as had been observed earlier. During insertion, the amplitude recorded from (1) showed large variations corresponding to the insertion dynamic and the recording site within the cochlea, while the potentials remained comparatively stable in (2).

Conclusion
Regarding the effect on the CMP amplitude, observations suggest, that the RWM predominantly presents as electrical isolation rather than affecting hydromechanical properties. The large amplitude variation in (1) can be explained by the position of the measuring electrode relative to the generator or by the electrode blocking the basilar membrane. Reductions in amplitude can be due to increasing distance from the generator or such blockage. Observing amplitudes at (1) may help with cochlear frequency mapping and may support surgeons during the insertion. Stable and robust CMPs at site (2) during insertion seems of greater value when aiming for structure preservation. The two measurments complement another.

Goals
Residual hearing after cochlear implantation could contribute to hearing performance of cochlear implant (CI) users. However, the extent to which objective measures of residual cochlear function predict hearing performance remains unclear. In this study, we investigated to which extent speech perception in noise and spectral resolution is related to electrocochleography (ECochG) and pure-tone thresholds one year after cochlear implantation.

Material and Methods
Forty-eight adults with severe sensorineural hearing loss, aged 25 to 93 years, were enrolled in a randomized controlled trial (CIPRES; Jwair et al., 2021), which compared surgical approaches (round window versus cochleostomy) and CI electrode array types (lateral wall versus perimodiolar) of Advanced Bionics. Intraoperatively and at four moments postoperatively (1.5, 3, 6 and 12 months), residual cochlear function was assessed using unaided pure-tone average (PTA) and ECochG, including cochlear microphonic (CM) and auditory nerve neurophonic (ANN). Speech perception in quiet and in noise (CVC words, 5 and 10 dB speech to noise ratio) and spectral resolution (spectral-temporally modulated ripple test, SMRT; Aronoff & Landsberger, 2013) were assessed at 12 months postoperatively.

Results
Preliminary analyses in 24 participants showed that 58% had both CM responses and tone perception, which changed to 39% at 12 months. At 6 months, 25% of the participants showed a CM without tone perception, compared to 43% at 12 months. Individuals that exhibited a CM , ANN and tone perception performed significantly better in SMRT than individuals that exhibited CM and ANN without tone perception (p = 0.02). CM explained 40% of variance in SMRT (p = 0.01). Adding PTA and ANN did not improve the model. None of the predictors CM, PTA and ANN explained variance in CVC in quiet or in noise.

Conclusion
Residual cochlear hair cell survival as reflected by CM contributes to non-linguistic auditory processing after cochlear implantation.

Goals: This study examined the association between intraoperative cochlear microphonic (CM) response patterns obtained via intracochlear electrocochleography (ECochG) during electrode insertion and postoperative loss of residual hearing (RH) in cochlear implant recipients. A secondary aim was to determine whether electrode array configuration and etiology of hearing loss provide additional explanatory value in predicting hearing preservation outcomes.

Material and Methods: A retrospective analysis was conducted on cochlear implant recipients with preoperative RH implanted at Ghent University Hospital between August 2019 and December 2025 using Slim Straight or Slim Modiolar arrays (Cochlear Ltd., Sydney, Australia) and Slim J or Mid-Scala arrays (Advanced Bionics, Valencia, CA, USA). Continuous CM recordings were obtained from the most apical electrode contact during insertion using 250 Hz and/or 500 Hz acoustic stimuli. Outcomes measures included CM response pattern classification (Harris et al. 2024), maximal CM amplitude (µV), and hearing preservation, defined as the absolute shift in low-frequency pure-tone average (LFPTA; 250 - 500 Hz) between pre- and postoperative assessments.

Results: Forty-two patients (mean age 50 years) were included. The mean absolute LFPTA shift was 27.7 dB HL (SD 20.67). Postoperative short-term follow-up was 5 weeks (SD 3.7), with a range from 1 to 17 weeks. Complete hearing preservation was observed in 42.9% of patients, while complete loss of RH occurred in 2.4%. Type A CM patterns were most frequent (42.9%). CM response pattern, electrode array configuration, and etiology of hearing loss were not significant predictors of LFPTA shift. Although no statistically significant associations were identified, estimated marginal means suggested a trend toward smaller LFPTA shifts in Type A, C and CC patterns compared with Type B and D.

