Search

1) To determine the relationship of electrocochleography (ECochG) responses measured on the promontory with responses measured at the round window (RW) and various intracochlear sites. 2) To evaluate if promontory ECochG responses correlate with postoperative speech-perception performance using the cochlear implant (CI).Prospective cohort study.Tertiary referral center.Ninety-six adult CI recipients with no cochlear malformations or previous otologic surgery.Acoustically evoked ECochG responses were measured intraoperatively at both extracochlear and intracochlear locations. ECochG total response (ECochG-TR), a measure of residual cochlear function, was calculated by summing the fast Fourier transformation amplitudes in response to 250-Hz to 2-kHz acoustic stimuli. Speech-perception performance was measured at 3 months.There were strong linear correlations for promontory ECochG-TR with the ECochG-TRs measured at the RW ( r = 0.95), just inside scala tympani ( r = 0.91), and after full insertion ( r = 0.83). For an individual subject, the morphology of the ECochG response was similar in character across all positions; however, the response amplitude increased from promontory to RW (~1.6-fold) to just inside scala tympani (~2.6-fold), with the largest response at full insertion (~13.1-fold). Promontory ECochG-TR independently explained 51.8% of the variability ( r2 ) in consonant-nucleus-consonant at 3 months.Promontory ECochG recordings are strongly correlated with responses previously recorded at extracochlear and intracochlear sites and explain a substantial portion of the variability in CI performance. These findings are a critical step in supporting translation of transtympanic ECochG into the clinic preoperatively to help predict postoperative CI performance.

To assess the clinical application of five recently published cochlear implant (CI) candidacy evaluation (CICE) referral screening tools through external validation.Retrospective cohort study.Tertiary otology/neurotology practice.Adults who underwent CICE between December 2020 and September 2021.CICE referral screening tools versus CI candidacy criteria.CICE screening tool performance, based on the ability to identify patients who met the CI candidacy criteria, was evaluated. CI candidacy criteria were defined as best-aided AzBio sentences at +10 signal-to-noise ratio and either 60% or less accuracy to reflect traditional criteria used in clinical settings or 40% or less accuracy (only patients 65 years or older) to reflect Medicare-eligible criteria.Screening criteria of proposed CICE referral tools vary widely across pure-tone average and word recognition scores. When screened by traditional criteria, the sensitivities and specificities of these referral tools varied from 40 to 77% and from 22 to 86%, respectively. When screened by Medicare-eligible criteria, sensitivities and specificities varied from 41 to 81% and from 24 to 91%, respectively. The screening tool proposed by Zwolan et al. ( Otol Neurotol 2020;41(7):895-900) demonstrated the best overall performance for traditional (Youden's J , 0.37; sensitivity, 62%; specificity, 75%) and Medicare-eligible patients (Youden's J , 0.44; sensitivity, 66%; specificity, 78%). All screening tools performed worse on the validation cohort compared with their respective development cohorts.Current tools for determining CICE referral have diverse screening criteria. These combinations of pure-tone average and word recognition score are modestly successful at identifying CI candidates.

The cochlea’s capacity to decode sound frequencies is enhanced by a unique structural arrangement along its longitudinal axis, a feature termed ‘tonotopy’ or place coding. Auditory hair cells at the cochlea’s base are activated by high-frequency sounds, while those at the apex respond to lower frequencies. Presently, our understanding of tonotopy primarily hinges on electrophysiological, mechanical, and anatomical studies conducted in animals or human cadavers. However, directin vivomeasurements of tonotopy in humans have been elusive due to the invasive nature of these procedures. This absence of live human data has posed an obstacle in establishing an accurate tonotopic map for patients, potentially limiting advancements in cochlear implant and hearing enhancement technologies. In this study, we conducted acoustically-evoked intracochlear recordings in 50 human subjects using a longitudinal multi-electrode array. These electrophysiological measures, combined with postoperative imaging to accurately locate the electrode contacts allow us to create the firstin vivotonotopic map of the human cochlea. Furthermore, we examined the influences of sound intensity, electrode array presence, and the creation of an artificial third window on the tonotopic map. Our findings reveal a significant disparity between the tonotopic map at daily speech conversational levels and the conventional (i.e., Greenwood) map derived at close-to-threshold levels. Our findings have implications for advancing cochlear implant and hearing augmentation technologies, but also offer novel insights into future investigations into auditory disorders, speech processing, language development, age-related hearing loss, and could potentially inform more effective educational and communication strategies for those with hearing impairments.Significance StatementThe ability to discriminate sound frequencies, or pitch, is vital for communication and facilitated by a unique arrangement of cells along the cochlear spiral (tonotopic place). While earlier studies have provided insight into frequency selectivity based on animal and human cadaver studies, our understanding of thein vivohuman cochlea remains limited. Our research offers, for the first time,in vivoelectrophysiological evidence from humans, detailing the tonotopic organization of the human cochlea. We demonstrate that the functional arrangement in humans significantly deviates from the conventional Greenwood function, with the operating point of thein vivotonotopic map showing a basal (or frequency downward) shift. This pivotal finding could have far-reaching implications for the study and treatment of auditory disorders.

OBJECTIVE: Describe early hearing preservation (HP) cochlear implantation (CI) outcomes using a new slim lateral wall electrode (SLWE). STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Adult CI candidates with preoperative low-frequency pure tone average (LFPTA; 125, 250, 500Hz) ≤60 dB HL INTERVENTION(S): CI with and without intracochlear real-time electrocochleography (RT-ECochG) MAIN OUTCOME MEASURE(S): HP (LFPTA ≤80dB HL), LFPTA shift, speech-perception performance measures, postoperative CT reconstruction RESULTS: Forty-two subjects were implanted with the SLWE. Thirty patients underwent full insertion without RT-ECochG feedback, and HP was maintained at 3-months postactivation for 7 (23.3%) patients with mean LFPTA shift of 57.5 ± 25.6 dB HL. RT-ECochG feedback was utilized on 12 patients, of which 6 patients had full insertions and 6 patients had anywhere from 1–3 electrodes left outside of the cochlea based on RT-ECochG feedback. At 3-months postoperatively, HP was achieved on 10 (83.3%) patients and mean LFPTA shift was 18.9 c 11.7 dB HL. Mean difference between LFPTA threshold shift at 3-months postactivation with and without RT-ECochG was 38.6 dB HL (95% CI, 25.6 – 51.67). There was an improvement in delta CNC from preoperative to 3-months postactivation when using RT-ECochG, with mean difference 20.7% (95% CI, 3.3 to 38.1). CONCLUSIONS: Use of RT-ECochG monitoring during SLWE placement results in fewer full electrode insertions and significantly better HP rates and speech-perception outcomes when compared to unmonitored insertions. Further investigation is needed to evaluate long-term audiologic outcomes to better understand the relationships among ECochG, cochlear trauma, functional outcomes, and HP.

