Simultaneous versus Sequential Cochlear Implantation in Adults: Quantitative and Qualitative Outcomes.

OBJECTIVE: To compare speech recognition and quality of life outcomes between bilateral sequentially and simultaneously implanted adult cochlear implant (CI) recipients who initially qualify for a CI in both ears. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. METHODS: Retrospective chart review identified adults who underwent bilateral CI, either simultaneously or sequentially, at a high-volume center between 2012 and 2022. Sequentially implanted patients were only included if the second ear qualified for CI in quiet (defined as best-aided AzBio quiet testing <60%), at time of initial CI evaluation. RESULTS: Of 112 bilateral CI patients who qualified in both ears at initial evaluation, 95 underwent sequential implantation and 17 simultaneous. Age, duration, and etiology of hearing loss, and CI usage were similar between groups. Preoperatively, the sequential group had lower pure-tone average (PTA) in the 1st ear than the simultaneously implanted group (P = <.001) but, no difference in 2nd ear PTA (P = .657). Preoperative speech recognition scores were significantly higher for the sequential group; however, this was not true for postoperative scores. There was no difference in the proportion of patients showing significant CI-only or bilateral performance improvement between the groups. Both groups demonstrated similar benefit in quality of life measures. CONCLUSION: Our findings indicate both simultaneous and sequential cochlear implantation are effective in improving hearing performance and quality of life. Thus, bilateral versus simultaneous implantation should be discussed and tailored for each individual patient.

The natural history and genotype-phenotype correlations of TMPRSS3 hearing loss: an international, multi-center, cohort analysis.

TMPRSS3-related hearing loss presents challenges in correlating genotypic variants with clinical phenotypes due to the small sample sizes of previous studies. We conducted a cross-sectional genomics study coupled with retrospective clinical phenotype analysis on 127 individuals. These individuals were from 16 academic medical centers across 6 countries. Key findings revealed 47 unique TMPRSS3 variants with significant differences in hearing thresholds between those with missense variants versus those with loss-of-function genotypes. The hearing loss progression rate for the DFNB8 subtype was 0.3 dB/year. Post-cochlear implantation, an average word recognition score of 76% was observed. Of the 51 individuals with two missense variants, 10 had DFNB10 with profound hearing loss. These 10 all had at least one of 4 TMPRSS3 variants predicted by computational modeling to be damaging to TMPRSS3 structure and function. To our knowledge, this is the largest study of TMPRSS3 genotype-phenotype correlations. We find significant differences in hearing thresholds, hearing loss progression, and age of presentation, by TMPRSS3 genotype and protein domain affected. Most individuals with TMPRSS3 variants perform well on speech recognition tests after cochlear implant, however increased age at implant is associated with worse outcomes. These findings provide insight for genetic counseling and the on-going design of novel therapeutic approaches.

Improved Postoperative Speech Recognition and Processor Use With Early Cochlear Implant Activation.

OBJECTIVE: To report speech recognition outcomes and processor use based on timing of cochlear implant (CI) activation. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary referral center. PATIENTS: A total of 604 adult CI recipients from October 2011 to March 2022, stratified by timing of CI activation (group 1: ≤10 d, n = 47; group 2: >10 d, n = 557). MAIN OUTCOME MEASURES: Average daily processor use; Consonant-Nucleus-Consonant (CNC) and Arizona Biomedical (AzBio) in quiet at 1-, 3-, 6-, and 12-month visits; time to peak performance. RESULTS: The groups did not differ in sex ( p = 0.887), age at CI ( p = 0.109), preoperative CNC ( p = 0.070), or preoperative AzBio in quiet ( p = 0.113). Group 1 had higher median daily processor use than group 2 at the 1-month visit (12.3 versus 10.7 h/d, p = 0.017), with no significant differences at 3, 6, and 12 months. The early activation group had superior median CNC performance at 3 months (56% versus 46%, p = 0.007) and 12 months (60% versus 52%, p = 0.044). Similarly, the early activation group had superior median AzBio in quiet performance at 3 months (72% versus 59%, p = 0.008) and 12 months (75% versus 68%, p = 0.049). Both groups were equivalent in time to peak performance for CNC and AzBio. Earlier CI activation was significantly correlated with higher average daily processor use at all follow-up intervals. CONCLUSION: CI activation within 10 days of surgery is associated with increased early device usage and superior speech recognition at both early and late follow-up visits. Timing of activation and device usage are modifiable factors that can help optimize postoperative outcomes in the CI population.

