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Pérez-Valenzuela C, Vicencio-Jiménez S, Caballero M, Delano PH, Elgueda D. Wireless electrocochleography in awake chinchillas: A model to study crossmodal modulations at the peripheral level. Hear Res 2024; 451:109093. [PMID: 39094370 DOI: 10.1016/j.heares.2024.109093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 07/07/2024] [Accepted: 07/25/2024] [Indexed: 08/04/2024]
Abstract
The discovery and development of electrocochleography (ECochG) in animal models has been fundamental for its implementation in clinical audiology and neurotology. In our laboratory, the use of round-window ECochG recordings in chinchillas has allowed a better understanding of auditory efferent functioning. In previous works, we gave evidence of the corticofugal modulation of auditory-nerve and cochlear responses during visual attention and working memory. However, whether these cognitive top-down mechanisms to the most peripheral structures of the auditory pathway are also active during audiovisual crossmodal stimulation is unknown. Here, we introduce a new technique, wireless ECochG to record compound-action potentials of the auditory nerve (CAP), cochlear microphonics (CM), and round-window noise (RWN) in awake chinchillas during a paradigm of crossmodal (visual and auditory) stimulation. We compared ECochG data obtained from four awake chinchillas recorded with a wireless ECochG system with wired ECochG recordings from six anesthetized animals. Although ECochG experiments with the wireless system had a lower signal-to-noise ratio than wired recordings, their quality was sufficient to compare ECochG potentials in awake crossmodal conditions. We found non-significant differences in CAP and CM amplitudes in response to audiovisual stimulation compared to auditory stimulation alone (clicks and tones). On the other hand, spontaneous auditory-nerve activity (RWN) was modulated by visual crossmodal stimulation, suggesting that visual crossmodal simulation can modulate spontaneous but not evoked auditory-nerve activity. However, given the limited sample of 10 animals (4 wireless and 6 wired), these results should be interpreted cautiously. Future experiments are required to substantiate these conclusions. In addition, we introduce the use of wireless ECochG in animal models as a useful tool for translational research.
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Affiliation(s)
| | - Sergio Vicencio-Jiménez
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile; Johns Hopkins School of Medicine, Otolaryngology-Head and Neck Surgery Department, Baltimore, MD 21231, USA; Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mia Caballero
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H Delano
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile; Servicio Otorrinolaringología, Hospital Clínico de la Universidad de Chile, Santiago, Chile; Centro Avanzado de Ingeniería Eléctrica y Electrónica, AC3E, Universidad Técnica Federico Santa María, Valparaíso, Chile; Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Diego Elgueda
- Departamento de Patología Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile 8820808, Santiago, Chile.
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Walia A, Ortmann AJ, Lefler S, Holden TA, Puram SV, Herzog JA, Buchman CA. Electrocochleography-Based Tonotopic Map: I. Place Coding of the Human Cochlea With Hearing Loss. Ear Hear 2024:00003446-990000000-00336. [PMID: 39233326 DOI: 10.1097/aud.0000000000001579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
OBJECTIVES Due to the challenges of direct in vivo measurements in humans, previous studies of cochlear tonotopy primarily utilized human cadavers and animal models. This study uses cochlear implant electrodes as a tool for intracochlear recordings of acoustically evoked responses to achieve two primary goals: (1) to map the in vivo tonotopy of the human cochlea, and (2) to assess the impact of sound intensity and the creation of an artificial "third window" on this tonotopic map. DESIGN Fifty patients with hearing loss received cochlear implant electrode arrays. Postimplantation, pure-tone acoustic stimuli (0.25 to 4 kHz) were delivered, and electrophysiological responses were recorded from all 22 electrode contacts. The analysis included fast Fourier transformation to determine the amplitude of the first harmonic, indicative of predominantly outer hair cell activity, and tuning curves to identify the best frequency (BF) electrode. These measures, coupled with postoperative imaging for precise electrode localization, facilitated the construction of an in vivo frequency-position function. The study included a specific examination of 2 patients with auditory neuropathy spectrum disorder (ANSD), with preserved cochlear function as assessed by present distortion-product otoacoustic emissions, to determine the impact of sound intensity on the frequency-position map. In addition, the electrophysiological map was recorded in a patient undergoing a translabyrinthine craniotomy for vestibular schwannoma removal, before and after creating an artificial third window, to explore whether an experimental artifact conducted in cadaveric experiments, as was performed in von Békésy landmark experiments, would produce a shift in the frequency-position map. RESULTS A significant deviation from the Greenwood model was observed in the electrophysiological frequency-position function, particularly at high-intensity stimulations. In subjects with hearing loss, frequency tuning, and BF location remained consistent across sound intensities. In contrast, ANSD patients exhibited Greenwood-like place coding at low intensities (~40 dB SPL) and a basal shift in BF location at higher intensities (~70 dB SPL or greater). Notably, creating an artificial "third-window" did not alter the frequency-position map. CONCLUSIONS This study successfully maps in vivo tonotopy of human cochleae with hearing loss, demonstrating a near-octave shift from traditional frequency-position maps. In patients with ANSD, representing more typical cochlear function, intermediate intensity levels (~70 to 80 dB SPL) produced results similar to high-intensity stimulation. These findings highlight the influence of stimulus intensity on the cochlear operational point in subjects with hearing loss. This knowledge could enhance cochlear implant programming and improve auditory rehabilitation by more accurately aligning electrode stimulation with natural cochlear responses.
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Affiliation(s)
- Amit Walia
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
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Panario J, Bester C, O'Leary S. Predicting Postoperative Speech Perception and Audiometric Thresholds Using Intracochlear Electrocochleography in Cochlear Implant Recipients. Ear Hear 2024; 45:1173-1190. [PMID: 38816899 DOI: 10.1097/aud.0000000000001506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
OBJECTIVES Electrocochleography (ECochG) appears to offer the most accurate prediction of post-cochlear implant hearing outcomes. This may be related to its capacity to interrogate the health of underlying cochlear tissue. The four major components of ECochG (cochlear microphonic [CM], summating potential [SP], compound action potential [CAP], and auditory nerve neurophonic [ANN]) are generated by different cochlear tissue components. Analyzing characteristics of these components can reveal the state of hair and neural cell in a cochlea. There is limited evidence on the characteristics of intracochlear (IC) ECochG recordings measured across the array postinsertion but compared with extracochlear recordings has better signal to noise ratio and spatial specificity. The present study aimed to examine the relationship between ECochG components recorded from an IC approach and postoperative speech perception or audiometric thresholds. DESIGN In 113 human subjects, responses to 500 Hz tone bursts were recorded at 11 IC electrodes across a 22-electrode cochlear implant array immediately following insertion. Responses to condensation and rarefaction stimuli were then subtracted from one another to emphasize the CM and added to one another to emphasize the SP, ANN, and CAP. Maximum amplitudes and extracochlear electrode locations were recorded for each of these ECochG components. These were added stepwise to a multi-factor generalized additive model to develop a best-fit model predictive model for pure-tone audiometric thresholds (PTA) and speech perception scores (speech recognition threshold [SRT] and consonant-vowel-consonant phoneme [CVC-P]) at 3- and 12-month postoperative timepoints. This best-fit model was tested against a generalized additive model using clinical factors alone (preoperative score, age, and gender) as a null model proxy. RESULTS ECochG-factor models were superior to clinical factor models in predicting postoperative PTA, CVC-P, and SRT outcomes at both timepoints. Clinical factor models explained a moderate amount of PTA variance ( r2 = 45.9% at 3-month, 31.8% at 12-month, both p < 0.001) and smaller variances of CVC-P and SRT ( r2 range = 6 to 13.7%, p = 0.008 to 0.113). Age was not a significant predictive factor. ECochG models explained more variance at the 12-month timepoint ( r2 for PTA = 52.9%, CVC-P = 39.6%, SRT = 36.4%) compared with the 3-month one timepoint ( r2 for PTA = 49.4%, CVC-P = 26.5%, SRT = 22.3%). The ECochG model was based on three factors: maximum SP deflection amplitude, and electrode position of CM and SP peaks. Adding neural (ANN and/or CAP) factors to the model did not improve variance explanation. Large negative SP deflection was associated with poorer outcomes and a large positive SP deflection with better postoperative outcomes. Mid-array peaks of SP and CM were both associated with poorer outcomes. CONCLUSIONS Postinsertion IC-ECochG recordings across the array can explain a moderate amount of postoperative speech perception and audiometric thresholds. Maximum SP deflection and its location across the array appear to have a significant predictive value which may reflect the underlying state of cochlear health.
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Affiliation(s)
- Jared Panario
- Department Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
| | - Christofer Bester
- Department Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen O'Leary
- Department Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
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Geys M, Sijgers L, Dobrev I, Dalbert A, Röösli C, Pfiffner F, Huber A. ZH-ECochG Bode Plot: A Novel Approach to Visualize Electrocochleographic Data in Cochlear Implant Users. J Clin Med 2024; 13:3470. [PMID: 38929998 PMCID: PMC11205027 DOI: 10.3390/jcm13123470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/08/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Background: Various representations exist in the literature to visualize electrocochleography (ECochG) recordings along the basilar membrane (BM). This lack of generalization complicates comparisons within and between cochlear implant (CI) users, as well as between publications. This study synthesized the visual representations available in the literature via a systematic review and provides a novel approach to visualize ECochG data in CI users. Methods: A systematic review was conducted within PubMed and EMBASE to evaluate studies investigating ECochG and CI. Figures that visualized ECochG responses were selected and analyzed. A novel visualization of individual ECochG data, the ZH-ECochG Bode plot (ZH = Zurich), was devised, and the recordings from three CI recipients were used to demonstrate and assess the new framework. Results: Within the database search, 74 articles with a total of 115 figures met the inclusion criteria. Analysis revealed various types of representations using different axes; their advantages were incorporated into the novel visualization framework. The ZH-ECochG Bode plot visualizes the amplitude and phase of the ECochG recordings along the different tonotopic regions and angular insertion depths of the recording sites. The graph includes the pre- and postoperative audiograms to enable a comparison of ECochG responses with the audiometric profile, and allows different measurements to be shown in the same graph. Conclusions: The ZH-ECochG Bode plot provides a generalized visual representation of ECochG data, using well-defined axes. This will facilitate the investigation of the complex ECochG potentials generated along the BM and allows for better comparisons of ECochG recordings within and among CI users and publications. The scripts used to construct the ZH-ECochG Bode plot are provided by the authors.
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Affiliation(s)
- Marlies Geys
- Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland
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Dalbert A, Weder S. [Application of extra- and intracochlear electrocochleography during and after cochlear implantation]. HNO 2024:10.1007/s00106-024-01481-4. [PMID: 38761228 DOI: 10.1007/s00106-024-01481-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2024] [Indexed: 05/20/2024]
Abstract
Electrocochleography (ECochG) represents a promising approach for monitoring cochlear function during cochlear implantation and for investigating the causes of residual cochlear function loss after implantation. This paper provides an overview of the current research and application status of ECochG, both during and after cochlear implantation. Intraoperative ECochG can be conducted either via the implant itself or an extracochlear measuring electrode. Postoperative ECochG recordings are also feasible via the implant. Various studies have demonstrated that a significant decrease in ECochG amplitude during electrode insertion correlates with an increased risk of losing residual cochlear function, with critical cochlear events occurring primarily towards the end of the insertion. Postoperative data suggest that the loss of cochlear function mainly occurs in the early postoperative phase. Future research directions include the automation and objectification of signal analysis, as well as a more in-depth investigation into the underlying mechanisms of these signal changes.
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Affiliation(s)
- Adrian Dalbert
- Klinik für Ohren‑, Nasen‑, Hals- und Gesichtschirurgie, Universitätsspital Zürich, Zürich, Schweiz
| | - Stefan Weder
- Universitätsklinik für Hals‑, Nasen- und Ohrenkrankheiten, Kopf- und Halschirurgie Inselspital, Universitätsspital Bern, Freiburgstrasse 20, 3012, Bern, Schweiz.