OBJECTIVES. To compare intraoperative intracochlear electrocochleography (ECochG) with hearing preservation outcomes in cochlear implant (CI) subjects. DESIGN. Intraoperative electrocochleography was performed in adult CI subjects who were recipients of Advanced Bionics’ Bionics LLC precurved HiFocus(™) MidScala or straight HiFocus(™) SlimJ electrode arrays. ECochG responses were recorded from the most apical electrode contact during insertion. No changes to the insertions were made due to ECochG monitoring. No information about insertion resistance was collected. ECochG drops were estimated as the change in amplitude from peak (defined as maximum amplitude response) to drop (largest drop) point after the peak during insertion was measured following the peak response. .Audiometric thresholds from each subject were obtained before and approximately one month after CI surgery. The change in pure tone average (PTA) for frequencies between 125 Hz and 500 Hz was measured after surgery. No post-operative CT scans were collected as part of this study. RESULTS. A total of 68 subjects from 5 surgical centers participated in the study. The study sample included 30 MidScala and 38 SlimJ electrodes implanted by approximately 20 surgeons who contributed to the study. Although a wide range of results were observed, there was a moderate positive correlation (Pearson Correlation coefficient r = 0.56, p < 0.01) between the size of the ECochG drop and the magnitude of PTA change. This trend was present for both the MidScala and SlimJ arrays. The SlimJ and MidScala arrays produced significantly different hearing loss after surgery. CONCLUSION. Large ECochG amplitude drops observed during electrode insertion indicated poorer hearing preservation. Although the outcomes were variable, this information may be helpful to guide surgical decision-making when contemplating full electrode insertion and the likelihood of hearing preservation.

To evaluate the impact of different open set sentence recognition tests in quiet, +10 dB signal to noise ratio (SNR), and +5 dB SNR in adult cochlear implant (CI) recipients above and below 65 years of age.Multi-institution, prospective, non-randomized, single-subject repeated measures design.Ninety six adults more than or equal to 18 years old with postlingual bilateral sensorineural hearing loss.Participants received a CI532 in one ear. Speech perception measures were evaluated before and 6-months after activation.Subjects completed consonant-nucleus-constant (CNC) words in quiet and AzBio sentences in noise using +10 and +5 dB SNR, and Montreal Cognitive Assessment (MOCA).Ninety six adult patients were enrolled (n = 70 older [≥65 yr], n = 26 younger [65 yr]). There was no difference in CNC scores (CI alone 58.4% versus 67.5%, p = 0.0857; best aided 66.7% versus 76.1%, p = 0.3357). Older adults performed worse on AzBio +10 dB SNR compared with younger patients (CI alone 37.4% versus 56.9%, p = 0.0006; best aided 51.4% versus 68.2%; p = 0.01), and in AzBio +5 dB SNR (CI alone 7.7% versus 11.2%, p = 0.0002; best aided 15.3% versus 22.3%, p = 0.0005). The magnitude of change in AzBio +10 dB SNR was significantly less in older adults in CI alone (15.3% versus 22.3%; p = 0.0493) but not best aided (21.5% versus 31.3%; p = 0.105). The magnitude of change was drastically worse in AzBio +5 dB SNR for older adults (CI alone 6.7% versus 22.1%, p = 0.0014; best aided 9.5% versus 21.5%; p = 0.0142). There was no significant difference in MOCA between the two age groups.While both older and younger patients have similar outcomes with respect to CNC word scores in quiet, the addition of noise disproportionally impacts older patients. Caution should be exercised testing the elderly in noise; testing in noise may disproportionally impact performance expectations and should be more carefully considered when used for candidacy criteria and counseling. Future studies need to further investigate the disproportionate effect of noise on candidacy testing and its impact on how elderly patients are qualified.

OBJECTIVE Describe audiologic outcomes in hearing preservation (HP) cochlear implant candidates using a slim modiolar electrode (SME). STUDY DESIGN Retrospective. SETTING Tertiary referral center. PATIENTS Two hundred three adult cochlear implant patients with preoperative low-frequency pure-tone average (LFPTA) ≤ 80 dB HL that received the SME. INTERVENTION Implantation with a SME electrode. MAIN OUTCOME MEASURES Primary outcome was postoperative HP, defined as LFPTA ≤80 dB HL. HP status was analyzed at "early" (activation or 3 mo) and "long-term" (6 or 12 mo) time frames using the patient's worst audiogram. Speech perception tests were compared between HP and non-HP cohorts. RESULTS Of the 203 HP candidates, the tip fold-over rate was 7.4%. The mean shifts in LFPTA at the "early" and "long-term" time points were 25.9 ± 16.2 dB HL and 29.6 ± 16.9 dB HL, respectively. Of 117 patients with preoperative LFPTA ≤60 dB HL, the early and long-term mean LFPTA shifts were 19.5 ± 12.3 dB HL and 32.6 ± 17.2 dB HL, respectively; early and long-term HP rates were 61.1% and 50.8%, respectively. For patients with preoperative LFPTA ≤80 dB HL, early and long-term HP rates were 45.5% and 43.7%, respectively. No significant difference was observed in postoperative speech perception performance (CNC, AzBio, HINT) at 3, 6, or 12 months between HP versus non-HP groups. CONCLUSIONS HP is feasible using the SME. While electroacoustic stimulation was not studied in this cohort, HP provided no clear advantage in speech perception abilities in this group of patients. The current reporting standard of what constitutes HP candidacy (preoperative LFPTA ≤80 dB HL) should be reconsidered.

To examine long-term speech and cognition outcomes in older adult cochlear implant (CI) recipients. First, by evaluating if CI performance was maintained over an extended follow-up period regardless of preoperative cognitive status. Secondly, by evaluating if there was a difference in the rate of cognitive decline between preoperative mild and normal cognition following CI over an extended period of time.Retrospective cohort study.CI recipients ≥65 years of age implanted between 2009 and 2014 with 4+ years follow up. Pre- and postoperative audiometric and speech outcome assessments were collected. Cognitive status was measured using the mini mental status examination (MMSE) at numerous time points.Fifty-three patients met inclusion. Patients were divided into two groups based on preoperative MMSE with scores considered normal (28-30) and those with mildly impaired cognition (MIC, scores 25-27). Audiometric and speech performance improved significantly at one-year post implantation and this was maintained without significant change at 4+ years, regardless of cognitive status. Mixed modeling analysis controlling for age demonstrated no significant difference in the rate of cognitive decline at 4+ years post implantation between the normal cognition cohort (1.74; 95%CI 0.89-2.6) and MIC (2.9; 95%1.91-3.88).Speech performance was significantly improved and sustained after CI in both normal cognition and MIC patients. The rate of cognitive decline in older adult CI patients appears to be similar regardless of preoperative cognitive status. Although results demonstrate rates of cognitive decline following CI did not differ between cognition groups over 4+ years, future studies will need to further investigate this over extended time periods with a more comprehensive cognitive testing battery.Level 4 Laryngoscope, 2022.

