Cochlear implants in the management of hearing loss in Neurofibromatosis Type 2

Longitudinal Performance of Cochlear Implants in Neurofibromatosis Type 2

OBJECTIVE

Cochlear implants (CIs) are a well-established treatment modality for hearing loss due to neurofibromatosis type 2 (NF2). Our aim is to investigate variables that affect longitudinal performance of CIs among patients with NF2.

STUDY DESIGN

Retrospective review at a single academic institution consisting of patients who have received cochlear implants following hearing loss due to NF2.

METHODS

The primary outcome examined was CI disuse or explantation. Associated clinical and surgical variables were analyzed using descriptive statistics. These included postoperative pure tone average (PTA) at 500, 1000, and 2000 Hz, tumor size, previous surgery, and comorbid depression.

RESULTS

A total of 12 patients and 14 cochlear implants received at our institution from 2001 to 2022 were included. Notably, 35.7% of CIs (5 out of 14 cases) resulted in disuse or explantation. The average interval until explant was 9.4 years (range 3-14 years). In explanted CI cases, 20% had previous surgery and 80% had a diagnosis of comorbid depression as compared to 22.2% and 22.2%, respectively, in intact CI cases. Maximum tumor diameter was the only variable found to impact CI usage outcome (p = 0.028). Long-term data showed that on average, patients benefit from 13.85 years of CI utility and a maximum PTA improvement of 45.0 ± 29.0 dB.

CONCLUSION

Despite the recurrent nature of NF2, patients continue to receive audiological benefit from cochlear implants. We found that larger tumor size may be associated with longitudinal CI failure.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1847-1853, 2024.

Cochlear Implantation after Stereotactic Radiosurgery for Vestibular Schwannoma: Initial Hearing Improvement and Longevity of Hearing Restoration

OBJECTIVE

The following research question was asked: In patients with vestibular schwannoma (VS) that underwent stereotactic radiosurgery (SRS) and cochlear implantation, were improvements in hearing function observed, and what was the cochlear implant (CI) failure rate of in these patients?

DATA SOURCES

PubMed/Medline, CINAHL (EBSCOhost), and Web of Science articles without restrictions on publication dates were searched.

STUDY SELECTION

Inclusion criteria required that the article was a report, a series, or a retrospective review with individual case data available. Non-English articles were excluded. Inclusion criteria required that patients were with VS and underwent subsequent SRS and cochlear implantation. Patients receiving microsurgery or stereotactic radiotherapy on the ipsilateral ear were excluded from this study.

DATA EXTRACTION

Included studies were evaluated using full-text evaluation, and data on study characteristics (author names, gender), clinical data (syndromic information, SRS modality), hearing outcomes, and device failure were extracted.

DATA SYNTHESIS

Means and averages were obtained for all continuous variables. Percentages were ascertained for all categorical variables.

CONCLUSIONS

The majority of patients undergoing CI placement in VS treated with SRS achieved open-set speech perception (79.2%) or environmental sound awareness (6.8%). Twelve implants (20.3%) failed. Three patterns were associated with failure: 1) immediate-onset failure, 2) initial benefit with delayed failure, 3) poor local control with device explantation.

Efficacy of Cochlear Implantation in Neurofibromatosis Type 2 Related Hearing Loss

OBJECTIVE

To investigate the results of cochlear implantation in subjects with neurofibromatosis type 2 (NF2) and bilateral vestibular schwannomas (VS).

STUDY DESIGN

Retrospective case series.

SETTING

University-based tertiary referral center.

SUBJECTS

Five subjects with NF2 and severe-to-profound sensorineural hearing loss.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURE

Surgical outcomes and audiometric performance after cochlear implantation.

RESULTS

Five subjects (3 female, 2 male) were included in the study. The mean age at the time of implantation was 54 years old (range 35-78 years). Follow-up after cochlear implantation averaged 38 months (range 21-106 months). In the 5 implanted ears, 2 had no prior treatment, 1 had undergone prior radiation therapy, 1 underwent prior microsurgical removal, and 1 underwent prior microsurgical removal with adjuvant radiation therapy. The mean ipsilateral VS dimensions at time of implantation were 14 mm × 7.2 mm × 6.1 mm (mediolateral × anteroposterior × craniocaudal). Following cochlear implant activation, all 5 subjects achieved sound awareness, open set speech recognition, and 4 continue to be daily users of the devices.

