Residual hearing preservation after pediatric cochlear implantation

Hearing Preservation of Slim Modiolar and Slim Straight Electrodes: A Systematic Review and Meta-Analysis

PURPOSE

This meta-analysis aims to investigate the hearing preservation (HP) rates of slim straight electrodes (SSE) and slim modiolar electrodes (SME) after cochlear implantation, in the short- and long-term (≤4 months and 4-12 months, respectively).

METHODS

A systematic search was conducted in PubMed, Embase, Cochrane Library, and ClinicalTrials databases for studies published between 1 January, 2014, and 1 January, 2024. Cohort studies, case series, and randomized controlled trials written in English, reporting HP rates using the HEARRING classification system, were included.

RESULTS

Sixteen studies were included, comprising 15 observational studies and 1 randomized controlled trial. The overall short-term HP rate for SSE was 68.70% (95% CI: 52.27-85.12%), which decreased to 56.38% (95% CI: 42.87-69.90%) in the long-term. In contrast, SME maintained stable HP rates of 59.07% (95% CI: 50.03-68.10%) in the short-term, and 59.09% (95% CI: 46.48-71.70%) in the long-term.

CONCLUSION

The meta-analysis revealed that SME and SSE have a similar HP ability in both the short- and long-terms. Notably, a prominent decline in HP rate over time was observed in the SSE compared with SME.

Hearing Preservation Techniques in Pediatric Cochlear Implantation: A Systematic Review and Meta-Analysis

OBJECTIVE

Preserving residual hearing following cochlear implantation (CI) improves outcomes and allows patients to use electrical and acoustic stimulation. Hearing preservation and minimizing intracochlear trauma during implantation have become key areas of research and device development in recent years. This meta-analysis evaluated whether patient characteristics or surgical methodology impact hearing preservation postpediatric CI.

DATA SOURCES

A systematic search was performed in PubMed, Web of Science, Cochrane Library, PsycINFO, and Cumulative Index to Nursing and Allied Health Literature.

REVIEW METHODS

Per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the databases were searched for English studies published before August 2024. Search terms were "hearing preservation," "cochlear implant," "audiometry," and "pediatric" and their synonyms. The main outcome was the percentage of ears with hearing preservation after CI. Patient, audiological, device, and surgical technique characteristics were extracted. The impact of these factors on hearing preservation was evaluated.

RESULTS

Twenty-four studies were included, with a total of 567 patients. Males comprised 50% of patients (95% confidence interval [CI]: 45%-55%). Mean patient age was 9.68 years (95% CI: 8.27-11.09 years). Mean pure tone averages (PTAs) before and after CI were 60.48 dB (95% CI: 48.81-72.14 dB) and 70.95 dB (95% CI: 56.75-85.15 dB), respectively. Hearing preservation was reported in 78% of ears (95% CI: 71%-85%), with high heterogeneity between studies (I2 = 79.96%). Gender, surgical approach, electrode array, topical corticosteroids, and initial PTA were not significantly associated with hearing preservation.

CONCLUSIONS

Hearing preservation following pediatric CI occurred in 78% of ears. In this meta-analysis, no patient characteristic or surgical technique was significantly associated with hearing preservation.

Benefits of Cochlear Implantation and Hearing Preservation for Children With Preoperative Functional Hearing: A Prospective Clinical Trial

OBJECTIVES

This study was designed to (1) compare preactivation and postactivation performance with a cochlear implant for children with functional preoperative low-frequency hearing, (2) compare outcomes of electric-acoustic stimulation (EAS) versus electric-only stimulation (ES) for children with versus without hearing preservation to understand the benefits of low-frequency acoustic cues, and (3) to investigate the relationship between postoperative acoustic hearing thresholds and performance.

DESIGN

This was a prospective, 12-month between-subjects trial including 24 pediatric cochlear implant recipients with preoperative low-frequency functional hearing. Participant ages ranged from 5 to 17 years old. They were recruited at their device activation and fit with EAS or ES based on their postoperative thresholds. Group outcomes were compared for single-word recognition, masked sentence recognition, perceived hearing abilities, speech production, receptive language, expressive language, and prosodic identification.

RESULTS

Children experienced improvements in word recognition, subjective hearing, speech production, and expressive language with EAS or ES as compared with their preoperative abilities. Children using EAS performed better on a prosodic identification task and had higher subjective hearing scores postactivation as compared with children using ES. There was a significant relationship between postoperative thresholds at 125 Hz and prosodic identification.

CONCLUSIONS

The results of this study support cochlear implantation for children with normal-to-moderate low-frequency hearing thresholds and severe-to-profound high-frequency hearing loss. They also highlight the benefits of postoperative hearing preservation for language development.

Hearing preservation in paediatric cochlear implantation with the Nucleus Slim Straight Electrode - our experience

OBJECTIVE

to evaluate the levels of successful hearing preservation and preservation of functional hearing following cochlear implantation (HPCI) in children using the Cochlear Nucleus® Slim Straight Electrode (SSE).

DESIGN

retrospective case note review of paediatric HPCI cases in our CI centre from 2013 to 2023. Inclusion criteria were attempted hearing preservation surgery, SSE used for implantation, pre-operative hearing thresholds ≤80dBHL at 250 Hz, CI before 18 years of age. Patients were excluded if no postoperative unaided PTA was obtained (poor attendance). Primairy outcome was hearing preservation using the HEARRING group formula; secondary outcome was residual functional hearing (≤80dBHL at 250 Hz/<90dB LFPTA).

STUDY SAMPLE

56 patients with 94 CI's were included for review.

RESULTS

Hearing preservation was achieved in 94.7% (89/94) of ears and complete preservation in 72% (68/94)). Average functional hearing was preserved in 89% using both criteria for preservation. Long-term follow up data was available for 36 ears (average 35.2 months), demonstrating 88.9% (32/36) complete preservation.

CONCLUSION

We have reliably achieved and maintained a high success rate of HPCI using the SSE in our paediatric population. The field of HPCI would benefit from unification of outcome reporting in order to optimise the evidence available to professionals, patients and their carers.

Noise exposure of the inner ear during robotic drilling

INTRODUCTION

Preserving the cochlear structures and thus hearing preservation, has become a prominent topic of discussion in cochlear implant (CI) surgery. Various approaches and soft surgical techniques have been described when approaching the inner ear. Robot-assisted cochlear implant surgery (RACIS) reaches the round window in a minimally invasive manner by following a trajectory of minimal trauma. This involves the drilling of a keyhole trajectory to the round window, through the facial recess, with no need for a complete mastoidectomy. It involves less drilling, less drilling time and less structural damage. A lot of attention has been paid to the structural traumatic causes of hearing loss but acoustic trauma during the exposure of the inner ear appears to be neglected topic.