Studies have shown that hearing preservation is possible in the context of reimplantation, but residual hearing could not be predicted or expected in these cases. We describe a case in which a patient with mild to profound sensorineural hearing loss who underwent cochlear implantation with a lateral wall array and had hearing preserved postoperatively. She developed facial nerve stimulation which was unresponsive to reprogramming. Using electrocochleography to measure intracochlear trauma during the insertion process, the patient underwent reimplantation with a perimodiolar electrode and hearing was preserved postoperatively. This case demonstrates the potential to use electrocochleography for hearing preservation during reimplantation. Laryngoscope, 131:2348-2351, 2021.

To evaluate the utility of intracochlear electrocochleography (ECochG) monitoring during cochlear implant (CI) surgery on postoperative hearing preservation.Prospective, randomized clinical trial.Ten high-volume, tertiary care CI centers.Adult patients with sensorineural hearing loss meeting the CI criteria who selected an Advanced Bionics CI.Patients were randomized to CI surgery either with audible ECochG monitoring available to the surgeon during electrode insertion or without ECochG monitoring. Hearing preservation was determined by comparing preoperative unaided low-frequency (125-, 250-, and 500-Hz) pure-tone average (LF-PTA) to postoperative LF-PTA at CI activation. Pre- and post-CI computed tomography was used to determine electrode scalar location and electrode translocation.Eighty-five adult CI candidates were enrolled. The mean (standard deviation [SD]) unaided preoperative LF-PTA across the sample was 54 (17) dB HL. For the whole sample, hearing preservation was "good" (i.e., LF-PTA change 0-15 dB) in 34.5%, "fair" (i.e., LF-PTA change15-29 dB) in 22.5%, and "poor" (i.e., LF-PTA change ≥30 dB) in 43%. For patients randomized to ECochG "on," mean (SD) LF-PTA change was 27 (20) dB compared with 27 (23) dB for patients randomized to ECochG "off" ( p = 0.89). Seven percent of patients, all of whom were randomized to ECochG off, showed electrode translocation from the scala tympani into the scala vestibuli.Although intracochlear ECochG during CI surgery has important prognostic utility, our data did not show significantly better hearing preservation in patients randomized to ECochG "on" compared with ECochG "off."

A fundamental property of mammalian hearing is the conversion of sound pressure into a frequency-specific place of maximum vibration along the cochlear length, thereby creating a tonotopic map. The tonotopic map makes possible systematic frequency tuning across auditory-nerve fibers, which enables the brain to use pitch to separate sounds from different environmental sources and process the speech and music that connects us to people and the world. Sometimes a tone has a different pitch in the left and right ears, a perceptual anomaly known as diplacusis. Diplacusis has been attributed to a change in the cochlear frequency-place map, but the hypothesized abnormal cochlear map has never been demonstrated. Here we assess cochlear frequency-place maps in guinea-pig ears with experimentally-induced endolymphatic hydrops, a hallmark of Ménière’s disease. Our findings are consistent with the hypothesis that diplacusis is due to an altered cochlear map. Map changes can lead to altered pitch, but the size of the pitch change is also affected by neural synchrony. Our data show that the cochlear frequency-place map is not fixed but can be altered by endolymphatic hydrops. Map changes should be considered in assessing hearing pathologies and treatments.

OBJECTIVES Electrocochleography (ECochG), obtained before the insertion of a cochlear implant (CI) array, provides a measure of residual cochlear function that accounts for a substantial portion of variability in postoperative speech perception outcomes in adults. It is postulated that subsequent surgical factors represent independent sources of variance in outcomes. Prior work has demonstrated a positive correlation between angular insertion depth (AID) of straight arrays and speech perception under the CI-alone condition, with an inverse relationship observed for precurved arrays. The purpose of the present study was to determine the combined effects of ECochG, AID, and array design on speech perception outcomes. DESIGN Participants were 50 postlingually deafened adult CI recipients who received one of three straight arrays (MED-EL Flex24, MED-EL Flex28, and MED-EL Standard) and two precurved arrays (Cochlear Contour Advance and Advanced Bionics HiFocus Mid-Scala). Residual cochlear function was determined by the intraoperative ECochG total response (TR) measured before array insertion, which is the sum of magnitudes of spectral components in response to tones of different stimulus frequencies across the speech spectrum. The AID was then determined with postoperative imaging. Multiple linear regression was used to predict consonant-nucleus-consonant (CNC) word recognition in the CI-alone condition at 6 months postactivation based on AID, TR, and array design. RESULTS Forty-one participants received a straight array and nine received a precurved array. The AID of the most apical electrode contact ranged from 341° to 696°. The TR measured by ECochG accounted for 43% of variance in speech perception outcomes (p < 0.001). A regression model predicting CNC word scores with the TR tended to underestimate the performance for precurved arrays and deeply inserted straight arrays, and to overestimate the performance for straight arrays with shallower insertions. When combined in a multivariate linear regression, the TR, AID, and array design accounted for 72% of variability in speech perception outcomes (p < 0.001). CONCLUSIONS A model of speech perception outcomes that incorporates TR, AID, and array design represents an improvement over a model based on TR alone. The success of this model shows that peripheral factors including cochlear health and electrode placement may play a predominant role in speech perception with CIs.

Objective To evaluate the prevalence, surgical management, and audiologic impact of pulsatile tinnitus caused by sigmoid sinus dehiscence. Study design and setting Retrospective chart review at a tertiary care hospital. Patients Adults with unilateral pulsatile tinnitus attributable to sigmoid sinus dehiscence who underwent resurfacing between January 2010 and January 2020. Interventions Transmastoid sigmoid resurfacing. Main outcome measures Resolution of pulsatile tinnitus; audiologic outcomes; complications; tinnitus etiologies. Results Nineteen patients (89.4% women) had surgery for suspected sigmoid sinus dehiscence. The mean dehiscence size was 6.1 mm (range, 1-10.7 mm). Eight patients had concurrent sigmoid sinus diverticulum and one patient also had jugular bulb dehiscence. Only two patients (10.5%) had the defect identified by radiology. Low-frequency pure-tone average, measured at frequencies of 250 and 500 Hz, showed a significant median improvement of 8.8 dB following resurfacing (18.8 dB versus 10.0 dB, p = 0.02). The majority of patients had complete resolution of pulsatile tinnitus (16/19, 84.2%). Of those without complete resolution, two patients had partial response and one patient had no improvement. There were no significant complications. Of 41 consecutively tracked patients with a pulsatile tinnitus chief complaint, sigmoid pathology represented 32% of cases. Conclusions Sigmoid sinus dehiscence represents a common vascular cause of pulsatile tinnitus that, if properly assessed, may be amenable to surgical intervention. Sigmoid sinus resurfacing is safe, does not require decompression, and may improve low-frequency hearing. Radiographic findings of dehiscence are often overlooked without a high index of clinical suspicion. Its relationship with transverse sinus pathology and idiopathic intracranial hypertension remain unclear.

