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

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.

The Role of Steroids in the Preservation of Hearing and Vestibular Function in Cochlear Implantation

OBJECTIVE

Cochlear implant surgery is guided by principles of atraumatic insertion as to protect the inner ear. Previous studies suggest the potential benefit of steroids in patients undergoing cochlear implantation (CI), although the optimal route of administration has yet to be determined. We aim to systematically review the human studies of hearing and vestibular function preservation in patients undergoing CI receiving perioperative steroids and to discuss their role.

DATA SOURCES

Search performed in PubMed, EMBASE, and CENTRAL databases in December 2023.

REVIEW METHODS

Studies comparing several methods of steroid delivery and conventional management for patients undergoing CI were identified. Primary outcomes included hearing and vestibular function preservation. Secondary outcomes included reported adverse events, routes of steroid administration, and the presence of a control group without steroid administration.

RESULTS

A total of 15 studies (N = 659) met inclusion criteria. Methodology, doses, route of steroid administration, and follow-up duration differed between most studies. Audiometric, vestibular, and hearing preservation (HP) results were inconsistent. In 12 studies, perioperative steroids were associated with either increased HP or vestibular function preservation. Only two studies reported adverse events related to oral corticosteroid therapy.

CONCLUSIONS

There is a tendency for perioperative steroids to have a positive impact, at least in the short term, on hearing and vestibular function preservation in CI. Topical corticosteroid therapy appears to have a superior risk-benefit profile. There is a need for future carefully designed randomized controlled trials to determine the ideal route of steroid administration and its real impact in the long term. Laryngoscope, 134:3458-3465, 2024.

Recent advances in Otology: Current landscape and future direction

Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.

Evaluating calcium channel blockers and bisphosphonates as otoprotective agents in cochlear implantation hearing preservation candidates

OBJECTIVES

Evaluate potential effects of calcium channel blockers (CCB) and bisphosphonates (BP) on residual hearing following cochlear implantation.

METHODS

Medications of 303 adult hearing preservation (HP) candidates (low frequency pure tone average [LFPTA] of 125, 250, and 500 Hz ≤80 dB HL) were reviewed. Postimplantation LFPTA of patients taking CCBs and BPs were compared to controls matched by age and preimplantation LFPTA.

RESULTS

Twenty-six HP candidates were taking a CCB (N = 14) or bisphosphonate (N = 12) at implantation. Median follow-up was 1.37 years (range 0.22-4.64y). Among subjects with initial HP, 29% (N = 2 of 7) CCB users compared to 50% (N = 2 of 4) controls subsequently lost residual hearing 3-6 months later (OR = 0.40, 95% CI = 0.04-4.32, p = 0.58). None of the four BP patients with initial HP experienced delayed loss compared to 50% (N = 2 of 4) controls with initial HP (OR = 0.00, 95% CI = 0.00-1.95, P = 0.43). Two CCB and one BP patients improved to a LFPTA <80 dB HL following initial unaided thresholds that suggested loss of residual hearing.

DISCUSSION

There were no significant differences in the odds of delayed loss of residual hearing with CCBs or BPs.

CONCLUSION

Further investigation into potential otoprotective adjuvants for maintaining residual hearing following initial successful hearing preservation is warranted, with larger cohorts and additional CCB/BP agents.

Functional Hearing Preservation in Cochlear Implantation: The Miami Cocktail Effect

OBJECTIVE

To investigate if pharmacological treatment with prednisone and L-N-acetylcysteine (STE + NAC) influence functional hearing preservation in cochlear implant (CI) surgery.

STUDY DESIGNS

Preimplantation and postimplantation longitudinal case-control study.

SETTING

Tertiary referral center.

PATIENTS

Pediatric and adult recipients of CI with preimplantation functional hearing defined as an average of air-conducted thresholds at 125, 250, and 500 Hz (low-frequency pure-tone average [LFPTA]) <80 dB.

INTERVENTIONS

Preimplantation and postimplantation audiometry. Weight-adjusted oral prednisone and L-N-acetylcysteine starting 2 days before surgery (Miami cocktail). Prednisone was continued for 3 days and L-N-acetylcysteine for 12 days after surgery, respectively. Cochlear implantation with conventional length electrodes.

MAIN OUTCOME MEASURES

Proportion of patients with LFPTA <80 dB, and LFPTA change at 1-year postimplantation.