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Haumann S, Timm ME, Büchner A, Lenarz T, Salcher RB. Intracochlear Recording of Electrocochleography During and After Cochlear Implant Insertion Dependent on the Location in the Cochlea. Trends Hear 2024; 28:23312165241248973. [PMID: 38717441 PMCID: PMC11080744 DOI: 10.1177/23312165241248973] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 02/23/2024] [Accepted: 04/04/2024] [Indexed: 05/12/2024] Open
Abstract
To preserve residual hearing during cochlear implant (CI) surgery it is desirable to use intraoperative monitoring of inner ear function (cochlear monitoring). A promising method is electrocochleography (ECochG). Within this project the relations between intracochlear ECochG recordings, position of the recording contact in the cochlea with respect to anatomy and frequency and preservation of residual hearing were investigated. The aim was to better understand the changes in ECochG signals and whether these are due to the electrode position in the cochlea or to trauma generated during insertion. During and after insertion of hearing preservation electrodes, intraoperative ECochG recordings were performed using the CI electrode (MED-EL). During insertion, the recordings were performed at discrete insertion steps on electrode contact 1. After insertion as well as postoperatively the recordings were performed at different electrode contacts. The electrode location in the cochlea during insertion was estimated by mathematical models using preoperative clinical imaging, the postoperative location was measured using postoperative clinical imaging. The recordings were analyzed from six adult CI recipients. In the four patients with good residual hearing in the low frequencies the signal amplitude rose with largest amplitudes being recorded closest to the generators of the stimulation frequency, while in both cases with severe pantonal hearing losses the amplitude initially rose and then dropped. This might be due to various reasons as discussed in the following. Our results indicate that this approach can provide valuable information for the interpretation of intracochlearly recorded ECochG signals.
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Affiliation(s)
- Sabine Haumann
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Max E. Timm
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Andreas Büchner
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Rolf B. Salcher
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
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Scheperle R, Etler C, Oleson J, Dunn C, Kashani R, Claussen A, Gantz BJ, Hansen MR. Evaluation of Real-Time Intracochlear Electrocochleography for Guiding Cochlear Implant Electrode Array Position. J Clin Med 2023; 12:7409. [PMID: 38068461 PMCID: PMC10707171 DOI: 10.3390/jcm12237409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/12/2023] [Accepted: 11/24/2023] [Indexed: 02/12/2024] Open
Abstract
This study evaluates intracochlear electrocochleography (ECochG) for real-time monitoring during cochlear implantation. One aim tested whether adjusting the recording electrode site would help differentiate between atraumatic and traumatic ECochG amplitude decrements. A second aim assessed whether associations between ECochG amplitude decrements and post-operative hearing loss were weaker when considering hearing sensitivity at the ECochG stimulus frequency compared to a broader frequency range. Eleven adult cochlear implant recipients who were candidates for electro-acoustic stimulation participated. Single-frequency (500-Hz) ECochG was performed during cochlear implantation; the amplitude of the first harmonic of the difference waveform was considered. Post-operative hearing preservation at 500 Hz ranged from 0 to 94%. The expected relationship between ECochG amplitude decrements and hearing preservation was observed, though the trend was not statistically significant, and predictions were grossly inaccurate for two participants. Associations did not improve when considering alternative recording sites or hearing sensitivity two octaves above the ECochG stimulus frequency. Intracochlear location of a moving recording electrode is a known confound to real-time interpretation of ECochG amplitude fluctuations, which was illustrated by the strength of the correlation with ECochG amplitude decrements. Multiple factors contribute to ECochG amplitude patterns and to hearing preservation; these results highlight the confounding influence of intracochlear recording electrode location on the ECochG.
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Affiliation(s)
- Rachel Scheperle
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
| | - Christine Etler
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
| | - Jacob Oleson
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Camille Dunn
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
| | - Rustin Kashani
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
| | - Alexander Claussen
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
| | - Bruce J. Gantz
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
| | - Marlan R. Hansen
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA; (C.E.); (C.D.); (R.K.); (A.C.); (B.J.G.); (M.R.H.)
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
- Department of Molecular Physiology and Biophysics, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
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Andonie RR, Wimmer W, Wildhaber RA, Caversaccio M, Weder S. Real-Time Feature Extraction From Electrocochleography With Impedance Measurements During Cochlear Implantation Using Linear State-Space Models. IEEE Trans Biomed Eng 2023; 70:3137-3146. [PMID: 37195836 DOI: 10.1109/tbme.2023.3276993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Electrocochleography (ECochG) is increasingly used to monitor the inner ear function of cochlear implant (CI) patients during surgery. Current ECochG-based trauma detection shows low sensitivity and specificity and depends on visual analysis by experts. Trauma detection could be improved by including electric impedance data recorded simultaneously with the ECochG. However, combined recordings are rarely used because the impedance measurements produce artifacts in the ECochG. In this study, we propose a framework for automated real-time analysis of intraoperative ECochG signals using Autonomous Linear State-Space Models (ALSSMs). We developed ALSSM based algorithms for noise reduction, artifact removal, and feature extraction in ECochG. Feature extraction includes local amplitude and phase estimations and a confidence metric over the presence of a physiological response in a recording. We tested the algorithms in a controlled sensitivity analysis using simulations and validated them with real patient data recorded during surgeries. The results from simulation data show that the ALSSM method provides improved accuracy in the amplitude estimation together with a more robust confidence metric of ECochG signals compared to the state-of-the-art methods based on the fast Fourier transform (FFT). Tests with patient data showed promising clinical applicability and consistency with the findings from the simulations. We showed that ALSSMs are a valid tool for real-time analysis of ECochG recordings. Removal of artifacts using ALSSMs enables simultaneous recording of ECochG and impedance data. The proposed feature extraction method provides the means to automate the assessment of ECochG. Further validation of the algorithms in clinical data is needed.
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Panario J, Bester C, O'Leary SJ. Characteristics of the Summating Potential Measured Across a Cochlear Implant Array as an Indicator of Cochlear Function. Ear Hear 2023; 44:1088-1106. [PMID: 36935398 PMCID: PMC10426787 DOI: 10.1097/aud.0000000000001347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 01/13/2023] [Indexed: 03/21/2023]
Abstract
OBJECTIVES The underlying state of cochlear and neural tissue function is known to affect postoperative speech perception following cochlear implantation. The ability to assess these tissues in patients can be performed using intracochlear electrocochleography (IC ECochG). One component of ECochG is the summating potential (SP) that appears to be generated by multiple cochlear tissues. Its qualities may be able to detect the presence of functional inner hair cells, but evidence for this is limited in human cochleae. This study aimed to examine the IC SP characteristics in cochlear implantation recipients, its relationship to preoperative speech perception and audiometric thresholds, and to other IC ECochG components. DESIGN This is a retrospective analysis of 113 patients' IC ECochG recordings across the array in response to a 500 Hz tone burst stimulus. Responses to condensation and rarefaction stimuli were then subtracted from one another to emphasize the cochlear microphonic and added to one another to emphasize the SP, auditory nerve neurophonic, and compound action potential. Patients were grouped based on their maximum SP deflection being large and positive (+SP), large and negative (-SP), or minimal (0 SP) to further investigate these relationships. RESULTS Patients in the +SP group had better preoperative speech perception (mean consonant-vowel-consonant phoneme score 46%) compared to the -SP and 0 SP groups (consonant-vowel-consonant phoneme scores 34% and 36%, respectively, difference to +SP: p < 0.05). Audiometric thresholds were lowest for +SP (mean pure-tone average 50 dB HL), then -SP (65 dB HL), and highest for 0 SP patients (70 dB HL), but there was not a statistical significance between +SP and -SP groups ( p > 0.1). There were also distinct differences between SP groups in the qualities of their other ECochG components. These included the +SP patients having larger cochlear microphonic maximum amplitude, more apical SP peak electrode locations, and a more spatially specific SP magnitude growth pattern across the array. CONCLUSIONS Patients with large positive SP deflection in IC ECochG have preoperatively better speech perception and lower audiometric thresholds than those without. Patterns in other ECochG components suggest its positive deflection may be an indicator of cochlear function.
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Affiliation(s)
- Jared Panario
- Department Otolaryngology, University of Melbourne, Victoria, Australia
| | - Christofer Bester
- Department Otolaryngology, University of Melbourne, Victoria, Australia
| | - Stephen John O'Leary
- Department Otolaryngology, University of Melbourne, Victoria, Australia
- Royal Victorian Eye and Ear Hospital, Victoria, Australia
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Kim JS, Brown CJ. Acoustically Evoked Compound Action Potentials Recorded From Cochlear Implant Users With Preserved Acoustic Hearing. Ear Hear 2023; 44:1061-1077. [PMID: 36882917 PMCID: PMC10440213 DOI: 10.1097/aud.0000000000001350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
OBJECTIVES Less traumatic intracochlear electrode design and the introduction of the soft surgery technique allow for the preservation of low-frequency acoustic hearing in many cochlear implant (CI) users. Recently, new electrophysiologic methods have also been developed that allow acoustically evoked peripheral responses to be measured in vivo from an intracochlear electrode. These recordings provide clues to the status of peripheral auditory structures. Unfortunately, responses generated from the auditory nerve (auditory nerve neurophonic [ANN]) are somewhat difficult to record because they are smaller than the hair cell responses (cochlear microphonic). Additionally, it is difficult to completely segregate the ANN from the cochlear microphonic, complicating the interpretation and limiting clinical applications. The compound action potential (CAP) is a synchronous response of multiple auditory nerve fibers and may provide an alternative to ANN where the status of the auditory nerve is of primary interest. This study is a within-subject comparison of CAPs recorded using traditional stimuli (clicks and 500 Hz tone bursts) and a new stimulus (CAP chirp). We hypothesized that the chirp stimulus might result in a more robust CAP than that recorded using traditional stimuli, allowing for a more accurate assessment of the status of the auditory nerve. DESIGN Nineteen adult Nucleus L24 Hybrid CI users with residual low-frequency hearing participated in this study. CAP responses were recorded from the most apical intracochlear electrode using a 100 μs click, 500 Hz tone bursts, and chirp stimuli presented via the insert phone to the implanted ear. The chirp stimulus used in this study was CAP chirp generated using parameters from human-derived band CAPs ( Chertoff et al. 2010 ). Additionally, nine custom chirps were created by systematically varying the frequency sweep rate of the power function used to construct the standard CAP chirp stimulus. CAPs were recorded using all acoustic stimuli, allowing for within-subject comparisons of the CAP amplitude, threshold, percentage of measurable CAP responses, and waveform morphology. RESULTS Considerable variation in response morphology was apparent across stimuli and stimulation levels. Clicks and CAP chirp significantly evoked identifiable CAP response more compared to 500 Hz tone bursts. At relatively high stimulation levels, the chirp-evoked CAPs were significantly larger in amplitude and less ambiguous in morphology than the click-evoked CAPs. The status of residual acoustic hearing at high frequencies influenced the likelihood that a CAP could be reliably recorded. Subjects with better preserved hearing at high frequencies had significantly larger CAP amplitudes when CAP chirp was used. Customizing the chirp stimulus by varying the frequency sweep rates significantly affected the CAP amplitudes; however, pairwise comparisons did not show significant differences between chirps. CONCLUSIONS CAPs can be measured more effectively using broadband acoustic stimuli than 500 Hz tone bursts in CI users with residual low-frequency acoustic hearing. The advantage of using CAP chirp stimulus relative to standard clicks is dependent on the extent of preserved acoustic hearing at high frequencies and the stimulus level. The chirp stimulus may present an attractive alternative to standard clicks or tone bursts for this CI population when the goal is to record robust CAP responses.