Conclusion: Intraoperative CM response pattern, electrode configuration, and etiology of hearing loss did not significantly predict postoperative RH. Nonetheless, observed trends indicate potentially more favorable hearing preservation for CM patterns A, C, and CC. Larger prospective studies are needed to validate these findings and further determine the clinical relevance of CM response patterns during cochlear implantation.

Goals:
To evaluate whether a novel multi-frequency electrocochleography (ECochG) algorithm reduces drop alarms and alters insertion track patterns compared to conventional single-frequency ECochG during cochlear implant (CI) electrode insertion.

Material and Methods:
Multi-institutional cohort study across 18 high-volume CI centers. Adult CI candidates with residual low-frequency hearing (≤90 dB HL at 500 Hz) undergoing implantation with an Advanced Bionics Ultra 3D device were included (2024–2025). Intraoperative ECochG was recorded using simultaneous stimulation at 125, 250, 500, and 1000 Hz. A post hoc comparison was performed using the same recordings to evaluate single-frequency (500 Hz) versus multi-frequency algorithms. A ≥6 dB amplitude decrease defined a drop alarm. Insertion track patterns were classified and compared between approaches.

Results:
A total of 195 ears were analyzed. The mean number of drop alarms was significantly lower with multi-frequency ECochG (0.42; 95% CI 0.31–0.53; median 0) compared to single-frequency ECochG (1.72; 95% CI 1.52–1.92; median 1; P < 0.001). Multi-frequency ECochG reduced the prevalence of Type C insertion patterns and decreased Type D (no-response) patterns, while increasing more favorable insertion trajectories. These findings suggest improved signal specificity and broader cochlear response detection.

Conclusion:
Multi-frequency ECochG is associated with significantly fewer drop alarms and more favorable insertion track patterns compared to single-frequency ECochG. These findings support improved discrimination between true cochlear trauma and electrode advancement effects, potentially reducing false-positive alarms and unnecessary intraoperative adjustments. This approach may provide a more accurate real-time assessment of cochlear status during CI insertion and represents a promising advancement in intraoperative monitoring.

Goal: Post inflammatory medial meatal fibrosis (PIMMF) is a rare hearing impairment that can cause different levels of conductive hearing loss due to progressive fixation of tympanic membrane (TM). In this experimental study, we investigated the use of the middle ear implant Vibrant Soundbridge (VSB, MEDEL, Austria) as a treatment strategy.

Methods: We used ten temporal bone specimens to simulate PIMMF with two degrees of TM fixation: (1) gel loading of the TM (Agar-Agar, Bacteriological; Carl Roth GmbH, Karlsruhe, Germany) and (2) total fixation using cyanoacrylate glue (Sekundenkleber, UHU GmbH & Co. KG, Bühl, Germany).These conditions were identified using tympanometry and the middle ear transfer function using laser Doppler vibrometry (LDV). The stapes vibration measurement was used to assess the effectiveness of sound transmission in three different coupling modalities of the VSB.

Results: Stapes velocity measurements in temporal bone specimens showed that the stapes head (SH) coupler attached to the FMT generally produced the highest velocity levels, particularly in the speech-relevant frequency range. Progressive stiffening of the tympanic membrane (TM) significantly reduced (p < 0.05) transmission for short process (SP) and long process (LP) incus couplers at low frequencies, whereas SH coupling was not affected. However, these changes remained mostly below 5 dB at frequencies between 0.5 and 4 kHz.

Conclusion: Overall, increasing TM rigidity—simulating PIMMF—compromised SP and LP electromechanical stimulation, while SH coupling demonstrated an advantage over LP and SP coupling under strongly stiffened TM conditions.

Background & Aim: The Contact Forte system from BHM Inc (Grafenschachen, Austria). is a non-implantable bone conduction device allowing different wearing options. Our aim was to evaluate the audiological performance of two of its wearing options—an adhesive adapter and headband—worn unilaterally and bilaterally.