AIM

The aim was to measure the noise exposure of the inner ear during the robotic drilling of the mastoid and bony overhang of the round window. The results were compared with the milling in conventional cochlear implantation surgery.

INTERVENTION

RACIS on fresh frozen human cadavers.

OUTCOME MEASUREMENTS

The equivalent frequency-weighted and time-averaged sound pressure level LAF in dB and the noise dose in % derived from a noise damage model, both obtained during RACIS.

MATERIALS AND METHODS

The robotic drilling of 6 trajectories towards the inner ear were performed, including 4 trajectories through round window access and 2 trajectories through cochleostomy. The results were compared with the data of 7 cases of conventional CI surgery that have been described in literature. The induced equivalent sound pressure level LAF was determined via an accelleration sensor at the zygomatic arch and a calibration according to bone conduction audiometry. A noise dose for the whole procedure was calculated from the equivalent sound pressure level LAF and the exposure time using a noise damage model. A noise dose of 100% is considered a critical exposure limit and values above are considered potentially harmful, with the risk of hearing impairment.

RESULTS

The maximum LAF was 82 dB during fiducial screw placement; 87 dB during middle ear access; 95 dB for the accesses through the round window and 88 dB for the accesses through cochleostomy. The noise dose due to the HEARO®-procedure was always far below the critical value of 100%. There was no acoustic trauma of the inner ear in all cases with the noise dose being smaller than 0.1% in five out of the six cases. The maximum LAF in the seven cases of conventional CI surgery was 118 dB with a maximum cumulative noise dose of 172.6%. The critical exposure limit of 100% was exceeded in three cases of conventional CI surgery.

CONCLUSION

RACIS provokes significantly less acoustic trauma than conventional mastoid surgery in our findings. There were no observable differences in noise exposure levels between a cochleostomy or a round window approach where the bony overhang needed to be drilled.

Advances in Evaluation of Electrode Insertion Trauma Induced Residual Hearing loss in Cochlear Implant Recipients and its significance- A Narrative Review

Cochlear implant surgery has revolutionized the management of profound hearing loss, with a growing focus on preserving residual hearing, particularly low-frequency hearing. This review synthesizes existing literature on cochlear implantation techniques, surgical principles, and emerging therapies aimed at reducing post-implantation hearing loss. Methodologically, a comprehensive narrative literature review was conducted, encompassing various study designs and participant demographics. The search strategy involved major biomedical databases, focusing on articles in English. Surgical techniques such as "soft surgery" emphasize minimizing mechanical stress on the cochlea, while advancements in pharmacological agents explore the use of corticosteroids, neurotrophins, and growth factors to enhance hearing preservation. Electrode design and insertion strategies are evolving to minimize trauma and optimize hearing outcomes, including consideration of insertion forces and electrode array designs. Evaluating residual hearing loss involves sophisticated techniques like electrocochleography and radiological imaging. The impact of residual hearing on auditory verbal outcomes is variable, with studies indicating positive correlations with language development, particularly in speech production. Emerging strategies in electrode design, surgical techniques, and drug delivery hold promise for improving outcomes in cochlear implantation. However, challenges such as the lack of standardized guidelines and the need for further clinical trials remain. Future directions include the exploration of nanotechnologies, gene therapies, and stem cells for constructing bionic ears, although ethical and technical hurdles persist. This review underscores the ongoing efforts to enhance cochlear implant functionality and the need for continued research to optimize outcomes for patients with hearing loss.

Effects of Cochlear Implantation and Steroids on the Aging Guinea Pig Cochlea

OBJECTIVE

The objective was to determine the effects of older age on hearing preservation after cochlear implantation (CI), and whether steroids improve hearing preservation in older animals. We hypothesized greater hearing preservation would be observed in (1) young animals compared to older animals and (2) older animals receiving steroids compared to no steroids. The secondary objective was to assess levels of fibrosis utilizing optical coherence tomography (OCT).

STUDY DESIGN

Experimental Animal Study.

SETTING

Laboratory.

METHODS

Three groups of guinea pigs: young (YCI; 8.5 ± 0.5 weeks; n = 10), old (OCI; 19.1 ± 1.0 months; n = 9) and old + steroids (OCI+S; 19.1 ± 1.0 months; n = 9) underwent CI. The OCI+S group received a steroid taper over 7 days starting 2 days before surgery to 4 days after. Auditory brainstem response (ABR) measurements were performed preoperatively and postoperatively. OCT imaging was performed to assess cochleae for extent of fibrotic tissue growth in the scala tympani.

RESULTS

The YCI group had significantly better hearing preservation as measured by smaller increases in ABR thresholds [mean shift: 2.79 ± 0.66] compared to the OCI group [mean shift = 12.44 ± 5.6]. The OCI+S group had significantly better hearing preservation [2.66 ± 1.50] compared to the OCI group. No significant differences was seen in fibrosis across groups.

CONCLUSIONS

Young animals and older animals that received steroids had better hearing after CI than older animals not given steroids, but hearing preservation was not correlated with the level of fibrosis assessed using OCT. This work is the first to investigate differences in hearing preservation by age in an animal model, and supports the protective effects of steroids on hearing preservation in older individuals.

Benefits and risks related to cochlear implantation for children with residual hearing: a systematic review

OBJECTIVE

This study aimed to synthesise information concerning the potential benefits and risks related to cochlear implants (CIs) versus hearing aids (HAs) in children with residual hearing.

DESIGN

A systematic review of articles published from January 2003 to January 2019 was conducted.

STUDY SAMPLE

Our review included studies that compared the benefits and risks of CIs versus HAs in children (≤18 years old) with residual hearing. A total of 3265 citations were identified; 8 studies met inclusion criteria.

RESULTS

Children with CIs showed significantly better speech perception scores post-CI than pre-CI. There was limited evidence related to improvement in everyday auditory performance, and the results showed non-significant improvement in speech intelligibility. One study on social-emotional functioning suggested benefits from CIs. In four studies, 37.2% (16/43) of children showed loss of residual hearing and 14.0% (8/57) had discontinued or limited use of their device.

CONCLUSIONS

Children with CIs showed improvement in speech perception outcomes compared to those with HAs. However, due to the limited number of studies and information to guide decision-making related to other areas of development, it will be important to conduct further research of both benefits and risks of CIs in this specific population to facilitate decision-making.

Preservation of Residual Hearing: Long-Term Results With a Mid-Scala Electrode

OBJECTIVE

The long-term preservation of residual hearing after cochlear implantation has become a major goal over the past few years. The aim of the present study was to evaluate residual hearing in the long-term follow-up using mid-scala electrodes.