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Affiliation(s)
- Jeong-Seo Kim
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
- Department of Otolaryngology – Head & Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
- Hearing Research Laboratory, Samsung Medical Center, Seoul, South Korea
- Medical Research Institute, Sungkyunkwan University, Suwon, South Korea
| | - Carolyn J. Brown
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
- Department of Otolaryngology – Head & Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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Tejani VD, Kim JS, Etler CP, Skidmore J, Yuan Y, He S, Hansen MR, Gantz BJ, Abbas PJ, Brown CJ. Longitudinal Electrocochleography as an Objective Measure of Serial Behavioral Audiometry in Electro-Acoustic Stimulation Patients. Ear Hear 2023; 44:1014-1028. [PMID: 36790447 PMCID: PMC10425573 DOI: 10.1097/aud.0000000000001342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
OBJECTIVE Minimally traumatic surgical techniques and advances in cochlear implant (CI) electrode array designs have allowed acoustic hearing present in a CI candidate prior to surgery to be preserved postoperatively. As a result, these patients benefit from combined electric-acoustic stimulation (EAS) postoperatively. However, 30% to 40% of EAS CI users experience a partial loss of hearing up to 30 dB after surgery. This additional hearing loss is generally not severe enough to preclude use of acoustic amplification; however, it can still impact EAS benefits. The use of electrocochleography (ECoG) measures of peripheral hair cell and neural auditory function have shed insight into the pathophysiology of postimplant loss of residual acoustic hearing. The present study aims to assess the long-term stability of ECoG measures and to establish ECoG as an objective method of monitoring residual hearing over the course of EAS CI use. We hypothesize that repeated measures of ECoG should remain stable over time for EAS CI users with stable postoperative hearing preservation. We also hypothesize that changes in behavioral audiometry for EAS CI users with loss of residual hearing should also be reflected in changes in ECoG measures. DESIGN A pool of 40 subjects implanted under hearing preservation protocol was included in the study. Subjects were seen at postoperative visits for behavioral audiometry and ECoG recordings. Test sessions occurred 0.5, 1, 3, 6, 12 months, and annually after 12 months postoperatively. Changes in pure-tone behavioral audiometric thresholds relative to baseline were used to classify subjects into two groups: one group with stable acoustic hearing and another group with loss of acoustic hearing. At each test session, ECoG amplitude growth functions for several low-frequency stimuli were obtained. The threshold, slope, and suprathreshold amplitude at a fixed stimulation level was obtained from each growth function at each time point. Longitudinal linear mixed effects models were used to study trends in ECoG thresholds, slopes, and amplitudes for subjects with stable hearing and subjects with hearing loss. RESULTS Preoperative, behavioral audiometry indicated that subjects had an average low-frequency pure-tone average (125 to 500 Hz) of 40.88 ± 13.12 dB HL. Postoperatively, results showed that ECoG thresholds and amplitudes were stable in EAS CI users with preserved residual hearing. ECoG thresholds increased (worsened) while ECoG amplitudes decreased (worsened) for those with delayed hearing loss. The slope did not distinguish between EAS CI users with stable hearing and subjects with delayed loss of hearing. CONCLUSIONS These results provide a new application of postoperative ECoG as an objective tool to monitor residual hearing and understand the pathophysiology of delayed hearing loss. While our measures were conducted with custom-designed in-house equipment, CI companies are also designing and implementing hardware and software adaptations to conduct ECoG recordings. Thus, postoperative ECoG recordings can potentially be integrated into clinical practice.
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Affiliation(s)
- Viral D Tejani
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, Iowa, USA
| | - Jeong-Seo Kim
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, Iowa, USA
- Hearing Research Laboratory, Samsung Medical Center, Seoul, South Korea
| | - Christine P Etler
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Jeffrey Skidmore
- Department of Otolaryngology-Head and Neck Surgery, Eye and Ear Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Yi Yuan
- Department of Otolaryngology-Head and Neck Surgery, Eye and Ear Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Shuman He
- Department of Otolaryngology-Head and Neck Surgery, Eye and Ear Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Marlan R Hansen
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Bruce J Gantz
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Paul J Abbas
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, Iowa, USA
| | - Carolyn J Brown
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, Iowa, USA
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Schuerch K, Wimmer W, Rummel C, Caversaccio MD, Weder S. Objective evaluation of intracochlear electrocochleography: repeatability, thresholds, and tonotopic patterns. Front Neurol 2023; 14:1181539. [PMID: 37621854 PMCID: PMC10446839 DOI: 10.3389/fneur.2023.1181539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 06/26/2023] [Indexed: 08/26/2023] Open
Abstract
Introduction Intracochlear electrocochleography (ECochG) is increasingly being used to measure residual inner ear function in cochlear implant (CI) recipients. ECochG signals reflect the state of the inner ear and can be measured during implantation and post-operatively. The aim of our study was to apply an objective deep learning (DL)-based algorithm to assess the reproducibility of longitudinally recorded ECochG signals, compare them with audiometric hearing thresholds, and identify signal patterns and tonotopic behavior. Methods We used a previously published objective DL-based algorithm to evaluate post-operative intracochlear ECochG signals collected from 21 ears. The same measurement protocol was repeated three times over 3 months. Additionally, we measured the pure-tone thresholds and subjective loudness estimates for correlation with the objectively detected ECochG signals. Recordings were made on at least four electrodes at three intensity levels. We extracted the electrode positions from computed tomography (CT) scans and used this information to evaluate the tonotopic characteristics of the ECochG responses. Results The objectively detected ECochG signals exhibited substantial repeatability over a 3-month period (bias-adjusted kappa, 0.68; accuracy 83.8%). Additionally, we observed a moderate-to-strong dependence of the ECochG thresholds on audiometric and subjective hearing levels. Using radiographically determined tonotopic measurement positions, we observed a tendency for tonotopic allocation with a large variance. Furthermore, maximum ECochG amplitudes exhibited a substantial basal shift. Regarding maximal amplitude patterns, most subjects exhibited a flat pattern with amplitudes evenly distributed over the electrode carrier. At higher stimulation frequencies, we observed a shift in the maximum amplitudes toward the basal turn of the cochlea. Conclusions We successfully implemented an objective DL-based algorithm for evaluating post-operative intracochlear ECochG recordings. We can only evaluate and compare ECochG recordings systematically and independently from experts with an objective analysis. Our results help to identify signal patterns and create a better understanding of the inner ear function with the electrode in place. In the next step, the algorithm can be applied to intra-operative measurements.
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Affiliation(s)
- Klaus Schuerch
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Wilhelm Wimmer
- Department of Otorhinolaryngology, TUM School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Domenico Caversaccio
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Stefan Weder
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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Haggerty RA, Hutson KA, Riggs WJ, Brown KD, Pillsbury HC, Adunka OF, Buchman CA, Fitzpatrick DC. Assessment of cochlear synaptopathy by electrocochleography to low frequencies in a preclinical model and human subjects. Front Neurol 2023; 14:1104574. [PMID: 37483448 PMCID: PMC10361575 DOI: 10.3389/fneur.2023.1104574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Cochlear synaptopathy is the loss of synapses between the inner hair cells and the auditory nerve despite survival of sensory hair cells. The findings of extensive cochlear synaptopathy in animals after moderate noise exposures challenged the long-held view that hair cells are the cochlear elements most sensitive to insults that lead to hearing loss. However, cochlear synaptopathy has been difficult to identify in humans. We applied novel algorithms to determine hair cell and neural contributions to electrocochleographic (ECochG) recordings from the round window of animal and human subjects. Gerbils with normal hearing provided training and test sets for a deep learning algorithm to detect the presence of neural responses to low frequency sounds, and an analytic model was used to quantify the proportion of neural and hair cell contributions to the ECochG response. The capacity to detect cochlear synaptopathy was validated in normal hearing and noise-exposed animals by using neurotoxins to reduce or eliminate the neural contributions. When the analytical methods were applied to human surgical subjects with access to the round window, the neural contribution resembled the partial cochlear synaptopathy present after neurotoxin application in animals. This result demonstrates the presence of viable hair cells not connected to auditory nerve fibers in human subjects with substantial hearing loss and indicates that efforts to regenerate nerve fibers may find a ready cochlear substrate for innervation and resumption of function.
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Affiliation(s)
- Raymond A. Haggerty
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kendall A. Hutson
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William J. Riggs
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Kevin D. Brown
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Harold C. Pillsbury
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Oliver F. Adunka
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Craig A. Buchman
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, United States
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Bayri Ulukan M, Ciprut A. Intracochlear electrocochleography findings in cochlear implant recipients with auditory neuropathy spectrum disorder. Int J Pediatr Otorhinolaryngol 2023; 170:111596. [PMID: 37267660 DOI: 10.1016/j.ijporl.2023.111596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/21/2023] [Accepted: 05/03/2023] [Indexed: 06/04/2023]
Abstract
OBJECTIVES This study aimed to compare intracochlear electrocochleography (ECochG) findings in a group of cochlear implant (CI) recipients with auditory neuropathy spectrum disorder (ANSD) with a group of CI recipients with sensorineural hearing loss (SNHL). Auditory outcome and spectral resolution findings were also compared among CI recipients with and without cochlear microphonic (CM) responses. METHODS This single-center, prospective cohort study was undertaken at a tertiary referral center. CM responses by the intracochlear ECochG test were recorded in CI recipients at 0.25-2 kHz. Speech, spatial, and hearing quality (SSQ) outcomes and spectral resolution measured with the spectral-temporally modulated ripple test were obtained for each recipient. The study included 62 implanted ears in 46 recipients, of which 59% (n = 27) were male and 41% (n = 19) were female. Twenty-nine ears with ANSD and 33 ears with SNHL were included. The mean age of the participants was 11 years. The results compared the intracochlear ECochG findings of the ANSD group with those of the SNHL group. RESULTS Participants were divided into two groups with and without obtainable CM responses. CM responses were obtained in 13 of 29 ears in the ANSD group and 14 of 33 ears in the SNHL group. CM thresholds obtained were better according to behavioral audiometric responses in some frequencies in the ANSD group. No significant difference was found in the auditory outcome and spectral resolution among CI recipients with and without CM responses. CONCLUSIONS Intracochlear ECochG has a limited potential clinical value for monitoring ANSD. CM thresholds obtained using ECochG may not reflect behavioral hearing thresholds.
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Affiliation(s)
- Merve Bayri Ulukan
- Marmara University, Health Sciences Institute, Istanbul, Turkey; Cochlear, Turkey.
| | - Ayca Ciprut
- Marmara University, Medical School, Audiology Department, Istanbul, Turkey
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15
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O'Leary S, Mylanus E, Venail F, Lenarz T, Birman C, Di Lella F, Roland JT, Gantz B, Beynon A, Sicard M, Buechner A, Lai WK, Boccio C, Choudhury B, Tejani VD, Plant K, English R, Arts R, Bester C. Monitoring Cochlear Health With Intracochlear Electrocochleography During Cochlear Implantation: Findings From an International Clinical Investigation. Ear Hear 2023; 44:358-370. [PMID: 36395515 PMCID: PMC9957964 DOI: 10.1097/aud.0000000000001288] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Electrocochleography (ECochG) is emerging as a tool for monitoring cochlear function during cochlear implant (CI) surgery. ECochG may be recorded directly from electrodes on the implant array intraoperatively. For low-frequency stimulation, its amplitude tends to rise or may plateau as the electrode is inserted. The aim of this study was to explore whether compromise of the ECochG signal, defined as a fall in its amplitude of 30% or more during insertion, whether transient or permanent, is associated with poorer postoperative acoustic hearing, and to examine how preoperative hearing levels may influence the ability to record ECochG. The specific hypotheses tested were threefold: (a) deterioration in the pure-tone average of low-frequency hearing at the first postoperative follow-up interval (follow-up visit 1 [FUV1], 4 to 6 weeks) will be associated with compromise of the cochlear microphonic (CM) amplitude during electrode insertion (primary hypothesis); (b) an association is observed at the second postoperative follow-up interval (FUV2, 3 months) (secondary hypothesis 1); and (c) the CM response will be recorded earlier during electrode array insertion when the preoperative high-frequency hearing is better (secondary hypothesis 2). DESIGN International, multi-site prospective, observational, between groups design, targeting 41 adult participants in each of two groups, (compromised CM versus preserved CM). Adult CI candidates who were scheduled to receive a Cochlear Nucleus CI with a Slim Straight or a Slim Modiolar electrode array and had a preoperative audiometric low-frequency average thresholds of ≤80 dB HL at 500, 750, and 1000 Hz in the ear to be implanted, were recruited from eight international implant sites. Pure tone audiometry was measured preoperatively and at postoperative visits (FUV1 and follow-up visit 2 [FUV2]). ECochG was measured during and immediately after the implantation of the array. RESULTS From a total of 78 enrolled individuals (80 ears), 77 participants (79 ears) underwent surgery. Due to protocol deviations, 18 ears (23%) were excluded. Of the 61 ears with ECochG responses, amplitudes were < 1 µV throughout implantation for 18 ears (23%) and deemed "unclear" for classification. EcochG responses >1 µV in 43 ears (55%) were stable throughout implantation for 8 ears and compromised in 35 ears. For the primary endpoint at FUV1, 7/41 ears (17%) with preserved CM had a median hearing loss of 12.6 dB versus 34/41 ears (83%) with compromised CM and a median hearing loss of 26.9 dB ( p < 0.014). In assessing the practicalities of measuring intraoperative ECochG, the presence of a measurable CM (>1 µV) during implantation was dependent on preoperative, low-frequency thresholds, particularly at the stimulus frequency (0.5 kHz). High-frequency, preoperative thresholds were also associated with a measurable CM > 1 µV during surgery. CONCLUSIONS Our data shows that CM drops occurring during electrode insertion were correlated with significantly poorer hearing preservation postoperatively compared to CMs that remained stable throughout the electrode insertion. The practicality of measuring ECochG in a large cohort is discussed, regarding the suggested optimal preoperative low-frequency hearing levels ( < 80 dB HL) considered necessary to obtain a CM signal >1 µV.
