DeJong, Melissa D.

Background/Objectives: Speech perception is measured in quiet and in the presence of background noise, such as multi-talker babble (MTB), to establish cochlear implant (CI) candidacy and measure post-operative outcomes. Testing protocols often use interrupted noise that begins just before and ends shortly after the target sentence, providing insufficient time for the noise-reduction algorithms to activate in the hearing device and provide an improved signal-to-noise ratio (SNR). Furthermore, interrupted noise does not allow the hearing-impaired user to acclimatize to the abrupt onset of noise or to focus on the target sentence, a challenge related to auditory stream segregation. The present study compares speech perception in bimodal CI users across interrupted and continuous MTB noise conditions to highlight performance differences between these two distinct listening environments. Methods: Speech perception was evaluated for two different bimodal CI groups. Group 1: This group evaluated an automatic hearing aid program across three environments: quiet, continuous MTB, and interrupted MTB. Group 2: This group evaluated two manual hearing aid programs across the same three environments (quiet, continuous, and interrupted MTB). Results: For Group 1, scores in quiet reached 88%, significantly declined in interrupted MTB (38%), but improved in continuous MTB (67%). For Group 2, no significant mean differences were found between interrupted and continuous noise across the two manual programs, though individual variations persisted. Conclusions: Based on the findings of this study, continuous noise rather than interrupted noise should be utilized for establishing CI candidacy and evaluating post-implantation speech perception.

Objective: Auditory nerve monitoring through electrically evoked compound action potentials (eCAP) can be used to assess cochlear neural integrity during vestibular schwannoma (VS) resection. Herein, we report on 5 cochlear implant (CI) patients who underwent VS resection with present eCAP responses both intraoperatively and postoperatively. Patients either did not perceive any sound through their CI or rapidly adapted to electrical stimulation, suggesting that the presence of eCAP does not guarantee auditory nerve function in patients with VS resection. Patients: Five patients who underwent simultaneous VS translabyrinthine resection and cochlear implantation. Interventions: Simultaneous cochlear implantation and translabyrinthine microsurgical VS resection. Main outcome measure: Electrically evoked compound action potential. Results: All patients had eCAP responses present during their VS resection and for at least 50 days post-surgery. Three of the 5 patients did not perceive any sound with their cochlear implant. This shows that the presence of an eCAP alone does not guarantee a functional auditory nerve or auditory perception. The other 2 patients could hear non-speech sounds, but these sounds quickly became inaudible, indicating that their auditory nerve lacked the ability to integrate the electrical stimulus over time. Conclusions: The presence of an eCAP response does not guarantee auditory sensation through a CI. Although eCAP measurements provide insight into the function of the distal end of the nerve, it does not ascertain integrity or function of the larger auditory nerve pathway. Therefore, eCAPs should not be used in isolation to monitor auditory nerve function during VS resection.

Objective: The Complete Cochlear Implant Care (CCIC) model is a highly coordinated care delivery model reducing and condensing in-person visits for cochlear implant (CI) patients, leveraging telehealth and remote programming. Clinical, quality-of-life, implementation, patient experience, and financial outcomes of the clinical trial are reported. Study design: Prospective, nonrandomized, 2-arm clinical trial Setting: Tertiary referral CI center Patients: Adult CI candidates Interventions: Cochlear implantation Main outcome measures: Speech perception, quality of life, implementation, patient experience, and financial outcomes for both CCIC and traditional care delivery models. Results: Patients participating in the traditional and CCIC delivery models demonstrated 12-month postoperative speech perception scores comparable to nationally reported outcomes (CNC 61% and 72% and AzBio in quiet 75% and 87% for traditional and CCIC cohorts, respectively). Quality-of-life evaluation using the CIQOL-10 demonstrated similar 12-month postoperative scores between groups (52 and 54 for traditional and CCIC cohorts, respectively). The CI Patient Experience Survey demonstrated high satisfaction outcomes in ease of communication, preparedness for surgery, and overall care in both cohorts. Implementation analysis of the CCIC model revealed perceived benefits from staff and clinicians; however, support for expansion of the program was contingent upon the availability of app-based or web-based remote programming technology. Finally, financial analysis revealed decreased out-of-pocket costs for CCIC patients. Conclusion: The CCIC model has the potential to dramatically streamline hearing health care delivery and reduce out-of-pocket costs for CI recipients. Clinical outcomes between cohorts were comparable in this feasibility study; however, a sufficiently powered trial is required to definitively comment on clinical outcomes with the new care delivery model.