OBJECTIVE Hearing loss remains a significant morbidity for patients with vestibular schwannomas (VS). A growing number of reports suggest audibility with cochlear implantation following VS resection; however, there is little consensus on preferred timing and cochlear implant (CI) performance. DATA SOURCES A systematic literature search of the Ovid Medline, Embase, Scopus, and clinicaltrails.gov databases was performed on 9/7/2018. PRISMA reporting guidelines were followed. STUDY SELECTION Included studies reported CI outcomes in an ear that underwent a VS resection. Untreated VSs, radiated VSs, and CIs in the contralateral ear were excluded. DATA EXTRACTION Primary outcomes were daily CI use and attainment of open-set speech. Baseline tumor and patient characteristics were recorded. Subjects were divided into two groups: simultaneous CI placement with VS resection (Group 1) versus delayed CI placement after VS resection (Group 2). DATA SYNTHESIS Twenty-nine articles with 93 patients met inclusion criteria. Most studies were poor quality due to their small, retrospective design. Group 1 had 46 patients, of whom 80.4% used their CI on a daily basis and 50.0% achieved open-set speech. Group 2 had 47 patients, of whom 87.2% used their CI on a daily basis and 59.6% achieved open-set speech. Group 2 had more NF2 patients and larger tumors. CI timing did not significantly impact outcomes. CONCLUSIONS Audibility with CI after VS resection is feasible. Timing of CI placement (simultaneous versus delayed) did not significantly affect performance. Overall, 83.9% used their CI on a daily basis and 54.8% achieved open-set speech.

OBJECTIVES/HYPOTHESIS Results from a prospective trial demonstrated better speech recognition for cochlear implant (CI) recipients implanted with a long lateral wall electrode array compared to subjects with a short array after 1 year of listening experience. As short array recipients may require an extended adaptation period, this study investigated whether differences in speech recognition continued through 4 years of CI use. STUDY DESIGN Long-term follow-up of a prospective randomized trial. METHODS Subjects were randomized to receive a MED-EL medium (24 mm) or standard (31.5 mm) array. Linear mixed models compared speech recognition between cohorts with word recognition in quiet and sentence recognition in noise at 1, 3, 6, 12, 24, and 48 months postactivation. Postoperative imaging and electric frequency filters were reviewed to assess the influence of frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with peripheral spectral selectivity. RESULTS Long (31.5 mm) array recipients demonstrated superior speech recognition out to 4 years postactivation. There was a significant effect of angular separation between contacts, with more closely spaced contacts associated with poorer speech recognition. There was no significant effect of mismatch, yet this may have been obscured by changes in frequency filters over time. CONCLUSIONS Conventional MED-EL CI recipients implanted with 31.5-mm arrays experience better speech recognition than 24-mm array recipients, initially and with long-term listening experience. The benefit conferred by longer arrays in the present cohort can be partially attributed to more widely spaced electrode contacts, presumably a result of reduced channel interaction. LEVEL OF EVIDENCE 2 Laryngoscope, 131:892-897, 2021.

Endolymphatic hydrops is associated with low-frequency sensorineural hearing loss, with a large body of research dedicated to examining its putative causal role in low-frequency hearing loss. Investigations have been thwarted by the fact that hearing loss is measured in intact ears, but gold standard assessments of endolymphatic hydrops are made postmortem only; and that no objective low-frequency hearing measure has existed. Yet the association of endolymphatic hydrops with low-frequency hearing loss is so strong that it has been established as one of the important defining features for Ménière’s disease, rendering it critical to detect endolymphatic hydrops early, regardless of whether it serves a causal role or is the result of other disease mechanisms. We surgically induced endolymphatic hydrops in guinea pigs and employed our recently developed objective neural measure of low-frequency hearing, the Auditory Nerve Overlapped Waveform (ANOW). Hearing loss and endolymphatic hydrops were assessed at various time points after surgery. The ANOW detected low-frequency hearing loss as early as the first day after surgery, well before endolymphatic hydrops was found histologically. The ANOW detected low-frequency hearing loss with perfect sensitivity and specificity in all ears after endolymphatic hydrops developed, where there was a strong linear relationship between degree of endolymphatic hydrops and severity of low-frequency hearing loss. Further, histological data demonstrated that endolymphatic hydrops is seen first in the high-frequency cochlear base, though the ANOW demonstrated that dysfunction begins in the low-frequency apical cochlear half. The results lay the groundwork for future investigations of the causal role of endolymphatic hydrops in low-frequency hearing loss.

Objective Assess the real-world performance of popular imputation algorithms on cochlear implant (CI) candidate audiometric data. Methods 7,451 audiograms from patients undergoing CI candidacy evaluation were pooled from 32 institutions with complete case analysis yielding 1,304 audiograms. Imputation model performance was assessed with nested cross-validation on randomly generated sparse datasets with various amounts of missing data, distributions of sparsity, and dataset sizes. A threshold for safe imputation was defined as root mean square error (RMSE) Results Greater quantities of missing data were associated with worse performance. Sparsity in audiometric data is not uniformly distributed, as inter-octave frequencies are less commonly tested. With 3–8 missing features per instance, a real-world sparsity distribution was associated with significantly better performance compared to other sparsity distributions (Δ RMSE 0.3 dB– 5.8 dB, non-overlapping 99% confidence intervals). With a real-world sparsity distribution, models were able to safely impute up to 6 missing datapoints in an 11-frequency audiogram. MICE consistently outperformed other models across all metrics and sparsity distributions (p < 0.01, Wilcoxon rank sum test). With sparsity capped at 6 missing features per audiogram but otherwise equivalent to the raw dataset, MICE imputed with RMSE of 7.83 dB [95% CI 7.81–7.86]. Imputing up to 6 missing features captures 99.3% of the audiograms in our dataset, allowing for a 5.7-fold increase in dataset size (1,304 to 7,399 audiograms) as compared with complete case analysis. Conclusion Precision medicine will inevitably play an integral role in the future of hearing healthcare. These methods are data dependent, and rigorously validated imputation models are a key tool for maximizing datasets. Using the largest CI audiogram dataset to-date, we demonstrate that in a real-world scenario MICE can safely impute missing data for the vast majority (>99%) of audiograms with RMSE well below a clinically significant threshold of 10dB. Evaluation across a range of dataset sizes and sparsity distributions suggests a high degree of generalizability to future applications.