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Affiliation(s)
- S O'Leary
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- The University of Melbourne, Melbourne, Australia
| | - E Mylanus
- Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - F Venail
- University Hospital of Montpellier & Institute of Neurosciences of Montpellier INSERM U1298, Montpellier, France
| | - T Lenarz
- Department Otolaryngology, Hannover Medical School, Hannover, Germany
| | - C Birman
- Cochlear Implant Program, NextSense, Sydney, Australia
| | - F Di Lella
- Hospital Italiano de Buenos Aires, Argentina
| | - J T Roland
- NYU Grossman School of Medicine, New York, USA
| | - B Gantz
- University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - A Beynon
- Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - M Sicard
- University Hospital of Montpellier & Institute of Neurosciences of Montpellier INSERM U1298, Montpellier, France
| | - A Buechner
- Department Otolaryngology, Hannover Medical School, Hannover, Germany
| | - W K Lai
- Cochlear Implant Program, NextSense, Sydney, Australia
| | - C Boccio
- Hospital Italiano de Buenos Aires, Argentina
| | - B Choudhury
- NYU Grossman School of Medicine, New York, USA
| | - V D Tejani
- University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - K Plant
- Cochlear Limited, Sydney, Australia
| | | | - R Arts
- Cochlear Benelux NV, Mechelen, Belgium
| | - C Bester
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
- The University of Melbourne, Melbourne, Australia
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Summating Potential as Marker of Intracochlear Position in Bipolar Electrocochleography. Ear Hear 2023; 44:118-134. [PMID: 35894668 DOI: 10.1097/aud.0000000000001259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Cochlear implantation criteria include subjects with residual low-frequency hearing. To minimize implantation trauma and to avoid unwanted interactions of electric- and acoustic stimuli, it is often recommended to stop cochlear implantation before the cochlear implant (CI) reaches the cochlear partition with residual hearing, as determined by an audiogram. For this purpose, the implant can be used to record acoustically evoked signals during implantation, including cochlear compound action potentials (CAP), cochlear microphonics (CMs), and summating potentials (SPs). The former two have previously been used to monitor residual hearing in clinical settings. DESIGN In the present study we investigated the use of intracochlear, bipolar SP recordings to determine the exact cochlear position of the contacts of implanted CIs in guinea pig cochleae (n = 13). Polarity reversals of SPs were used as a functional marker of intracochlear position. Micro computed tomography (µCT) imaging and a modified Greenwood function were used to determine the cochleotopic positions of the contacts in the cochlea. These anatomical reconstructions were used to validate the SP-based position estimates. RESULTS The precision of the SP-based position estimation was on average within ± 0.37 octaves and was not impaired by moderate hearing loss caused by noise exposure after implantation. It is important to note that acute hearing impairment did not reduce the precision of the method. The cochleotopic position of CI accounted for ~70% of the variability of SP polarity reversals. Outliers in the dataset were associated with lateral CI positions. Last, we propose a simplified method to avoid implantation in functioning parts of the cochlea by approaching a predefined frequency region using bipolar SP recordings through a CI. CONCLUSIONS Bipolar SP recordings provide reliable information on electrode position in the cochlea. The position estimate remains reliable after moderate hearing loss. The technique presented here could be applied during CI surgery to monitor the CI approach to a predefined frequency region.
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Electrocochleographic Patterns Predicting Increased Impedances and Hearing Loss after Cochlear Implantation. Ear Hear 2022:00003446-990000000-00095. [PMID: 36550618 DOI: 10.1097/aud.0000000000001319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Different patterns of electrocochleographic responses along the electrode array after insertion of the cochlear implant electrode array have been described. However, the implications of these patterns remain unclear. Therefore, the aim of the study was to correlate different peri- and postoperative electrocochleographic patterns with four-point impedance measurements and preservation of residual hearing. DESIGN Thirty-nine subjects with residual low-frequency hearing which were implanted with a slim-straight electrode array could prospectively be included. Intracochlear electrocochleographic recordings and four-point impedance measurements along the 22 electrodes of the array (EL, most apical EL22) were conducted immediately after complete insertion and 3 months after surgery. Hearing preservation was assessed after 3 months. RESULTS In perioperative electrocochleographic recordings, 22 subjects (56%) showed the largest amplitude around the tip of the electrode array (apical-peak, AP, EL20 or EL22), whereas 17 subjects (44%) exhibited a maximum amplitude in more basal regions (mid-peak, MP, EL18 or lower). At 3 months, in six subjects with an AP pattern perioperatively, the location of the largest electrocochleographic response had shifted basally (apical-to-mid-peak, AP-MP). Latency was analyzed along the electrode array when this could be discerned. This was the case in 68 peri- and postoperative recordings (87% of all recordings, n = 78). The latency increased with increasing insertion depth in AP recordings (n = 38, median of EL with maximum latency shift = EL21). In MP recordings (n = 30), the maximum latency shift was detectable more basally (median EL12, p < 0.001). Four-point impedance measurements were available at both time points in 90% (n = 35) of all subjects. At the 3-month time point, recordings revealed lower impedances in the AP group (n = 15, mean = 222 Ω, SD = 63) than in the MP (n = 14, mean = 295 Ω, SD= 7 6) and AP-MP groups (n = 6, mean = 234 Ω, SD = 129; AP versus MP p = 0.026, AP versus AP-MP p = 0.023, MP versus AP-MP p > 0.999). The amplitudes of perioperative AP recordings showed a correlation with preoperative hearing thresholds (r2=0.351, p = 0.004). No such correlation was detectable in MP recordings (r2 = 0.033, p = 0.484). Audiograms were available at both time points in 97% (n = 38) of all subjects. The mean postoperative hearing loss in the AP group was 13 dB (n = 16, SD = 9). A significantly larger hearing loss was detectable in the MP and AP-MP groups with 28 (n = 17, SD = 10) and 35 dB (n = 6, SD = 13), respectively (AP versus MP p = 0.002, AP versus AP-MP p = 0.002, MP versus AP-MP p = 0.926). CONCLUSION MP and AP-MP response patterns of the electrocochleographic responses along the electrode array after cochlear implantation are correlated with higher four-point impedances and poorer postoperative hearing compared to AP response patterns. The higher impedances suggest that MP and AP-MP patterns are associated with increased intracochlear fibrosis.
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Riggs WJ, Fontenot TE, Hiss MM, Varadarajan V, Moberly AC, Adunka OF, Fitzpatrick DC. Lack of neural contributions to the summating potential in humans with Meniere's disease. Front Neurosci 2022; 16:1039986. [PMID: 36570833 PMCID: PMC9768452 DOI: 10.3389/fnins.2022.1039986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/10/2022] [Indexed: 12/12/2022] Open
Abstract
Objective To investigate the electrophysiology of the cochlear summating potential (SP) in patients with Meniere's disease (MD). Although long considered a purely hair cell potential, recent studies show a neural contribution to the SP. Patients with MD have an enhanced SP compared to those without the disease. Consequently, this study was to determine if the enhancement of the SP was in whole or part due to neural dysfunction. Design Study participants included 41 adults with MD and 53 subjects with auditory neuropathy spectrum disorder (ANSD), undergoing surgery where the round window was accessible. ANSD is a condition with known neural dysfunction, and thus represents a control group for the study. The ANSD subjects and 17 of the MD subjects were undergoing cochlear implantation (CI) surgery; the remaining MD subjects were undergoing either endolymphatic sac decompression or labyrinthectomy to alleviate the symptoms of MD. Electrocochleography was recorded from the round window using high intensity (90 dB nHL) tone bursts. The SP and compound action potential (CAP) were measured to high frequencies (> = 2 kHz) and the SP, cochlear microphonic (CM) and auditory nerve neurophonic (ANN) to low frequencies. Linear mixed models were used to assess differences between MD and ANSD subjects. Results Across frequencies, the MD subjects had smaller alternating current (AC) response than the ANSD subjects (F = 31.61,534, p < 0.001), but the SP magnitudes were larger (F = 94.31,534, p < 0.001). For frequencies less than 4 kHz the SP magnitude in the MD group was significantly correlated with the magnitude of the CM (p's < 0.001) but not in the ANSD group (p's > 0.05). Finally, the relative proportions of both ANN and CAP were greater in MD compared to ANSD subjects. The shapes of the waveforms in the MD subjects showed the presence of multiple components contributing to the SP, including outer and inner hair cells and neural activity. Conclusion The results support the view that the increased negative polarity SP in MD subjects is due to a change in the operating point of hair cells rather than a loss of neural contribution. The steady-state SP to tones in human subjects is a mixture of different sources with different polarities.
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Affiliation(s)
- William J. Riggs
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
- Department of Audiology, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Tatyana E. Fontenot
- Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Meghan M. Hiss
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
| | - Varun Varadarajan
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
| | - Aaron C. Moberly
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
| | - Oliver F. Adunka
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States
- Department of Audiology, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Bester C, Collins A, Razmovski T, Weder S, Briggs RJ, Wei B, Zakaria AF, Gerard JM, Mitchell-Innes A, Tykocinski M, Kennedy R, Iseli C, Dahm M, Ellul S, O'Leary S. Electrocochleography triggered intervention successfully preserves residual hearing during cochlear implantation: Results of a randomised clinical trial. Hear Res 2022; 426:108353. [PMID: 34600798 DOI: 10.1016/j.heares.2021.108353] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/19/2021] [Accepted: 09/15/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Preservation of natural hearing during cochlear implantation is associated with improved speech outcomes, however more than half of implant recipients lose this hearing. Real-time electrophysiological monitoring of cochlear output during implantation, made possible by recording electrocochleography using the electrodes on the cochlear implant, has shown promise in predicting hearing preservation. Sudden drops in the amplitude of the cochlear microphonic (CM) have been shown to predict more severe hearing losses. Here, we report on a randomized clinical trial investigating whether immediate surgical intervention triggered by these drops can save residual hearing. METHODS A single-blinded placebo-controlled trial of surgical intervention triggered when CM amplitude dropped by at least 30% of a prior maximum amplitude during cochlear implantation. Intraoperative electrocochleography was recorded in 60 adults implanted with Cochlear Ltd's Thin Straight Electrode, half randomly assigned to a control group and half to an interventional group. The surgical intervention was to withdraw the electrode in ½-mm steps to recover CM amplitude. The primary outcome was hearing preservation 3 months following implantation, with secondary outcomes of speech-in-noise reception thresholds by group or CM outcome, and depth of implantation. RESULTS Sixty patients were recruited; neither pre-operative audiometry nor speech reception thresholds were significantly different between groups. Post-operatively, hearing preservation was significantly better in the interventional group. This was the case in absolute difference (median of 30 dB for control, 20 dB for interventional, χ² = 6.2, p = .013), as well as for relative difference (medians of 66% for the control, 31% for the interventional, χ² = 5.9, p = .015). Speech-in-noise reception thresholds were significantly better in patients with no CM drop at any point during insertion compared with patients with a CM drop; however, those with successfully recovered CMs after an initial drop were not significantly different (median gain required for speech reception score of 50% above noise of 6.9 dB for no drop, 8.6 for recovered CM, and 9.8 for CM drop, χ² = 6.8, p = .032). Angular insertion depth was not significantly different between control and interventional groups. CONCLUSIONS This is the first demonstration that surgical intervention in response to intraoperative hearing monitoring can save residual hearing during cochlear implantation.
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Affiliation(s)
- Christofer Bester
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital.
| | - Aaron Collins
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital
| | - Tayla Razmovski
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital
| | - Stefan Weder
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital; Department of ENT, Head and Neck Surgery, University Hospital, Bern, Switzerland
| | | | | | - Atiqah Farah Zakaria
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital; Department of Otorhinolaryngology, University Putra Malaysia, Malaysia
| | - Jean-Marc Gerard
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital; Department of ENT, RVEEH
| | - Alistair Mitchell-Innes
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital; Department of ENT, RVEEH
| | | | | | | | | | | | - Stephen O'Leary
- The University of Melbourne, Department of Surgery and The Royal Victorian Eye and Ear Hospital; Department of ENT, RVEEH.
