Preservation Of Low-frequency Hearing Research Articles

Long-Term Hearing Outcomes After Hybrid Cochlear Implantation.

To examine long-term (>5 yr) low-frequency hearing preservation after hybrid cochlear implantation. Retrospective cross-sectional study. Tertiary care center outpatient clinic. All patients older than 21 years implanted with a Cochlear Hybrid L24 device from 2014 to 2021. Changes in low-frequency pure-tone average (LFPTA) were calculated at each of several time points relative to the date of implantation. The proportion of patients with preserved LFPTA at last follow-up and Kaplan-Meier estimates for loss of residual hearing were calculated in addition to hazard ratios for hearing loss according to patient- and surgery-specific factors. Thirty ears in 29 patients underwent hybrid cochlear implantation and were eligible for inclusion (mean age, 59 yr; 65% female). Mean preoperative LFPTA was 31.7 dB. Mean LFPTA across all implanted ears at first follow-up was 45.1 dB; no patient had experienced loss of residual hearing at first follow-up. Six patients had loss of residual hearing during the follow-up period, with Kaplan-Meier probability estimates of preserved hearing of 100% at 1 month, 90% at 12 months, 87% at 24 months, and 80% at 48 months. There was no association between loss of residual hearing and patient age, preoperative LFPTA, surgeon, or use of topical steroids intraoperatively (hazard ratios, 1.05 [0.96-1.15], 0.97 [0.88-1.05], 1.39 [0.20-9.46], 0.93 [0.09-9.74], respectively). Long-term (>5 yr) outcomes after hybrid cochlear implantation demonstrate good preservation of low-frequency hearing, with only modest decline in the long-term postimplantation, and a low proportion of loss of residual low-frequency hearing.

Hearing Asymmetry Biases Spatial Hearing in Bimodal Cochlear-Implant Users Despite Bilateral Low-Frequency Hearing Preservation.

Many cochlear implant users with binaural residual (acoustic) hearing benefit from combining electric and acoustic stimulation (EAS) in the implanted ear with acoustic amplification in the other. These bimodal EAS listeners can potentially use low-frequency binaural cues to localize sounds. However, their hearing is generally asymmetric for mid- and high-frequency sounds, perturbing or even abolishing binaural cues. Here, we investigated the effect of a frequency-dependent binaural asymmetry in hearing thresholds on sound localization by seven bimodal EAS listeners. Frequency dependence was probed by presenting sounds with power in low-, mid-, high-, or mid-to-high-frequency bands. Frequency-dependent hearing asymmetry was present in the bimodal EAS listening condition (when using both devices) but was also induced by independently switching devices on or off. Using both devices, hearing was near symmetric for low frequencies, asymmetric for mid frequencies with better hearing thresholds in the implanted ear, and monaural for high frequencies with no hearing in the non-implanted ear. Results show that sound-localization performance was poor in general. Typically, localization was strongly biased toward the better hearing ear. We observed that hearing asymmetry was a good predictor for these biases. Notably, even when hearing was symmetric a preferential bias toward the ear using the hearing aid was revealed. We discuss how frequency dependence of any hearing asymmetry may lead to binaural cues that are spatially inconsistent as the spectrum of a sound changes. We speculate that this inconsistency may prevent accurate sound-localization even after long-term exposure to the hearing asymmetry.

Hearing Preservation and Spatial Hearing Outcomes After Cochlear Implantation in Children With TMPRSS3 Mutations.

Investigate hearing preservation and spatial hearing outcomes in children with TMPRSS3 mutations who received bilateral cochlear implantation. Longitudinal case series report. Two siblings (ages, 7 and 4 yr) with TMPRSS3 mutations with down-sloping audiograms received sequential bilateral cochlear implantation with hearing preservation with low-frequency acoustic amplification and high-frequency electrical stimulation. Spatial hearing, including speech perception and localization, was assessed at three time points: preoperative, postoperative of first and second cochlear implant (CI). Both children showed low-frequency hearing preservation in unaided, acoustic-only audiograms. Both children demonstrated improvements in speech perception in both quiet and noise after CI activations. The emergence of spatial hearing was observed. Each child's overall speech perception and spatial hearing when listening with bilateral CIs were within the range or better than published group data from children with bilateral CIs of other etiology. Bilateral cochlear implantation with hearing preservation is a viable option for managing hearing loss for pediatric patients with TMPRSS3 mutations.