Although significant progress has been made in understanding outcomes following cochlear implantation, predicting performance remains a challenge. Duration of hearing loss, age at implantation, and electrode positioning within the cochlea together explain ~ 25% of the variability in speech-perception scores in quiet using the cochlear implant (CI). Electrocochleography (ECochG) responses, prior to implantation, account for 47% of the variance in the same speech-perception measures. No study to date has explored CI performance in noise, a more realistic measure of natural listening. This study aimed to (1) validate ECochG total response (ECochG-TR) as a predictor of performance in quiet and (2) evaluate whether ECochG-TR explained variability in noise performance. Thirty-five adult CI recipients were enrolled with outcomes assessed at 3-months post-implantation. The results confirm previous studies showing a strong correlation of ECochG-TR with speech-perception in quiet (r = 0.77). ECochG-TR independently explained 34% of the variability in noise performance. Multivariate modeling using ECochG-TR and Montreal Cognitive Assessment (MoCA) scores explained 60% of the variability in speech-perception in noise. Thus, ECochG-TR, a measure of the cochlear substrate prior to implantation, is necessary but not sufficient for explaining performance in noise. Rather, a cognitive measure is also needed to improve prediction of noise performance.

Importance Vestibular schwannomas have long been treated as a homogeneous entity. Clinical symptoms at presentation may help elucidate the underlaying pathophysiologic characteristics of tumor subtypes. Describing the heterogeneity of these benign tumors may assist in predicting clinical outcomes associated with their treatment. Objective To create a tumor staging system that incorporates symptoms at presentation and tumor size to predict severe surgical complications. Design, setting, and participants A retrospective cohort of patients at a single-center tertiary referral center from January 1, 1998, to October 13, 2020, was studied. Patients diagnosed with sporadic vestibular schwannoma surgically treated at Washington University in St Louis, Missouri, were included. Main outcomes and measures Severe surgical complications within 30 days of surgery as determined by the Clavien-Dindo classification system. Patients experiencing a complication of grade 3 or above were determined to have a severe complication. Results Of 185 patients evaluated, 40 (22%) had severe postoperative complications. Twenty of the 40 patients (50%) were women; mean (SD) age was 46 (13) years. Patients with severe complications were more likely to have large tumors (>2.5 cm in largest diameter), vestibular symptoms, and recent hearing loss at presentation. Using conjunctive consolidation, a 4-stage clinical severity staging system that incorporates clinical symptoms and tumor size at presentation was created to predict severe complications. The clinical severity staging system demonstrated an improvement in the ability to discriminate severe complications (C index, 0.754; 95% CI, 0.67-0.84) from a model of tumor size alone (C index, 0.706; 95% CI 0.62-0.79). Conclusions and relevance This cohort study found that, among patients with vestibular schwannoma, symptoms present at initial evaluation, in addition to tumor size, served as predictors of severe postoperative complications. A new clinical severity staging system incorporating symptoms at presentation can be helpful for clinicians to identify patients at high risk for severe postoperative complications.

Introduction: We assess early hearing preservation (HP) outcomes of patients implanted with the new Slim 20 lateral wall array (CI624);compare early HP outcomes with and without real-time electrocochleography (RT-ECochG);and explain the role of RT-ECochG feedback to improve HP. We believe this abstract is suitable for a late-breaking abstract as we are the first to report early HP outcomes for a new Slim 20 lateral wall electrode (CI624). Since the CI624's release in May 2020, it is becoming increasingly popular among centers as a potential HP array. To our knowledge, there have not been any discussions at major conferences or published studies reviewing experiences with the CI624. Based on our early experience with 29 implantations using this electrode, we have found poor HP outcomes 1 month postoperatively with preservation in only 16 of the recipients. As a result, we began using real-time monitoring of cochlear health during the insertion (ie, electrocochleography [ECochG]) to potentially improve HP outcomes with the CI624. By using real-time ECochG (RT-ECochG) and particularly focusing on minimizing trauma at the end of insertion, we achieved superior early HP rates with this array (8/9 patients, 88.9%). Our preliminary data suggest that full insertion of the CI624 without ECochG results in unpredictable and relatively poor HP outcomes. We suspect that this is related to the CI624 being a longer electrode than previous hybrid arrays resulting in trauma to the apical-most hair cells and neural elements at full insertion. Thus, RT-ECochG may be required for predictable early HP using the CI624. As a result of the COVID-19 pandemic, we were unable to achieve sufficient implantations for submission of an abstract in January 2021. However, we have now performed 9 implants with the CI624 in the past 6 months using RT-ECochG for HP candidates. We believe that our experience with and without ECochG has resulted in an early critical finding that may influence how this implant is used in HP candidates. Methods: A longitudinal study was designed with postlinguistically deafened adults undergoing implantation with CI624 from 2020 to 2021. Pure-tone audiometry preoperatively and 1 month postoperatively were obtained. HP was defined as low-frequency pure-tone average (LFPTA;125, 250, 500 Hz) 5 μV ECochG response drop, array adjustments (ie, withdrawal ∼1 mm, 5° anti-modiolar rotation) were made to facilitate response recovery. Results: A total of 38 implants were performed. There was no scalar translocation on postoperative CT scans and mean apical insertion angle was 338.1° ± 86.4°. Full insertion was performed in most cases;however, partial insertion was performed if the RT-ECochG response dropped during insertion of the final 3 electrodes (n = 4). Of the 29 patients where RT-ECochG was not used, 16 (55.2%) had low-frequency HP postoperatively with preoperative LFPTA 42.4 ± 16.4 dB and threshold shift to 83.9 ± 27.8 dB. Among the 9 patients where RT-ECochG was used, 8 (88.9%) had low-frequency HP postoperatively with preoperative LFPTA 46.5 ± 16.0 dB and threshold shift to 62.6 ± 19.0 dB. Difference between threshold shift postoperatively with and without RT-ECochG was significant (P = .002, Mann-Whitney U test). Conclusion: RT-ECochG-guided insertion may be required for consistent HP outcomes following CI624 implantation. This may allow the surgeon to decide the depth of electrode insertion in the effort to preserve low-frequency hearing. Further investigation is needed to evaluate whether long-term HP can be maintained using CI624.

Among the various cochlear implant systems approved by the Food and Drug Administration, current labeling for pediatric usage encompasses (1) bilateral profound bilateral sensorineural hearing loss in children aged 9 to 24 months and bilateral severe to profound sensorineural hearing loss in children older than 2 years; (2) use of appropriately fitted hearing aids for 3 months (this can be waived if there is evidence of ossification); and (3) demonstration of limited progress with auditory, speech, and language development. Pediatric guidelines require children to have significantly worse speech understanding before qualifying for cochlear implantation. The early years of life have been shown to be critical for speech and language development, and auditory deprivation is especially detrimental during this crucial time.Level of evidence: 2.