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20
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Characterizing Electrophysiological Response Properties of the Peripheral Auditory System Evoked by Phonemes in Normal and Hearing Impaired Ears. Ear Hear 2022; 43:1526-1539. [DOI: 10.1097/aud.0000000000001213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Walia A, Shew MA, Lee DS, Lefler SM, Kallogjeri D, Wick CC, Durakovic N, Fitzpatrick DC, Ortmann AJ, Herzog JA, Buchman CA. Promontory Electrocochleography Recordings to Predict Speech-Perception Performance in Cochlear Implant Recipients. Otol Neurotol 2022; 43:915-923. [PMID: 35861658 PMCID: PMC9621328 DOI: 10.1097/mao.0000000000003628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE 1) To determine the relationship of electrocochleography (ECochG) responses measured on the promontory with responses measured at the round window (RW) and various intracochlear sites. 2) To evaluate if promontory ECochG responses correlate with postoperative speech-perception performance using the cochlear implant (CI). STUDY DESIGN Prospective cohort study. SETTING Tertiary referral center. PATIENTS AND INTERVENTIONS Ninety-six adult CI recipients with no cochlear malformations or previous otologic surgery. MAIN OUTCOME MEASURES Acoustically evoked ECochG responses were measured intraoperatively at both extracochlear and intracochlear locations. ECochG total response (ECochG-TR), a measure of residual cochlear function, was calculated by summing the fast Fourier transformation amplitudes in response to 250-Hz to 2-kHz acoustic stimuli. Speech-perception performance was measured at 3 months. RESULTS There were strong linear correlations for promontory ECochG-TR with the ECochG-TRs measured at the RW ( r = 0.95), just inside scala tympani ( r = 0.91), and after full insertion ( r = 0.83). For an individual subject, the morphology of the ECochG response was similar in character across all positions; however, the response amplitude increased from promontory to RW (~1.6-fold) to just inside scala tympani (~2.6-fold), with the largest response at full insertion (~13.1-fold). Promontory ECochG-TR independently explained 51.8% of the variability ( r2 ) in consonant-nucleus-consonant at 3 months. CONCLUSIONS Promontory ECochG recordings are strongly correlated with responses previously recorded at extracochlear and intracochlear sites and explain a substantial portion of the variability in CI performance. These findings are a critical step in supporting translation of transtympanic ECochG into the clinic preoperatively to help predict postoperative CI performance.
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Affiliation(s)
- Amit Walia
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Matthew A. Shew
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - David S. Lee
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Shannon M. Lefler
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Dorina Kallogjeri
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Cameron C. Wick
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Nedim Durakovic
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Amanda J. Ortmann
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Jacques A. Herzog
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
| | - Craig A. Buchman
- Department of Otolaryngology—Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA
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22
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Schuerch K, Wimmer W, Dalbert A, Rummel C, Caversaccio M, Mantokoudis G, Weder S. Objectification of intracochlear electrocochleography using machine learning. Front Neurol 2022; 13:943816. [PMID: 36105773 PMCID: PMC9465334 DOI: 10.3389/fneur.2022.943816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Electrocochleography (ECochG) measures inner ear potentials in response to acoustic stimulation. In patients with cochlear implant (CI), the technique is increasingly used to monitor residual inner ear function. So far, when analyzing ECochG potentials, the visual assessment has been the gold standard. However, visual assessment requires a high level of experience to interpret the signals. Furthermore, expert-dependent assessment leads to inconsistency and a lack of reproducibility. The aim of this study was to automate and objectify the analysis of cochlear microphonic (CM) signals in ECochG recordings. Methods Prospective cohort study including 41 implanted ears with residual hearing. We measured ECochG potentials at four different electrodes and only at stable electrode positions (after full insertion or postoperatively). When stimulating acoustically, depending on the individual residual hearing, we used three different intensity levels of pure tones (i.e., supra-, near-, and sub-threshold stimulation; 250–2,000 Hz). Our aim was to obtain ECochG potentials with differing SNRs. To objectify the detection of CM signals, we compared three different methods: correlation analysis, Hotelling's T2 test, and deep learning. We benchmarked these methods against the visual analysis of three ECochG experts. Results For the visual analysis of ECochG recordings, the Fleiss' kappa value demonstrated a substantial to almost perfect agreement among the three examiners. We used the labels as ground truth to train our objectification methods. Thereby, the deep learning algorithm performed best (area under curve = 0.97, accuracy = 0.92), closely followed by Hotelling's T2 test. The correlation method slightly underperformed due to its susceptibility to noise interference. Conclusions Objectification of ECochG signals is possible with the presented methods. Deep learning and Hotelling's T2 methods achieved excellent discrimination performance. Objective automatic analysis of CM signals enables standardized, fast, accurate, and examiner-independent evaluation of ECochG measurements.
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Affiliation(s)
- Klaus Schuerch
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Wilhelm Wimmer
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Adrian Dalbert
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Caversaccio
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Georgios Mantokoudis
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan Weder
- Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- *Correspondence: Stefan Weder
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23
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Round Window Electrocochleography to Low Frequency Tones in Pediatric Cochlear Implant Recipients with and Without Auditory Neuropathy Spectrum Disorder: Separating Hair Cell and Neural Contributions Using a Computational Model. Otol Neurotol 2022; 43:781-788. [PMID: 35763496 PMCID: PMC9329248 DOI: 10.1097/mao.0000000000003568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS Characterize the contribution of the auditory nerve neurophonic (ANN) to electrocochleography (ECochG) of pediatric cochlear implant (CI) recipients with and without auditory nerve spectrum disorder (ANSD). BACKGROUND ECochG is an emerging technique for predicting outcomes in CI recipients. Its utility may be increased by separating the cochlear microphonic (CM), produced by hair cells, from the ANN, the evoked potential correlate of neural phase-locking, which are mixed in the ongoing portion of the response to low frequency tone bursts. METHODS Responses to tone bursts of different frequency and intensities were recorded from the round window of pediatric CI recipients. Separation of the CM and ANN was performed using a model of the underlying processes that lead to the shapes of the observed waveforms. RESULTS Preoperative mean pure tone amplitudes of the included ANSD (n = 36) and non-ANSD subjects (n = 123), were similar (89.5 and 93.5, p = 0.1). Total of 1,024 ECochG responses to frequency and intensity series were recorded. The mean correlation (r) between the input and the modeled signals was 0.973 ± 0.056 (standard deviation). The ANN magnitudes were higher in the ANSD group (ANOVAs, F = 26.5 for frequency and 21.9 for intensity, df's = 1, p's < 0.001). However, its relative contribution to the overall signal was lower (ANOVAs, F = 25.8 and 12.1, df = 1, p's < 0.001). CONCLUSIONS ANN was detected in low frequency ECochG responses but not high frequency responses in both ANSD and non-ANSD subjects. ANSD subjects, evidence of neural contribution in responses to low frequency stimuli was highly variable and often comparable to signals recorded in non-ANSD subjects. The computational model revealed that on average the ANN comprised a lower proportion of the overall signal than in non-ANSD subjects.
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24
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Min S, Lu T, Chen M, Mao J, Hu X, Li S. Forward Electric Stimulation-Induced Interference in Intracochlear Electrocochleography of Acoustic Stimulation in the Cochlea of Guinea Pigs. Front Neurosci 2022; 16:853275. [PMID: 35733936 PMCID: PMC9207313 DOI: 10.3389/fnins.2022.853275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Electric-acoustic stimulation (EAS) uses amplified sound by a hearing aid to stimulate an apical low-frequency region of the cochlea and electrical current from a cochlear implant (CI) to stimulate the basal high-frequency region. EAS recipients had significantly improved speech perception, music appreciation, and hearing function in noise compared to those relying on CI electrical stimulation (ES) alone. However, the interaction between basal ES and apical acoustic stimulation (AS) in the cochlea potentially affects EAS advantages. To investigate ES-AS interaction, we designed a system that recorded the electrically evoked compound action potential (ECAP) and the auditory evoked potential (AEP). We used an intracochlear electrode array to deliver ES at the basal cochlea and detect intracochlear electrocochleography (iECochG) generated from apical AS. Within iECochG, 3 or 6 dB (double or quadruple intensity of ECAP threshold) electric stimulation, 1 ms-forward ES significantly increased CAP amplitudes of 4 kHz/20 dB AS compared to 0 dB ES. Notably, 1 ms-forward 3 dB ES significantly increased CAP amplitudes of 4 kHz/20 dB AS, while 3 or 5 ms-forward ES did not change the CAP amplitudes. The elevation in CAP amplitude of 40 dB/4 kHz AS induced by 1 ms-forward 3 dB ES was significantly lower than that in 20 dB/4 kHz AS. With 1 ms-forward 3 dB ES, AS frequency and stimulating electrode location have no significant impact on relative CAP amplitudes of 20 dB AS. These results suggest that the basal forward ES and the following apical AS could produce a cumulative effect on the auditory nerve response.
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Affiliation(s)
- Shiyao Min
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Tianhao Lu
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Min Chen
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Jiabao Mao
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Xuerui Hu
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Shufeng Li
- Department of Otolaryngology–Head and Neck Surgery, ENT Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
- *Correspondence: Shufeng Li,
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25
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Polak M, Lorens A, Walkowiak A, Furmanek M, Skarzynski PH, Skarzynski H. In Vivo Basilar Membrane Time Delays in Humans. Brain Sci 2022; 12:400. [PMID: 35326357 PMCID: PMC8946056 DOI: 10.3390/brainsci12030400] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 12/10/2022] Open
Abstract
To date, objective measurements and psychophysical experiments have been used to measure frequency dependent basilar membrane (BM) delays in humans; however, in vivo measurements have not been made. This study aimed to measure BM delays by performing intracochlear electrocochleography in cochlear implant recipients. Sixteen subjects with various degrees of hearing abilities were selected. Postoperative Computer Tomography was performed to determine electrode locations. Electrical potentials in response to acoustic tone pips at 0.25, 0.5, 1, 2, and 4 kHz and clicks were recorded with electrodes at the frequency specific region. The electrode array was inserted up to the characteristic cochlear frequency region of 250 Hz for 6 subjects. Furthermore, the array was inserted in the region of 500 Hz for 15 subjects, and 1, 2, and 4 kHz were reached in all subjects. Intracochlear electrocochleography for each frequency-specific tone pip and clicks showed detectable responses in all subjects. The latencies differed among the cochlear location and the cochlear microphonic (CM) onset latency increased with decreasing frequency and were consistent with click derived band technique. Accordingly, BM delays in humans could be derived. The BM delays increased systematically along the cochlea from basal to apical end and were in accordance with Ruggero and Temchin, 2007.
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Affiliation(s)
- Marek Polak
- R&D Med-El, Furstenweg 77A, 6020 Innsbruck, Austria
| | - Artur Lorens
- Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland; (A.L.); (A.W.); (M.F.); (P.H.S.); (H.S.)
| | - Adam Walkowiak
- Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland; (A.L.); (A.W.); (M.F.); (P.H.S.); (H.S.)
| | - Mariusz Furmanek
- Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland; (A.L.); (A.W.); (M.F.); (P.H.S.); (H.S.)
| | - Piotr Henryk Skarzynski
- Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland; (A.L.); (A.W.); (M.F.); (P.H.S.); (H.S.)
| | - Henryk Skarzynski
- Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland; (A.L.); (A.W.); (M.F.); (P.H.S.); (H.S.)
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26
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Lutz BT, Hutson KA, Trecca EMC, Hamby M, Fitzpatrick DC. Neural Contributions to the Cochlear Summating Potential: Spiking and Dendritic Components. J Assoc Res Otolaryngol 2022; 23:351-363. [PMID: 35254541 DOI: 10.1007/s10162-022-00842-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/21/2022] [Indexed: 11/30/2022] Open
Abstract
Using electrocochleography, the summating potential (SP) is a deflection from baseline to tones and an early rise in the response to clicks. Here, we use normal hearing gerbils and gerbils with outer hair cells removed with a combination of furosemide and kanamycin to investigate cellular origins of the SP. Round window electrocochleography to tones and clicks was performed before and after application of tetrodotoxin to prevent action potentials, and then again after kainic acid to prevent generation of an EPSP. With appropriate subtractions of the response curves from the different conditions, the contributions to the SP from outer hair cells, inner hair cell, and neural "spiking" and "dendritic" responses were isolated. Like hair cells, the spiking and dendritic components had opposite polarities to tones - the dendritic component had negative polarity and the spiking component had positive polarity. The magnitude of the spiking component was larger than the dendritic across frequencies and intensities. The onset to tones and to clicks followed a similar sequence; the outer hair cells responded first, then inner hair cells, then the dendritic component, and then the compound action potential of the spiking response. These results show the sources of the SP include at least the four components studied, and that these have a mixture of polarities and magnitudes that vary across frequency and intensity. Thus, multiple possible interactions must be considered when interpreting the SP for clinical uses.