Molecular aetiology of ski-slope hearing loss and audiological course of cochlear implantees.

A challenge for patients with ski-slope hearing loss is that hearing aids do not adequately amplify the mid-to-high frequencies necessary for speech perception and conversely, cochlear implant (CI) may damage low-frequency hearing. We aimed to describe the clinical profile of patients with ski-slope hearing loss, with a special focus on aetiology of such hearing loss and audiological course of low-frequency hearing after CI. We recruited hearing-impaired patients who visited a tertiary referral centre and met the criteria for ski-slope hearing loss patients from 2015 to 2021. Genetic testing was performed in all ski-slope hearing loss patients unless refused. Baseline audiograms of patients who continued to use hearing aids or who finally underwent CIs were reviewed. As for CI patients, outcome and hearing preservation rate were rigorously analysed. Of 46 recruited patients with ski-slope hearing loss, 45 agreed to undergo genetic testing and causative variants were identified in 17 (37.8%) patients. The TMC1, MYO7A, and TMPRSS3 variants were the most common, while LRTOMT was newly identified as a causative gene. Twenty-five patients eventually received CI, while 13 continued to wear the hearing aid and 8 patients did not ever try hearing aids. CI in ski-slope hearing loss led to immediate and sufficient improvement of sentence recognition by as early as 3months, however, the duration of hearing loss was inversely correlated with the sentence recognition score. The average hearing preservation rate (using the HEARRING classification) after CI was 53.0% (SD 30.0) and 45.6% (SD 31.1) at 1year. Seventy-nine percent of implantees maintained functional low-frequency hearing (better than 85dB at 250 and 500Hz) eligible for electric-acoustic stimulation (EAS). A trend was found that patients with hair cell stereocilia-associated genetic variants may have a slightly better preservation, albeit with no statistical significance. Detection rate of a molecular genetic aetiology of ski-slope hearing loss appears to be lower than other type of hearing loss reported in the literature. Especially with short hearing loss duration, CI in ski-slope hearing loss leads to immediate and sufficient speech improvement, while preserving functional low-frequency hearing eligible for EAS as many as in 79%. A certain genetic aetiology might be associated with a trend towards better low-frequency hearing preservation.

Timing of Acoustic Hearing Changes After Cochlear Implantation.

To determine the timing of acoustic hearing changes among hearing preservation Cochlear implant (CI) recipients. To determine differences in hearing outcomes based on device type and demographic factors. To determine if there is a relationship between the extent of early hearing loss after CI and the subsequent rate of continued hearing loss. Prospective, single subject study. Two hundred and eleven subjects who received a hearing preservation CI were included in the study-80 Nucleus Hybrid L24 (Cochlear), 47 422/522 (Cochlear), 24 S8 (Cochlear), 14 S12 (Cochlear), 6 SRW (Cochlear), 21 SLIM J (Advanced Bionics), and 19 Flex (Med-EL). Of these, 127 were included in the subsequent analyses. Audiometric thresholds (low frequency pure-tone-averages) were collected and compared pre and postoperatively. Long-term hearing preservation rates were 65% (52/80) for L24, 83% (20/24) for S8, 79% (11/14) for S12, 83% (5/6) for SRW, 54% (25/47) for 422/522, 91% (21/23) for SLIM J, and 84% (16/19) for Flex. Hearing loss was not related to device type (P=.9105) or gender (P=.2169). Older subjects (age ≥65) had worse hearing outcomes than younger subjects after initial device activation (age <65, P=.0262). There was no significant difference in rate of hearing loss over time between older and younger patients (P=.0938). Initial postoperative hearing loss was not associated with the rate of long-term hearing loss. Long-term low frequency hearing preservation is possible for CI recipients and is not associated with gender or device type. Rate of hearing loss over time is not dependent on patient age. Early hearing loss after CI does not predict the rate of long-term hearing loss. 3 Laryngoscope, 132:2036-2043, 2022.