Material & Methods: Both ears of 15 subjects with normal hearing were occluded to simulate a bilateral conductive hearing loss. The average hearing threshold became 45dB HL (500 to 4000 Hz). Measurements were performed in unaided conditions, with Contact Forte devices (unilateral and bilateral), with a headband, and with the self-adhesive wearing option. Speech understanding was measured in quiet (Freiburg words) at 50 and 65 dB and in noise (OLSA) in a diffuse noise field.

Results: The self-adhesive adapter option resulted in a mean improvement in free sound field hearing thresholds of 16.3 dB for unilateral fitting and 19.1 dB for bilateral fitting. With the headband, the thresholds were, on average, better by 1.0 dB. Word understanding in quiet improved by 58 % to 75 % and was slightly better with the headband (3 %) and with two devices (5%). In background noise, speech understanding from the front was improved by an average of 2.8 dB. When speech was presented from the contralateral side, speech understanding deteriorated slightly by -0.8 dB with the unilateral fitting, whereas bilateral fitting led to an improvement of +4.2 dB. In noise, there was no significant difference between the headband and the self-adhesive adapter.

Conclusions: Significant improvements in speech understanding in quiet and noise were found, both with the headband and with the self-adhesive adapter. Using a bilateral fitting can improve speech understanding in noise.

Background: This study presents a methodology for the numerical and experimental validation of finite-element models of bone specimens under bone conduction.
Methods: Using an exemplary calvarial bone piece from a fresh-frozen cadaver head, several model geometries were generated to evaluate the influence of cortical bone and diploë volume definitions obtained through automatic and semi-manual segmentation. A mesh convergence study based on eigenfrequencies was performed for all segmentations to minimize variability caused by element type and size. Point frequency response functions (FRFs) were compared to assess segmentation-related differences. For experimental validation, a spatial registration procedure based on metal fiducials was developed. Material properties of one selected model were then fitted to one-dimensional laser Doppler vibrometer measurements of the bone piece under both dry and wet conditions.
Results: The mesh convergence study limited natural-frequency variability to below 1% for the selected quadratic mesh. Point FRFs across all segmentations showed only minor differences, particularly below 10 kHz. After manual fitting, the model showed good agreement with measured FRFs up to 10 kHz in both dry and wet conditions, and vibration pattern similarities above 90% were obtained for at least four mode shapes in each case.
Conclusions: The proposed methodology can be extended to larger sample sizes to assess material property variability across individuals. It can be the basis for related applications such as automatic model updating for parameter identification, and experimental validation of individualized full-head bone conduction hearing models.

Hearing loss affects more than 1.5 billion people worldwide, with approximately one third requiring rehabilitation according to the World Health Organization. Around 15% of these cases are related to conductive hearing loss, where bone conduction hearing implants (BCHI) provide an effective treatment option. However, objective intraoperative methods to verify implant performance are currently lacking.
We propose a novel objective measurement protocol that enables intraoperative assessment of BCHI efficiency by using the implant itself as the stimulation source. The method integrates frequency- and intensity-specific measurements into existing objective audiological frameworks, allowing real-time verification of implant placement and function during surgery.
Unlike current techniques such as aided brainstem evoked response audiometry (BERA) and auditory steady-state response (ASSR), the proposed approach directly stimulates via the implant, eliminating signal distortion caused by external transmission pathways. This enables more accurate evaluation of device functionality and patient-specific auditory response under anesthesia.
Its intraoperative application has the potential to reduce revision surgeries, optimize implant positioning, and improve long-term rehabilitation outcomes. The method is designed for integration into implant centers and surgical workflows, providing clinicians with a reliable, objective tool for real-time decision-making during BCHI implantation.