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Affiliation(s)
- Brendan T Lutz
- The University of North Carolina at Chapel Hill, Department of Otolaryngology - Head & Neck Surgery, 101 Mason Farm Rd, CB#7546, Chapel Hill, NC, USA
| | - Kendall A Hutson
- The University of North Carolina at Chapel Hill, Department of Otolaryngology - Head & Neck Surgery, 101 Mason Farm Rd, CB#7546, Chapel Hill, NC, USA
| | - Eleonora M C Trecca
- IRCCS Casa Sollievo Della Sofferenza, Department of Maxillofacial Surgery and Otolaryngology, San Giovanni Rotondo (Foggia), Italy.,University Hospital of Foggia, Department of Otolaryngology- Head and Neck Surgery, Foggia, Italy
| | - Meredith Hamby
- The University of North Carolina at Chapel Hill, Department of Otolaryngology - Head & Neck Surgery, 101 Mason Farm Rd, CB#7546, Chapel Hill, NC, USA
| | - Douglas C Fitzpatrick
- The University of North Carolina at Chapel Hill, Department of Otolaryngology - Head & Neck Surgery, 101 Mason Farm Rd, CB#7546, Chapel Hill, NC, USA.
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27
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Implications of Phase Changes in Extracochlear Electrocochleographic Recordings During Cochlear Implantation. Otol Neurotol 2021; 43:e181-e190. [PMID: 34772884 DOI: 10.1097/mao.0000000000003414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To assess the prevalence and implications of phase changes in extracochlear electrocochleography (ECochG) recordings during cochlear implantation. MATERIALS AND METHODS Extracochlear ECochG recordings were performed before and after insertion of the cochlear implant (CI) electrode by a recording electrode placed on the promontory. Acoustic stimuli were tone bursts at 250, 500, 750, and 1,000 Hz. The pure tone average (PTA) was determined before and approximately 4 weeks after surgery. RESULTS Extracochlear ECochG recordings in 69 ears of 68 subjects were included. At 250 Hz, the mean phase change was 43° (n = 50, standard deviation (SD) 44°), at 500 Hz 36° (n = 64, SD 36°), at 750 Hz 33° (n = 42, SD 39°), and at 1,000 Hz 22° (n = 54, SD 27°). Overall, in 48 out of 210 ECochG recordings a phase change of ≥45° (23%) was detectable. Ears with an amplitude drop >3 dB and a phase change ≥45° (n = 3) had a complete or near complete loss of residual cochlear function in all cases. A phase change of ≥90° in one recording was not associated with a larger amplitude change of the ECochG signal (1.9 dB vs. -0.9 dB, p = 0.1052, n = 69), but with a significantly larger postoperative hearing loss (17 dB vs. 26 dB, p = 0.0156, n = 69). CONCLUSIONS Phase changes occur regularly in extracochlear ECochG recordings during cochlear implantation. Phase changes of ≥90° with or without amplitude changes in the ECochG signal are associated with a larger postoperative hearing loss and could therefore represent an independent marker for cochlear trauma or changes of inner ear mechanics relevant for the postoperative hearing outcome.
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28
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Using electrocochleography to detect sensory and neural damages in a gerbil model. Sci Rep 2021; 11:19557. [PMID: 34599220 PMCID: PMC8486782 DOI: 10.1038/s41598-021-98658-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/13/2021] [Indexed: 11/09/2022] Open
Abstract
Hearing is one of the five sensory organs that allows us to interact with society and our environment. However, one in eight Americans suffers from sensorineural hearing loss that is great enough to adversely impact their daily life. There is an urgent need to identify what part/degree of the auditory pathway (sensory or neural) is compromised so that appropriate treatment/intervention can be implemented. Single- or two-tone evoked potentials, the electrocochleography (eCochG), were measured along the auditory pathway, i.e., at the round window and remotely at the vertex, with simultaneous recordings of ear canal distortion product otoacoustic emissions. Sensory (cochlear) and neural components in the (remote-) eCochG responses showed distinct level- and frequency-dependent features allowing to be differentiated from each other. Specifically, the distortion products in the (remote-)eCochGs can precisely localize the sensory damage showing that they are effective to determine the sensory or neural damage along the auditory pathway.
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29
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Sijgers L, Pfiffner F, Grosse J, Dillier N, Koka K, Röösli C, Huber A, Dalbert A. Simultaneous Intra- and Extracochlear Electrocochleography During Cochlear Implantation to Enhance Response Interpretation. Trends Hear 2021; 25:2331216521990594. [PMID: 33710919 PMCID: PMC7958165 DOI: 10.1177/2331216521990594] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The use of electrocochleography (ECochG) for providing real-time feedback of
cochlear function during cochlear implantation is receiving increased attention
for preventing cochlear trauma and preserving residual hearing. Although various
studies investigated the relationship between intra-operative ECochG
measurements and surgical outcomes in recent years, the limited interpretability
of ECochG response changes leads to conflicting study results and prevents the
adoption of this method for clinical use. Specifically, the movement of the
recording electrode with respect to the different signal generators in
intracochlear recordings makes the interpretation of signal changes with respect
to cochlear trauma difficult. Here, we demonstrate that comparison of ECochG
signals recorded simultaneously from intracochlear locations and from a fixed
extracochlear location can potentially allow a differentiation between traumatic
and atraumatic signal changes in intracochlear recordings. We measured ECochG
responses to 500 Hz tone bursts with alternating starting phases during cochlear
implant insertions in six human cochlear implant recipients. Our results show
that an amplitude decrease with associated near 180° phase shift and harmonic
distortions in the intracochlear difference curve during the first half of
insertion was not accompanied by a decrease in the extracochlear difference
curve’s amplitude (n = 1), while late amplitude decreases in
intracochlear difference curves (near full insertion, n = 2)
did correspond to extracochlear amplitude decreases. These findings suggest a
role for phase shifts, harmonic distortions, and recording location in
interpreting intracochlear ECochG responses.
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Affiliation(s)
- Leanne Sijgers
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Flurin Pfiffner
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Julian Grosse
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Norbert Dillier
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Kanthaiah Koka
- Research and Technology, Advanced Bionics LLC, Santa Clarita, California, United States
| | - Christof Röösli
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Alexander Huber
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Adrian Dalbert
- University of Zurich, Zurich, Switzerland.,Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland
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Correlation Between Electrocochleographic Changes During Surgery and Hearing Outcome in Cochlear Implant Recipients: A Case Report and Systematic Review of the Literature. Otol Neurotol 2021; 41:318-326. [PMID: 31834213 DOI: 10.1097/mao.0000000000002506] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine the correlation between intraoperative changes of electrocochleography (ECochG) responses and traumatic cochlear implant insertions as well as postoperative hearing loss. METHODS ECochG, radiological, and audiological data were collected prospectively in a cochlear implant recipient with otosclerosis and assumed cochlear trauma during electrode insertion. A systematic review was conducted within PubMed-NCBI, EMBASE, and the Cochrane Library using the terms "Cochlear implant" and "Electrocochleography." Original studies that evaluated intraoperative ECochG responses and postoperative hearing loss were selected and analyzed. RESULTS The case report revealed a drop of intra- and extracochlear ECochG signals during electrode insertion. The postoperative computed tomography scan suggested a scalar dislocation. There was no measurable hearing 4 weeks after surgery. Within the database search, nine articles met the inclusion criteria. All were case series reports (range from 2 to 36 subjects) with a total of 173 subjects. Due to the heterogeneous data, a meta-analysis was unfeasible. CONCLUSIONS In concordance with some findings in the literature, the presented case report suggests that a drop of intra- and extracochlear ECochG signals during the insertion of the electrode array is associated with cochlear trauma and postoperative hearing loss in some cases. However, the literature is inconclusive regarding the correlation between intraoperative changes of the ECochG signals and postoperative hearing preservation. More studies investigating the correlation are needed to provide sufficient data.
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Abstract
OBJECTIVE Given the heterogeneity of papers about electrocochleography (ECochG) and cochlear implantation (CI) and the absence of a systematic review in the current literature, the aim of this work was to analyze the uses of ECochG in the different stages of CI. DATA SOURCES A search of PubMed from inception to December 8, 2019, with cross-references, was executed. Keywords were: "Cochlear Implant" OR "Cochlear Implantation" AND "Electrocochleography" OR "ECochG." The main eligibility criteria were English-language articles, investigating the use of ECochG in the different phases of CI. STUDY SELECTION Literature reviews, editorials, case reports, conference papers were excluded, as were papers in which ECochG was just sporadically executed. DATA EXTRACTION The quality of the included studies was assessed using "The Strengthening the Reporting of Observational Studies in Epidemiology" (STROBE) Statement. DATA SYNTHESIS A total of 95 articles were identified and 60 papers were included. The included articles covered a timeframe from 2003 to 2019. Of the 60 papers, 46 were human studies, 12 animal studies, and two involved more data sets. Eleven related to the diagnostic phase, 43 described intraoperative monitoring, and 10 were regarding follow-up testing. Hearing preservation was the most discussed topic with 25 included articles. CONCLUSIONS AND RELEVANCE ECochG measurements appeared to be useful in many aspects of CI, such as hearing preservation. Our review is the first that shows the evolution of the technique and how much has been achieved from the earliest experiments to the most recent signal process refinements and device implementation in CI.
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Trecca EMC, Adunka OF, Mattingly JK, Hiss MM, Cassano M, Malhotra PS, Riggs WJ. Electrocochleography Observations in a Series of Cochlear Implant Electrode Tip Fold-Overs. Otol Neurotol 2021; 42:e433-e437. [PMID: 33196531 DOI: 10.1097/mao.0000000000003008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Tip fold-over is a rare but serious complication of cochlear implant (CI) surgery. The purpose of this study was to present intraoperative electrocochleography (ECochG) observations in a series of CI electrode tip fold-overs. PATIENTS Five pediatric subjects undergoing CI surgery through a round window (RW) approach with a perimodiolar electrode array, who were diagnosed with either auditory neuropathy spectrum disorder or enlarged vestibular aqueduct. INTERVENTIONS Intraoperative RW ECochG during CI surgery: tone burst stimuli were presented from 95 to 110 dB SPL. MAIN OUTCOME MEASURES Magnitude and phase characteristics of ECochG responses obtained intraoperatively before and immediately after electrode insertion were examined for patients with and without tip fold-over. RESULTS Three subjects presented with tip fold-over and two formed the control group. Among fold-over cases, one participant exhibited an inversion in the starting phase of the cochlear microphonic response and a decrease in spectral magnitude from pre- to postinsertion. Both subjects who did not exhibit a change in phase had an increase in the ECochG-total response (ECochG-TR) magnitude. No case in the control group exhibited a change in starting phase. In regard to the ECochG-TR, all controls showed a decrease in the magnitude. CONCLUSIONS Despite the small number of patients, heterogeneous ECochG response patterns were observed within the fold-over group. Though these results are not conclusive, they can serve as a framework to begin to understand ECochG's utility in detecting intraoperative tip fold-over.
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Affiliation(s)
- Eleonora M C Trecca
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Otolaryngology - Head and Neck Surgery, University Hospital of Foggia, Foggia, Italy
| | - Oliver F Adunka
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Jameson K Mattingly
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Meghan M Hiss
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Michele Cassano
- Department of Otolaryngology - Head and Neck Surgery, University Hospital of Foggia, Foggia, Italy
| | - Prashant S Malhotra
- Department of Otolaryngology - Head and Neck Surgery, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - William J Riggs
- Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Tejani VD, Kim JS, Oleson JJ, Abbas PJ, Brown CJ, Hansen MR, Gantz BJ. Residual Hair Cell Responses in Electric-Acoustic Stimulation Cochlear Implant Users with Complete Loss of Acoustic Hearing After Implantation. J Assoc Res Otolaryngol 2021; 22:161-176. [PMID: 33538936 DOI: 10.1007/s10162-021-00785-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/03/2021] [Indexed: 11/27/2022] Open
Abstract
Changes in cochlear implant (CI) design and surgical techniques have enabled the preservation of residual acoustic hearing in the implanted ear. While most Nucleus Hybrid L24 CI users retain significant acoustic hearing years after surgery, 6-17 % experience a complete loss of acoustic hearing (Roland et al. Laryngoscope. 126(1):175-81. (2016), Laryngoscope. 128(8):1939-1945 (2018); Scheperle et al. Hear Res. 350:45-57 (2017)). Electrocochleography (ECoG) enables non-invasive monitoring of peripheral auditory function and may provide insight into the pathophysiology of hearing loss. The ECoG response is evoked using an acoustic stimulus and includes contributions from the hair cells (cochlear microphonic-CM) as well as the auditory nerve (auditory nerve neurophonic-ANN). Seven Hybrid L24 CI users with complete loss of residual hearing months after surgery underwent ECoG measures before and after loss of hearing. While significant reductions in CMs were evident after hearing loss, all participants had measurable CMs despite having no measurable acoustic hearing. None retained measurable ANNs. Given histological data suggesting stable hair cell and neural counts after hearing loss (e.g., Quesnel et al. Hear Res. 333:225-234. (2016)), the loss of ECoG and audiometric hearing may reflect reduced synaptic input. This is consistent with the theory that residual CM responses coupled with little to no ANN responses reflect a "disconnect" between hair cells and auditory nerve fibers (Fontenot et al. Ear Hear. 40(3):577-591. 2019). This "disconnection" may prevent proper encoding of auditory stimulation at higher auditory pathways, leading to a lack of audiometric responses, even in the presence of viable cochlear hair cells.
