Monitoring of the Inner Ear Function During and After Cochlear Implant Insertion Using Electrocochleography

To preserve residual hearing during cochlear implant (CI) surgery, it is desirable to use intraoperative monitoring of inner ear function (cochlear monitoring), especially during electrode insertion. A promising method is electrocochleography (ECochG). Within this project, the relations between ongoing responses (ORs), recorded extra- and intracochlearly (EC and IC), and preservation of residual hearing were investigated. Before, during, and after insertion of hearing preservation electrodes, intraoperative ECochG recordings were performed EC using a cotton wick electrode and after insertion also IC using the CI electrode (MED-EL) and a research software tool. The stimulation was delivered acoustically using low frequency tone bursts. The recordings were conducted in 10 adult CI recipients. The amplitudes of IC ORs were detected to be larger than EC ORs. Intraoperative EC thresholds correlated highly to preoperative audiometric thresholds at 1000 Hz, IC thresholds highly at 250 Hz and 500 Hz. The correlations of both intraoperative ECochG recordings to postoperative pure tone thresholds were low. When measured postoperatively at the same appointments, IC OR thresholds correlated highly to audiometric pure tone thresholds. For all patients, it was possible to record ORs during or directly after electrode insertion. Consequently, we conclude that we did not observe any cases with severe IC trauma. Delayed hearing loss could not be predicted with our method. Nevertheless, intraoperative ECochG recordings are a promising tool to gain further insight into mechanisms impacting residual hearing. Postoperatively recorded IC OR thresholds seem to be a reliable tool for frequency specific hearing threshold estimation.

Download Full-text

Delayed loss of residual hearing in Clarion® cochlear implant users

The Journal of Laryngology & Otology ◽

10.1258/002221503322542836 ◽

2003 ◽

Vol 117 (11) ◽

pp. 850-853 ◽

Cited By ~ 17

Author(s):

M. Barbara ◽

A. Mattioni ◽

S. Monini ◽

I. Chiappini ◽

F. Ronchetti ◽

...

Keyword(s):

Cochlear Implant ◽

Cochlear Implantation ◽

Pure Tone ◽

Hearing Threshold ◽

Auditory Threshold ◽

Residual Hearing ◽

Equal Distribution ◽

Hearing Thresholds ◽

Number Of Patients ◽

Over Time

Hearing threshold has been measured in a group of patients following cochlear implantation with a Clarion® device for the last eight years. The patients had received either a pre-curved carrier or the Hi-Focus I plus Electrode Positioner System (EPS). The assessment was carried out within the first post-operative week as well as at a later stage, between six and 87 months, post-operatively. Residual hearing thresholds were still measurable early after surgery in 24.5 per cent of the patients, without differences between the two different Clarion® models. However, the number of subjects with measurable hearing dropped to 16.3 per cent as observed when hearing was measured at a later stage, with an equal distribution between the two groups of patients. From this study it has been possible to observe that only a limited number of patients maintain residual hearing after Clarion® cochlear implantation, and that this tends to decrease further over time. Nevertheless, the performance of these patients for speech tests did not appear to be affected by deterioration of the pure-tone auditory threshold.

Download Full-text

Impact of Electric Stimulation on Residual Hearing

Journal of the American Academy of Audiology ◽

10.3766/jaaa.15013 ◽

2015 ◽

Vol 26 (08) ◽

pp. 732-740 ◽

Cited By ~ 3

Author(s):

Margaret T. Dillon ◽

Andrea L. Bucker ◽

Marcia C. Adunka ◽

English R. King ◽

Oliver F. Adunka ◽

...

Keyword(s):