Background Neurofibromatosis type 2 (NF2) often results in profound hearing loss and cochlear implantation is an emerging hearing rehabilitation option. However, cochlear implant (CI) outcomes in this population vary, and intraoperative monitoring to predict cochlear nerve viability and subsequent outcomes is not well-established. Objective To review the use of intraoperative electrically evoked cochlear nerve monitoring in patients with NF2 simultaneous translabyrinthine (TL) vestibular schwannoma (VS) resection and cochlear implantation. Methods A retrospective review was performed of 3 patients with NF2 that underwent simultaneous TL VS resection and cochlear implantation with electrical auditory brainstem response (eABR) measured throughout tumor resection. Patient demographics, preoperative assessments, surgical procedures, and outcomes were reviewed. Results Patients 1 and 3 had a reliable eABR throughout tumor removal. Patient 2 had eABR pretumor removal, but post-tumor removal eABR presence could not be reliably determined because of electrical artifact interference. All patients achieved auditory percepts upon CI activation. Patients 1 and 2 experienced a decline in CI performance after 1 yr and after 3 mo, respectively. Patient 3 continues to perform well at 9 mo. Patients 2 and 3 are daily users of their CI. Conclusion Cochlear implantation is attainable in cases of NF2-associated VS resection. Intraoperative eABR may facilitate cochlear nerve preservation during tumor removal, though more data and long-term outcomes are needed to refine eABR methodology and predictive value for this population.

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve “tails,” and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1.NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

OBJECTIVES/HYPOTHESIS Previous studies have demonstrated that electrocochleography (ECochG) measurements made at the round window prior to cochlear implant (CI) electrode insertion can account for 47% of the variability in 6-month speech perception scores. Recent advances have made it possible to use the apical CI electrode to record intracochlear responses to acoustic stimuli. Study objectives were to determine 1) the relationship between intracochlear ECochG response amplitudes and 6-month speech perception scores and 2) to determine the relationship between behavioral auditory thresholds and ECochG threshold estimates. The hypothesis was that intracochlear ECochG response amplitudes made immediately after electrode insertion would be larger than historical controls (at the extracochlear site) and explain more variability in speech perception scores. STUDY DESIGN Prospective case series. METHODS Twenty-two adult CI recipients with varying degrees of low-frequency hearing had intracochlear ECochG measurements made immediately after CI electrode insertion using 110 dB SPL tone bursts. Tone bursts were centered at five octave-spaced frequencies between 125 and 2,000 Hz. RESULTS There was no association between intracochlear ECochG response amplitudes and speech perception scores. But, the data suggest a mild to moderate relationship between preoperative behavioral audiometric testing and intraoperative ECochG threshold estimates. CONCLUSION Performing intracochlear ECochG is highly feasible and results in larger response amplitudes, but performing ECochG before, rather than after, CI insertion may provide a more accurate assessment of a patient's speech perception potential. LEVEL OF EVIDENCE 4 Laryngoscope, 131:E2681-E2688, 2021.

Importance Hearing loss, especially moderate to severe forms, has the potential to negatively affect an individual’s physical, social, emotional, and cognitive well-being. Moreover, having ineffective binaural hearing increases difficulty understanding speech in noise and leads to a greater degree of social isolation and loneliness and a reduced quality of life (QoL). Objective To explore the audiometric and holistic effects of cochlear implantation in a group of adults 65 years or older compared with an optimized bilateral hearing aid condition. Design, Setting, and Participants This ad hoc secondary analysis of a prospective, single-subject, repeated-measures nonrandomized clinical trial included 13 cochlear implantation centers across the United States. Participants 65 years or older with postlingual bilateral moderate-to-profound sensorineural hearing loss with aided Consonant-Vowel Nucleus-Consonant (CNC) word scores in quiet of 40% or less in the ear to undergo implantation and 50% or less in the contralateral ear were included in the analysis. Baseline QoL testing was performed after 1 month of optimized bilateral hearing aid use. Participants were enrolled from February 20, 2017, to May 3, 2018, and follow-up was completed December 21, 2018. Data were analyzed from March 25, 2019, to March 31, 2020. Interventions Unilateral implantation with a slim, modiolar cochlear implant device. Hearing aid use in the contralateral ear was required through the 6-month primary end-point interval. Main Outcomes and Measures The primary objective was to evaluate speech perception before and 6 months after activation of a new cochlear implant. Secondary objectives were QoL metrics in the everyday listening condition before and 6 months after implantation. Results Seventy participants (51 men [73%]) with a median age of 74 (range, 65-91) years were included in the analysis. No major adverse events occurred. Mixed-model analysis with estimated marginal means and 95% CIs compared preimplantation baseline performance with 6-month postimplantation performance. A clinically important improvement in CNC words was shown in the bimodal condition, with a mean difference of 37.2% (95% CI, 32.0%-42.4%), and in the unilateral (cochlear implant only) condition, with a mean difference of 44.1% (95% CI, 39.0%-49.2%). A clinically important improvement in noise (AzBio sentences signal-to-noise ratio of +10 dB) was also shown, with a mean difference of 21.6% (95% CI, 15.7%-27.5%) in the bimodal condition and 24.5% (95% CI, 18.3%-30.7%) in the unilateral condition. The Health Utilities Index Mark 3 multiple-attribute score improved by 0.186 (95% CI, 0.136-0.234); the Speech, Spatial, and Qualities of Hearing Scale total score improved by 2.58 (95% CI, 2.18-2.99); and a novel Device Use Questionnaire reported 94% of participants were satisfied with overall hearing in the everyday listening condition. Conclusions and Relevance This subgroup analysis of patients 65 years or older enrolled in a within-subject clinical trial of cochlear implantation demonstrated clinically meaningful audiometric and QoL benefit with an acceptable risk profile. These findings suggest that cochlear implantation in older adults may facilitate the concept of healthy aging. Trial Registration ClinicalTrials.gov Identifier:NCT03007472