RESULTS

All 61 patients received intratympanic and intravenous dexamethasone intraoperatively, with 41 patients receiving STE + NAC and 20 patients not receiving STE + NAC. At 1-year postimplantation, the proportion of functional hearing preservation was 83% in the STE + NAC group compared with 55% of subjects who did not receive STE + NAC ( p = 0.0302). The median LFPTA change for STE + NAC-treated and not treated subjects was 8.33 dB (mean, 13.82 ± 17.4 dB) and 18.34 dB (mean, 26.5 ± 23.4 dB), respectively ( p = 0.0401, Wilcoxon rank test). Perioperative STE + NAC treatment resulted in 10 dB of LFPTA better hearing than when not receiving this treatment. Better low-frequency preimplantation hearing thresholds were predictive of postimplantation functional hearing. No serious side effects were reported.

CONCLUSION

Perioperative STE + NAC, "The Miami Cocktail," was safe and superior to intraoperative steroids alone in functional hearing preservation 1-year after cochlear implantation.

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.

Variability in Perioperative Steroid Therapy Regimen for Cochlear Implantation as It Relates to Hearing Preservation

HYPOTHESIS

We aimed to identify practice trends and association between physician training and administration of perioperative steroids for cochlear implantation (CI) as it relates to hearing preservation.

BACKGROUND

Perioperative steroid therapy regimens are postulated to protect residual hearing and improve hearing preservation outcomes in CI.

METHODS

A 27-question online survey was developed by the senior authors using the Qualtrics Survey Tool, then distributed via email from September to November 2022 to otolaryngologists specializing in otology or neurotology and who practice in the United States or Canada.

RESULTS

The survey was sent to 463 physicians, 162 (35.0%) of whom completed the survey. One hundred forty-four (31.1%) responses underwent analysis. All physicians administering preoperative steroids (n = 31) prefer preoperative oral prednisone. Of 143 physicians administering intraoperative steroids, 54.5% prefer intraoperative intravenous dexamethasone. More than half (77.6%) of 85 physicians administering postoperative steroids prefer postoperative oral prednisone. Postoperative steroid administration (p < 0.006) and taper utilization (p < 0.041) were greater among physicians who complete greater than 40 CIs annually (n = 47 [71.2%]; n = 30 [49.2%]) than physicians who complete up to 40 CIs annually (n = 37 [48.7%]; n = 20 [31.3%]), respectively. Physicians practicing for 5 to 20 years after residency are more prevalent in using postoperative steroid tapers than physicians practicing for fewer than 5 years after and more than 20 years after residency (n = 37 [51.4%] versus n = 14 [25.5%], p < 0.001).

CONCLUSION

Consensus is needed about the optimal steroid treatment for CI patients.

LEVEL OF EVIDENCE

4.

Timing of Acoustic Hearing Changes After Cochlear Implantation

OBJECTIVES/HYPOTHESIS

To determine the timing of acoustic hearing changes among hearing preservation Cochlear implant (CI) recipients. To determine differences in hearing outcomes based on device type and demographic factors. To determine if there is a relationship between the extent of early hearing loss after CI and the subsequent rate of continued hearing loss.

STUDY DESIGN

Prospective, single subject study.

METHODS

Two hundred and eleven subjects who received a hearing preservation CI were included in the study-80 Nucleus Hybrid L24 (Cochlear), 47 422/522 (Cochlear), 24 S8 (Cochlear), 14 S12 (Cochlear), 6 SRW (Cochlear), 21 SLIM J (Advanced Bionics), and 19 Flex (Med-EL). Of these, 127 were included in the subsequent analyses. Audiometric thresholds (low frequency pure-tone-averages) were collected and compared pre and postoperatively.

RESULTS

Long-term hearing preservation rates were 65% (52/80) for L24, 83% (20/24) for S8, 79% (11/14) for S12, 83% (5/6) for SRW, 54% (25/47) for 422/522, 91% (21/23) for SLIM J, and 84% (16/19) for Flex. Hearing loss was not related to device type (P = .9105) or gender (P = .2169). Older subjects (age ≥65) had worse hearing outcomes than younger subjects after initial device activation (age <65, P = .0262). There was no significant difference in rate of hearing loss over time between older and younger patients (P = .0938). Initial postoperative hearing loss was not associated with the rate of long-term hearing loss.