Cochlear Implant ◽

Electric Stimulation ◽

Bone Conduction ◽

Low Frequency ◽

Electrode Array ◽

Hearing Preservation ◽

Acoustic Stimulation ◽

First Year ◽

Residual Hearing ◽

Listening Experience

Background: Candidacy criteria for cochlear implantation are expanding to include patients with substantial low-to-mid frequency hearing sensitivity. Postoperative hearing preservation has been achieved in cochlear implant recipients, though with variable outcomes. Previous investigations on postoperative hearing preservation outcomes have evaluated intraoperative procedures. There has been limited review as to whether electric stimulation influences hearing preservation. Purpose: The purpose of this analysis was to evaluate whether charge levels associated with electric stimulation influence postoperative hearing preservation within the first year of listening experience. Research Design: Retrospective analysis of unaided residual hearing and charge levels. Study Sample: Twenty-eight cochlear implant recipients with postoperative residual hearing in the operative ear and at least 12 mo of listening experience with electric-acoustic stimulation (EAS). Data Collection and Analysis: Assessment intervals included initial cochlear implant activation, initial EAS activation, and 3-, 6-, and 12-mo postinitial EAS activation. A masked low-frequency bone-conduction (BC) pure-tone average (PTA) was calculated for all participants at each assessment interval. Charge levels for each electrode were determined using the most comfortable loudness level and pulse width values. Charge levels associated with different regions of the electrode array were compared to the change in the low-frequency BC PTA between two consecutive intervals. Results: Charge levels had little to no association with the postoperative change in low-frequency BC PTA within the first year of listening experience. Conclusions: Electric charge levels do not appear to be reliably related to the subsequent loss of residual low-frequency hearing in the implanted ear within the first year of EAS listening experience.

Download Full-text

Evaluation of Intracochlear Trauma Caused by Insertion of Cochlear Implant Electrode Arrays through Different Quadrants of the Round Window

BioMed Research International ◽

10.1155/2015/236364 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

Graziela de Souza Queiroz Martins ◽

Rubens Vuono Brito Neto ◽

Robinson Koji Tsuji ◽

Eloisa Maria Mello Santiago Gebrim ◽

Ricardo Ferreira Bento

Keyword(s):

Cochlear Implant ◽

Round Window ◽

Electrode Array ◽

Hearing Preservation ◽

Round Window Membrane ◽

Residual Hearing ◽

Electrode Arrays ◽

Minimal Trauma ◽

Electrode Insertion ◽

Temporal Bones

Hypothesis. This study aimed to evaluate whether there is a difference in the degree of intracochlear trauma when the cochlear implant electrode arrays is inserted through different quadrants of the round window membrane.Background. The benefits of residual hearing preservation in cochlear implant recipients have promoted the development of atraumatic surgeries. Minimal trauma during electrode insertion is crucial for residual hearing preservation.Methods. In total, 25 fresh human temporal bones were subjected to mastoidectomy and posterior tympanotomy. The cochlear implant electrode array was inserted through the anterosuperior quadrant of the round window membrane in 50% of the bones and through the anteroinferior quadrant in the remaining 50%. The temporal bones were dehydrated, embedded in epoxy, serially polished, stained, viewed through a stereomicroscope, and photographed with the electrode arraysin situ. The resulting images were analyzed for signs of intracochlear trauma.Results. Histological examinations revealed varying degrees of damage to the intracochlear structures, although the incidence and severity of intracochlear trauma were not influenced by the quadrant of insertion.Conclusions. The incidence and severity of intracochlear trauma were similar in all samples, irrespective of electrode array insertion through the anterosuperior or anteroinferior quadrant of the round window membrane.

Download Full-text

Benefits of Binaural Integration in Cochlear Implant Patients with Single-Sided Deafness and Residual Hearing in the Implanted Ear

Life ◽

10.3390/life11030265 ◽

2021 ◽

Vol 11 (3) ◽

pp. 265

Author(s):

Artur Lorens ◽

Anita Obrycka ◽

Piotr Henryk Skarzynski ◽

Henryk Skarzynski

Keyword(s):

Cochlear Implant ◽

Sound Localization ◽

Low Frequency ◽

Hearing Preservation ◽

Residual Hearing ◽

Low Frequencies ◽

Monosyllabic Words ◽

Localization Ability ◽

Single Sided Deafness ◽

Spatial Locations

The purpose of the study is to gauge the benefits of binaural integration effects (redundancy and squelch) due to preserved low-frequency residual hearing in the implanted ear of cochlear implant users with single-sided deafness. There were 11 cochlear implant users (age 18–61 years old) who had preserved low-frequency hearing in the implanted ear; they had a normal hearing or mild hearing loss in the contralateral ear. Patients were tested with monosyllabic words, under different spatial locations of speech and noise and with the cochlear implant activated and deactivated, in two listening configurations—one in which low frequencies in the implanted ear were masked and another in which they were unmasked. We also investigated how cochlear implant benefit due to binaural integration depended on unaided sound localization ability. Patients benefited from the binaural integration effects of redundancy and squelch only in the unmasked condition. Pearson correlations between binaural integration effects and unaided sound localization error showed significance only for squelch (r = −0.67; p = 0.02). Hearing preservation after cochlear implantation has considerable benefits because the preserved low-frequency hearing in the implanted ear contributes to binaural integration, presumably through the preserved temporal fine structure.