Importance Current indications for Medicare beneficiaries to receive a cochlear implant are outdated. Multichannel cochlear implant systems may be effective when provided to Medicare beneficiaries using expanded indications. Objective To examine the effectiveness of cochlear implants, as measured by improvement on the AzBio Sentence Test, for newly implanted Medicare beneficiaries who meet the expanded indications of an AzBio Sentence Test score of 41% to 60% in their best-aided condition. Design, Setting, and Participants A multicenter nonrandomized trial examined preoperative and postoperative speech recognition, telephone communication, hearing device benefit, health utility, and quality of life for 34 participants enrolled at 8 different centers who received a cochlear implant between September 17, 2014, and July 10, 2018. All participants were 65 years or older, had bilateral moderate to profound hearing loss, and had a best-aided preoperative AzBio Sentence Test score in quiet of 41% to 60%. Analysis was performed on an intention-to-treat basis. Statistical analysis of final results took place from July 29 to October 1, 2019. Intervention Multichannel cochlear implants. Main Outcomes and Measures The study examined the a priori hypothesis that the cochlear implant would improve the AzBio Sentence Test score in the best-aided condition by 25% or more and in the implanted ear–alone condition by 30% or more. The study additionally examined word and telephone recognition and examined device benefit, health utility, and quality of life. Results A total of 34 participants received a cochlear implant; 31 (23 men [74%]; median age, 73.6 years [range, 65.7-85.1 years]) completed testing through the 6-month evaluation, and 29 completed testing through the 12-month evaluation. Median preoperative AzBio Sentence Test scores were 53% (range, 26%-60%) for the best-aided condition and 24% (range, 0%-53%) for the cochlear implant–alone condition; median scores 12 months after implantation improved to 89% (range, 36%-100%) for the best-aided condition and 77% (range, 13%-100%) for the cochlear implant–alone condition. This outcome represents a median change of 36% (range, –22% to 75%) for the best-aided condition (lower bound of 1-sided 95% CI, 31%) and a median change of 53% (range, –15% to 93%) for the cochlear implant–alone condition (lower bound of 1-sided 95% CI, 45%). Conclusions and Relevance Intervention with a cochlear implant was associated with improved sentence, word, and telephone recognition in adult Medicare beneficiaries whose preoperative AzBio Sentence Test scores were between 41% and 60%. These findings support expansion of the Center for Medicare & Medicaid current indications for cochlear implants. Trial Registration ClinicalTrials.gov Identifier:NCT02075229

Importance Cochlear implants were approved for use in adults in the 1980s, but use remains low owing to a lack of awareness regarding cochlear implantation candidacy criteria and expected outcomes. There have been limited, small series examining the safety and effectiveness of cochlear implantation in adult hearing aid (HA) users with and without mild cognitive impairment (MCI). Objective To investigate the safety and effectiveness of a single-ear cochlear implant in a group of optimized adult HA users with and without MCI across a variety of domains. Design, Setting, and Participants In this nonrandomized controlled trial, a multicenter, prospective, repeated-measures investigation was conducted at 13 US institutions. The setting was academic and community-based cochlear implant programs. Eligible participants were 100 adults (aged >18 years) with postlinguistic onset of bilateral moderate sloping to profound or worse sensorineural hearing loss (≤20 years’ duration). Fluent English speakers underwent an optimized bilateral HA trial for at least 30 days. Individuals with aided Consonant-Vowel Nucleus-Consonant (CNC) word score in quiet of 40% or less correct in the ear to be implanted and 50% or less correct in the contralateral ear were offered cochlear implants. The first participant was enrolled on February 20, 2017, and the last participant was enrolled on May 3, 2018. The final follow-up was on December 21, 2018. Interventions Participants received the same cochlear implant system and contralateral HA. Main Outcomes and Measures The primary outcome measure was speech understanding in quiet (CNC word score) using both the cochlear implant and opposite ear HA. Secondary outcome measures included the following: adverse events; speech understanding in noise (AzBio signal-to-noise ratio of +10 db [+10 SNR]) Health Utilities Index Mark 3 (HUI3); Speech, Spatial, and Qualities of Hearing Questionnaire 49 (SSQ49); and Montreal Cognitive Assessment (MoCA). Results The median age at cochlear implantation of the 96 patients included in the trial was 71 years (range, 23-91 years), and 62 patients (65%) were male. Three serious adverse events requiring revision surgery occurred, and all resolved without sequelae. By 6 months after activation, the absolute marginal mean change in CNC word score and AzBio +10 SNR was 40.5% (95% CI, 35.9%-45.0%) and 24.1% (95% CI, 18.9%-29.4%), respectively. Ninety-one percent (87 of 96) of participants had a clinically important improvement (>15%) in the CNC word score in the implant ear. Mild cognitive impairment (MoCA total score ≤25) was observed in 48 of 81 study participants (59%) at baseline. Speech perception marginal mean improvements were similar between individuals with and without baseline MCI, with values of 40.9% (95% CI, 35.2%-46.6%) and 39.6% (95% CI, 31.8%-47.4%), respectively, for CNC word score and 27.5% (95% CI, 21.0%-33.9%) and 17.8% (95% CI, 9.0%-26.6%), respectively, for AzBio +10 SNR. Statistically significant and clinically important improvements in the HUI3 and SSQ49 were evident at 6 months. Conclusions and Relevance The findings of this nonrandomized controlled trial seem to indicate that cochlear implants are safe and effective in restoring speech understanding in both quiet and noise and improve quality of life in individuals with and without MCI. Trial Registration ClinicalTrials.gov Identifier:NCT03007472

International audience; Importance Cochlear implants are a treatment option for individuals with severe, profound, or moderate sloping to profound bilateral sensorineural hearing loss (SNHL) who receive little or no benefit from hearing aids; however, cochlear implantation in adults is still not routine.Objective To develop consensus statements regarding the use of unilateral cochlear implants in adults with severe, profound, or moderate sloping to profound bilateral SNHL.Design, Setting, and Participants This study was a modified Delphi consensus process that was informed by a systematic review of the literature and clinical expertise. Searches were conducted in the following databases: (1) MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE, (2) Embase, and (3) the Cochrane Library. Consensus statements on cochlear implantation were developed using the evidence identified. This consensus process was relevant for the use of unilateral cochlear implantation in adults with severe, profound, or moderate sloping to profound bilateral SNHL. The literature searches were conducted on July 18, 2018, and the 3-step Delphi consensus method took place over the subsequent 9-month period up to March 30, 2019.Main Outcomes and Measures A Delphi consensus panel of 30 international specialists voted on consensus statements about cochlear implantation, informed by an SR of the literature and clinical expertise. This vote resulted in 20 evidence-based consensus statements that are in line with clinical experience. A modified 3-step Delphi consensus method was used to vote on and refine the consensus statements. This method consisted of 2 rounds of email questionnaires and a face-to-face meeting of panel members at the final round. All consensus statements were reviewed, discussed, and finalized at the face-to-face meeting.Results In total, 6492 articles were identified in the searches of the electronic databases. After removal of duplicate articles, 74 articles fulfilled all of the inclusion criteria and were used to create the 20 evidence-based consensus statements. These 20 consensus statements on the use of unilateral cochlear implantation in adults with SNHL were relevant to the following 7 key areas of interest: level of awareness of cochlear implantation (1 consensus statement); best practice clinical pathway from diagnosis to surgery (3 consensus statements); best practice guidelines for surgery (2 consensus statements); clinical effectiveness of cochlear implantation (4 consensus statements); factors associated with postimplantation outcomes (4 consensus statements); association between hearing loss and depression, cognition, and dementia (5 consensus statements); and cost implications of cochlear implantation (1 consensus statement).Conclusions and Relevance These consensus statements represent the first step toward the development of international guidelines on best practices for cochlear implantation in adults with SNHL. Further research to develop consensus statements for unilateral cochlear implantation in children, bilateral cochlear implantation, combined electric-acoustic stimulation, unilateral cochlear implantation for single-sided deafness, and asymmetrical hearing loss in children and adults may be beneficial for optimizing hearing and quality of life for these patients.