Otology/Neurotology

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.

Advances in hearing preservation in cochlear implant surgery.

Advancements in cochlear implant surgical approaches and electrode designs have enabled preservation of residual acoustic hearing. Preservation of low-frequency hearing allows cochlear implant users to benefit from electroacoustic stimulation, which improves performance in complex listening situations, such as music appreciation and speech understanding in noise. Despite the relative high rates of success of hearing preservation, postoperative acoustic hearing outcomes remain unpredictable. Thin, flexible, lateral wall arrays are preferred for hearing preservation. Both shortened and thin, lateral wall arrays have shown success with hearing preservation and the optimal implant choice is an issue of ongoing investigation. Electrocochleography can monitor cochlear function during and after insertion of the electrode array. The pathophysiology of hearing loss acutely after cochlear implant may differ from that involved in delayed hearing loss following cochlear implant. Emerging innovations may reduce cochlear trauma and improve hearing preservation. Hearing preservation is possible using soft surgical techniques and electrode arrays designed to minimize cochlear trauma; however, a subset of patients suffer from partial to total loss of acoustic hearing months to years following surgery despite evidence of residual apical hair cell function. Early investigations in robotic-assisted insertion and dexamethasone-eluting implants show promise.

Initial Hearing Preservation Is Correlated With Cochlear Duct Length in Fully-inserted Long Flexible Lateral Wall Arrays.

To characterize the relationship between cochlear duct length (CDL) and initial hearing preservation among cochlear implant recipients of a fully inserted 31.5 mm flexible lateral wall electrode array. Retrospective review. Tertiary academic referral center. Adult cochlear implant recipients who presented preoperatively with unaided hearing detection thresholds of ≤ 65 dB HL at 125 Hz and underwent cochlear implantation with a 31.5 mm flexible lateral wall array. Cochlear implantation with a hearing preservation surgical approach. Computed tomography was reviewed to determine CDL. Hearing preservation was characterized by the shift in low-frequency pure-tone average (LFPTA; 125, 250, and 500 Hz), and shift in individual unaided hearing detection thresholds at 125, 250, and 500 Hz. Nineteen patients met the criteria for inclusion. The mean CDL was 34.2 mm (range: 30.8-36.5 mm). Recipients experienced a mean LFPTA shift of 27.6 dB HL (range: 10-50 dB HL). Significant, negative correlations were observed between CDL and smaller threshold shifts at individual frequencies and LFPTA (p ≤ 0.048). A longer CDL is associated with greater likelihood of preserving low-frequency hearing with long arrays. Low-frequency hearing preservation is feasible with fully inserted long flexible arrays within the initial months after cochlear implantation. Preoperative measurement of CDL may facilitate a more individualized approach in array selection to permit optimal cochlear coverage while enhancing hearing preservation outcomes.

Hearing preservation with a slim modiolar cochlear implant in a pediatric cohort

ObjectivesRecent cochlear implant (CI) electrodes are designed to be atraumatic to inner ear structures. Studies in adults have demonstrated improved hearing preservation rates with the CI532/632 electrode, but none have examined this in children. Our objective is to describe the hearing preservation rate with CI532/632 in pediatric patients and determine factors that influence hearing preservation. MethodsWe conducted a retrospective cohort study of children undergoing CI over a three-year period. Inclusion criteria were: CI with the 532/632 electrode, presence of pre-operative low frequency hearing defined by pure tone average (PTA) of ≤80 dB at 250 Hz or at the average of 250 and 500 Hz, and post-operative unaided audiometry. Other data collected included demographics, otologic history, imaging, and surgical details. ResultsA total of 13 patients and 15 ears were included. Hearing was preserved in 10/15 (66%) ears at an average follow-up of 6 months, similar to that reported in the adult literature. Patients with preserved hearing post-operatively were more likely to have a positive family history of hearing loss. There was a trend towards patients with anatomic inner ear abnormalities being more likely to lose hearing after CI, but this was not statistically significant. Pre-operative thresholds were not predictive of hearing preservation. Patients with preserved hearing had a significantly smaller shift in thresholds after cochlear implantation. Therefore, hearing preserved and non-preserved groups differed more by the magnitude of change in threshold, rather than their preoperative threshold. Other factors such as age, sex, surgeon, and surgery duration were not associated with hearing preservation. ConclusionThis study describes low frequency hearing preservation after pediatric CI532/632 implantation. The hearing preservation rate in our cohort was consistent with that reported in the adult literature. Our data suggest that preoperative thresholds do not solely determine which patients will go on to experience hearing preservation. We believe this will aid surgeons with patient-specific device selection and counseling potential pediatric CI recipients with preserved hearing.