Objectives To compare electrical stimulation and speech perception in vestibular schwannoma (VS) patients across treatment modalities and standard cochlear implant (CI) patients. Study Design Retrospective review. Setting Tertiary academic center. Patients Sixty-seven CI ears consisting of 23 standard CI controls and 44 VS patients with ipsilateral CI. VS patients were separated by treatment modality: 24 microsurgical resection, 15 radiation therapy, and 5 observation. Eleven VS patients with CI did not receive auditory sensation from electrical stimulation. Interventions VS microsurgical resection, radiation therapy, and observation. Main Outcome Measures Threshold (T-levels), comfort (C-levels), consonant-nucleus-consonant (CNC) word score, and AzBio sentence recognition scores. Results Patients who underwent microsurgical resection required significantly higher (p < 0.001) T-levels and C-levels compared with the standard CI group. Stimulation levels in the VS radiation therapy and observation groups were higher but not significantly different compared with standard CI controls. Overall rate of CI nonstimulation across all VS patients was 25%: 38% for microsurgery and 13% for radiation. Average CNC score for microsurgery group was 18% compared with 44% for radiation, 55% for observation, and 68.5% for standard CI controls. CNC word and AzBio scores were significantly lower (p < 0.001) for the microsurgery group compared with standard CI group. Conclusions Resection may negatively affect auditory nerve function, leading to higher stimulation levels, increased risk of nonstimulation, and poorer postoperative CI speech outcomes compared with observation or radiosurgery. When medically appropriate, nonsurgical VS management may be used to allow for optimization of CI programming and postoperative hearing outcomes.

Background/Objectives: Electrode impedance is crucial for optimizing cochlear implant (CI) stimulation and hearing outcomes. While typically stable, some patients experience unexplained impedance fluctuations. This study used electrode impedance subcomponent analysis to identify the subcomponents contributing to these impedance fluctuations. Methods: This study analyzed clinical electrode impedances and transimpedance matrix (TIM) measurements in 10 CI patients with Nucleus devices (CI422, CI522, or CI622 electrode arrays) who exhibited fluctuating or rising electrode impedances. TIM measurements used a cathodic-leading biphasic pulse (110 CLs, 75 µs/phase, 7 µs interphase interval). Electrode impedances were determined at 6, 12, 18, 24, and 75 µs, and subcomponents (access resistance [near-field/far-field] and polarization impedance [Warburg capacitance/Faraday resistance]) were calculated. Results: Both access resistance and polarization impedance changes contributed to impedance fluctuations. Large changes in near-field resistance compared to far-field resistance were associated with increased resistance to current flow closer to the surface of the electrode. The decreased double-layer capacitance and slightly increased Faraday resistance further suggested increased resistance to charge transfer at the electrode–electrolyte interface. Conclusions: Electrode impedance subcomponent analysis reveals changes in the electrochemical reaction at the electrode surface that cause fluctuating or rising CI electrode impedances.

Objective To analyze the use of electrical field imaging (EFI) in the detection of extracochlear electrodes in cochlear implants (CI) Study Design Retrospective cohort study Setting Tertiary academic medical center Methods EFI patterns from 6 recipients with extracochlear electrodes were compared with 10 recipients with all intracochlear electrodes to identify differences in EFI patterns between these two groups. For the extracochlear group, EFI patterns were analyzed using two methods: visual inspection and calculation of the average impedance difference (AID) between specific EFI curves. These results were then compared with information from CT and plain film imaging, surgical notes, and audiology tests to confirm the placement of the electrodes in each recipient. Results An average AID of 0.06 kΩ was calculated from the EFI patterns for recipients with complete electrode insertion, whereas an average AID of 0.15 kΩ was calculated from the EFI curves measured for the extracochlear electrodes. Visual analysis of the EFI impedance curves for extracochlear electrodes showed a distinct separation from those measured for intracochlear electrodes. Based on AID analysis and visual inspection the EFI, patterns were in close agreement with the number of extracochlear electrodes detected based on either imaging, intraoperative surgical note, or audiological findings. Conclusion EFI is a noninvasive, inexpensive, and time-efficient measurement that can be used to detect extracochlear electrodes and monitor electrode migration from the cochlea.

Background/Objectives: Adult hearing-impaired patients qualifying for cochlear implants typically exhibit less than 60% sentence recognition under the best hearing aid conditions, either in quiet or noisy environments, with speech and noise presented through a single speaker. This study examines the influence of deep neural network-based (DNN-based) noise reduction on cochlear implant evaluation. Methods: Speech perception was assessed using AzBio sentences in both quiet and noisy conditions (multi-talker babble) at 5 and 10 dB signal-to-noise ratios (SNRs) through one loudspeaker. Sentence recognition scores were measured for 10 hearing-impaired patients using three hearing aid programs: calm situation, speech in noise, and spheric speech in loud noise (DNN-based noise reduction). Speech perception results were compared to bench analyses comprising the phase inversion technique, employed to predict SNR improvement, and the Hearing-Aid Speech Perception Index (HASPI v2), utilized to predict speech intelligibility. Results: The spheric speech in loud noise program improved speech perception by 20 to 32% points as compared to the calm situation program. Thus, DNN-based noise reduction can improve speech perception in noisy environments, potentially reducing the need for cochlear implants in some cases. The phase inversion method showed a 4–5 dB SNR improvement for the DNN-based noise reduction program compared to the other two programs. HASPI v2 predicted slightly better speech intelligibility than was measured in this study. Conclusions: DNN-based noise reduction might make it difficult for some patients with significant residual hearing to qualify for cochlear implantation, potentially delaying its adoption or eliminating the need for it entirely.