Endolymphatic hydrops is an enlargement of scala media that is most often associated with Meniere's disease, though the pathophysiologic mechanism(s) remain unclear. In order to adequately study the attributes of endolymphatic hydrops, such as the origins of low-frequency hearing loss, a reliable model is needed. The guinea pig is a good model because it hears in the low-frequency regions that are putatively affected by endolymphatic hydrops. Previous research has demonstrated that endolymphatic hydrops can be induced surgically via intradural or extradural approaches that involve drilling on the endolymphatic duct and sac. However, whether it was possible to create an endolymphatic hydrops model using an extradural approach that avoided dangerous drilling on the endolymphatic duct and sac was unknown. The objective of this study was to demonstrate a revised extradural approach to induce experimental endolymphatic hydrops at 30 days post-operatively by obliterating the endolymphatic sac and injuring the endolymphatic duct with a fine pick. The sample size consisted of seven guinea pigs. Functional measurements of hearing were made and temporal bones were subsequently harvested for histologic analysis. The approach had a success rate of 86% in achieving endolymphatic hydrops. The risk of cerebrospinal fluid leak was minimal. No perioperative deaths or injuries to the posterior semicircular canal occurred in the sample. The presented method demonstrates a safe and reliable way to induce endolymphatic hydrops at a relatively quick time point of 30 days. The clinical implications are that the presented method provides a reliable model to further explore the origins of low-frequency hearing loss that can be associated endolymphatic hydrops.

Faculty are the single most important component of any academic department. They provide the innovation, skills, and experience needed to educate students, carry out research across the scientific continuum, and care for patients in the academic medical center. This chapter focuses on both the philosophical approach and pragmatics around recruitment, retention, and dismissal of faculty. Having effective control of these dimensions of departmental leadership are fundamental to maintaining an engaged, productive, and diversified faculty that functions toward a common mission.

OBJECTIVES: Electrocochleography (ECochG) is increasingly being utilized as an intraoperative monitor of cochlear function during cochlear implantation (CI). Intracochlear recordings from the advancing electrode can be obtained through the device by on-board capabilities. However, such recordings may not be ideal as a monitor because the recording electrode moves in relation to the neural and hair cell generators producing the responses. The purposes of this study were to compare two extracochlear recording locations in terms of signal strength and feasibility as intraoperative monitoring sites, and to characterize changes in cochlear physiology during CI insertion. DESIGN: In 83 human subjects, responses to 90 dB nHL tone bursts were recorded both at the round window (RW) and then at an extracochlear position – either adjacent to the stapes or on the promontory just superior to the RW. Recording from the fixed, extracochlear position continued during insertion of the CI in 63 cases. RESULTS: Prior to CI insertion, responses to low-frequency tones at the RW were roughly 6 dB larger than when recording at either extracochlear site, but the two extracochlear sites did not differ from one another. During CI insertion, response losses from the promontory or adjacent to the stapes stayed within 5 dB in ~61% (38/63) of cases, presumably indicating atraumatic insertions. Among responses which dropped more than 5 dB at any time during CI insertion, 12 subjects showed no response recovery while in 13 the drop was followed by partial or complete response recovery by the end of CI insertion. In cases with recovery the drop in response occurred relatively early (

Hypothesis Electrocochleography (ECochG) patterns observed during cochlear implant (CI) electrode insertion may provide information about scalar location of the electrode array. Background Conventional CI surgery is performed without actively monitoring auditory function and potential damage to intracochlear structures. The central hypothesis of this study was that ECochG obtained directly through the CI may be used to estimate intracochlear electrode position and, ultimately, residual hearing preservation. Methods Intracochlear ECochG was performed on 32 patients across 3 different implant centers. During electrode insertion, a 50-ms tone burst stimulus (500 Hz) was delivered at 110 dB SPL. The ECochG response was monitored from the apical-most electrode. The amplitude and phase changes of the first harmonic were imported into an algorithm in an attempt to predict the intracochlear electrode location (scala tympani [ST], translocation from ST to scala vestibuli [SV], or interaction with basilar membrane). Anatomic electrode position was verified using postoperative computed tomography (CT) with image processing. Results CT analysis confirmed 25 electrodes with ST position and 7 electrode arrays translocating from ST into SV. The ECochG algorithm correctly estimated electrode position in 26 (82%) of 32 subjects while 6 (18%) electrodes were wrongly identified as translocated (sensitivity = 100%, specificity = 77%, positive predictive value = 54%, and a negative predictive value = 100%). Greater hearing loss was observed postoperatively in participants with translocated electrode arrays (36 ± 15 dB) when compared with isolated ST insertions (28 ± 20 dB HL). This result, however, was not significant (p = 0.789). Conclusion Intracochlear ECochG may provide information about CI electrode location and hearing preservation.

OBJECTIVES The objectives of this study were to demonstrate the safety of auditory brainstem implant (ABI) surgery and document the subsequent development of auditory and spoken language skills in children without neurofibromatosis type II (NFII). DESIGN A prospective, single-subject observational study of ABI in children without NFII was undertaken at the University of North Carolina at Chapel Hill. Five children were enrolled under an investigational device exemption sponsored by the investigators. Over 3 years, patient demographics, medical/surgical findings, complications, device mapping, electrophysiologic measures, audiologic outcomes, and speech and language measures were collected. RESULTS Five children without NFII have received ABIs to date without permanent medical sequelae, although 2 children required treatment after surgery for temporary complications. All children wear their device daily, and the benefits of sound awareness have developed slowly. Intra-and postoperative electrophysiologic measures augmented surgical placement and device programming. The slow development of audition skills precipitated limited changes in speech production but had little impact on growth in spoken language. CONCLUSIONS ABI surgery is safe in young children without NFII. Benefits from device use develop slowly and include sound awareness and the use of pattern and timing aspects of sound. These skills may augment progress in speech production but progress in language development is dependent upon visual communication. Further monitoring of this cohort is needed to better delineate the benefits of this intervention in this patient population.