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Affiliation(s)
- Viral D Tejani
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA. .,Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA.
| | - Jeong-Seo Kim
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
| | - Jacob J Oleson
- Department of Biostatistics, University of Iowa, Iowa City, IA, USA
| | - Paul J Abbas
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
| | - Carolyn J Brown
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
| | - Marlan R Hansen
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Bruce J Gantz
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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Zhan KY, Adunka OF, Eshraghi A, Riggs WJ, Prentiss SM, Yan D, Telischi FF, Liu X, He S. Electrophysiology and genetic testing in the precision medicine of congenital deafness: A review. J Otol 2021; 16:40-46. [PMID: 33505449 PMCID: PMC7814082 DOI: 10.1016/j.joto.2020.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/11/2020] [Accepted: 07/21/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Congenital hearing loss is remarkably heterogeneous, with over 130 deafness genes and thousands of variants, making for innumerable genotype/phenotype combinations. Understanding both the pathophysiology of hearing loss and molecular site of lesion along the auditory pathway permits for significantly individualized counseling. Electrophysiologic techniques such as electrocochleography (ECochG) and electrically-evoked compound action potentials (eCAP) are being studied to localize pathology and estimate residual cochlear vs. neural health. This review describes the expanding roles of genetic and electrophysiologic evaluation in the precision medicine of congenital hearing loss.The basics of genetic mutations in hearing loss and electrophysiologic testing (ECochG and eCAP) are reviewed, and how they complement each other in the diagnostics and prognostication of hearing outcomes. Used together, these measures improve the understanding of insults to the auditory system, allowing for individualized counseling for CI candidacy/outcomes or other habilitation strategies. CONCLUSION Despite tremendous discovery in deafness genes, the effects of individual genes on neural function remain poorly understood. Bridging the understanding between molecular genotype and neural and functional phenotype is paramount to interpreting genetic results in clinical practice. The future hearing healthcare provider must consolidate an ever-increasing amount of genetic and phenotypic information in the precision medicine of hearing loss.
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Affiliation(s)
- Kevin Y. Zhan
- Department of Otolaryngology – Head & Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Oliver F. Adunka
- Department of Otolaryngology – Head & Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Audiology, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Adrien Eshraghi
- Department of Otolaryngology – Head & Neck Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - William J. Riggs
- Department of Otolaryngology – Head & Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Audiology, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Sandra M. Prentiss
- Department of Otolaryngology – Head & Neck Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Denise Yan
- Department of Otolaryngology – Head & Neck Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Fred F. Telischi
- Department of Otolaryngology – Head & Neck Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Xuezhong Liu
- Department of Otolaryngology – Head & Neck Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. John T. MacDonald Foundation, Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Shuman He
- Department of Otolaryngology – Head & Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Audiology, Nationwide Children’s Hospital, Columbus, OH, USA
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Toward a Better Understanding of Electrocochleography: Analysis of Real-Time Recordings. ACTA ACUST UNITED AC 2020; 41:1560-1567. [DOI: 10.1097/aud.0000000000000871] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cochlear microphonic latency predicts outer hair cell function in animal models and clinical populations. Hear Res 2020; 398:108094. [PMID: 33099252 DOI: 10.1016/j.heares.2020.108094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 11/24/2022]
Abstract
As recently reported, electrocochleography recorded in cochlear implant recipients showed reduced amplitude and shorter latency in patients with more severe high-frequency hearing loss compared with those with some residual hearing. As the response is generated primarily by receptor currents in outer hair cells, these variations in amplitude and latency may indicate outer hair cell function after cochlear implantation. We propose that an absence of latency shift when the cochlear microphonic is measured on two adjacent electrodes indicates an absence or dysfunction of outer hair cells between these electrodes. We test this preclinically in noise deafened guinea pigs (2 h of a 124 dB HL, 16-24 kHz narrow-band noise), and clinically, in electrocochleographic recordings made in cochlear implant recipients immediately after implantation. We found that normal hearing guinea pigs showed a progressive increase in latency from basal to apical electrodes. In contrast, guinea pigs with significantly elevated high-frequency hearing thresholds showed no change in cochlear microphonic latency measured on basal electrodes (located approximately at the 16-24 kHz location in the cochlea).. In the clinical cohort, a significant negative correlation existed between cochlear microphonic latency shifts and hearing thresholds at 1-, 2-, & 4 kHz when tested on electrodes located at the relevant cochlear tonotopic place. This reduction in latency shift was such that patients with no measurable hearing also had no detectable latency shift (place assessed by CT scan, r's of -.70 to -.83). These findings suggest that electrocochleography can be used as a diagnostic tool to detect cochlear regions with functioning hair cells, which may be important for defining cross-over point for electro-acoustic stimulation.
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Comparison of Pure-Tone Thresholds and Cochlear Microphonics Thresholds in Pediatric Cochlear Implant Patients. Ear Hear 2020; 41:1320-1326. [DOI: 10.1097/aud.0000000000000870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Hutson KA, Pulver SH, Ariel P, Naso C, Fitzpatrick DC. Light sheet microscopy of the gerbil cochlea. J Comp Neurol 2020; 529:757-785. [PMID: 32632959 DOI: 10.1002/cne.24977] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 05/13/2020] [Accepted: 06/21/2020] [Indexed: 01/19/2023]
Abstract
Light sheet fluorescence microscopy (LSFM) provides a rapid and complete three-dimensional image of the cochlea. The method retains anatomical relationships-on a micrometer scale-between internal structures such as hair cells, basilar membrane (BM), and modiolus with external surface structures such as the round and oval windows. Immunolabeled hair cells were used to visualize the spiraling BM in the intact cochlea without time intensive dissections or additional histological processing; yet material prepared for LSFM could be rehydrated, the BM dissected out and reimaged at higher resolution with the confocal microscope. In immersion-fixed material, details of the cochlear vasculature were seen throughout the cochlea. Hair cell counts (both inner and outer) as well as frequency maps of the BM were comparable to those obtained by other methods, but with the added dimension of depth. The material provided measures of angular, linear, and vector distance between characteristic frequency regions along the BM. Thus, LSFM provides a unique ability to rapidly image the entire cochlea in a manner applicable to model and interpret physiological results. Furthermore, the three-dimensional organization of the cochlea can be studied at the organ and cellular level with LSFM, and this same material can be taken to the confocal microscope for detailed analysis at the subcellular level.
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Affiliation(s)
- Kendall A Hutson
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stephen H Pulver
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Pablo Ariel
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Caroline Naso
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Douglas C Fitzpatrick
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Band-Limited Chirp-Evoked Compound Action Potential in Guinea Pig: Comprehensive Neural Measure for Cochlear Implantation Monitoring. Ear Hear 2020; 42:142-162. [PMID: 32665481 DOI: 10.1097/aud.0000000000000910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Patients with severely impaired high-frequency hearing and sufficient residual low-frequency hearing can be provided with a cochlear implant (CI), thereby facilitating ipsilateral electric and acoustic stimulation with established advantages over electric stimulation alone. However, partial or complete hearing loss often occurred after implantation due to, inter alia, acute mechanical trauma to cochlear structures during electrode insertion. Possibilities of intraoperative monitoring using electrocochleography (ECochG) have recently been studied in CI patients, primarily using the ongoing response to low-frequency tone bursts consisting of the cochlear microphonic (CM) and the auditory nerve neurophonic. By contrast, the transient neural response to tone bursts, that is, compound action potential (CAP), was generally less detectable or less sensitive as a monitoring measure, thus falling short of providing useful contribution to electrocochleography analysis. In this study, we investigate using chirps to evoke more robust CAP responses in a limited frequency band by synchronizing neural firing, and thereby improving CAP sensitivity to mechanical trauma in a guinea pig model of cochlear implantation. DESIGN Stimuli were band-limited between 100 Hz and 10 kHz to investigate their frequency range selectivity as a preliminary model for low-frequency hearing. They were constructed by adding a harmonic series either with zero phase delay (click) or by adjusting the phase delay at a rate that is inversely related to a traveling wave delay model (chirp), with three different parameters to examine level-dependent delay compression. The amplitude spectrum was thus identical between stimuli with differences only in phase. In Experiment 1, we compared input-output functions recorded at the round window in normal-hearing guinea pigs and implemented a high-pass noise masking paradigm to infer neural contribution to the CAP. In Experiment 2, guinea pigs were implanted with a custom-built CI electrode using a motorized micromanipulator. Acute mechanical trauma was simulated during the electrode insertion. At each insertion step, CAP and CM responses were measured at the round window for the following stimuli: broad-band click, band-limited click, and band-limited chirps (3 parameters), and tone bursts at frequencies 1, 2, 4, and 8 kHz. RESULTS Chirps compared with the equal-band click showed significantly lower thresholds and steeper slopes of sigmoid-fitted input-output functions. The shorter chirp evoked significantly larger amplitudes than click when compared at equal sensation level. However, the click evoked larger amplitudes than chirps at higher levels and correspondingly achieved larger saturation amplitudes. The results of the high-pass noise masking paradigm suggest that chirps could efficiently synchronize neural firing in their targeted frequency band, while the click recruited more basal fibers outside its limited band. Finally, monitoring sensitivity during electrode insertion, defined as relative amplitude change per unit distance, was higher for chirp-evoked CAP and tone burst-evoked CM, but smaller for CAP responses evoked by clicks or tone bursts. CONCLUSION The chirp was shown to be an efficient stimulus in synchronizing neural firing for a limited frequency band in the guinea pig model. This study provides a proof of principle for using chirp-evoked CAP as a comprehensive neural measure in CI patients with residual hearing.
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Riggs WJ, Hiss MM, Varadarajan VV, Mattingly JK, Adunka OF. Enlarged vestibular aqueduct: Intraoperative electrocochleography findings during cochlear implantation. Int J Pediatr Otorhinolaryngol 2020; 134:110065. [PMID: 32361253 DOI: 10.1016/j.ijporl.2020.110065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 10/24/2022]
Abstract
Enlarged vestibular aqueduct (EVA) is the most frequent inner ear abnormality found on computed tomography in children with sensorineural hearing loss. The effects EVA abnormalities have on electrocochleography (ECochG) are unknown. Positive deflections in summation potential evoked by tone bursts were observed in 3/5 subjects, while a large negative deflection, similar to endolymphatic hydrops (EH), was observed for 2/5 subjects. The presence of an enlarged summation potential, with and without a compound action potential, was observed in response to a broadband click stimulus. Results suggest likely effects of a third window on ECochG responses and presence of EH in EVA.
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Affiliation(s)
- William J Riggs
- The Ohio State University, College of Medicine, Department of Otolaryngology- Head and Neck Surgery, Columbus, OH, USA; Nationwide Children's Hospital, Department of Audiology, Columbus, OH, USA.
| | - Meghan M Hiss
- The Ohio State University, College of Medicine, Department of Otolaryngology- Head and Neck Surgery, Columbus, OH, USA
| | - Varun V Varadarajan
- The Ohio State University, College of Medicine, Department of Otolaryngology- Head and Neck Surgery, Columbus, OH, USA
| | - Jameson K Mattingly
- The Ohio State University, College of Medicine, Department of Otolaryngology- Head and Neck Surgery, Columbus, OH, USA
| | - Oliver F Adunka
- The Ohio State University, College of Medicine, Department of Otolaryngology- Head and Neck Surgery, Columbus, OH, USA; Nationwide Children's Hospital, Department of Otolaryngology-Head and Neck Surgery, Columbus, OH, USA
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41
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Electrocochleography During Translabyrinthine Approach for Vestibular Schwannoma Removal. Otol Neurotol 2020; 41:e369-e377. [DOI: 10.1097/mao.0000000000002543] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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van Gendt MJ, Koka K, Kalkman RK, Stronks HC, Briaire JJ, Litvak L, Frijns JHM. Simulating intracochlear electrocochleography with a combined model of acoustic hearing and electric current spread in the cochlea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:2049. [PMID: 32237816 DOI: 10.1121/10.0000948] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
Intracochlear electrocochleography (ECochG) is a potential tool for the assessment of residual hearing in cochlear implant users during implantation and acoustical tuning postoperatively. It is, however, unclear how these ECochG recordings from different locations in the cochlea depend on the stimulus parameters, cochlear morphology, implant design, or hair cell degeneration. In this paper, a model is presented that simulates intracochlear ECochG recordings by combining two existing models, namely a peripheral one that simulates hair cell activation and a three-dimensional (3D) volume-conduction model of the current spread in the cochlea. The outcomes were compared to actual ECochG recordings from subjects with a cochlear implant (CI). The 3D volume conduction simulations showed that the intracochlear ECochG is a local measure of activation. Simulations showed that increasing stimulus frequency resulted in a basal shift of the peak cochlear microphonic (CM) amplitude. Increasing the stimulus level resulted in wider tuning curves as recorded along the array. Simulations with hair cell degeneration resulted in ECochG responses that resembled the recordings from the two subjects in terms of CM onset responses, higher harmonics, and the width of the tuning curve. It was concluded that the model reproduced the patterns seen in intracochlear hair cell responses recorded from CI-subjects.