Low-Frequency Hearing Preservation With Long Electrode Arrays: Inclusion of Unaided Hearing Threshold Assessment in the Postoperative Test Battery.

PurposeThe goal of this work was to evaluate the low-frequency hearing preservation of long electrode array cochlear implant (CI) recipients.MethodTwenty-five participants presented with an unaided hearing threshold of ≤ 80 dB HL at 125 Hz pre-operatively in the ear to be implanted. Participants were implanted with a long (31.5-mm) electrode array. The unaided hearing threshold at 125 Hz was compared between the preoperative and postoperative intervals (i.e., initial CI activation, and 1, 3, 6, 9, and 12 months after activation).ResultsEight participants maintained an unaided hearing threshold of ≤ 80 dB HL at 125 Hz postoperatively. The majority (n = 5) demonstrated aidable low-frequency hearing at initial activation, whereas 3 other participants experienced an improvement in unaided low-frequency hearing thresholds at subsequent intervals.ConclusionsCI recipients can retain residual hearing sensitivity with fully inserted long electrode arrays, and low-frequency hearing thresholds may improve during the postoperative period. Therefore, unaided hearing thresholds obtained within the initial weeks after surgery may not reflect later hearing sensitivity. Routine measurement of postoperative unaided hearing thresholds—even for patients who did not demonstrate aidable hearing thresholds initially after cochlear implantation—will identify CI recipients who may benefit from electric–acoustic stimulation.Supplemental Material https://doi.org/10.23641/asha.11356637

Initial surgical and clinical experience with the Nucleus CI532 slim modiolar electrode in the UK

ObjectiveThe goal of this work is to describe the first experience in the UK with the slim pre-curved perimodiolar electrode Nucleus CI532 in a continuous series of patients in terms of surgical and clinical reliability and early performance outcomes.MethodIn this retrospective review we describe the complication rate (including electrode array tip fold-over), NRT thresholds, hearing preservation, power efficiency and CI performance outcomes in a continuous series of 40 cochlear implants CI532 performed between October 2016 and November 2017 in 17 adults and 13 children with severe to profound hearing loss.ResultsPreliminary data from these groups reveals some low-frequency hearing preservation in the CI532 group although none of the patients were conventional hearing preservation candidates. NRT thresholds, power efficiency, and BKB sentences in quiet were measured at 3 and 6 months post activation. There were no significant differences in these results. The average BKB score in quiet increases from 22% pre-operatively to 58% at 3 months and 70% at 6 months. In addition, although hearing preservation was not an objective, low-frequency thresholds were preserved in 20% of cases at 3 and 6 months post-operatively. Complications were observed in 5 cases, one case with non-device related aerocoele and four related to the device array: two cases of tip roll over, one case of the electrode array being placed extra-cochlea, and one case with the electrode buckling into the middle ear. The last 2 cases were dealt with per-operatively.DiscussionOur preliminary results with the CI532 implant indicate that it may be reliably placed with standard surgical techniques but care is needed during the deployment of the electrode. Further initial data suggest that switch on and early electrophysiological measures are comparable to the existing CI 512 device. However whilst preliminary, our data suggest that it may be possible to use this electrode for hearing preservation. However, further studies are required to determine its definitive advantage over other electrode designs.ConclusionCI532 is a reliable device offering good initial results and could be an option for hearing preservation although further studies are required.