METHODS

In this retrospective, single-center study, we collected data from 27 patients who were implanted between 2014 and 2015 with residual hearing in the low-frequency range using a mid-scala electrode. Measurements of the hearing thresholds were carried out directly postoperatively (day 1 after surgery) and in the long-term follow-up 43.7 ± 6.9 months. The calculation of the extent of audiological hearing preservation was determined using the HEARRING group formula by Skarsynski.

RESULTS

Postoperative preservation of residual hearing was achieved in 69.2% of the cases in the low-frequency range between 250 Hz and 1 kHz, of which 89.5% of the patients had frequencies that suggested using electroacoustic stimulation (EAS). In the long-term follow-up, 30.8% of the patients showed residual hearing; however, 57.1% had apparently benefited from EAS.

CONCLUSION

Preservation of residual hearing is feasible in the long term using mid-scala electrodes. Postoperatively, there is over the half of patients who benefit from an EAS strategy. The long-term follow-up shows a certain decrease in residual hearing. However, these results are comparable to studies relating to other types of electrodes. Further research should be conducted in future to better evaluate hearing loss in long-term follow-up, compared to direct postoperative audiological results.

Acceptance and Benefit of Electroacoustic Stimulation in Children

OBJECTIVE

Children with high-frequency severe-to-profound hearing loss and low-frequency residual hearing who do not derive significant benefit from hearing aids are now being considered for cochlear implantation. Previous research shows that hearing preservation is possible and may be desirable for the use of electroacoustic stimulation (EAS) in adults, but this topic remains underexplored in children. The goal of this study was to explore factors relating to hearing preservation, acceptance, and benefits of EAS for children.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary academic medical center.

PATIENTS

Forty children (48 ears) with preoperative low-frequency pure-tone averages of 75 dB HL or less at 250 and 500 Hz (n = 48).

INTERVENTION

All patients underwent cochlear implantation with a standard-length electrode.

MAIN OUTCOME MEASURE

Low-frequency audiometric thresholds, speech perception, and EAS usage were measured at initial stimulation, and 3 and 12 months postoperatively. Outcomes were compared between children with and without hearing preservation, and between EAS users and nonusers.

RESULTS

Hearing was preserved at similar rates as adults but worse for children with an enlarged vestibular aqueduct. Fewer than half of children who qualified to use EAS chose to do so, citing a variety of audiologic and nonaudiologic reasons. No differences were detected in speech perception scores across the groups for words, sentences, or sentences in noise tests.

CONCLUSIONS

Neither hearing preservation nor EAS use resulted in superior speech perception in children with preoperative residual hearing; rather, all children performed well after implantation.

Comparison of Speech Test Outcomes After Cochlear Implantation in Patients With and Without Asymmetric Hearing Loss

OBJECTIVES

Determine whether asymmetric hearing loss (AHL) affects postoperative speech outcomes in cochlear implant (CI) patients.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care hospital.

PATIENTS

Adult English-speaking patients with unilateral CIs implanted between 2014 and 2018 were stratified into NonAHL and AHL groups based on preoperative AzBio scores in quiet from the nonimplanted ear (0-50% vs. 51-100%, respectively).

INTERVENTIONS

CI surgery in the poorer performing ear.

MAIN OUTCOME MEASURES

Postoperative consonant-nucleusconsonant (CNC) word and AzBio sentence test scores in quiet and/or noise at +5 dB signal-to-noise ratio (SNR).

RESULTS

Of 512 patients, 33 non-AHL and 27 AHL patients were included. Average ages were 65.6 and 63.6 years, respectively. As expected, preoperative AzBio scores in quiet from the nonimplanted ear were higher in the AHL group (95% confidence interval [95%CI]: 66.4-76.4%) than the non-AHL group at baseline (95%CI: 12.3-23.6%). In both cohorts, AzBio scores in quiet from the implanted ear improved from baseline, with 24-month scores (95%CI: 73.8 - 84.9%) being higher than preoperative scores (95%CI: 13.2-23.1%). There were also significant differences in AzBio scores in quiet between cohorts overall (p  = 0.0120) on mixed model analysis, with the AHL group performing ∼6.4% better than the non-AHL group; however, differences were not significant when scores were stratified by time. In addition, there were no significant differences in CNC in quiet and AzBio scores in noise at +5 dB SNR between cohorts (p  = 0.1786 and p  = 0.6215, respectively).

CONCLUSIONS

After CI, patients with AHL can achieve scores on word and sentence tests at least comparable to traditional CI candidates, supporting the expansion of CI candidacy to include patients with AHL.

Calibrated Ling Sounds Test for Cochlear Implant fitting in children

The Implanted children audiometric evaluation inaccuracies may lead to an extended period of the time to achieve proper cochlear implant (CI) electric stimulation. In this work we hypothesized that the relationship between implanted patient hearing thresholds estimation based on the Electrical Cochlear Response (ECR) and detection thresholds to Ling Sounds intensity calibrated according to higher energy spectral component allow electrical current stimulation adjustment of intracochlear electrodes. ECR is an objective test which is performed while patient is asleep and using the CI in everyday operation mode. Stimulus are variable intensity pip tones whose frequency is coincident with the central frequency of the band frequencies in which incoming sound is divided. The ECR Hearing Threshold is determinate by initial ECR detection and is defined as the minimum intensity level which auditory nerve portion involved with test electrode responds to electric stimulation hence producing an auditive experience to subject. Correlation observed between ECR Hearing Thresholds and Calibrated Ling Sounds detection thresholds is high enough (r²= 0.99) for electrodes electric current adjustment based on patient detection thresholds obtained in a Calibrated Ling Sound Test.

Combined Electric and Acoustic Stimulation (EAS) in Children: Investigating Benefit Afforded by Bilateral Versus Unilateral Acoustic Hearing

PURPOSE

Electric and acoustic stimulation (EAS) with preserved hearing in the implanted ear provides benefit for speech understanding, spatial hearing, and quality of life in adults. However, there is limited research on EAS outcomes in children. The aims of this study were to estimate the magnitude of EAS-related benefit on speech understanding in children with preserved acoustic hearing and to determine what role acoustic interaural time difference (ITD) sensitivity may have on said EAS benefit.

METHODS

Six children with acoustic hearing preservation and 20 children with normal hearing (NH) were recruited to participate. Speech recognition was assessed via an eight-loudspeaker array with speech presented from one loudspeaker at 0 degree and restaurant noise from all other loudspeakers (45-315 degrees). ITD thresholds were measured for a 250-Hz signal presented acoustically via insert earphones.