CONCLUSION

Cochlear implantation is a viable hearing rehabilitation option for subjects with NF2 and severe-to-profound sensorineural hearing loss. All subjects reported benefit with their cochlear implant, including open set speech recognition, enhanced lip-reading skills and environmental awareness of sound. Four subjects continued to demonstrate improved open-set speech recognition at the time of their last evaluations.

Cochlear Implantation Outcomes in Patients With Retrocochlear Pathology: A Systematic Review and Pooled Analysis

OBJECTIVE

To review the current literature regarding cochlear implantation in patients with retrocochlear pathologies and extract speech perception scores between 6 months and 1 year after surgery.

DATABASES REVIEWED

PubMed/MEDLINE, Embase and Cochrane CENTRAL via Ovid, CINAHL Complete via Ebsco, and Web of Science.

METHODS

The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Search strategies included keywords and subject headings to maximize retrieval and reflect cochlear implants and retrocochlear pathologies. Patients with previously resected vestibular schwannoma (VS) were excluded.

RESULTS

There were 2,524 abstracts screened against inclusion criteria, and 53 studies were included, with individual data available for 171 adult patients. Pathologies included were either observed or irradiated VS (previously operated tumors were excluded) (n = 99, 57.9%), superficial siderosis (n = 39, 22.8%), neurosarcoidosis (n = 11, 6.4%), and previous central nervous system or skull base radiation (n = 22, 12.9%). Mean (standard deviation) postoperative consonant-nucleus-consonant (CNC) word scores were 45.4% (24.2) for observed VS, 44.4% (20.8) for irradiated VS, 43.6% (21.0) for superficial siderosis, 89.5% (3.0) for neurosarcoidosis, and 30.0% (30.2) in patients with previous central nervous system or skull base irradiation. Irradiated compared with observed VS had similar postoperative CNC word scores (effect size, 0.06; p = 0.71). Age, sex, maximal tumor dimension, and neurofibromatosis type 2 status did not significantly impact cochlear implant performance in patients with VS. Eighty-two percent of patients with reported device usage were daily users, and overall, 82% of cases benefitted from cochlear implantation.

CONCLUSION

Cochlear implantation in patients with concomitant retrocochlear pathology generally results in improved speech discrimination scores sustained over time.

Cochlear Implantation in Neurofibromatosis Type 2: Experience From the UK Neurofibromatosis Type 2 Service

OBJECTIVE

To review the outcomes of cochlear implants (CI) in patients with neurofibromatosis type 2 (NF2) in a large cohort, and identify factors associated with poor hearing benefit.

STUDY DESIGN

Fifteen-year retrospective national observational case series.

SETTING

United Kingdom regional NF2 multidisciplinary teams.

PATIENTS

Consecutive patients with NF2 receiving a CI.

INTERVENTIONS

CI for hearing rehabilitation.

MAIN OUTCOME MEASURES

1) Audiometric performance at 9 to 12 months after implantation using City University of New York (CUNY) sentence recognition score, and Bamford- Kowal-Bench (BKB) word recognition score in quiet (BKBq), and in noise (BKBn). 2) CI use at most recent review.

RESULTS

Sixty four consecutive patients, median age 43 years, were included. Nine to 12 months mean audiometric scores were: CUNY 60.9%, BKBq 45.8%, BKBn 41.6%. There was no difference in audiometric outcomes between VS treatment modalities. At most recent review (median 3.6 years from implantation), 84.9% with device in situ/available data were full or part-time users. Between 9 and 12 months and most recent review there was an interval reduction in mean audiometric scores: CUNY -12.9%, BKBq -3.3%, BKBn -4.9%. Larger tumor size and shorter duration of profound hearing loss were the only variables associated with poorer audiometric scores. Tumor growth at the time of surgery was the only variable associated with CI non-use. Individual patient response was highly variable.