CONCLUSIONS

Long-term low frequency hearing preservation is possible for CI recipients and is not associated with gender or device type. Rate of hearing loss over time is not dependent on patient age. Early hearing loss after CI does not predict the rate of long-term hearing loss.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:2036-2043, 2022.

The Clinical Effect of Steroids for Hearing Preservation in Cochlear Implantation: Conclusions Based on Three Cochlear Implant Systems and Two Administration Regimes

The main aim of this study was to assess the clinical effect of steroids (dexamethasone and prednisone) on hearing preservation in patients who underwent cochlear implantation with different cochlear implant systems (Oticon®, Advanced Bionics®, Med-El®). 147 adult patients met the inclusion criteria and were enrolled to the study and divided into three groups depending on the brand of cochlear implant they received and participated in all follow-up visits regularly. They were also randomly divided into three subgroups depending on the steroid administration regime: (1) intravenous dexamethasone (0.1 mg/kg body weight twice a day for three days); (2) combined intravenous and oral steroids (dexamethasone 0.1 mg/kg body weight twice a day plus prednisone 1 mg/kg weight once a day); and (3) no steroids (control group). The results were measured by pure tone audiometry (PTA) at three time points: (i) before implantation, (ii) at processor activation, and (iii) 12 months after activation. A hearing preservation (HP) figure was also calculated by comparing the preoperative results and the results after 12 months. Further measures collected were electrode impedance and hearing threshold in the non-operated ear. The highest HP measures (partial and complete) were obtained in the subgroups who were given steroids. Of the 102 patients given steroids, HP was partial or complete in 63 of them (62%). In comparison, partial or complete HP was achieved in only 15 patients out of 45 (33%) who were not given steroids. There were differences between the three cochlear implant groups, with the Med-El and Advanced Bionics groups performing better than the Oticon group (45% and 43% of the former two groups achieved partial or complete HP compared to 20% in the latter). Hearing thresholds in the non-operated ear were stable over 12 months. Generally, impedance was slightly lower in the 12 month follow-up in comparison with the activation period, with the exception of the Oticon group. (4) Conclusions: Pharmacological treatment with steroids in patients undergoing cochlear implantation helps to preserve residual hearing.

Advances in hearing preservation in cochlear implant surgery

PURPOSE OF REVIEW

Advancements in cochlear implant surgical approaches and electrode designs have enabled preservation of residual acoustic hearing. Preservation of low-frequency hearing allows cochlear implant users to benefit from electroacoustic stimulation, which improves performance in complex listening situations, such as music appreciation and speech understanding in noise. Despite the relative high rates of success of hearing preservation, postoperative acoustic hearing outcomes remain unpredictable.

RECENT FINDINGS

Thin, flexible, lateral wall arrays are preferred for hearing preservation. Both shortened and thin, lateral wall arrays have shown success with hearing preservation and the optimal implant choice is an issue of ongoing investigation. Electrocochleography can monitor cochlear function during and after insertion of the electrode array. The pathophysiology of hearing loss acutely after cochlear implant may differ from that involved in delayed hearing loss following cochlear implant. Emerging innovations may reduce cochlear trauma and improve hearing preservation.

SUMMARY

Hearing preservation is possible using soft surgical techniques and electrode arrays designed to minimize cochlear trauma; however, a subset of patients suffer from partial to total loss of acoustic hearing months to years following surgery despite evidence of residual apical hair cell function. Early investigations in robotic-assisted insertion and dexamethasone-eluting implants show promise.

Improving Clinical Outcomes in Cochlear Implantation Using Glucocorticoid Therapy: A Review

Cochlear implant surgery is a successful procedure for auditory rehabilitation of patients with severe to profound hearing loss. However, cochlear implantation may lead to damage to the inner ear, which decreases residual hearing and alters vestibular function. It is now of increasing interest to preserve residual hearing during this surgery because this is related to better speech, music perception, and hearing in complex listening environments. Thus, different efforts have been tried to reduce cochlear implantation-related injury, including periprocedural glucocorticoids because of their anti-inflammatory properties. Different routes of administration have been tried to deliver glucocorticoids. However, several drawbacks still remain, including their systemic side effects, unknown pharmacokinetic profiles, and complex delivery methods. In the present review, we discuss the role of periprocedural glucocorticoid therapy to decrease cochlear implantation-related injury, thus preserving inner ear function after surgery. Moreover, we highlight the pharmacokinetic evidence and clinical outcomes which would sustain further interventions.