Bone conduction depends strongly on the dynamic behavior of the skull, yet the contribution of subject-specific skull geometry to response variability remains insufficiently understood. This study aims to investigate geometric skull variability by comparing individualized models with a validated 3D-printed skull model.
Individualized full-head models derived from CT scans were reduced to the cranial bone structure only, while all non-bony tissues were omitted. To isolate geometric effects, the material properties of the validated 3D-printed skull were assigned to the cranial bone in all models. Harmonic finite element analyses were then performed to compare the vibratory response of the validated 3D-printed skull model with the segmented skull models. In addition, different segmentation and structural assumptions were assessed by considering masks with open or filled cavities and by comparing cortical-bone-only representations with models that explicitly include the diploë layer.
The proposed comparison framework allows geometry-driven variability to be separated from variability introduced by segmentation and skull representation. The analyses show how differences in skull shape, cavity treatment and internal bone layering affect the predicted vibratory response of the skull in bone conduction applications.
The presented first-generation framework provides a systematic basis for assessing the influence of skull geometry on bone conduction simulations. It further highlights the importance of segmentation choices, cavity representation and diploë modeling when developing anatomically informed skull models for bone conduction research and related applications.

Introduction: Bone conduction hearing aids (BCHA) are widely used for patients with conductive hearing loss and single-sided deafness. However, their effectiveness is limited by rapid transcranial transmission and low transcranial attenuation, resulting in sometimes unwanted bilateral cochlear stimulation and impaired binaural hearing. Directed ultrasound (DU) stimulation has been proposed as a novel approach to selectively activate a single (ipsilateral) cochlea, while minimizing unwanted contralateral stimulation in conventional bone conduction (BC) stimulation.
Methods: Five normal-hearing participants were enrolled in this experimental study. DU stimulation was delivered using a commercially available transcranial pulse stimulation (TPS) device (Neurolith, Storz Medical, Switzerland). An optimal stimulation location and orientation were determined individually through psychoacoustic-based manual search. A bone-anchored hearing aid (BAHA) was used as a BC stimulus reference, psychoacoustically calibrated to match the perceived loudness of the DU. Acoustic responses were recorded using six calibrated microphones positioned at the outside and inside of the ipsilateral and contralateral ear canals, nasal cavity, and forehead surface (via a surface microphone). Signal timing and amplitude were analyzed to assess transcranial transmission and attenuation for the DU versus the BC stimulation.
Results: No significant differences were observed between DU and BC stimulation in relative timing or amplitude between ipsilateral and contralateral measurement sites, indicating comparable transcranial transmission and attenuation characteristics within the skull bone. However, absolute sound pressure levels were consistently 4–30 times lower for ultrasound stimulation across all measured locations, despite similar reported psychoacoustic stimulation levels.
Conclusions: DU stimulation resulted in reduced overall skull activation, at the same psychoacoustic level, relative to BC stimulation. The induced BC response, under DU stimulus, showed similar behavior to conventional BC. This supports the DU potential for localized cochlear activation. Further studies incorporating spatial registration of the DU simulation focus and controlled ex-vivo experimental conditions are needed to better understand the stimulation mechanism and its clinical applicability.

Goal
The aim of this study was to evaluate whether impeded biomechanics of the basilar membrane influence hearing preservation after cochlear implantation with flexible lateral wall electrode arrays. Preservation of residual hearing is an important objective in cochlear implantation and may be related to proper propagation of the travelling wave along the basilar membrane. Intracochlear electrocochleography (ECochG) allows assessment of cochlear responses to acoustic stimulation and can indicate potential alterations in cochlear mechanics.
Material and Methods
Seventeen adult cochlear implant recipients (9 females, 8 males; mean age 47 years) implanted with MED-EL flexible electrode arrays were included in the study. All implants were inserted via the round window approach. Intracochlear ECochG responses were recorded from implant electrodes using a 500 Hz tone pip presented at the maximum comfortable level. Postoperative CT imaging was used to determine electrode insertion depth and estimate the cochlear location corresponding to the 500 Hz characteristic frequency using the Greenwood function. Patients were classified into a tonotopy group, when the electrode with the maximal ECochG response corresponded to the predicted excitation area, and a non-tonotopy group when the maximal response occurred at least two contacts away. Audiological thresholds before and after implantation were compared between the groups.
Results
The mean electrode insertion depth was 515°. In 16 of 17 cases the electrode reached the region corresponding to 500 Hz excitation. Nine patients were classified into the tonotopy group and eight into the non-tonotopy group. In the tonotopy group, the maximal ECochG amplitude corresponded to the expected tonotopic location. In the non-tonotopy group, the maximal response was shifted from the predicted region, suggesting altered basilar membrane biomechanics. However, statistical analysis showed no significant differences in postoperative hearing thresholds or hearing preservation between the two groups (p > 0.05).
Conclusions
These preliminary results suggest that impeded biomechanics of the basilar membrane do not necessarily affect hearing preservation after cochlear implantation with flexible electrode arrays. Further studies with larger cohorts are required to better understand the relationship between cochlear biomechanics and functional outcomes.