CONCLUSIONS

CI can provide significant and sustained auditory benefits to patients with NF2 independent of tumor treatment modality, with the majority of those implanted becoming at least part-time users. Larger datasets are required to reliably assess the role of independent variables.

Multidisciplinary neurocutaneous syndrome clinics: a systematic review and institutional experience

OBJECTIVE

Neurocutaneous syndromes have variable multisystem involvement. The multiorgan involvement, potential pathologies, and various treatment options necessitate collaboration and open discussion to ensure optimal treatment in any given patient. These disorders provide quintessential examples of chronic medical conditions that require a lifelong, multidisciplinary approach. The objectives of this study were to 1) perform a systematic review, thoroughly assessing different multidisciplinary clinic layouts utilized in centers worldwide; and 2) characterize an institutional experience with the management of these conditions, focusing on the patient demographics, clinical presentation, complications, and therapeutic strategies seen in a patient population.

METHODS

A systematic review of studies involving multidisciplinary clinics and their reported structure was performed according to PRISMA guidelines using the PubMed database. Then a retrospective chart review of patients enrolled in the Oklahoma Children’s Hospital Neurocutaneous Syndromes Clinic was conducted.

RESULTS

A search of the PubMed database yielded 251 unique results. Of these, 15 papers were included in the analysis, which identified 16 clinics that treated more than 2000 patients worldwide. The majority of these clinics treated patients with neurofibromatosis (13/16). The remaining clinics treated patients with von Hippel–Lindau syndrome (n = 1), tuberous sclerosis complex (n = 1), and multiple neurocutaneous syndromes (n = 1). The most commonly represented subspecialties in these clinics were genetics (15/16) and neurology (13/16). Five clinics (31%) solely saw pediatric patients, 10 clinics saw a combination of children and adults, and the final clinic had separate pediatric and adult clinics. The retrospective chart review of the Neurocutaneous Syndromes Clinic demonstrated that 164 patients were enrolled and seen in the clinic from April 2013 to December 2021. Diagnoses were made based on clinical findings or results of genetic testing; 115 (70%) had neurofibromatosis type 1, 9 (5.5%) had neurofibromatosis type 2, 35 (21%) had tuberous sclerosis complex, 2 (1%) had von Hippel–Lindau syndrome, 2 (1%) had Gorlin syndrome, and the remaining patient (0.6%) had Aarskog-Scott syndrome. Patient demographics, clinical presentation, complications, and therapeutic strategies are also discussed.

CONCLUSIONS

To the best of the authors’ knowledge, this is the first detailed description of a comprehensive pediatric neurocutaneous clinic in the US that serves patients with multiple syndromes. There is currently heterogeneity between described multidisciplinary clinic structures and practices. More detailed accounts of clinic compositions and practices along with patient data and outcomes are needed in order to establish the most comprehensive and efficient multidisciplinary approach for neurocutaneous syndromes.

Cochlear Implantation in Vestibular Schwannoma: A Systematic Literature Review

Objective  Ipsilateral cochlear implantation (CI) in vestibular schwannoma (VS) has been an emerging trend over the last two decades. We conducted the first systematic review of hearing outcomes comparing neurofibromatosis 2 (NF2) and sporadic VS undergoing CI. A comparison of the two populations and predictor of outcome was assessed. This is an update to a previously presented study. Data Sources  Systemic data searches were performed in PubMed NCBI and Scopus by an academic librarian. No restrictions based on the year of publication were used. Study Selection  Studies were selected if patients had a diagnosis of NF2 and a CI placed in the affected side with reports of hearing outcome. Two independent reviewers screened each abstract and full-text article. Data Extraction  Studies were extracted at the patient level, and the assessment of quality and bias was evaluated according to the National Institutes of Health Quality Assessment Tool. Main Outcome Measures  Outcome predictors were determined by using the chi-square test and Student's t -test. Results  Overall, most CI recipients functioned in the high-to-intermediate performer category for both sporadic and NF2-related VS. Median AzBio (Arizona Biomedical Institute Sentence Test) was 72% (interquartile range [IQR]: 50) in NF2 patients and 70% (IQR: 7.25) in sporadic patients. Larger tumor size predicted a poorer final audiometric outcome. Conclusions  Categorization of hearing outcome into superior performance and inferior performance based on sentence recognition revealed a generally good hearing outcome regardless of treatment or patient population. Select patients with sporadic and NF2 VS may benefit from CI.