RESULTS

Only one EAS listener demonstrated significant benefit from bilateral acoustic hearing as compared with acoustic hearing from a single ear. ITD thresholds were poor in the range of 302 to 1000+ ms and were considerably poorer than ITD thresholds for the NH group.

CONCLUSION

These data suggest that children with acoustic hearing preservation may not exhibit initial EAS benefit for speech recognition in semi-diffuse noise; however, because none exhibited a decrement in performance with bilateral acoustic stimulation, EAS fittings are recommended to provide binaural acoustic access allowing for EAS adaptation to binaural cues over time. Future research should address the emergence of EAS benefit, binaural cue sensitivity, and the role of EAS experience in children and adults.

Spectral resolution and speech perception after cochlear implantation using the round window versus cochleostomy technique

OBJECTIVE

To evaluate the spectral resolution achieved with a cochlear implant in users who were implanted using round window route electrode insertion versus a traditional cochleostomy technique.

METHODS

Twenty-six patients were classified into two groups according to the surgical approach: one group (n = 13) underwent cochlear implantation via the round window technique and the other group (n = 13) underwent surgery via cochleostomy.

RESULTS

A statistically significant difference was found in spectral ripple discrimination scores between the round window and cochleostomy groups. The round window group performed almost two times better than the cochleostomy group. Differences between Turkish matrix sentence test scores were not statistically significant.

CONCLUSION

The spectral ripple discrimination scores of patients who had undergone round window cochlear implant electrode insertion were superior to those of patients whose cochlear implants were inserted using a classical cochleostomy technique.

Bilateral Cochlear Implants or Bimodal Hearing for Children with Bilateral Sensorineural Hearing Loss

Purpose of review

This review describes speech perception and language outcomes for children using bimodal hearing (cochlear implant (CI) plus contralateral hearing aid) as compared to children with bilateral CIs and contrasts said findings with the adult literature. There is a lack of clinical evidence driving recommendations for bimodal versus bilateral CI candidacy and as such, clinicians are often unsure about when to recommend a second CI for children with residual acoustic hearing. Thus the goal of this review is to identify scientific information that may influence clinical decision making for pediatric CI candidates with residual acoustic hearing.

Recent findings

Bilateral CIs are considered standard of care for children with bilateral severe-to-profound sensorineural hearing loss. For children with aidable acoustic hearing-even in just the low frequencies-an early period of bimodal stimulation has been associated with significantly better speech perception, vocabulary, and language development. HA audibility, however, is generally poorer than that offered by a CI resulting in interaural asymmetry in speech perception, head shadow, as well as brainstem and cortical activity and development. Thus there is a need to optimize "two-eared" hearing while maximizing a child's potential with respect to hearing, speech, and language while ensuring that we limit asymmetrically driven auditory neuroplasticity. A recent large study of bimodal and bilateral CI users suggested that a period of bimodal stimulation was only beneficial for children with a better-ear pure tone average (PTA) ≤ 73 dB HL. This 73-dB-HL cutoff applied even to children who ultimately received bilateral CIs.

Summary

Though we do not yet have definitive guidelines for determining bimodal versus bilateral CI candidacy, there is increasing evidence that 1) bilateral CIs yield superior outcomes for children with bilateral severe-to-profound hearing loss and, 2) an early period of bimodal stimulation is beneficial for speech perception and language development, but only for children with better-ear PTA ≤ 73 dB HL. For children with residual acoustic hearing, even in just the low-frequency range, rapid sequential bilateral cochlear implantation following a trial period with bimodal stimulation will yield best outcomes for auditory, language, and academic development. Of course, there is also an increasing prevalence of cochlear implantation with acoustic hearing preservation allowing for combined electric and acoustic stimulation even following bilateral implantation.

Developmental performance among pediatric candidates for cochlear implantation

BACKGROUND

Developmental evaluation of deaf children before cochlear implantation (CI) has not been given enough attention.

OBJECTIVES

This study was designed to evaluate the comprehensive developmental performance of deaf children who are CI candidates.

MATERIALS AND METHODS

The medical records of pediatric candidates for CI were reviewed. Five hundred children (287 boys; median age: 21.00 months; range: 6-72 months) with a diagnosis of severe-to-profound hearing loss were included. Preoperative developmental evaluation, including gross motor, fine motor, adaptability, language and social skill were retrieved. Comprehensive developmental performances including verbal and nonverbal skill were assessed. Multivariate linear regression analysis was used to analyze the related developmental factors.

RESULTS

Compared with normal developmental metrics, deaf children had developmental delay (p < .001), which occurred in not only the verbal but also nonverbal skill (all p < .05). Of the 500 deaf children, 50 (10%) had normal performance; the majority (51.6%) had mild neurological dysfunction. Of all the sub-developments, language developed worst (normal rate: 4.2%) and gross motor developed best (normal rate: 42%). Age of intervention was a risk factor for the developmental level of deaf children (β = -0.340, p < .05).

CONCLUSIONS

Pediatric candidates for CI had both verbal and nonverbal developmental delay. Age of intervention was a risk factor for the developmental level.

SIGNIFICANCE

Comprehensive developmental evaluation of deaf children before cochlear implantation (CI) should be paid enough attention. Early intervention for improving hearing was of significance.

The influence of Slim Modiolar electrode on residual hearing in pediatric patients

PURPOSE

Hearing preservation cochlear implantation is an established procedure in patients with low-frequency residual hearing, especially in pediatric cochlear implantation. More delicate, thin electrode arrays can minimize damage in the inner ear and enhance the possibility for residual hearing preservation. The Cochlear^® CI532 electrode has been reported as an electrode with the potential for residual hearing preservation. No similar studies pertaining to hearing preservation in pediatric patients have appeared to date. The aim of this study was to investigate whether the Cochlear^® CI532 Slim Modiolar electrode allows the preservation of low-frequency residual hearing in children undergoing cochlear implantation.

METHODS

In this multicenter, nonrandomized, prospective clinical cohort study, medical data of 14 pediatric patients implanted with the CI532 were collected. All patients had residual low-frequency hearing (preoperative audiogram or ABR with at least one threshold better than 90 dB HL at 125, 250, 500, or 1000 Hz). Postoperative thresholds were obtained 1, 3, 6, and 12 months after cochlear implantation.

RESULTS

Based on the HEARRING classification, 78.6% of children (11/14) had complete hearing preservation at the last follow-up visit (12 months after CI, or if not available, 6 months). A total of 21.4% (3/14) had partial hearing preservation. At the last follow-up visit, neither minimal hearing preservation nor loss of hearing was observed. Functional low-frequency hearing was preserved in 13 out of 14 patients (93%).