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Affiliation(s)
- Margriet J van Gendt
- Department of Otorhinolaryngology, Leiden University Medical Centre, P.O Box 9600, 2300 RC Leiden, The Netherlands
| | - Kanthaiah Koka
- Research and Technology, Advanced Bionics, Valencia, California 91355, USA
| | - Randy K Kalkman
- Department of Otorhinolaryngology, Leiden University Medical Centre, P.O Box 9600, 2300 RC Leiden, The Netherlands
| | - H Christiaan Stronks
- Department of Otorhinolaryngology, Leiden University Medical Centre, P.O Box 9600, 2300 RC Leiden, The Netherlands
| | - Jeroen J Briaire
- Department of Otorhinolaryngology, Leiden University Medical Centre, P.O Box 9600, 2300 RC Leiden, The Netherlands
| | - Leonid Litvak
- Research and Technology, Advanced Bionics, Valencia, California 91355, USA
| | - Johan H M Frijns
- Department of Otorhinolaryngology, Leiden University Medical Centre, P.O Box 9600, 2300 RC Leiden, The Netherlands
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44
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Psychoacoustic and electrophysiological electric-acoustic interaction effects in cochlear implant users with ipsilateral residual hearing. Hear Res 2020; 386:107873. [DOI: 10.1016/j.heares.2019.107873] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 11/19/2022]
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Krüger B, Büchner A, Lenarz T, Nogueira W. Amplitude growth of intracochlear electrocochleography in cochlear implant users with residual hearing. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:1147. [PMID: 32113296 DOI: 10.1121/10.0000744] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
In cochlear implant (CI) users with residual hearing, the electrode-nerve interface can be investigated combining electric-acoustic stimulation (EAS) via electrocochleography (ECochG), a technique to record cochlear potentials evoked by acoustic stimulation. EAS interaction was shown in previous studies using psychoacoustic experiments. This work characterizes EAS interaction through psychophysical experiments and the amplitude growth of cochlear microphonics (CM) and auditory nerve neurophonics (ANN) derived from intracochlear ECochG recordings. Significant CM responses were recorded at psychoacoustic threshold levels. The mean difference between psychoacoustic and CM threshold was 17.5 dB. No significant ANN responses were recorded at the psychoacoustic threshold level. At the psychoacoustic most comfortable level, significant CM and ANN responses were recorded. In the presence of electrical stimulation, the psychoacoustic detection thresholds were elevated on average by 2.38 dB while the recorded CM amplitudes were attenuated on average by 1.15 dB. No significant differences in electrophysiological EAS interaction across acoustic stimulation levels were observed from CM recordings. The presence of psychophysical and electrophysiological EAS interaction demonstrates that some aspects of psychoacoustic EAS interaction can be measured via intracochlear ECochG.
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Affiliation(s)
- Benjamin Krüger
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Andreas Büchner
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Waldo Nogueira
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
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Intracochlear Electrocochleography: Response Patterns During Cochlear Implantation and Hearing Preservation. Ear Hear 2020; 40:833-848. [PMID: 30335669 DOI: 10.1097/aud.0000000000000659] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVES Electrocochleography (ECochG) obtained through a cochlear implant (CI) is increasingly being tested as an intraoperative monitor during implantation with the goal of reducing surgical trauma. Reducing trauma should aid in preserving residual hearing and improve speech perception overall. The purpose of this study was to characterize intracochlear ECochG responses throughout insertion in a range of array types and, when applicable, relate these measures to hearing preservation. The ECochG signal in cochlear implant subjects is complex, consisting of hair cell and neural generators with differing distributions depending on the etiology and history of hearing loss. Consequently, a focus was to observe and characterize response changes as an electrode advances. DESIGN In 36 human subjects, responses to 90 dB nHL tone bursts were recorded both at the round window (RW) and then through the apical contact of the CI as the array advanced into the cochlea. The specific setup used a sterile clip in the surgical field, attached to the ground of the implant with a software-controlled short to the apical contact. The end of the clip was then connected to standard audiometric recording equipment. The stimuli were 500 Hz tone bursts at 90 dB nHL. Audiometry for cases with intended hearing preservation (12/36 subjects) was correlated with intraoperative recordings. RESULTS Successful intracochlear recordings were obtained in 28 subjects. For the eight unsuccessful cases, the clip introduced excessive line noise, which saturated the amplifier. Among the successful subjects, the initial intracochlear response was a median 5.8 dB larger than the response at the RW. Throughout insertion, modiolar arrays showed median response drops after stylet removal while in lateral wall arrays the maximal median response magnitude was typically at the deepest insertion depth. Four main patterns of response magnitude were seen: increases > 5 dB (12/28), steady responses within 5 dB (4/28), drops > 5 dB (from the initial response) at shallow insertion depths (< 15 mm deep, 7/28), or drops > 5 dB occurring at deeper depths (5/28). Hearing preservation, defined as < 80 dB threshold at 250 Hz, was successful in 9/12 subjects. In these subjects, an intracochlear loss of response magnitude afforded a prediction model with poor sensitivity and specificity, which improved when phase, latency, and proportion of neural components was considered. The change in hearing thresholds across cases was significantly correlated with various measures of the absolute magnitudes of response, including RW response, starting response, maximal response, and final responses (p's < 0.05, minimum of 0.0001 for the maximal response, r's > 0.57, maximum of 0.80 for the maximal response). CONCLUSIONS Monitoring the cochlea with intracochlear ECochG during cochlear implantation is feasible, and patterns of response vary by device type. Changes in magnitude alone did not account for hearing preservation rates, but considerations of phase, latency, and neural contribution can help to interpret the changes seen and improve sensitivity and specificity. The correlation between the absolute magnitude obtained either before or during insertion of the ECochG and the hearing threshold changes suggest that cochlear health, which varies by subject, plays an important role.
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Krüger B, Büchner A, Lenarz T, Nogueira W. Electric-acoustic interaction measurements in cochlear-implant users with ipsilateral residual hearing using electrocochleography. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:350. [PMID: 32006967 DOI: 10.1121/10.0000577] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
Cochlear implantation is increasingly being used as a hearing-loss treatment for patients with residual hearing in the low acoustic frequencies. These patients obtain combined electric-acoustic stimulation (EAS). Substantial residual hearing and relatively long electrode arrays can lead to interactions between the electric and acoustic stimulation. This work investigated EAS interaction through psychophysical and electrophysiological measures. Moreover, cone-beam computed-tomography data was used to characterize the interaction along spatial cochlear locations. Psychophysical EAS interaction was estimated based on the threshold of audibility of an acoustic probe stimulus in the presence of a simultaneously presented electric masker stimulus. Intracochlear electrocochleography was used to estimate electrophysiological EAS interaction via the telemetry capability of the cochlear implant. EAS interaction was observed using psychophysical and electrophysiological measurements. While psychoacoustic EAS interaction was most pronounced close to the electrical stimulation site, electrophysiological EAS interaction was observed over a wider range of spatial cochlear locations. Psychophysical EAS interaction was significantly larger than electrophysiological EAS interaction for acoustic probes close to the electrode position.
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Affiliation(s)
- Benjamin Krüger
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Andreas Büchner
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Waldo Nogueira
- Department of Otolaryngology, Hannover Medical School, Cluster of Excellence Hearing4all, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
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Residual Cochlear Function in Adults and Children Receiving Cochlear Implants: Correlations With Speech Perception Outcomes. Ear Hear 2019; 40:577-591. [PMID: 30169463 DOI: 10.1097/aud.0000000000000630] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES Variability in speech perception outcomes with cochlear implants remains largely unexplained. Recently, electrocochleography, or measurements of cochlear potentials in response to sound, has been used to assess residual cochlear function at the time of implantation. Our objective was to characterize the potentials recorded preimplantation in subjects of all ages, and evaluate the relationship between the responses, including a subjective estimate of neural activity, and speech perception outcomes. DESIGN Electrocochleography was recorded in a prospective cohort of 284 candidates for cochlear implant at University of North Carolina (10 months to 88 years of ages). Measurement of residual cochlear function called the "total response" (TR), which is the sum of magnitudes of spectral components in response to tones of different stimulus frequencies, was obtained for each subject. The TR was then related to results on age-appropriate monosyllabic word score tests presented in quiet. In addition to the TR, the electrocochleography results were also assessed for neural activity in the forms of the compound action potential and auditory nerve neurophonic. RESULTS The TR magnitude ranged from a barely detectable response of about 0.02 µV to more than 100 µV. In adults (18 to 79 years old), the TR accounted for 46% of variability in speech perception outcome by linear regression (r = 0.46; p < 0.001). In children between 6 and 17 years old, the variability accounted for was 36% (p < 0.001). In younger children, the TR accounted for less of the variability, 15% (p = 0.012). Subjects over 80 years old tended to perform worse for a given TR than younger adults at the 6-month testing interval. The subjectively assessed neural activity did not increase the information compared with the TR alone, which is primarily composed of the cochlear microphonic produced by hair cells. CONCLUSIONS The status of the auditory periphery, particularly of hair cells rather than neural activity, accounts for a large fraction of variability in speech perception outcomes in adults and older children. In younger children, the relationship is weaker, and the elderly differ from other adults. This simple measurement can be applied with high throughput so that peripheral status can be assessed to help manage patient expectations, create individually-tailored treatment plans, and identify subjects performing below expectations based on residual cochlear function.
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Haumann S, Imsiecke M, Bauernfeind G, Büchner A, Helmstaedter V, Lenarz T, Salcher RB. Monitoring of the Inner Ear Function During and After Cochlear Implant Insertion Using Electrocochleography. Trends Hear 2019; 23:2331216519833567. [PMID: 30909815 PMCID: PMC6435875 DOI: 10.1177/2331216519833567] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
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.
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Affiliation(s)
- Sabine Haumann
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
| | - Marina Imsiecke
- 1 Department of Otolaryngology, Hannover Medical School, Germany
| | - Günther Bauernfeind
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
| | - Andreas Büchner
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
| | - Victor Helmstaedter
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
| | - Thomas Lenarz
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
| | - Rolf B Salcher
- 1 Department of Otolaryngology, Hannover Medical School, Germany.,2 Cluster of Excellence Hearing4All, Hannover, Germany
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Impact of stimulus frequency and recording electrode on electrocochleography in Hybrid cochlear implant users. Hear Res 2019; 384:107815. [PMID: 31678892 DOI: 10.1016/j.heares.2019.107815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 10/02/2019] [Accepted: 10/09/2019] [Indexed: 11/21/2022]
Abstract
This report explores the impact of recording electrode position and stimulus frequency on intracochlear electrocochleography (ECoG) responses recorded from six Nucleus L24 Hybrid CI users. Acoustic tone bursts (250 Hz, 500 Hz, 750 Hz, and 1000 Hz) were presented to the implanted ear via an insert earphone. Recordings were obtained from intracochlear electrodes 6 (most basal), 8, 10, 12, 14, 16, 18, 20, and 22 (most apical). Responses to condensation and rarefaction stimuli were subtracted from one another to emphasize hair cell responses (CM/DIF) and added to one another to emphasize neural responses (ANN/SUM). For a fixed stimulus frequency, the CM/DIF and ANN/SUM magnitudes increased as the recording electrode moved apically. For a fixed recording electrode, as the stimulus frequency was lowered, response magnitudes increased. The CM/DIF and ANN/SUM response phase were generally stable across recording electrodes, although substantial phase shifts were noted for a few conditions. Given the recent interest in ECoG for assessing peripheral auditory function in CI users, the impact of stimulus frequency and recording electrode position on response magnitude should be considered. Results suggest optimal ECoG responses are obtained using the most apical recording electrode and a low frequency acoustic stimulus (250 Hz or 500 Hz).
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