Cochlear Implant Qualification in Noise Versus Quiet: Do Patients Demonstrate Similar Postoperative Benefits?

OBJECTIVE: To assess patient factors, audiometric performance, and patient-reported outcomes in cochlear implant (CI) patients who would not have qualified with in-quiet testing alone. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. METHODS: Adult CI recipients implanted between 2012 and 2022 were identified. Patients with preoperative AzBio Quiet > 60% in the implanted ear, requiring multitalker babble to qualify, comprised the in-noise qualifying (NQ) group. NQ postoperative performance was compared with the in-quiet qualifying (QQ) group using CNC, AzBio Quiet, and AzBio +5 dB signal-to-noise ratio. Speech, Spatial and Qualities of Hearing Scale (SSQ), Cochlear Implant Quality of Life scale (CIQOL-10), and daily device usage were also compared between the groups. RESULTS: The QQ group (n = 771) and NQ group (n = 67) were similar in age and hearing loss duration. NQ had higher average preoperative and postoperative speech recognition scores. A larger proportion of QQ saw significant improvement in CNC and AzBio Quiet scores in the CI-only listening condition (eg, CI-only AzBio Quiet: 88% QQ vs 51% NQ, P < .001). Improvement in CI-only AzBio +5 dB and in all open set testing in the best-aided binaural listening condition was similar between groups (eg, Binaural AzBio Quiet 73% QQ vs 59% NQ, P = .345). Postoperative SSQ ratings, CIQOL scores, and device usage were also equivalent between both groups. CONCLUSION: Patients who require in-noise testing to meet CI candidacy demonstrate similar improvements in best-aided speech perception and patient-reported outcomes as in-QQ, supporting the use of in-noise testing to determine CI qualification for borderline CI candidates.

Development of an Optimized Protocol for Cochlear Implant Care to Increase Cochlear Implant Access.

OBJECTIVE: To develop an evidence-based protocol for audiology-based, cochlear implant (CI) programming in the first year after activation. STUDY DESIGN: Retrospective case review. SETTING: CI program at a tertiary medical center. PATIENTS: One-hundred seventy-one patients (178 ears; mean age at implantation, 62.3 yr; 44.4% female) implanted between 2016 and 2021 with postlingual onset of deafness and no history of CI revision surgery. Patients included here had confirmed CI programming optimization based on CI-aided thresholds in the 20- to 30-dB-HL range as well as upper stimulation levels guided by electrically evoked stapedial reflex thresholds. MAIN OUTCOME MEASURES: Consonant-nucleus-consonant monosyllabic word recognition scores in the CI-alone and bilateral best-aided conditions at five time points: preoperative evaluation, and 1, 3, 6, and 12 months after activation. RESULTS: For both the CI-alone and bilateral best-aided conditions, consonant-nucleus-consonant word recognition significantly improved from preoperative evaluation to all postactivation time points. For the CI-alone condition, no significant differences were observed between 3 and 6 months, or from 6 to 12 months after activation. In contrast, for the bilateral best-aided condition, significant differences were observed between 1 and 3 months, and 3 and 6 months, but no difference in scores between 6 and 12 months. CONCLUSIONS: Based on the current data set and associated analyses, CI centers programming adult patients could eliminate either the 3- or 6-month visit from their clinical follow-up schedule if patient mapping of lower and upper stimulation levels is validated via CI-aided audiometric thresholds and electrically evoked stapedial reflex thresholds, respectively.

Cochlear Implantation in Very Young Children With Single-Sided Deafness.