Intraoperative Cochlear Nerve Monitoring for Vestibular Schwannoma Resection and Simultaneous Cochlear Implantation in Neurofibromatosis Type 2: A Case Series

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.

Diagnostic Accuracy of Intracochlear Test Electrode for Acoustic Nerve Monitoring in Vestibular Schwannoma Surgery

OBJECTIVES

Cochlear implants (CIs) are a well-known hearing restoration option for patients with vestibular schwannoma (VS) in cases of neurofibromatosis type-2 and, more recently, for patients with sporadic VS. One of the main limitations when performing CI during VS surgery is the capability to preserve the acoustic nerve (AN) anatomically and functionally. Significant efforts have been directed toward developing an intraoperative testing method for monitoring the AN function to determine if, after tumor removal, it is suitable for conducting stimuli delivered by a CI. However, all these methods have significant limitations, and none of them have documented diagnostic efficacy. To overcome these limitations and to obtain reliable information before CI insertion, a minimally invasive intracochlear test electrode (TE) has been recently developed. This TE has demonstrated to be suitable to test the integrity of the AN before CI in patients without any residual hearing by recording electrically evoked auditory brainstem responses (EABR). The present study constitutes the next phase of this research, which was to determine the usefulness of EABR obtained intraoperatively with the intracochlear TE after the resection of a VS and to calculate its diagnostic accuracy to assess the functionality of the AN for CI.

DESIGN

This was a prospective, multicenter study of diagnostic accuracy. It was conducted in three tertiary referral centers between January 2015 and 2018. This study was designed following the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement guidelines. The STARD statement are guidelines to improve the completeness and transparency of reports of diagnostic accuracy studies. The diagnostic accuracy of the EABR evoked with the intracochlear TE after tumor removal was studied. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Patients eligible for the study were consecutive adults undergoing surgery for VS with simultaneous CI. The test under evaluation (index test) was the EABR obtained with the intracochlear TE after resection of the tumor. The reference test (gold standard) was the presence of auditory perception with the CI, defined as the presence of sound detection on an audiogram at 500, 1000, 2000, and 4000 Hz of no greater than 50 dB. In all the cases, auditory perception was verified by the presence of a positive EABR evoked with the CI.

RESULTS

Twenty-one patients were included during the study period; seven patients were excluded from the diagnostic efficacy analysis due to inconclusive EABR results or absence of the gold standard to compare (they did not finally receive the CI). Thus, the outcome of the gold standard was assessed in 14 cases: 9 cases had positive EABR, all of them obtained auditory perception with the CI, and 5 cases had negative EABR, only one case had auditory perception with the CI, which constitutes the only false negative of this study. Accuracy of the TE was 93% (95% confidence interval, 66 to 100%), sensitivity 90% (95% confidence interval, 71 to 100%), specificity 100% (95% confidence interval, 100 to 100%), positive predictive value 100% (95% confidence interval, 100 to 100%), and negative predictive value 80% (95% confidence interval, 45 to 100%).

CONCLUSIONS

EABR elicited with the intracochlear TE had a diagnostic accuracy of 93% for predicting auditory perception with CIs after VS removal. These results suggest that the intracochlear TE can be used intraoperatively after tumor removal to test the integrity of the AN as a useful tool to complement the surgeon's perception for decision-making regarding implantation.

Options and strategies for hearing restoration in pediatric neurofibromatosis type 2

PURPOSE

In this article, we will review the mechanisms and natural history of hearing loss in neurofibromatosis type 2 (NF2) and discuss the hearing outcomes with different rehabilitation options.

METHODS

Review of the published literature.