OTOPLAN is surgical planning tool that helps choose the optimal electrode array before cochlear implant surgery. It gives detailed information about the shape and size of the cochlea and how the electrode fits inside each cochlea.
Aim
Aim of this study is to determine accuracy of OTOPLAN in choosing the electrode array. It also examines features of the electrode array that are important when selecting an electrode array.
Method:
Data from 181 ears were reviewed. OTOPLAN was used to measure the cochlea’s length, diameter, width and height. The study also checks how the electrode fits - how deep it goes in (angular insertion depth), how much of the cochlea it covers, and what anatomical frequency each channel is most sensitive to (tonotopical frequency). The study then compared the tonotopic frequency predicted for each channel by OTOPLAN to the ones used by the cochlear implant system (seen in Maestro). A smaller difference between these two means a better match.
Results:
1. In all 181 ears, the electrode array recommended by OTOPLAN was used successfully without problems during surgery.
2. The mean cochlear duct length was 33.4 mm, diameter of cochlea was 8.7 mm, width of cochlea was 6.3 mm and height of cochlea was 2.8 mm.
3. There is a strong correlation between angle of insertion & percentage of cochlear coverage with mismatch between frequency.
4. The linear regression analysis between angle of insertion and frequency mismatch yielded the following equation:
Mismatch of Frequency= 994.5−1.463 × (Angle of Insertion)
The coefficient of determination (R^2) was 0.98, indicating high reliability.
5. The linear regression analysis between percentage of cochlear insertion and frequency mismatch yielded the following equation:
Mismatch of Frequency= 1008−1289 × (% Cochlear Insertion)
The coefficient of determination (R^2) was 0.98, indicating a high reliability of the model.
Conclusion:
OTOPLAN is a helpful tool for planning cochlear implant surgery in ears with normal anatomy. This recommendation should rely on factors like size of the cochlea as well as other features of electrode array like percentage of cochlear coverage and angle of insertion of each electrode array. In order to have perfect matching, angle of insertion recommended is 680 degrees and percentage of cochlear coverage is 78%.

Goals:
Surgical manipulation in cochlear implantation can generate traumatic intracochlear pressure transients [1]. At present, these pressure changes cannot be measured in vivo. To address this limitation and enable real-time surgical feedback, we propose and validate a non-invasive, surgically applicable approach for estimating intracochlear pressure transients.
Materials and Methods:
We estimate intracochlear pressure transients by measuring pressure variations in the external auditory canal, exploiting reverse pressure transmission through the ossicular chain. The setup consists of an infrasound microphone coupled to the ear canal via a non-compliant tube and an ear tip. A customised acquisition software setup enables the synchronised recording of pressure and surgical video, allowing for precise temporal labelling of surgical manoeuvres. System functionality was validated by gentle tapping of the incus, and pressure was monitored during the pre-insertion, insertion, and post-insertion phases.
Results:
Recordings were obtained from 15 cochlear implant surgeries, with successful system validation in all cases. Across all surgical phases, we identified frequent pressure transients associated with manoeuvres such as implant re-grasping, aspirator use, and facial recess sealing, consistent with previous in-vitro and ex-vivo findings. During insertion, pressure fluctuations were temporally associated with implant manipulation. Peak levels reached 134 dB SPL during facial recess sealing. A continuous pulsatile component corresponding to heart rate was observed in all surgeries.
Conclusions:
We present a simple, non-invasive system for estimating intracochlear pressure transients that could enable direct surgical feedback during cochlear implantation. We validated the in vivo feasibility of the acquisition setup and observed clear signatures of intracochlear pressure transients in ear canal pressure. Further signal processing is required to improve the isolation of intracochlear pressure transients from the physiological cardiac component.