OBJECTIVE: Cochlear implants (CIs) for single-sided deafness (SSD) have only been approved for patients 5 years and older despite data supporting that younger children can also benefit from implantation. This study describes our institution's experience with CI for SSD in children 5 years and younger. STUDY DESIGN: Case series with chart review. SETTING: Tertiary referral center. METHODS: A case series with chart review identified 19 patients up to age 5 years who underwent CI for SSD between 2014 and 2022. Baseline characteristics, perioperative complications, device usage, and speech outcomes were collected. RESULTS: The median age at CI was 2.8 (range, 1.0-5.4) years, with 15 (79%) patients being below age 5 at implantation. Etiologies of hearing loss were idiopathic (n = 8), cytomegalovirus (n = 4), enlarged vestibular aqueduct (n = 3), hypoplastic cochlear nerve (n = 3), and meningitis (n = 1). The median preoperative pure-tone average was 90 (range, 75-120) and 20 (range, 5-35) dB eHL in the poor and better hearing ears, respectively. No patients had postoperative complications. Twelve patients achieved consistent device use (average, 9 h/d). Three of the seven who were not consistent users had hypoplastic cochlear nerves and/or developmental delays. The three patients with available preoperative and postoperative speech testing showed significant benefits, and five patients with available postoperative testing demonstrated speech recognition in the implanted ear when isolated from the better ear. CONCLUSION: CI can safely be performed in younger children with SSD. Patients and families accept early implantation, as evidenced by consistent device use, and derive notable benefits in speech recognition. Candidacy can be broadened to include SSD patients under age five years, particularly individuals without hypoplastic cochlear nerves or developmental delay.

A Five-Year Update on the Profile of Adults Undergoing Cochlear Implant Evaluation and Surgery-Are We Doing Better?

OBJECTIVE: To characterize the influence of expanding indications on the profile of adults undergoing cochlear implantation (CI) at a high-volume CI center. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: 774 adults undergoing CI evaluation from August 2015 to August 2020. MAIN OUTCOME MEASURES: Demographics; audiometry; speech recognition; speech, spatial, and qualities of hearing scale (SSQ-12). RESULTS: Of 745 (96.3%) patients qualifying for implantation, 642 (86.6%) pursued surgery. Median age at evaluation was 69 years; 56.3% were men; 88.2% were Caucasian. Median distance to our center was 95 miles. The majority (51.8%) had public insurance (Medicare, Medicaid), followed by private (47.8%) and military (0.4%). Mean PTA, CNC, and AzBio in quiet and noise for the ear to be implanted were 85.2 dB HL, 15.0%, and 19.2% and 3.5%, respectively. Hybrid/EAS criteria were met by 138 (18.5%) CI candidates, and 436 (77.0%) unilateral CI recipients had aidable contralateral hearing for bimodal hearing configurations. Younger age (odds ratio [OR], 0.96; 95% confidence interval, 0.93-0.99) and non-Caucasian race (OR, 6.95; 95% confidence interval, 3.22-14.98) predicted candidacy. Likelihood of surgery increased for Caucasian (OR, 8.08; 95% confidence interval, 4.85-13.47) and married (OR, 2.28; 95% confidence interval, 1.50-3.47) patients and decreased for those with public insurance (OR, 0.45; 95% confidence interval, 0.29-0.69). A lower SSQ-12 score predicted both candidacy and surgery. CONCLUSION: Despite expansions in criteria, speech understanding remained extremely low at CI evaluation. Younger age and non-Caucasian race predicted candidacy, and Caucasian, married patients with private insurance and lower SSQ scores were more likely to pursue surgery.

HiRes Ultra Series Recall: Failure Rates and Revision Speech Recognition Outcomes.