Objectives A small number of cochlear implant (CI) users experience facial nerve stimulation (FNS), which can manifest as facial twitching. In some patients, this can be resolved by adjusting the electrical stimulation parameters. However, for others, facial stimulation can significantly impair CI outcomes or even prevent its use. The exact mechanisms underlying FNS are unclear and may vary among patients. Design Transimpedance measurements were used to assess lateral and longitudinal spread of current within 15 cochlea of nucleus CI recipients with FNS (13 unilateral recipients and 1 bilateral recipient). We compared the transimpedance measurements with programming parameters from clinical visits and pre- and postoperative temporal bone computed tomography (CT) scans to identify factors that may contribute to FNS in each CI ear. Results In nine ears, transimpedance curves showed inflection, which suggests a localized current sink within the cochlea. This indicates a low-impedance pathway through which current exits the cochlea and stimulates the labyrinthine segment of the facial nerve canal. Electrodes near this current sink were disabled or underfit to minimize facial stimulation. In the other seven ears, current flow peaked toward the basal end of the cochlea, suggesting that current exits through the round window or other structures near the basal end of the cochlea, stimulating the tympanic segment of the facial nerve. Conclusions Objective transimpedance measurements can be used to elucidate the mechanisms of FNS and to develop strategies for optimizing electrical stimulation parameters and speech coding to minimize or eliminate FNS in a small subset of CI users.

Objective To introduce and discuss implementation strategy for the Complete Cochlear Implant Care (CCIC) model, a highly-coordinated cochlear implant (CI) care delivery model requiring a single on-site visit for preoperative workup, surgery, and postoperative programming. Study Design Prospective, nonrandomized, two-arm clinical trial. Setting Tertiary referral CI center. Patients Adults who meet audiologic criteria for cochlear implantation. Interventions Cochlear implantation, coordinated care delivery, including remote programming. Main outcome measures Care delivery model feasibility and process implementation. Results Patients determined to be likely CI candidates based on routine audiometry are eligible for enrollment. The CCIC model uses telemedicine and electronic educational materials to prepare patients for same-day on-site consultation with CI surgery, same or next-day activation, and postoperative remote programming for 12 months. Implementation challenges include overcoming inertia related to the implementation of a new clinical workflow, whereas scalability of the CCIC model is limited by current hardware requirements for remote programming technology. A dedicated CCIC process coordinator is critical for overcoming obstacles in implementation and process improvement through feedback and iterative changes. Team and patient-facing materials are included and should be tailored to fit each unique CI program looking to implement CCIC. Conclusion The CCIC model has the potential to dramatically streamline hearing healthcare delivery. Implementation requires an adaptive approach, as obstacles may vary according to institutional infrastructure and policies.

Objective: To compare language and audiological outcomes among infants (<9 and <12 mo) and older children receiving cochlear implantation (CI). Study design: Retrospective chart review. Setting: Tertiary academic referral center. Patients: Pediatric patients receiving CI between October 1995 and October 2019. Intervention: Cochlear implantation Main Outcome Measures: Most recent language and audiological assessment scores were evaluated by age group. Results: A total of 118 children were studied, including 19 who were implanted <9 months of age, 19 implanted 9 to <12 months of age, and 80 implanted 12 to <36 months of age. The mean duration of follow-up was 7.4 ± 5.0 years. Most recent REEL-3 receptive (88 ± 12 vs. 73 ± 15; p = 0.020) and expressive (95 ± 13 vs. 79 ± 12; p = 0.013) communication scores were significantly higher in the <9 months group compared to the 9 to <12 months group. PLS and OWLS auditory comprehension and oral expression scores were significantly higher in the <12 months group compared to the 12 to <36 months group. The difference in NU-CHIPS scores between <12 and 12 to <36 months was statistically significant (89% ± 6 vs. 83% ± 12; p = 0.009). LNT scores differed significantly between <9 and 9 to <12 months (94% ± 4 vs. 86% ± 10; p = 0.028). Conclusions: The recent FDA expansion of pediatric CI eligibility criteria to include infants as young as 9 months of age should not serve as a strict clinical cutoff. Rather, CI can be pursued in appropriately selected younger infants to optimize language and audiological outcomes.