Evaluation of the Efficacy of Dexamethasone-Eluting Electrode Array on the Post-Implant Cochlear Fibrotic Reaction by Three-Dimensional Immunofluorescence Analysis in Mongolian Gerbil Cochlea

Cochlear implant is the method of choice for the rehabilitation of severe to profound sensorineural hearing loss. The study of the tissue response to cochlear implantation and the prevention of post-cochlear-implant damages are areas of interest in hearing protection research. The objective was to assess the efficacy of dexamethasone-eluting electrode array on endo canal fibrosis formation by three-dimensional immunofluorescence analysis in implanted Mongolian gerbil cochlea. Two trials were conducted after surgery using Mongolian gerbil implanted with dexamethasone-eluting or non-eluting intracochlear electrode arrays. The animals were then euthanised 10 weeks after implantation. The cochleae were prepared (electrode array in place) according to a 29-day protocol with immunofluorescent labelling and tissue clearing. The acquisition was carried out using light-sheet microscopy. Imaris software was then used for three-dimensional analysis of the cochleae and quantification of the fibrotic volume. The analysis of 12 cochleae showed a significantly different mean volume of fibrosis (2.16 × 10⁸ μm³ ± 0.15 in the dexamethasone eluting group versus 3.17 × 10⁸ μm³ ± 0.54 in the non-eluting group) (p = 0.004). The cochlear implant used as a corticosteroid delivery system appears to be an encouraging device for the protection of the inner ear against fibrosis induced by implantation. Three-dimensional analysis of the cochlea by light-sheet microscopy was suitable for studying post-implantation tissue damage.

First-in-human intracochlear application of human stromal cell-derived extracellular vesicles

Extracellular vesicles (EVs) derived from the secretome of human mesenchymal stromal cells (MSC) contain numerous factors that are known to exert anti‐inflammatory effects. MSC‐EVs may serve as promising cell‐based therapeutics for the inner ear to attenuate inflammation‐based side effects from cochlear implantation which represents an unmet clinical need. In an individual treatment performed on a ‘named patient basis’, we intraoperatively applied allogeneic umbilical cord‐derived MSC‐EVs (UC‐MSC‐EVs) produced according to good manufacturing practice. A 55‐year‐old patient suffering from Menière's disease was treated with intracochlear delivery of EVs prior to the insertion of a cochlear implant. This first‐in‐human use of UC‐MSC‐EVs demonstrates the feasibility of this novel adjuvant therapeutic approach. The safety and efficacy of intracochlear EV‐application to attenuate side effects of cochlea implants have to be determined in controlled clinical trials.

Clinical characteristics and outcomes of children with cochlear implants who had preoperative residual hearing

OBJECTIVE

Cochlear implants (CI) candidacy criteria have expanded to include children with more residual hearing. This study explored the clinical profiles and outcomes of children with CIs who had preoperative residual hearing in at least one ear.

DESIGN

A retrospective chart review was conducted to collect clinical characteristics and speech perception data. Pre- and post-CI auditory and speech perception data were analysed using a modified version of the Pediatric Ranked Order Speech Perception (PROSPER) score.

STUDY SAMPLE

This study included all children with residual hearing who received CIs in one Canadian paediatric centre from 1992 to 2018.

RESULTS

A total of 100 of 389 (25.7%) children with CIs had residual hearing (median 77.6 dB HL, better ear). The proportion of children with residual hearing increased from 1992 to 2018. Children who had auditory behaviour and speech perception tests (n = 83) showed higher modified PROSPER scores post-CI compared to pre-CI. Phonologically Balanced Kindergarten (PBK) test scores were available for 71 children post-CI; 81.7% (58/71) of children achieved > 80% on the PBK.

CONCLUSIONS

One in four children who received CIs had residual hearing, and most of them had severe hearing loss at pre-CI. These children showed a high level of speech perception with CIs.

Systemic methylprednisolone for hearing preservation during cochlear implant surgery: A double blinded placebo-controlled trial

AIM

To assess whether a single, peri-operative, high dose of methylprednisolone can improve the preservation of residual acoustic hearing following cochlear implantation (CI).