Hearing Preservation in Pediatric Recipients of Cochlear Implants.

To determine factors that influence low-frequency hearing preservation following pediatric cochlear implantation and compare hearing preservation outcomes between 20 and 24 mm depth lateral wall electrodes. Retrospective chart review. Tertiary academic referral center. Pediatric cochlear implant recipients (under the age of 18) who presented preoperatively with a low-frequency pure tone average (LFPTA; 125, 250 and 500 Hz) ≤ 70 dB HL. Cochlear implantation MAIN OUTCOME MEASURES:: Multiple logistic regression evaluating the influence of variables on change in LFPTA including preoperative low-frequency hearing, lateral wall or perimodiolar electrode, progressive vs stable hearing, side, time from surgery, and the presence or the absence of enlarged vestibular aqueduct. A second analysis reviews the 12-month postactivation hearing preservation of a subset of subjects implanted with modern lateral wall electrodes. A total of 105 subjects were included from the last 10 years for our multiple logistic regression analysis. This demonstrated a significant correlation of poorer preoperative low-frequency hearing with change in LFPTA. A significant negative effect of electrode type, specifically perimodiolar electrodes was also seen. Forty-five subjects from the last 3 years undergoing cochlear implantation with a lateral wall electrode demonstrated an overall 12-month preservation rate (LFPTA < 90 dB) of 82%. Differences in preservation rates existed between different electrodes. Preservation of low-frequency hearing following cochlear implantation is predicted both by preoperative low-frequency hearing as well as type of electrode implanted. Consistent low-frequency hearing preservation is possible in pediatric subjects receiving lateral wall electrodes, although differences exist between electrode types.

Surgical Experience and Early Outcomes With a Slim Perimodiolar Electrode.

In 2016 the Cochlear CI532 received FDA approval and has since been the primary full-length electrode from this manufacturer implanted at our center. Our experience to date including surgical technique and early patient outcomes are reviewed here. Since 2016, this array was used as our standard full length Cochlear array, including children with normal anatomy, with 237 total implantations. Surgical experience and clinical outcomes including low frequency hearing preservation and speech perception on CNC words were analyzed in those with at least 6 months follow-up implanted through June 2017 (n = 94). Speech perception scores are improving over clinical follow-up in accord with other electrode arrays. Hearing preservation is possible with a number of patients utilizing acoustic low frequency hearing in conjunction with electric stimulation from their CI. Tip fold overs were infrequent (4.6%) and always identified on intraoperative x-ray. No patients left the operating room with a tip fold over. Speech perception outcomes with the CI532 slim periomodiolar array are similar to other full length arrays with the added potential for at least short term preservation of residual acoustic hearing. There is a learning curve to its use and intraoperative x-rays are valuable to ensure optimal placement.

Electric and Acoustic Stimulation in Cochlear Implant Recipients with Hearing Preservation.

Hearing loss affects 30 million people in the United States, and a subset of these patients have normal low-frequency hearing and ski-sloped high-frequency hearing loss. For these patients, hearing aids alone may not provide adequate benefit. Cochlear implantation alone has been utilized to improve speech perception. The addition of high-frequency electric hearing to low-frequency acoustic hearing in these patients is beneficial. Technical improvements have allowed preservation of low-frequency hearing in cochlear implant recipients, allowing for electric and acoustic stimulation in the same ear with significant improvements in speech perception, sound localization, music appreciation, and quality of life.

The utilization of round window membrane surface tension in facilitating slim electrodes insertion during cochlear implantation.