RESULTS

NF2 is a rare autosomal dominant syndrome characterized by vestibular schwannomas and other intracranial and spinal tumors. Bilateral vestibular schwannomas are the hallmark of the disease which occur in 90 to 95% of the patients. As a result, hearing loss will eventually occur in almost all NF2 patients. Deafness can occur from tumor progression or from treatment of vestibular schwannomas and is among the most debilitating aspects of NF2. A number of surgical and non-surgical rehabilitation options are available for these patients including cochlear and auditory brainstem implants. The audiologic outcomes with surgical rehabilitation options have been variable but most patients are able to achieve sound awareness and benefit from auditory cues in lip reading.

CONCLUSION

Early identification and treatment of NF2 patients can help in achieving better hearing outcomes in the pediatric population. An increasing number of NF2 patients are receiving open set word understanding with refinement in surgical techniques.

Ipsilateral Cochlear Implantation in the Presence of Observed and Irradiated Vestibular Schwannomas

OBJECTIVES

Historically, eventual loss of cochlear nerve function has limited patients with neurofibromatosis type 2 (NF2) to auditory brainstem implants (ABI), which in general are less effective than modern cochlear implants (CI). Our objective is to evaluate hearing outcomes following ipsilateral cochlear implantation in patients with NF2 and irradiated vestibular schwannomas (VS), and sporadic VS that have been irradiated or observed.

METHODS

Multi-center retrospective analysis of ipsilateral cochlear implantation in the presence of observed and irradiated VS. MESH search in NCBI PubMed database between 1992 and 2019 for reported cases of cochlear implantation with unresected vestibular schwannoma.

RESULTS

Seven patients underwent ipsilateral cochlear implantation in the presence of observed or irradiated vestibular schwannomas. Four patients had sporadic tumors with severe-profound contralateral hearing loss caused by presbycusis/hereditary sensorineural hearing loss, and three patients with NF2 lost contralateral hearing after prior surgical resection. Prior to implantation, one VS was observed without growth for a period of 7 years and the others were treated with radiotherapy. Mean post-operative sentence score was 63.9% (range 48-91) at an average of 28 (range 2-84) months follow up. All patients in this cohort obtained open set speech perception. While analysis of the literature is limited by heterogenous data reporting, 85% of implants with observed schwannomas achieved some open set perception, and 67% of patients previously radiated schwannomas. Furthermore, blending literature outcomes for post implantation sentence testing in quiet without lip-reading show 59.0 ± 35% for patients with CI and observed tumors and 55.7 ± 35% for patients with radiated tumors, with both groups ranging 0 to 100%.

CONCLUSION

This retrospective series and literature review highlight that hearing outcomes with CI for VS patients are superior to those achieved with ABI. However, important considerations including imaging, delayed hearing loss, and observation time cannot be ignored in this population.

Simultaneous cochlear implantation and removal of acoustic neuroma: implications for hearing

OBJECTIVE

To present our data evaluating the feasibility of simultaneous cochlear implantation with resection of acoustic neuroma.

METHODS

This paper describes a case series of eight adult patients with a radiologically suspected acoustic neuroma, treated at a tertiary referral centre in Newcastle, Australia, between 2012 and 2015. Patients underwent cochlear implantation concurrently with removal of an acoustic neuroma. The approach was translabyrinthine, with facial nerve monitoring and electrically evoked auditory brainstem response testing. Standard post-implant rehabilitation was employed, with three and six months' follow-up data collected. The main outcome measures were: hearing, subjective benefit of implant, operative complications and tumour recurrence.

RESULTS

Eight patients underwent simultaneous cochlear implantation with resection of acoustic neuroma over a 3-year period, and had 25-63 months' follow up. There were no major complications. All patients except one gained usable hearing and were daily implant users.

CONCLUSION

Simultaneous cochlear implantation with resection of acoustic neuroma has been shown to be a safe treatment option, which will be applicable in a wide range of clinical scenarios as the indications for cochlear implantation continue to expand.