Download Full-text

Preservation of residual hearing following cochlear implantation: comparison between three surgical techniques

The Journal of Laryngology & Otology ◽

10.1017/s0022215107000254 ◽

2007 ◽

Vol 122 (3) ◽

pp. 246-252 ◽

Cited By ~ 36

Author(s):

S Berrettini ◽

F Forli ◽

S Passetti

Keyword(s):

Cochlear Implant ◽

Cochlear Implantation ◽

Surgical Techniques ◽

Electrode Array ◽

Lateral Wall ◽

Hearing Preservation ◽

Acoustic Stimulation ◽

Residual Hearing ◽

Electrode Arrays ◽

Electrode Insertion

AbstractThe preservation of residual hearing is becoming a high priority in cochlear implant surgery. It allows better speech understanding and ensures long-lasting and stable performance; it also allows the possibility, in selected cases, of combining electro-acoustic stimulation in the same ear.We present the results of a retrospective study of the conservation of residual hearing in three different groups of patients who had undergone cochlear implantation using three different cochlear implant electrode arrays, combined with three different surgical techniques for the cochleostomy. The study aimed to evaluate which approach allowed greater preservation of residual hearing.The best residual hearing preservation results (i.e. preservation in 81.8 per cent of patients) were achieved with the Contour Advance electrode array, using the Advance Off-Stylet technique and performing a modified anterior inferior cochleostomy; this combination enabled reduced trauma to the lateral wall of the cochlea during electrode insertion.

Download Full-text

In Situ 3D-Imaging of the Inner Ear Synapses with a Cochlear Implant

Life ◽

10.3390/life11040301 ◽

2021 ◽

Vol 11 (4) ◽

pp. 301

Author(s):

Kathrin Malfeld ◽

Nina Armbrecht ◽

Holger A. Volk ◽

Thomas Lenarz ◽

Verena Scheper

Keyword(s):

Cochlear Implant ◽

Inner Ear ◽

Laser Scanning ◽

3D Imaging ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Sensory Cells ◽

Residual Hearing ◽

Preparation Methods

In recent years sensorineural hearing loss was found to affect not exclusively, nor at first, the sensory cells of the inner ear. The sensory cells’ synapses and subsequent neurites are initially damaged. Auditory synaptopathies also play an important role in cochlear implant (CI) care, as they can lead to a loss of physiological hearing in patients with residual hearing. These auditory synaptopathies and in general the cascades of hearing pathologies have been in the focus of research in recent years with the aim to develop more targeted and individually tailored therapeutics. In the current study, a method to examine implanted inner ears of guinea pigs was developed to examine the synapse level. For this purpose, the cochlea is made transparent and scanned with the implant in situ using confocal laser scanning microscopy. Three different preparation methods were compared to enable both an overview image of the cochlea for assessing the CI position and images of the synapses on the same specimen. The best results were achieved by dissection of the bony capsule of the cochlea.

Download Full-text

Preservation of residual hearing after cochlear implant surgery with slim modiolar electrode

European Archives of Oto-Rhino-Laryngology ◽

10.1007/s00405-019-05708-x ◽

2019 ◽

Vol 277 (2) ◽

pp. 367-375 ◽

Cited By ~ 2

Author(s):

Matti Iso-Mustajärvi ◽

Sini Sipari ◽

Heikki Löppönen ◽

Aarno Dietz

Keyword(s):