OBJECTIVE: To report Advanced Bionics (AB) Ultra (V1) and Ultra 3D (V1) cochlear implant (CI) electrode failures and revision speech recognition outcomes for patients at a large CI program. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Patients receiving Ultra (V1) or Ultra 3D (V1) devices as of September 21, 2021. MAIN OUTCOME MEASURES: Failure rate, revision surgery, speech recognition scores. RESULTS: To data, 65 (21.1%) of the 308 implanted devices are known failures, with 63 (20.5%) associated with the recent voluntary field corrective action (FCA). Average time to failure was 2.2 ± 1.1 years. Fifty-two patients (82.5%) elected for revision surgery. Among adults, immediate prerevision scores demonstrated a significant decrease from best-achieved scores with the faulty implant, with mean difference of -15.2% (p = 0.0115) for consonant-nucleus-consonant (CNC) and -27.3% (p < 0.0001) for AzBio in quiet. By 3 months postactivation of the revised device, CNC (p = 0.9766) and AzBio in quiet (p = 0.9501) scores were not significantly different than best prerevision scores. Overall, 15 of 19 patients regained or improved their best prerevision CNC score. The current trajectory for FCA device failures is approximately 6% per year. CONCLUSION: Compared to manufacturer reporting, a high number of patients experienced hard failures of the Ultra (V1) and Ultra 3D (V1) devices. Early identification of failures is possibly because of the diligent use of electrical field imaging testing. Most patients affected by the FCA regain or exceed their prefailure speech recognition score as soon as 3 months after revision surgery.

Can Electrocochleography Help Preserve Hearing After Cochlear Implantation With Full Electrode Insertion?

OBJECTIVES: To evaluate the utility of intracochlear electrocochleography (ECochG) monitoring during cochlear implant (CI) surgery on postoperative hearing preservation. STUDY DESIGN: Prospective, randomized clinical trial. SETTING: Ten high-volume, tertiary care CI centers. PATIENTS: Adult patients with sensorineural hearing loss meeting the CI criteria who selected an Advanced Bionics CI. METHODS: 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. RESULTS: 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 change >15-29 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. CONCLUSIONS: 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."

Cochlear Implantation and Electric Acoustic Stimulation in Children With TMPRSS3 Genetic Mutation.

BACKGROUND: Mutations in the TMPRSS3 gene, although rare, can cause high frequency hearing loss with residual hearing at low frequencies. Several previous studies have reported cochlear implant (CI) outcomes for adults with TMPRSS3 mutation with mixed results. Although some studies have suggested that TMPRSS3 is expressed in spiral ganglion cells, it remains unclear if previously reported poor CI outcomes in this population were secondary to long durations of deafness or to the effects of the TMPRSS3 mutation. To date, no studies in the literature have reported CI outcomes for children with TMPRSS3 mutation treated with CI. OBJECTIVE: The current case series aimed to describe outcomes for three children with sloping hearing loss caused by TMPRSS3 mutation who underwent bilateral CI. STUDY DESIGN: Case series. SETTING: Academic medical center. PATIENTS: Three children (3-4 yr) with TMPRSS3 mutation and normal sloping to profound high frequency hearing loss. INTERVENTIONS: CI and electric acoustic stimulation (EAS). MAIN OUTCOME MEASURES: Outcome measures were residual hearing thresholds, speech recognition scores, and electrode placement determined via intraoperative CT imaging. RESULTS: All three children maintained residual acoustic hearing and received benefit from EAS. Mean change in low-frequency pure-tone average was 17 dB. Mean postoperative word and sentence recognition scores in the bilateral EAS condition were 80 and 75%, respectively. CONCLUSIONS: Results indicate that CI with EAS is an appropriate treatment for children with TMPRSS3 genetic mutation. Pediatric results from this case series show more favorable CI outcomes than are currently reported for adults with TMPRSS3 mutation suggesting that the intervention may be time sensitive.

Effect of Scala Tympani Height on Insertion Depth of Straight Cochlear Implant Electrodes.

