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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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Bawazeer N, Gagnon C, Maheu M, Saliba I. Click SP/AP Area Ratio Vesrus Tone Burst SP Amplitude to Diagnose Ménière's Disease Using Electrocochleography. Otolaryngol Head Neck Surg 2024; 171:494-501. [PMID: 38415882 DOI: 10.1002/ohn.693] [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: 11/29/2023] [Revised: 01/25/2024] [Accepted: 02/08/2024] [Indexed: 02/29/2024]
Abstract
OBJECTIVES To evaluate the sensitivity and the specificity of summating potential (SP)/action potential (AP) area under the curve (AUC) ratio by a transtympanic electrode and a click stimulus (TT-CS), SP/AP AUC ratio by an extratympanic electrode and a click stimulus (ET-CS) and SP amplitude value by a transtympanic electrode and tone burst stimulus (TT-TBS) in regard of Ménière's disease (MD) diagnosis. This is the first study that compares SP amplitude value performed by a TT-TBS and the SP/AP AUC ratio performed by a TT-CS. STUDY DESIGN Retrospective comparative study. SETTINGS Ninety-five patients met the inclusion criteria for electrocochleography (ECochG) testing in a tertiary care center. METHODS The sensitivity and specificity of our different ECochG protocols were calculated in regard of the diagnosis of MD. RESULTS The patients' mean age was 54 years old (female predominance). The sensitivity and the specificity of SP/AP area ratio by a TT-CS were 88.5% and 70.0%, respectively. On the other hand, the sensitivity and specificity for the SP amplitude value by a TT-TBS were 60.0% and 55.6%, respectively. SP/AP area ratio by TT-CS was statistically better than SP amplitude value by TT-TBS to detect MD disease (P = .016). However, no difference was identified between SP/AP area ratio by ET-CS and SP amplitude value by a TT-TBS (P = .573). CONCLUSION SP/AP area ratio by click stimulation has higher sensitivity and specificity to detect MD compared to SP amplitude value by tone burst stimulation. ECochG would be extremely useful in the diagnosis of MD if we use the SP/AP area ratio (sensitivity: 88.5%); therefore, it changes the bad reputation of ECochG sensitivity using SP/AP amplitude ratio (sensitivity: 51.7%) for the diagnosis of MD.
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Affiliation(s)
- Naif Bawazeer
- Division of Otolaryngology-Head & Neck Surgery, University of Montreal, Montreal, Québec, Canada
| | - Carolanne Gagnon
- Division of Otolaryngology-Head & Neck Surgery, University of Montreal, Montreal, Québec, Canada
| | - Maxime Maheu
- Faculty of Medicine, School of Speech Language Pathology and Audiology, University of Montreal, Montreal, Quebec, Canada
| | - Issam Saliba
- Division of Otolaryngology-Head & Neck Surgery, University of Montreal, Montreal, Québec, Canada
- Research Theme: Neuroscience-Otology & Neurotology, University of Montreal Hospital Centre Research Centre (CRCHUM), Montreal, Québec, Canada
- Department of Otolaryngology-Head & Neck Surgery, University of Montreal Hospital Centre (CHUM), Montreal, Québec, Canada
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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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Kim JS. Clinical Applications of Intracochlear Electrocochleography in Cochlear Implant Users With Residual Acoustic Hearing. J Audiol Otol 2024; 28:100-106. [PMID: 38695055 PMCID: PMC11065546 DOI: 10.7874/jao.2024.00129] [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: 02/12/2024] [Accepted: 03/20/2024] [Indexed: 05/05/2024] Open
Abstract
We herein review the use of electrocochleography (ECoG) to assess peripheral auditory system responsiveness in a growing population of cochlear implant (CI) users with preserved hearing in ears with implants. Twenty-eight recently published intracochlear ECoG articles were thoroughly reviewed to investigate the prognostic utility of intraoperative ECoG monitoring to assess hearing preservation, and the clinical applicability of postoperative ECoG for estimating audiometric thresholds and monitoring longitudinal changes in residual acoustic hearing in patients with EAS. Intraoperative ECoG studies have focused on monitoring the changes in the cochlear microphonics (CM) amplitudes during and after electrode insertion. Mixed results have been reported regarding the relationship between changes in CM amplitude in the operating room and changes in hearing thresholds after surgery. Postoperative ECoG studies have shown that CM and auditory nerve neurophonics thresholds correlate significantly with behavioral thresholds. ECoG thresholds sensitively detect changes as residual acoustic hearing decreases over time in some CI users. This indicates its potential clinical value for monitoring the post-implantation status of the peripheral auditory system. Intracochlear ECoG can provide real-time intraoperative feedback and monitor postoperative hearing preservation in a growing population of CI users.