Low Frequency ◽

Hearing Preservation ◽

Acoustic Stimulation ◽

Residual Hearing ◽

Insertion Depth ◽

Cochlear Implant Surgery ◽

Computed Tomography Scans ◽

Electric Acoustic Stimulation ◽

Speech Recognition In Noise

Abstract Purpose To evaluate the insertion results and hearing preservation of a novel slim modiolar electrode (SME) in patients with residual hearing. Methods We retrospectively collected the data from the medical files of 17 patients (18 ears) implanted with a SME. All patients had functional low frequency hearing (PTA (0.125–0.5 kHz) ≤ 80 dB HL). The insertion results were re-examined from the postoperative cone-beam computed tomography scans. Postoperative thresholds were obtained at the time of switch-on of the sound processors (mean 43 days) and at latest follow-up (mean 582 days). The speech recognition in noise was measured with the Finnish matrix sentence test preoperatively and at follow-up. Results The mean insertion depth angle (IDA) was 395°. Neither scala dislocations nor tip fold over were detected. There were no total hearing losses. Functional low-frequency hearing was preserved in 15/18 (83%) ears at switch-on and in 14/17 (82%) ears at follow-up. According to HEARRING classification, 55% (10/18) had complete HP at switch-on and 41% (7/17) still at follow-up. Thirteen patients (14 ears) were initially fitted with electric–acoustic stimulation and seven patients (8 ears) continued to use it after follow-up. Conclusions The preliminary hearing preservation results with the SME were more favorable than reported for other perimodiolar electrodes. The results show that the array may also be feasible for electro-acoustic stimulation; it is beneficial in that it provides adequate cochlear coverage for pure electrical stimulation in the event of postoperative or progressive hearing loss.

Download Full-text

Immediate and 1-Year Outcomes with a Slim Modiolar Cochlear Implant Electrode Array

Otolaryngology ◽

10.1177/0194599820907336 ◽

2020 ◽

Vol 162 (5) ◽

pp. 731-736

Author(s):

Nedim Durakovic ◽

Dorina Kallogjeri ◽

Cameron C. Wick ◽

Jonathan L. McJunkin ◽

Craig A. Buchman ◽

...

Keyword(s):

Pure Tone ◽

Signal To Noise Ratio ◽

Case Series ◽

Low Frequency ◽

Electrode Array ◽

Hearing Preservation ◽

X Rays ◽

Case Volume ◽

Pure Tone Average ◽

Academic Center

Objective To explore the immediate and 1-year outcomes of patients who underwent implantation with the slim modiolar electrode (SME). Study Design Consecutive case series with chart review. Setting Tertiary referral academic center. Subject and Methods Between May 2016 and August 2018, a total of 326 cochlear implantations (CIs) were performed. Intraoperative x-rays were performed in all cases to identify tip rollovers. Scalar location was identified for 76 CIs that had postoperative computed tomography reconstructions. Speech outcomes were measured at 3, 6, and 12 months with consonant-nucleus-consonant word and AzBio sentences in quiet and noise (+10-dB signal-to-noise ratio). Preservation of hearing was defined as maintaining a low-frequency pure tone average ≤80 dB at 250 and 500 Hz. Results Among 326 CIs, 23 (7%) had tip rollovers. Postoperative reconstructions revealed 5 of 76 (6.6%) scalar translocations. A subset of 177 cases met criteria for evaluation of speech perception scores. The marginal mean differences between presurgery and 12 months for speech tests were as follows: consonant-nucleus-consonant, 43.7 (95% CI, 39.8-47.6); AzBio in quiet, 49.7 (95% CI, 44.9-54.4); and AzBio in noise, 29.9 (95% CI, 25.2-34.7). Sixty-one patients were identified with preservable hearing (low-frequency pure tone average ≤80 dB), and 12 of 61 (20%) preserved hearing at 1 year. Conclusion CI with SME provides reliable scala tympani insertion in a consistent perimodiolar position. An initially increased tip rollover rate improved with case volume and sheath design improvement. For long-term outcomes, speech performance was comparable to that of other cochlear implants. While hearing preservation for the SME may be better than prior perimodiolar electrodes, consistent outcomes are unlikely.