The emerging role of hearing loss rehabilitation in patients with vestibular schwannoma treated with Gamma Knife radiosurgery: literature review

Stereotactic radiosurgery (SRS) is currently the most common treatment for small- to medium-size vestibular schwannoma (VS). Despite favorable outcome, hearing deterioration still remains an underestimated problem, and the role of hearing rehabilitation is an underinvestigated topic. Among available technologies, cochlear implant (CI) should represent a valid alternative in sporadic VS with single-sided deafness and in neurofibromatosis (NF2) with bilateral profound hearing loss. A literature review of the current clinical data was performed searching scientific literature databases. From all of the articles found, 16 papers were selected. Forty-four subjects treated with radiosurgery (18 male, 19 female, and in 7 cases, sex were not specified; 43 NF2 and 1 sporadic VS) were included in the analysis. Epidemiological, clinical, tumor, treatment, and audiological data were collected. Clinical outcome at last follow-up showed an audiological improvement in 25 of the 44 patients. The audiological outcome was unchanged in 16 cases. Audiological deterioration was recorded in 3 cases. Severity of NF2 phenotype, long history of ipsilateral profound deafness before implantation, progressive tumor growth, and high radiation dose (20 and 40 Gy) were found in patients with a worst audiological outcome. Hearing rehabilitation can improve audiological results for VS patients following SRS in selected cases. Hearing rehabilitation with cochlear implant (CI) in SSD leads to partial restoration of binaural hearing with an improvement in speech comprehension in noise and in sound localization, and partial suppression of subjective incapacitating tinnitus. SRS followed by CI may represent in selected cases a potential emerging option in the management of these patients, aimed at improving their quality of life. Possible implications for the follow-up of these patients are still present, although partially resolved.

Hearing rehabilitation outcomes in cochlear implant recipients with vestibular schwannoma in observation or radiotherapy groups: A systematic review

Objectives: Vestibular schwannomas (VS) are rare benign tumours of the vestibular nerve that cause hearing loss. Management strategies include watchful waiting, radiotherapy or surgical resection. Historically, the presence of retrocochlear disease has been considered to be a contra-indication to cochlear implantation (CI). The aim of this systematic review is to assess hearing rehabilitation outcomes for CI recipients with VS, either sporadic or associated with neurofibromatosis type 2, whose tumours have been managed with either observation or radiotherapy.Methods: PubMed, Embase, and Cochrane Library databases were searched from inception through to November 2018. 50 cases from 12 studies met the inclusion criteria. Patient demographics, VS characteristics, management strategy, pre-CI hearing status, electrical promontory stimulation testing, post-CI hearing status and speech perception scores, functional benefits and follow-up length are reported.Results: Radiotherapy and observation groups had similar patient demographics in terms of age at CI, tumour size and duration of deafness. Following CI, 64% and 60% of patients in the radiotherapy and observation groups achieved open-set speech perception, respectively. Pure tone average thresholds (33 vs. 39 dB) and speech scores were also comparable between both groups.Conclusion: Ipsilateral CI in patients with VS that have not been surgically resected can provide beneficial hearing rehabilitation outcomes.

Impact of cochlear implantation on the management strategy of patients with neurofibromatosis type 2

PURPOSE

To investigate the outcomes of cochlear implantation in patients with neurofibromatosis type 2 (NF2), and to discuss the current management strategy for NF2 patients.

METHODS

The medical records of NF2 patients who received cochlear implants (CI) at our center between 2012 and 2016 were retrospectively reviewed. Pre-operative hearing status, tumor status, treatment of tumors, and auditory outcomes post-implantation were evaluated.

RESULTS

Twelve patients were included in the study. Five were implanted with the tumor in situ; two of them received radiotherapy pre-implantation, and three were implanted without any previous treatment. Four patients were implanted simultaneously with tumor removal. Three patients were implanted as second-stage after failed hearing preservation surgery. The mean pure tone audiometry with the implant was 44 dB (range 25-80 dB) and the mean sentence recognition score (SRS) in a quiet environment without lip reading was 63% (range 0-97%). A poorer objective auditory outcome was identified in one patient who showed no response to electrical promontory stimulation (EPS), but the sound perception was still helpful. In total, 11 of 12 (91%) patients were daily users, and the other patient used the implant as a "sleeper" device due to its interference with contralateral hearing provided by a hearing aid.

CONCLUSION

CI is an effective option in auditory rehabilitation and should be considered primarily for NF2 patients with intact cochlear nerve. EPS might be a predictor for cochlear implant performance. Good contralateral hearing may present a barrier to daily use.