METHODS

This was a double blinded placebo-controlled trial, performed in a tertiary academic centre. The hypothesis was that methylprednisolone would improve the preservation of hearing, and lower electrode impedances. Adult patients (18-85 years) with hearing at 85 dB or better at 500 Hz in the ear to be implanted were randomly allocated to either treatment (methylprednisolone, 1g administered intravenously upon induction of anaesthesia) or control (normal saline infusion). As per standard clinical practice, all patients received a routine dose of dexamethasone (8 mg intravenously) on induction of anaesthesia. Implantation was undertaken with a slim and flexible lateral wall electrode via the round window. Surgical technique was routine, with adherence to soft surgical principles. The primary outcome was hearing preservation within 20 dB at 500 Hz, 12 months following cochlear implantation. Secondary outcomes included hearing preservation at 6 weeks and 3 months, monopolar electrode impedance, and Consonant-Vowel-Consonant (CVC) Phoneme scores at 3 and 12 months after surgery.

RESULTS

Forty-five patients were enrolled into the control group and 48 patients received the steroid. The number of patients achieving hearing preservation at 12 months did not differ significantly between those receiving methylprednisolone treatment and the controls. There were no differences in hearing preservation at any frequency at either 6 weeks or 3 months after implantation. Neither CVC phoneme scores nor electrode impedances differed between the groups.

CONCLUSIONS

This paper demonstrates that high-dose local steroid injection at surgery was not effective in preventing a loss of residual hearing, improving speech perception, or lowering electrode impedances. The findings were contrary to the experimental literature, and emerging clinical evidence that steroid elution from implant electrodes influences cochlear biology in humans. We found no evidence to support the widely-held practice of administering intravenous steroids in the perioperative period, in an attempt to preserve residual hearing.

Preimplant Hearing Threshold: An Important Predictor of Hearing Preservation in Cochlear Implantation With Lateral Wall Electrodes

OBJECTIVE

To evaluate the outcomes and association factors of long-term hearing preservation (HP) in cochlear implantation with lateral wall (LW) electrode arrays.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary academic center.

PATIENTS

Thirty-four consecutive ears from 32 patients with a ≤ 80 dB HL preoperative low-frequency pure-tone average of 250 to 500 Hz were included.

INTERVENTION

Cochlear implantation with LW electrode arrays and the intention of achieving HP.

MAIN OUTCOME MEASURES

HP classifications according to the HEARRING group and functional HP methods (≤ 85 dB HL of pure-tone threshold at 250 Hz) at 1 year postoperatively.

RESULTS

Based on the HEARRING classification, complete, partial, and minimal HP was achieved in 7 ears (21%), 12 ears (35%), and 4 ears (12%), respectively. Under functional classification, 14 ears (41%) exhibited functional hearing after surgery. The average threshold shift was 17.1 dB HL (SD = 16.9 dB HL). Among various clinical features, a ≤ 60 dB HL preimplant pure-tone threshold of 250 Hz was associated with HP outcome in both classifications (OR = 12.95, 95% CI = 1.29-130.01, p = 0.029 in HEARRING classification; OR = 14.36, 95% CI = 1.07-191.40, p = 0.044 in functional classification). The following parameters were not associated with HP (p > 0.05): patient demographics, surgical aspects (insertion route and depth), electrode array size, scalar electrode position, and presence of comorbidity.

CONCLUSION

With LW electrode arrays, HP was achieved in 68% of HEARRRING group patients and 41% of functional classification patients. A ≤ 60 dB HL preimplant pure-tone threshold of 250 Hz was significantly associated with an increased rate of long-term HP.

Music perception and training for pediatric cochlear implant users

INTRODUCTION

Cochlear implants (CIs) are biomedical devices that restore sound perception for people with severe-to-profound sensorineural hearing loss. Most postlingually deafened CI users are able to achieve excellent speech recognition in quiet environments. However, current CI sound processors remain limited in their ability to deliver fine spectrotemporal information, making it difficult for CI users to perceive complex sounds. Limited access to complex acoustic cues such as music, environmental sounds, lexical tones, and voice emotion may have significant ramifications on quality of life, social development, and community interactions.

AREAS COVERED

The purpose of this review article is to summarize the literature on CIs and music perception, with an emphasis on music training in pediatric CI recipients. The findings have implications on our understanding of noninvasive, accessible methods for improving auditory processing and may help advance our ability to improve sound quality and performance for implantees.