This is a prospective randomized study aimed to evaluate the round window membrane (RWM) surface tension in facilitating slim electrodes insertion during cochlear implantation. A total number of (118) children were included in this study (118 implantations). Mean age was 36.72months (range from 18 to 60months). This study was conducted from January 2015 to September 2016 at a cochlear implant centre in a tertiary referral hospital. Slit incision in the anterosuperior quadrant of the RWM was done in 70 cases, While RWM cruciate incision was done in 48 cases. Of the 48 patients who underwent RWM cruciate incision, 13 cases had no problem, while in 35 cases, we faced difficult insertion. When slit incision of the RWM was done (70 cases), 68 cases showed smooth insertion, meanwhile, we faced increased operative time due to flopping of the electrode in 2 cases only. Moreover, residual low-frequency hearing preservation was more achieved when slit incision of the RWM was done. Tensile strength of the round window membrane after slit incision of the RWM offers support to slim electrodes during introduction, decreasing incidence of kinking and floppiness, hence shortening the maneuver time and minimizing the number of trials. This facilitates easy smooth slim electrodes introduction, decreasing intracochlear trauma. Moreover, slit incision of the RWM may offer better residual hearing preservations than cruciate incision of the RWM during slim electrodes introduction.

ELECTRO-ACOUSTIC STIMULATION - AN OPTION WHEN HEARING AIDS ARE NOT ENOUGH

SUMMARY Individuals with steeply sloping high frequency hearing loss can often hear speech but fail to understand it, and conventional treatments, including frequency transposition hearing aids, are usually ineffective when the hearing loss is severe or profound. Electro-acoustic stimulation (EAS) is a relatively new treatment option for this population, in which mid-high frequency information is provided by a cochlear implant (CI) inserted into the basal turn of the cochlea, supplemented by low frequency acoustic amplification. New atraumatic CI electrode arrays and surgical techniques have been shown to facilitate low frequency hearing preservation sufficiently to allow the use of EAS in the majority of suitable candidates. Clinical studies have consistently demonstrated synergistic combination of mid-high frequency information delivered electrically by a CI with low frequencies delivered acoustically, providing superior performance to that obtained from a CI alone.

Intraoperative Real-time Cochlear Response Telemetry Predicts Hearing Preservation in Cochlear Implantation.

To monitor cochlear function during cochlear implantation and determine correlations with postoperative acoustic hearing. Cochlear response telemetry measures cochlear function directly from cochlear implant electrodes. We have adapted this system to provide real-time cochlear response telemetry (RT-CRT) monitoring of a patient's acoustic hearing as the cochlear implant electrode array is inserted. Eighteen subjects (1 child and 17 adults) with sloping high frequency hearing loss were implanted with Cochlear Ltd slim straight arrays (CI422/CI522). Tone bursts (500 Hz, 100-110 dB) were presented at 14 Hz continuously during the array insertion. RT-CRT amplitudes were correlated with surgical manoeuvres recorded on the video from the operating microscope and with postoperative pure tone audiograms. Despite an excellent overall rate of complete or partial hearing preservation (79%), RT-CRT identified that in 47% of these implantations there was transient or permanent reduction in the amplitude of the cochlear microphonic (CM). Patients with a preserved CM at the end of insertion had on average 15 dB better low-frequency hearing preservation. The CM amplitude was most vulnerable during the last few millimeters of insertion or when inadvertent movement of the array occurred after full insertion. Physical contact/elevation of the basilar membrane is hypothesized as a likely mechanism of hearing loss rather than overt physical trauma. RT-CRT can be used to predict early postoperative hearing loss and to potentially refine surgical technique. In the future, feedback of RT-CRT may prove to be a valuable tool for maximizing preservation of residual hearing or providing feedback on electrode contact with the basilar membrane.

Hearing Preservation Outcomes With a Mid-Scala Electrode in Cochlear Implantation.