CONCLUSIONS

The residual hearing preservation results in children were superior to the results previously reported in adults.

Intracochlear Pressure Transients During Cochlear Implant Electrode Insertion: Effect of Micro-mechanical Control on Limiting Pressure Trauma

HYPOTHESIS

Use of micro-mechanical control during cochlear implant (CI) electrode insertion will result in reduced number and magnitude of pressure transients when compared with standard insertion by hand.

INTRODUCTION

With increasing focus on hearing preservation during CI surgery, atraumatic electrode insertion is of the utmost importance. It has been established that large intracochlear pressure spikes can be generated during the insertion of implant electrodes. Here, we examine the effect of using a micro-mechanical insertion control tool on pressure trauma exposures during implantation.

METHODS

Human cadaveric heads were surgically prepared with an extended facial recess. Electrodes from three manufacturers were placed both by using a micro-mechanical control tool and by hand. Insertions were performed at three different rates: 0.2 mm/s, 1.2 mm/s, and 2 mm/s (n = 20 each). Fiber-optic sensors measured pressures in scala vestibuli and tympani.

RESULTS

Electrode insertion produced pressure transients up to 174 dB SPL. ANOVA revealed that pressures were significantly lower when using the micro-mechanical control device compared with insertion by hand (p << 0.001). No difference was noted across electrode type or speed. Chi-square analysis showed a significantly lower proportion of insertions contained pressure spikes when the control system was used (p << 0.001).

CONCLUSION

Results confirm previous data that suggest CI electrode insertion can cause pressure transients with intensities similar to those elicited by high-level sounds. Results suggest that the use of a micro-mechanical insertion control system may mitigate trauma from pressure events, both by reducing the amplitude and the number of pressure spikes resulting from CI electrode insertion.

Hearing preservation in children with electric-acoustic stimulation after cochlear implantation : Outcome after electrode insertion with minimal insertion trauma

Background

Cochlear implantation in patients with functional residual low-frequency hearing is performed according to an established hearing-preserving surgical technique in order to cause minimal trauma of inner ear structures. Due to the increasing number of cochlear implants in children, the preservation of residual hearing is becoming increasingly important in this patient collective.

Objectives

Short- and mid-term hearing preservation outcome in pediatric patients is investigated.

Materials and methods

A group of 9 children (12 ears) between 5 and 12 years of age were examined after hearing-assisted cochlear implantation with respect to the pure tone audiometric thresholds. Retrospectively, short-term hearing preservation (up to 3 months after surgery) was examined. In a subgroup of 5 children, mid-term hearing preservation (7.5 to 16 months after surgery) was also analyzed. The mean values of hearing preserved (HL%) and hearing loss (HL) due to electrode insertion were calculated as measured values.

Results

In the whole group, the mean values of the preoperative PTA_low were 29.8 dB and the short-term postoperative PTA_low 42.6 dB. The mean value of the HL% was 73.6%, corresponding to an HL of 9.4 dB. In the subgroup, the mean PTA_low postoperatively was 46.0 dB in the mid-term and the HL% at 80.7% with a HL of 6.6 dB.

Conclusions

The results in children are consistent with the results in adults. Electric-acoustic stimulation (EAS) should be used in the treatment of children with existing low-frequency residual hearing, as good residual hearing preservation can also be achieved in children after implantation.

Evaluating inter-aural hearing preservation in bilateral paediatric cochlear implantation

OBJECTIVE

To examine inter-aural hearing preservation results in children undergoing simultaneous bilateral cochlear implantation (CI).

METHODS

Retrospective case review in tertiary referral centre. All children undergoing simultaneous bilateral CI between January 2013 and June 2014 (18 months). Patients eligible for inclusion in the study had pre-operative hearing thresholds of <90 dB at 250 Hz and ≥100 dB at 500 Hz. Patients with anatomical cochlear anomalies or missing data were excluded. Seven patients were included, 1 male, 6 female, mean age of 12 years 11 months at the time of surgery. All patients had simultaneous bilateral cochlear implant surgery, using the same implant and technique. All patients had pre- and post-operative unaided pure tone audiometry. Inter-aural hearing preservation results were compared in each patient.

RESULTS

The achieved hearing preservation for 14 ears was complete in 5, partial in 7, and minimal in 2. Measurable hearing preservation was achieved in 86% overall. Inter-aural analysis revealed that only 2 (subjects 1 and 4) of the 7 patients had preservation results within the same preservation group (complete/partial/minimal). The mean inter-aural preservation difference was 30.7% with a range from 12.4% to 65.2%.

CONCLUSIONS

Several factors and techniques have already been identified in the wider literature to explain differences in hearing preservation results in CI. However, despite controlling for known factors, we demonstrate variable inter-aural results. This suggests that there may be more factors beyond the surgeon's control influencing our ability to provide consistent results.

[Hearing preservation in children with electric-acoustic stimulation after cochlear implantation : Outcome after electrode insertion with minimal insertion trauma (German version)]

BACKGROUND

Cochlear implantation in patients with functional residual low-frequency hearing is performed according to an established hearing-preserving surgical technique in order to cause minimal trauma of inner ear structures. Due to the increasing number of cochlear implants in children, the preservation of residual hearing is becoming increasingly important in this patient collective.

OBJECTIVES

Short- and mid-term hearing preservation outcome in pediatric patients is investigated.

MATERIALS AND METHODS

A group of 9 children (12 ears) between 5 and 12 years of age were examined after hearing-assisted cochlear implantation with respect to the pure tone audiometric thresholds. Retrospectively, short-term hearing preservation (up to 3 months after surgery) was examined. In a subgroup of 5 children, mid-term hearing preservation (7.5 to 16 months after surgery) was also analyzed. The mean values of hearing preserved (HL%) and hearing loss (HL) due to electrode insertion were calculated as measured values.

RESULTS

In the whole group, the mean values of the preoperative PTA_low were 29.8 dB and the short-term postoperative PTA_low 42.6 dB. The mean value of the HL% was 73.6%, corresponding to an HL of 9.4 dB. In the subgroup, the mean PTA_low postoperatively was 46.0 dB in the mid-term and the HL% at 80.7% with a HL of 6.6 dB.

CONCLUSIONS

The results in children are consistent with the results in adults. Electric-acoustic stimulation (EAS) should be used in the treatment of children with existing low-frequency residual hearing, as good residual hearing preservation can also be achieved in children after implantation.

A Preliminary Investigation of the Air-Bone Gap: Changes in Intracochlear Sound Pressure With Air- and Bone-conducted Stimuli After Cochlear Implantation

HYPOTHESIS

A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion.