EXPERT OPINION

Music training, particularly in the pediatric population, may be able to continue to enhance auditory processing even after performance plateaus. The effects of these training programs appear generalizable to non-trained musical tasks, speech prosody and, emotion perception. Future studies should employ rigorous control groups involving a non-musical acoustic intervention, standardized auditory stimuli, and the provision of feedback.

Impedance Values Do Not Correlate With Speech Understanding in Cochlear Implant Recipients

OBJECTIVE

To evaluate a possible correlation between impedance values and speech perception after cochlear implantation.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS AND INTERVENTION

All patients implanted with a MedEl Flex28 device in our department with complete audiometric data (Freiburger monosyllabic testing at 65 dB, Hochmaier-Schulz-Moser testing in quiet and in 10 dB noise) and impedance measurements at the 1-year refitting appointment were enrolled in this study. Further inclusion criteria were age > 17 years, native speakers, and no use of electric-acoustic-stimulation.

MAIN OUTCOME MEASURES

Mean values for impedances were calculated over all electrode contacts and separately for basal, medial, and apical regions. These data were correlated statistically (Pearson's correlation) with speech testing results. Furthermore, groups of patients with extreme values were built and compared against each other and against the rest of the collective.

RESULTS

Impedance values did not correlate significantly with speech performance in any of the audiometric tests neither for all electrode contacts nor for specific clusters of contacts. Patients with the lowest impedances did not perform statistically different than patients with the highest impedances in any condition.

CONCLUSION

To our knowledge, this is the first data on a possible correlation between impedances and speech perception. The extent of the impedances as a benchmark for a good performance in speech discrimination tests could not be verified. Further prospective studies, possibly with more precise diagnostic tools, should be carried out to define the value of impedance measurements for cochlear implantation provision.

Dose-Dependent Transient Decrease of Impedances by Deep Intracochlear Injection of Triamcinolone With a Cochlear Catheter Prior to Cochlear Implantation-1 Year Data

Administration of low-dose steroids via a catheter inserted into the cochlea to apply pharmaceuticals to more apical regions was previously shown not to be sufficient for long-term reduction of electrode impedances. The aim of the present study was to investigate the effect of intra-cochlear high-dose triamcinolone application on impedances in cochlear implant recipients. Patients received low-dose (4 mg/ml; n = 5) or high-dose (20 mg/ml; n = 5) triamcinolone via a cochlear catheter just prior to the insertion of a Med-El Flex28 electrode. Impedances were measured at defined time points from intra-operatively up to 12 months after first fitting and retrospectively compared with a control group (no steroid application). Patients who received a high-dose application of crystalloid triamcinolone showed significantly reduced impedances in the first fitting measurements compared to the control group. This effect was no longer detectable in patients of the low-dose group at that time. Looking at the different regions of the electrode, the impedance values were lowered significantly only at the basal and medial contacts. At later time points, there were no significant differences between any of the groups. This is the first study to demonstrate a dose-dependent reduction of impedances by deep intra-cochlear injection of triamcinolone in cochlear implant patients. With a high-dose, single application of triamcinolone using a cochlear catheter prior to insertion of a Flex28 electrode, the impedances can be significantly reduced up to and including the first fitting. Although the effect was longer lasting than when compared to low-dose triamcinolone, it was also not permanent.

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

HYPOTHESIS

Electrocochleography (ECochG) patterns observed during cochlear implant (CI) electrode insertion may provide information about scalar location of the electrode array.

BACKGROUND

Conventional CI surgery is performed without actively monitoring auditory function and potential damage to intracochlear structures. The central hypothesis of this study was that ECochG obtained directly through the CI may be used to estimate intracochlear electrode position and, ultimately, residual hearing preservation.

METHODS

Intracochlear ECochG was performed on 32 patients across 3 different implant centers. During electrode insertion, a 50-ms tone burst stimulus (500 Hz) was delivered at 110 dB SPL. The ECochG response was monitored from the apical-most electrode. The amplitude and phase changes of the first harmonic were imported into an algorithm in an attempt to predict the intracochlear electrode location (scala tympani [ST], translocation from ST to scala vestibuli [SV], or interaction with basilar membrane). Anatomic electrode position was verified using postoperative computed tomography (CT) with image processing.