To evaluate hearing preservation (HP) outcomes in adult cochlear implant recipients with a mid-scala electrode. Tertiary academic center. Adult patients implanted with a mid-scala electrode between May 2013 and July 2015. Cochlear implantation. Age, sex, surgical approach, residual hearing changes post cochlear implantation, HP rates using different published classifications, and speech perception scores. Fifty ears for 47 patients (mean age, 58.2 yr; range, 23-86) were implanted with the electrode. Recognizing that not all patients were true HP candidates and/or underwent generally accepted HP surgical techniques, 39 ears had preoperative low-frequency hearing (audiometric threshold ≤ 85dB HL at 250Hz), 24 preserved acoustic hearing postoperatively (75.0%). Patients who had preserved acoustic hearing were implanted via round window (N = 18), extended round window (N = 4), or via cochleostomy (N = 2) approaches. Mean threshold elevation for low-frequency pure-tone average (125, 250, and 500 Hz) was 20.2 dB after surgery. 43.8% of patients had aidable low-frequency hearing at activation, 30.0% at 6-months postoperatively, and 30.8% 1-year postopera tively. Using a formula outlined by Skarzynski and colleagues, at 6-months postoperatively, 15.0% of patients had complete HP, whereas 40.0% had partial HP. At 1-year, these percentages decreased to 0% and 38.5%, respectively. Age, type of approach, and perioperative steroid use were not correlated with HP outcomes at activation and 6-months postoperatively (p > 0.05). The mid-scala electrode evaluated allows preservation of low-frequency hearing in patients undergoing cochlear implantation at rates and degrees of preservation close to other reports in the cochlear implant literature.

Impact of Perioperative Oral Steroid Use on Low-frequency Hearing Preservation After Cochlear Implantation.

To investigate the efficacy of a perioperative oral steroid taper on low-frequency hearing preservation after cochlear implantation. Retrospective case series. Tertiary referral center. Consecutive cochlear implant recipients between January 2012 and December 2014 who were candidates for a hearing preservation approach based on preoperative pure tone thresholds were identified. A subgroup of patients received a 2-week oral corticosteroid taper beginning 3 days before surgery. All patients were implanted using standard length electrodes. The preservation of low-frequency pure tone thresholds on the first postoperative audiogram was assessed. Secondary outcome measures included the respective impacts of age, diabetes, and electrode array type on hearing preservation, the durability of hearing preservation over time, and the development of medical complications related to steroid use. Twenty-seven ears met inclusion criterion, and the mean age at implantation was 49.8 years (median 62 yr, range 2-81 yr). Twenty patients (74.1%, mean age 48.7 yr) received an oral corticosteroid taper, whereas 7 (25.9%, mean age 53.1 yr) did not. The rate (p < 0.01) and degree (p < 0.01) of hearing preservation as measured at implant activation was greater for patients who received an oral steroid taper than those who did not. There were no medical complications related to steroid use. A 2-week oral prednisone taper beginning before surgery may positively affect the incidence and degree of low-frequency hearing preservation after cochlear implantation.

A Retrospective Analysis of the Contribution of Reported Factors in Cochlear Implantation on Hearing Preservation Outcomes.

Preservation of residual hearing is essential to perceive acoustic stimulation from hybrid cochlear implants (CI). Preservation is a good marker of atraumatic surgery and residual hearing may be exploited further or enhanced in future therapies, making complete hearing preservation a desirable goal for all current CI surgeries. There is large variability in the amount of hearing preserved and the timeframe over which it is lost after CI. The increase in numbers of patients with high levels of residual hearing at implantation means that understanding the variables affecting its preservation is more important than ever. An English search term with generic and specific items concerning hearing preservation and cochlear implantation was searched on the Web of Science service. The search timeframe was limited to 2000 to 2014, with no language limitations on results. Hearing preservation, retrospective CI outcome studies which reported pre- and post-surgical pure-tone audiometry (PTA) were identified and selected. PTA thresholds were extracted from audiograms or tables and converted into a low-frequency hearing preservation (LFHP) score. Data for 21 factors associated with hearing preservation were collected from studies. Factors were included in a hearing preservation model if they had both a significant bivariate correlation with LFHP and a significant Kruskal-Wallis H test result (for ordinal data) or a significant multiple regression analysis result (for scale data). Seven factors were found to have a significant effect on hearing preservation: insertion site, progressive versus stable hearing loss, insertion angle of electrode, use of intraoperative topical steroids, use of steroids (via any route/timing), hearing etiology, and electrode array type. The best hearing preservation options are given.