Download Full-text

Criteria for Selecting an Optimal Device for the Contralateral Ear of Children with a Unilateral Cochlear Implant

Audiology and Neurotology ◽

10.1159/000433509 ◽

2015 ◽

Vol 20 (5) ◽

pp. 314-321 ◽

Cited By ~ 6

Author(s):

Sung-Wook Jeong ◽

Min-Young Kang ◽

Lee-Suk Kim

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Hearing Threshold ◽

Low Frequency ◽

Hearing Level ◽

Monosyllabic Word ◽

Low Frequencies ◽

Speech Perception In Noise ◽

Clinical Criteria ◽

Contralateral Ear

Objective: To identify clinical criteria for selecting the aiding device for the contralateral ear of children with a unilateral cochlear implant (CI). Methods: Sixty-five children, including 36 bilateral CI users and 29 bimodal users, participated in the study. A speech perception test (monosyllabic word test) in noise was administered. The target speech (65 dB sound pressure level) was presented from the front loudspeaker, and noise (10 dB signal-to-noise ratio) was presented from 3 directions: from in front of the child and 90° to the child's right and left sides. The test was performed using the first CI alone and under bilateral CI or bimodal conditions. The bilateral benefits to speech perception in noise were compared between bilateral CI users and bimodal users. Results: Significant benefits in speech perception in noise were evident in bilateral CI users in all 3 noise conditions. In bimodal users, the hearing threshold at low frequencies of ≤1 kHz in the nonimplanted ear affected the bilateral benefit. Bimodal users with a low-frequency hearing threshold ≤90 dB hearing level (HL) showed a significant bilateral benefit in various noise conditions. By contrast, bimodal users with a low-frequency hearing threshold >90 dB HL showed no significant bilateral benefits in all 3 noise conditions. Conclusions: Bilateral CI and bimodal listening provide better speech perception in noise than unilateral CI alone in children. The contralateral CI is better than bimodal listening for children with a low-frequency hearing threshold >90 dB HL. A hearing threshold at low frequencies of ≤1 kHz may be a good criterion for deciding on the type of device for the contralateral ear of children with a unilateral CI.

Download Full-text

Extra- and Intracochlear Electrocochleography in Cochlear Implant Recipients

Audiology and Neurotology ◽

10.1159/000438742 ◽

2015 ◽

Vol 20 (5) ◽

pp. 339-348 ◽

Cited By ~ 31

Author(s):

Adrian Dalbert ◽

Flurin Pfiffner ◽

Christof Röösli ◽

Konrad Thoele ◽

Jae Hoon Sim ◽

...

Keyword(s):

Cochlear Implant ◽

Middle Ear ◽

Cochlear Implantation ◽

Low Frequency ◽

Electrode Array ◽

Postoperative Phase ◽

Residual Hearing ◽

Middle Ear Effusion ◽

Cochlear Function ◽

Ear Effusion

Objective: To monitor cochlear function by extra- and intracochlear electrocochleography (ECoG) during and after cochlear implantation and thereby to enhance the understanding of changes in cochlear function following cochlear implantation surgery. Methods: ECoG responses to acoustic stimuli of 250, 500 and 1,000 Hz were recorded in 9 cochlear implant recipients with presurgical residual hearing. During surgery extracochlear ECoG recordings were performed before and after insertion of the cochlear implant electrode array. After insertion of the electrode array, intracochlear ECoG recordings were conducted using intracochlear electrode contacts as recording electrodes. Intracochlear ECoG recordings were performed up to 6 months after implantation. ECoG findings were correlated with findings from audiometric tests. Results: Extra- and intracochlear ECoG responses could be recorded in all subjects. Extracochlear ECoG recordings during surgery showed moderate changes. Loss or reduction of the ECoG signal at all three frequencies did not occur during cochlear implantation. During the first week following surgery, conductive hearing loss, due to middle ear effusion, led to a decrease in intracochlear ECoG signal amplitudes. This was not attributable to changes of cochlear function. All persistent reductions in ECoG response magnitude after normalization of the tympanogram occurred during the first week following implantation. Thresholds of ECoG signals were at or below hearing thresholds in all cases. Conclusion: Gross intracochlear trauma during surgery appears to be rare. In the early postoperative phase the ability to assess cochlear status by ECoG recordings was limited due to the regular occurrence of middle ear effusion. Still, intracochlear ECoG along with tympanogram recordings suggests that any changes of low-frequency cochlear function occur mainly during the first week after cochlear implantation. ECoG seems to be a promising tool to objectively assess changes in cochlear function in cochlear implant recipients and may allow further insight into the mechanisms underlying the loss of residual hearing.

Download Full-text