BACKGROUND

Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative ABG.

METHODS

Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window.

RESULTS

Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with previous literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable after electrode placement.

CONCLUSION

Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity.

Rhesus Cochlear and Vestibular Functions Are Preserved After Inner Ear Injection of Saline Volume Sufficient for Gene Therapy Delivery

Sensorineural losses of hearing and vestibular sensation due to hair cell dysfunction are among the most common disabilities. Recent preclinical research demonstrates that treatment of the inner ear with a variety of compounds, including gene therapy agents, may elicit regeneration and/or repair of hair cells in animals exposed to ototoxic medications or other insults to the inner ear. Delivery of gene therapy may also offer a means for treatment of hereditary hearing loss. However, injection of a fluid volume sufficient to deliver an adequate dose of a pharmacologic agent could, in theory, cause inner ear trauma that compromises functional outcome. The primary goal of the present study was to assess that risk in rhesus monkeys, which closely approximates humans with regard to middle and inner ear anatomy. Secondary goals were to identify the best delivery route into the primate ear from among two common surgical approaches (i.e., via an oval window stapedotomy and via the round window) and to determine the relative volumes of rhesus, rodent, and human labyrinths for extrapolation of results to other species. We measured hearing and vestibular functions before and 2, 4, and 8 weeks after unilateral injection of phosphate-buffered saline vehicle (PBSV) into the perilymphatic space of normal rhesus monkeys at volumes sufficient to deliver an atoh1 gene therapy vector. To isolate effects of injection, PBSV without vector was used. Assays included behavioral observation, auditory brainstem responses, distortion product otoacoustic emissions, and scleral coil measurement of vestibulo-ocular reflexes during whole-body rotation in darkness. Three groups (N = 3 each) were studied. Group A received a 10 μL transmastoid/trans-stapes injection via a laser stapedotomy. Group B received a 10 μL transmastoid/trans-round window injection. Group C received a 30 μL transmastoid/trans-round window injection. We also measured inner ear fluid space volume via 3D reconstruction of computed tomography (CT) images of adult C57BL6 mouse, rat, rhesus macaque, and human temporal bones (N = 3 each). Injection was well tolerated by all animals, with eight of nine exhibiting no signs of disequilibrium and one animal exhibiting transient disequilibrium that resolved spontaneously by 24 h after surgery. Physiologic results at the final, 8-week post-injection measurement showed that injection was well tolerated. Compared to its pretreatment values, no treated ear's ABR threshold had worsened by more than 5 dB at any stimulus frequency; distortion product otoacoustic emissions remained detectable above the noise floor for every treated ear (mean, SD and maximum deviation from baseline: -1.3, 9.0, and -18 dB, respectively); and no animal exhibited a reduction of more than 3 % in vestibulo-ocular reflex gain during high-acceleration, whole-body, passive yaw rotations in darkness toward the treated side. All control ears and all operated ears with definite histologic evidence of injection through the intended site showed similar findings, with intact hair cells in all five inner ear sensory epithelia and intact auditory/vestibular neurons. The relative volumes of mouse, rat, rhesus, and human inner ears as measured by CT were (mean ± SD) 2.5 ± 0.1, 5.5 ± 0.4, 59.4 ± 4.7 and 191.1 ± 4.7 μL. These results indicate that injection of PBSV at volumes sufficient for gene therapy delivery can be accomplished without destruction of inner ear structures required for hearing and vestibular sensation.

Hearing Preservation: Does Electrode Choice Matter?

Objective Evaluate if electrode design affects hearing preservation (HP) following cochlear implantation (CI) with full-length electrodes. Study Design Case series with chart review. Setting Tertiary referral academic center. Subjects and Methods Forty-five adults with low-frequency hearing (≤85 dB at 250 and 500 Hz) who underwent unilateral CI with full-length electrode arrays made by 1 manufacturer were included. HP was calculated with (1) mean low-frequency pure-tone average (LFPTA) at 250 and 500 Hz (MEAN method), (2) a percentile method across the audiometric frequency spectrum generating an S-value (HEARRING method), and (3) functional if hearing remained ≤85 dB at 250 and 500 Hz. Audiometric testing was performed approximately 1 month and 1 year postoperatively, yielding short-term and long-term results, respectively. Results Of 45 patients who underwent CI, 46.7% received lateral wall (LW) and 53.3% received perimodiolar (PM) electrodes. At short-term follow-up, LW electrodes were associated with significantly better HP than PM (LFPTA method: 27.7 vs 39.3 dB, P < .05; S-value method: 48.2 vs 21.8%, P < .05). In multivariate regression of short-term outcomes, LW electrode use was a significant predictor of better HP ( P < .05). At long-term follow-up, electrode type was not associated with HP. Younger patient age was the only significant predictor of long-term HP on multivariate analysis ( P < .05). Conclusion The LW electrode is associated with short-term HP, suggesting its design is favorable for limiting trauma to the cochlea during and directly following CI. Other factors, including age, are relevant for maintaining HP over the long term. The data support further investigation into what modifiable factors may promote long-term HP.

An Evaluation of the Surgical Trauma to Intracochlear Structures After Insertion of Cochlear Implant Electrode Arrays: A Comparison by Round Window and Antero-Inferior Cochleostomy Techniques

To evaluate the extent of intracochlear damage by histologic assessment of cadaveric temporal bones after insertion of cochlear implants by: round window approach and cochleostomy approach. Cochlear implantation was performed by transmastoid facial recess approach in 10 human cadaveric temporal bones. In 5 temporal bones, electrode insertion was acheieved by round window approach and in the remaining 5 bones, by cochleostomy approach. The bones were fixed, decalcified, sectioned and studied histologically. Grading of insertion trauma was assessed. In the round window insertion group, 2 bones had to be excluded from the study: one was damaged during handling with electrode extrusion and another bone did not show any demonstrable identifiable cochlear structure. Out of the 3 temporal bones, a total of 35 sections were examined: 24 demonstrated normal cochlea, 4 had basilar membrane bulging and 7 had fracture of bony spiral lamina. In the cochleostomy group, histology of 2 bones had to be discarded due to lack of any identifiable inner ear structures. Out of the 3 bones studied, 18 sections were examined: only 3 were normal, 4 sections had some bulge in spiral lamina and 11 had fracture of bony spiral lamina. The fracture of spiral lamina and bulge of basement membrane proportion is relatively higher if we perform cochleostomy as compared to round window approach. Therefore, round window insertion is relatively less traumatic as compared to cochleostomy. However, our sample size was very small and a study with a larger sample is required to further validate these findings.