OBJECTIVE: Studies suggest lateral wall (LW) scala tympani (ST) height decreases apically, which may limit insertion depth. No studies have investigated the relationship of LW ST height with translocation rate or location. STUDY DESIGN: Retrospective review. SETTING: Cochlear implant program at tertiary referral center. SUBJECTS AND METHODS: LW ST height was measured in preoperative images for patients with straight electrodes. Scalar location, angle of insertion depth (AID), and translocation depth were measured in postoperative images. Audiologic outcomes were tracked. RESULTS: In total, 177 ears were identified with 39 translocations (22%). Median AID was 443° (interquartile range [IQR], 367°-550°). Audiologic outcomes (126 ears) showed a small, significant correlation between consonant-nucleus-consonant (CNC) word score and AID (r = 0.20, P = .027), although correlation was insignificant if translocation occurred (r = 0.11, P = .553). Translocation did not affect CNC score (P = .335). AID was higher for translocated electrodes (503° vs 445°, P = .004). Median translocation depth was 381° (IQR, 222°-399°). Median depth at which a 0.5-mm electrode would not fit within 0.1 mm of LW was 585° (IQR, 405°-585°). Median depth at which a 0.5-mm electrode would displace the basilar membrane by ≥0.1 mm was 585° (IQR, 518°-765°); this was defined as predicted translocation depth (PTD). Translocation rate was 39% for insertions deeper than PTD and 14% for insertions shallower than PTD (P = .008). CONCLUSION: AID and CNC are directly correlated for straight electrodes when not translocated. Translocations generally occur around 380° and are more common with deeper insertions due to decreasing LW ST height. Risk of translocation increases significantly after 580°.

Same-Day Patient Consultation and Cochlear Implantation: Innovations in Patient-Centered Health Care Delivery.

OBJECTIVE: To develop and implement a streamlined, patient-centered service delivery model for patients referred for cochlear implantation (CI) at a high-volume academic center. PATIENTS: CI candidate adults. INTERVENTIONS: CI, implementation of new CI delivery model. MAIN OUTCOME MEASURES: Referral-to-surgery time, patient travel burden. RESULTS: Data from 206 adults that underwent CI were used to develop a process map of the initial operational state from referral date to day of surgery (referral-to-surgery time). The initial referral-to-surgery time was 136 days on average, yet the average total work time by all involved providers was 17.6 hours. Prolonged wait times were associated with the following preoperative tasks: appointment scheduling, insurance approval, device ordering and shipment, and surgical scheduling. Patients traveled to the institution on at least two occasions for appointments. A new bundled, patient-centered CI delivery model was developed to address prolonged wait times, travel burden, and process inefficiencies. The new model implemented an interactive electronic medical record, coordinated appointments with same-day surgery, and stocked device inventory to reduce the referral-to-surgery time to 24 days-an improvement of 112 days. In the new model, new patient consultation and surgery were completed in one day, reducing the patient travel burden to the institution. CONCLUSIONS: The new CI program demonstrates that delivery innovations can have a substantial impact on measures of patient convenience and experience, and that these results are achievable without new technologies or changes in medical management. With a focus on patient-centered design, health care delivery models can be augmented to increase value for patients.

Intra-Cochlear Electrocochleography During Cochear Implant Electrode Insertion Is Predictive of Final Scalar Location.

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 ±â€Š15 dB) when compared with isolated ST insertions (28 ±â€Š20 dB HL). This result, however, was not significant (p = 0.789). CONCLUSION: Intracochlear ECochG may provide information about CI electrode location and hearing preservation.

Patterns Seen During Electrode Insertion Using Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant.

HYPOTHESIS: Intraoperative, intracochlear electrocochleography (ECochG) will provide a means to monitor cochlear hair cell and neural response during cochlear implant (CI) electrode insertion. Distinct patterns in the insertion track can be characterized. BACKGROUND: Conventional CI surgery is performed without a means of actively monitoring cochlear hair cell and neural responses. Intracochlear ECochG obtained directly through the CI may be a source of such feedback. Understanding the patterns observed in the "insertion track" is an essential step toward refining intracochlear ECochG as a tool that can be used to assist in intraoperative decision making and prognostication of hearing preservation. METHODS: Intracochlear ECochG was performed in 17 patients. During electrode insertion, a 50-ms tone burst acoustic stimulus was delivered with a frequency of 500 Hz at 110 dB SPL. The ECochG response was monitored from the apical-most electrode. The amplitude of the first harmonic was plotted and monitored in near real time by the audiologist-surgeon team during CI electrode insertion. RESULTS: Three distinct patterns in first harmonic amplitude change were observed across subjects during insertion: Type A (52%), overall increase in amplitude from the beginning of insertion until completion; Type B (11%), a maximum amplitude at the beginning of insertion, with a decrease in amplitude as insertion progressed to completion; and Type C (35%), comparable amplitudes at the beginning and completion of the insertion with the maximum amplitude mid-insertion. CONCLUSION: Three ECochG patterns were observed during electrode advancement into the cochlea. Ongoing and future work will broaden our scope of knowledge regarding the relationship among these patterns, the presence of cochlear trauma, and functional outcomes related to hearing preservation.