RESULTS

CT analysis confirmed 25 electrodes with ST position and 7 electrode arrays translocating from ST into SV. The ECochG algorithm correctly estimated electrode position in 26 (82%) of 32 subjects while 6 (18%) electrodes were wrongly identified as translocated (sensitivity = 100%, specificity = 77%, positive predictive value = 54%, and a negative predictive value = 100%). Greater hearing loss was observed postoperatively in participants with translocated electrode arrays (36 ± 15 dB) when compared with isolated ST insertions (28 ± 20 dB HL). This result, however, was not significant (p = 0.789).

CONCLUSION

Intracochlear ECochG may provide information about CI electrode location and hearing preservation.

Cochlear Implant

Cochlear implant is the first approved cranial nerve stimulator that works by directly stimulating the cochlear nerve. The medical and societal impact of this revolutionary device cannot be understated. This article reviews the evolving indications for cochlear implant, patient assessment, surgical approach, and outcomes for pediatric and adult cochlear implant that demonstrate its impact. Future concepts in cochlear implant are introduced briefly. This article covers a breadth of information; however, it is not intended be entirely comprehensive. Rather, it should serve as a foundation for understanding cochlear implant.

Preservation of Hearing Following Cochlear Implantation Using Different Steroid Therapy Regimens: A Prospective Clinical Study

Background

A prospective clinical study was conducted to assess different regimens of steroid therapy and preservation of hearing following cochlear implantation.

Material/Methods

Study participants were ≥18 years-of-age, with a cochlear duct length ≥27.1 mm measured by computed tomography (CT), with hearing sound levels in the range of 10–120 decibels (dB) and sound frequencies of 125–250 hertz (Hz); sound levels of 35–120 dB and frequencies of 500–1,000 Hz; sound levels of 75–120 dB and frequencies of 2,000–8,000 Hz. Study exclusion criteria included diseases with contraindications for steroid therapy or medications that increased the effects of steroids. Patients had cochlear implantation and were divided into three treatment groups: intravenous (IV) steroid therapy (standard steroid therapy): combined oral and IV steroid therapy (prolonged steroid therapy); and a control group (cochlear implantation without steroid therapy). Hearing preservation was established by pure tone audiometry based on the pre-operative and postoperative average hearing thresholds according to the formula developed by the HEARRING Network.

Results

There were 36 patients included in the study. In all cases, the cochlear implant electrode was inserted via the round window approach with a straight electrode length of 28 mm. Patients with combined oral and IV steroid therapy (prolonged steroid therapy) had better results when compared with patients with intravenous (IV) steroid therapy (standard steroid therapy) and the control group.

Conclusions

Prolonged steroid therapy using combined oral and IV steroids stabilized hearing thresholds and preserved hearing in adult patients following cochlear implantation.

Durability of Hearing Preservation after Cochlear Implantation with Conventional-Length Electrodes and Scala Tympani Insertion

OBJECTIVES

To analyze factors that influence hearing preservation over time in cochlear implant recipients with conventional-length electrode arrays located entirely within the scala tympani.

STUDY DESIGN

Case series with planned chart review.

SETTING

Single tertiary academic referral center.

SUBJECTS AND METHODS

A retrospective review was performed to analyze a subgroup of cochlear implant recipients with residual acoustic hearing. Patients were included in the study only if their electrode arrays remained fully in the scala tympani after insertion and serviceable acoustic hearing (≤80 dB at 250 Hz) was preserved. Electrode array location was verified through a validated radiographic assessment tool. Patients with <6 months of audiologic follow-up were excluded. The main outcome measure was change in acoustic hearing thresholds from implant activation to the last available follow-up.

RESULTS

A total of 16 cases met inclusion criteria (median age, 70.6 years; range, 29.4-82.2; 50% female). The average follow-up was 18.0 months (median, 16.1; range, 6.2-36.4). Patients with a lateral wall electrode array were more likely to have stable acoustic thresholds over time (P < .05). Positive correlations were seen between continued hearing loss following activation and larger initial postoperative acoustic threshold shifts, though statistical significance was not achieved. Age, sex, and noise exposure had no significant influence on continued hearing preservation over time.

CONCLUSIONS

To control for hearing loss associated with interscalar excursion during cochlear implantation, the present study evaluated patients only with conventional electrode arrays located entirely within the scala tympani. In this group, the style of electrode array may influence residual hearing preservation over time.