An Objective Estimation of Air-Bone-Gap in Cochlear Implant Recipients with Residual Hearing Using Electrocochleography

Although, cochlear implants (CI) traditionally have been used to treat individuals with bilateral profound sensorineural hearing loss, a recent trend is to implant individuals with residual low-frequency hearing. Notably, many of these individuals demonstrate an air-bone gap (ABG) in low-frequency, pure-tone thresholds following implantation. An ABG is the difference between audiometric thresholds measured using air conduction (AC) and bone conduction (BC) stimulation. Although, behavioral AC thresholds are straightforward to assess, BC thresholds can be difficult to measure in individuals with severe-to-profound hearing loss because of vibrotactile responses to high-level, low-frequency stimulation and the potential contribution of hearing in the contralateral ear. Because of these technical barriers to measuring behavioral BC thresholds in implanted patients with residual hearing, it would be helpful to have an objective method for determining ABG. This study evaluated an innovative technique for measuring electrocochleographic (ECochG) responses using the cochlear microphonic (CM) response to assess AC and BC thresholds in implanted patients with residual hearing. Results showed high correlations between CM thresholds and behavioral audiograms for AC and BC conditions, thereby demonstrating the feasibility of using ECochG as an objective tool for quantifying ABG in CI recipients.

Outcomes of Adolescents With a Short Electrode Cochlear Implant With Preserved Residual Hearing

OBJECTIVE

The purpose of this study was to determine if adolescents with preserved residual low-frequency hearing can develop improved speech perception and maintain localization abilities by combining their acoustic hearing with electrical processing from a short electrode cochlear implant.

STUDY DESIGN

Repeated-measure, single-subject experiment.

SETTING

Research hospital.

PATIENTS

Adolescents with sensorineural hearing loss with a pure-tone average (PTA) between 60 and 90 dB HL between 125 and 1500 Hz and profound loss at higher frequencies.

INTERVENTION(S)

rehabilitative.

MAIN OUTCOME MEASURE(S)

Five adolescents received a short electrode cochlear implant in their poorer ear. Audiometric, speech perception in quiet (CNC words), localization, speech production, and language outcomes were collected pre- and postoperatively at 4, 8, 12, and 24 months.

RESULTS

Functional hearing preservation was accomplished in all subjects at initial activation and was maintained through 24 months. In the Combined and Hybrid conditions, all subjects showed significant improvements by 4 months postimplantation, with exception of Subject 2 in the Combined condition, who showed a significant improvement by 8 months postimplantation. Results also indicated that all subjects continue to have localization abilities postimplantation.

CONCLUSIONS

All of the subjects have benefitted from the combined electric and acoustic processing for speech perception abilities. The results from this study suggest that it could be worthwhile to consider acoustic and electric hearing in the adolescent population that have some low-frequency residual hearing and are struggling with hearing aids.

Cochlear Implant Electrode Effect on Sound Energy Transfer Within the Cochlea During Acoustic Stimulation

HYPOTHESIS

Cochlear implants (CIs) designed for hearing preservation will not alter mechanical properties of the middle and inner ears as measured by intracochlear pressure (P(IC)) and stapes velocity (Vstap).

BACKGROUND

CIs designed to provide combined electroacoustic stimulation are now available. To maintain functional acoustic hearing, it is important to know if a CI electrode can alter middle or inner ear mechanics because any alteration could contribute to elevated low-frequency thresholds in electroacoustic stimulation patients.

METHODS

Seven human cadaveric temporal bones were prepared, and pure-tone stimuli from 120 Hz to 10 kHz were presented at a range of intensities up to 110 dB sound pressure level. P(IC) in the scala vestibuli (P(SV)) and tympani (PST) were measured with fiber-optic pressure sensors concurrently with VStap using laser Doppler vibrometry. Five CI electrodes from two different manufacturers with varying dimensions were inserted via a round window approach at six different depths (16-25 mm).

RESULTS

The responses of P(IC) and VStap to acoustic stimulation were assessed as a function of stimulus frequency, normalized to sound pressure level in the external auditory canal, at baseline and electrode-inserted conditions. Responses measured with electrodes inserted were generally within approximately 5 dB of baseline, indicating little effect of CI electrode insertion on P(IC) and VStap. Overall, mean differences across conditions were small for all responses, and no substantial differences were consistently visible across electrode types.

CONCLUSION

Results suggest that the influence of a CI electrode on middle and inner ear mechanics is minimal despite variation in electrode lengths and configurations.

Preoperative steroids for hearing preservation cochlear implantation: A review

Preoperative steroids have been shown to be beneficial in reducing the hearing loss associated with cochlear implantation. This review article discusses the mechanism of action, effects of differing routes of administration, and side effects of steroids administered to the inner ear. Studies on the role of preoperative steroids in animal and human studies are also examined and future directions for research in this area are discussed.

Deeper insertion of electrode array result in better rehabilitation outcomes - Do we have evidence?

OBJECTIVE

To study the outcome analysis in cochlear implantees in relation to depth of insertion.

METHODS

30 patients of non-syndromic congenital profound hearing loss in the age range of 2-12 years received cochlear implantation by a posterior tympanotomy round window approach. Depth of insertion was calculated using post-operative X-rays (modified Stenver's view) and categorized into four groups, viz. fair insertion (Group A <180°), good insertion (Group B 180-<270°), very good insertion(Group C 270-360°), excellent insertion (Group D >360°). The outcome analysis of each implantee was carried out in a follow up interval of every 3 months using Meaningful Auditory Integration Scale (MAIS), Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS), Category of Auditory Performance (CAP), and Speech Intelligibility Rating (SIR).

RESULTS

Overall 30, 29, 25, and 22 patients have completed 3, 6, 9, and 12 months follow up respectively. The MAIS scores in Group C were significantly better than Group B at 6, 9, and 12 months (P<0.05). The mean CAP score of Group C was more than rest of the groups with significant difference between Group C and Group D at 12 months (P<0.05). The mean SIR scores were maximum in Group C with significant difference between Group C and Group B at 9 and 12 months (P<0.05).

CONCLUSION

The study demonstrates that insertion from 270° to 360° gives optimum hearing outcomes as compared to deeper insertion, although larger sample and long term follow-up is warranted for definite conclusions.