Intra- and Postoperative Electrocochleography May Be Predictive of Final Electrode Position and Postoperative Hearing Preservation.

Introduction: The objectives of the current study were to (1) determine the relationship between electrocochleography (ECochG), measured from the cochlear implant (CI) electrode array during and after implantation, and postoperative audiometric thresholds, (2) determine the relationship between ECochG amplitude and electrode scalar location determined by computerized tomography (CT); and (3) determine whether changes in cochlear microphonic (CM) amplitude during electrode insertion were associated with postoperative hearing. Materials and Methods: Eighteen subjects undergoing CI with an Advanced Bionics Mid-Scala device were prospectively studied. ECochG responses were recorded using the implant coupled to a custom signal recording unit. ECochG amplitude collected intraoperatively concurrent with CI insertion and at activation was compared with audiometric thresholds postoperatively. Sixteen patients also underwent postoperative CT to determine scalar location and the relationship to ECochG measures and residual hearing. Results: Mean low-frequency pure tone average (LFPTA) increased following surgery by an average of 28 dB (range 8-50). Threshold elevation was significantly greater for electrodes with scalar dislocation. No correlation was found between intraoperative ECochG and postoperative behavioral thresholds collapsed across frequency; however, mean differences in thresholds measured by intraoperative ECochG and postoperative audiometry were significantly smaller for electrodes inserted completely within scala tympani (ST) vs. those translocating from ST to scala vestibuli. A significant correlation was observed between postoperative ECochG thresholds and behavioral thresholds obtained at activation. Discussion: Postoperative audiometry currently serves as a marker for intracochlear trauma though thresholds are not obtained until device activation or later. When measured at the same time-point postoperatively, low-frequency ECochG thresholds correlated with behavioral thresholds. Intraoperative ECochG thresholds, however, did not correlate significantly with postoperative behavioral thresholds suggesting that changes in cochlear physiology occur between electrode insertion and activation. ECochG may hold clinical utility providing surgeons with feedback regarding insertion trauma due to scalar translocation, which may be predictive of postoperative hearing preservation. Conclusion: CI insertion trauma is generally not evident until postoperative audiometry when loss of residual hearing is confirmed. ECochG has potential to provide estimates of trauma during insertion as well as reliable information regarding degree of hearing preservation.

Real-Time Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant.

HYPOTHESIS: Utilizing the cochlear implant to record electrophysiologic responses during device placement is a feasible and efficacious technique for monitoring near real-time cochlear physiology during and following electrode insertion. BACKGROUND: Minimizing intracochlear trauma during cochlear implantation has emerged as a highly researched area to help improve patient performance. Currently, conventional cochlear implant technology allows for the recording of electrically evoked compound action potentials (eCAPs). Acoustically evoked potentials may be more sensitive in detecting physiologic changes occurring as a result of electrode insertion. Electrocochleography obtained from within the cochlea allows hair cell and neural response monitoring along the cochlear spiral at locations where changes most likely would occur. METHODS: Intracochlear electrocochleography (ECochG) was recorded from the cochlear implant during surgery in 14 subjects. A long acquisition time (54.5 ms), capable of measuring potentials from the low frequency-serving apical region of the cochlea (125 and 500 Hz) was employed. Two distinct intracochlear processing methods were used and compared in obtaining electrophysiologic data. RESULTS: Measureable intracochlear ECochG responses were obtained from all 14 participants. The 1st harmonic distortions (cochlear microphonic and auditory nerve neurophonic) generally increased steadily with electrode insertion. Electrode and frequency scan following insertion revealed that response amplitude varied based on location of recording electrode and frequency of stimulation. Exquisite sensitivity to manipulation during round window muscle packing was demonstrated. CONCLUSION: Intracochlear ECochG recorded from the electrode array of the cochlear implant is a highly feasible technique that sheds light on cochlear micromechanics during cochlear implant electrode placement.