Residual Hearing Preservation with the Evo® Cochlear Implant Electrode Array: Preliminary Results

Introduction The preservation of residual hearing is currently an important challenge for cochlear implant surgeries. Indeed, if patients exhibit functional hearing after cochlear implantation, they can benefit from the combination of acoustical stimulation, usually in the low-frequencies and electrical stimulation in the high-frequencies. This combined mode of stimulation has proven to be beneficial both in terms of speech perception and of sound quality. Finding the right procedures for conducting soft-surgeries and designing electrode arrays dedicated to hearing preservation is an open issue. Objective The objective of this study is to evaluate the combination of a soft-surgery procedure implicating round-window insertion and the use of dexamethasone and hyaluronic acid during surgery, with the use of a specifically designed straight soft electrode array, on hearing preservation in patients with functional hearing in the low frequencies. Methods This pre-clinical trial was conducted on seven patients with residual hearing in the low frequencies. The surgical method used employed a round window insertion and the use of topical dexamethasone. Results The soft-surgery protocol could be successfully followed in five patients. In this group, the average hearing threshold shift compared with pre-operative values was of 18.7 +/- 16.1 dB HL up to 500 Hz and 15.7 +/- 15.1 up to 1 kHz, demonstrating satisfying levels of hearing preservation. Conclusion We were able to demonstrate the possibility of preserving residual hearing in most of the patients using the EVO electrode. Significant residual hearing preservation levels were was obtained when a soft surgical approach involving round window insertion, dexamethasone and hyaluronic use during the surgery.

Preservation of cochlear structures and hearing when using the Nucleus Slim Straight (CI422) electrode in children

OBJECTIVE

In cochlear implantation, there are two crucial factors promoting hearing preservation: an atraumatic surgical approach and selection of an electrode that does not damage cochlear structures. This study aimed to evaluate hearing preservation in children implanted with the Nucleus Slim Straight (CI422) electrode.

METHODS

Nineteen children aged 6-18 years, with partial deafness, were implanted using the 6-step Skarzynski procedure. Electrode insertion depth was 20-25 mm. Hearing status was assessed with pure tone audiometry before surgery, and at 1, 5, 9, 12 and 24 months after surgery. Electrode placement was confirmed with computed tomography.

RESULTS

Mean hearing preservation in the study group at activation of the cochlear implant was 73 per cent (standard deviation = 37 per cent). After 24 months, it was 67 per cent (standard deviation = 45 per cent). On a categorical scale, hearing preservation was possible in 100 per cent of cases.

CONCLUSION

Hearing preservation in children implanted with the Nucleus CI422 slim, straight electrode is possible even with 25 mm insertion depth, although the recommended insertion depth is 20 mm. A round window approach using a soft, straight electrode is most conducive to hearing preservation.

Cochlear Implantation for Profound Hearing Loss After Multimodal Treatment for Neuroblastoma in Children

Objectives

Neuroblastoma (NBL) predominantly affects children under 5 years of age. Through multimodal therapy, including chemotherapy, radiotherapy, surgery, and peripheral blood stem cell transplantation, the survival rate in patients with NBL have improved while treatment-related complications have also increased. Treatment-related ototoxicity, mainly from cisplatin, can result in profound hearing loss requiring cochlear implantation (CI). We analyzed the effectiveness and hearing preservation of CI recipients who had treated with multimodal therapy due to NBL.

Methods

Patients who received multimodal therapy for NBL and subsequent CIs were enrolled. A detailed review of the perioperative hearing test, speech evaluation, and posttreatment complications was conducted. Speech performance was analyzed using the category of auditory performance (CAP) score and the postoperative hearing preservation of low frequencies was also compared. Patients who were candidates for electro-acoustic stimulation (EAS) used an EAS electrode for low frequency hearing preservation.

Results

Three patients were identified and all patients showed improvement of speech performance after CI. The average of CAP score improved from 4.3 preoperatively to 5.8 at 1 year postoperatively. Two patients who were fitted with the Flex electrode showed complete hearing preservation and the preserved hearing was maintained over 1 year. The one remaining patient was given the standard CI-512 electrode and showed partial hearing preservation.

Conclusion

Patients with profound hearing loss resulting from NBL multimodal therapy can be good candidates for CI, especially for EAS. A soft surgical technique as well as a specifically designed electrode should be applied to this specific population during the CI operation in order to preserve residual hearing and achieve better outcomes.

Surgical findings and auditory performance after cochlear implant revision surgery

The objective of this study was to review cochlear reimplantation outcomes in the tertiary hospital and analyze whether facts such as type of failure, surgical findings, or etiology of deafness have an influence. A retrospective study including 38 patients who underwent cochlear implant revision surgery in a tertiary center is performed. Auditory outcomes (pure tone audiometry, % disyllabic words) along with etiology of deafness, type of complication, issues with insertion, and cochlear findings are included. Complication rate is 2.7 %. Technical failure rate is 57.9 % (50 % hard failure and 50 % soft failure), and medical failure (device infection or extrusion, migration, wound, or flap complication) is seen in 42.1 % of the cases. Management of cochlear implant complications and revision surgery is increasing due to a growing number of implantees. Cases that require explantation and reimplantation of the cochlear implant are safe procedures, where the depth of insertion and speech perception results are equal or higher in most cases. Nevertheless, there must be an increasing effort on using minimally traumatic electrode arrays and surgical techniques to improve currently obtained results.

Pediatric Cochlear Implantation in Residual Hearing Candidates

Objectives:

To propose categories for the various types of residual hearing in children and to review the outcomes of cochlear implantation (CI) in children with these different hearing conditions.

Methods:

We identified 53 children with residual hearing who had received a cochlear implant. Five groups were arbitrarily defined based on auditory features: G1, characterized by low-frequency residual hearing (n = 5); G2, characterized by severe sensorineural hearing loss (SNHL) and low speech discrimination (n = 12); G3, characterized by asymmetric SNHL (n = 9); G4, characterized by progressive SNHL (n = 15); and G5, characterized by fluctuating SNHL (n = 12). The main audiometric features and outcomes of the groups were analyzed.

Results:

The mean age at implantation was 10.15 years (range, 2.5-21 years). The mean preoperative score for the discrimination of open-set words was 48%; this score increased to 74% at 12 months and 81% at 24 months after the CI procedure (G1 to G5, respectively: 79/62/77%, 50/81/88%, 59/75/86%, 35/74/67%, and 39/69/80%). Children who were implanted after 10 years of age did not improve as much as those who were implanted at a younger age (open-set word list speech perception [OSW] score at 12 months: 62% vs 83%; P = .0009). Shorter delays before surgery were predictive of better performance ( P = .003). Inner ear malformation and SLC26A4 mutations were not predictive of the outcome.

Conclusions:

CIs provide better results compared with hearing aids in children with residual hearing. Factors that may impact the benefits of CIs in patients with residual hearing are age, delay in performing the CI procedure, which ear is implanted, and initial underestimation of the patient’s hearing difficulties.