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Affiliation(s)
- Jeong-Seo Kim
- Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea
- Medical Research Institute, Sungkyunkwan University, Suwon, Korea
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Tsilivigkos C, Vitkos EN, Ferekidis E, Warnecke A. Can Multifrequency Tympanometry Be Used in the Diagnosis of Meniere's Disease? A Systematic Review and Meta-Analysis. J Clin Med 2024; 13:1476. [PMID: 38592318 PMCID: PMC10932169 DOI: 10.3390/jcm13051476] [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: 01/02/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/10/2024] Open
Abstract
(1) Background: Ménière's disease (MD) is a disease of the inner ear, presenting with episodes of vertigo, hearing loss, and tinnitus.The aim of this study is to examine the role of multifrequency tympanometry (MFT) in the diagnosis of MD. (2) Methods: A systematic review of MEDLINE (via PubMed), Scopus, Google Scholar, and the Cochrane Library was performed, aligned with the PRISMA guidelines. Only studies that directly compare ears affected by Ménière's disease with unaffected or control ears were included. Random-effects model meta-analyses were performed. (3) Results: Seven prospective case-control studies reported a total of 899 ears, 282 of which were affected by Ménière's disease (affected ears-AE), 197 unaffected ears in patients with MD (UE), and 420 control ears (CE) in healthy controls. No statistically significant differences between the groups were observed regarding resonant frequency (RF). The pure tone audiometry average of the lower frequencies (PTA basic) was significantly greater in affected ears when compared with unaffected ears. The conductance tympanogram at 2 kHz revealed a statistically significantly greater G width of 2 kHz in the affected ears when compared to both unaffected and control ears, while control ears had a statistically significant lesser G width of 2 kHz compared to both the other two groups. (4) Conclusions: MFT, and specifically G width at 2 kHz, could be an important tool in the diagnosis of MD.
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Affiliation(s)
- Christos Tsilivigkos
- First Department of Otolaryngology, Hippokration General Hospital, National and Kapodistrian University of Athens, 15772 Athens, Greece;
| | - Evangelos N. Vitkos
- Department of Oral and Maxillofacial Surgery, George Papanikolaou General Hospital, 56429 Thessaloniki, Greece
| | - Eleftherios Ferekidis
- First Department of Otolaryngology, Hippokration General Hospital, National and Kapodistrian University of Athens, 15772 Athens, Greece;
| | - Athanasia Warnecke
- Department of Otorhinolaryngology—Head and Neck Surgery, Hannover Medical School, 30625 Hanover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, 30625 Hannover, Germany
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Deloche F, Parida S, Sivaprakasam A, Heinz MG. Estimation of Cochlear Frequency Selectivity Using a Convolution Model of Forward-Masked Compound Action Potentials. J Assoc Res Otolaryngol 2024; 25:35-51. [PMID: 38278969 PMCID: PMC10907335 DOI: 10.1007/s10162-023-00922-1] [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] [Received: 03/22/2023] [Accepted: 12/09/2023] [Indexed: 01/28/2024] Open
Abstract
PURPOSE Frequency selectivity is a fundamental property of the peripheral auditory system; however, the invasiveness of auditory nerve (AN) experiments limits its study in the human ear. Compound action potentials (CAPs) associated with forward masking have been suggested as an alternative to assess cochlear frequency selectivity. Previous methods relied on an empirical comparison of AN and CAP tuning curves in animal models, arguably not taking full advantage of the information contained in forward-masked CAP waveforms. METHODS To improve the estimation of cochlear frequency selectivity based on the CAP, we introduce a convolution model to fit forward-masked CAP waveforms. The model generates masking patterns that, when convolved with a unitary response, can predict the masking of the CAP waveform induced by Gaussian noise maskers. Model parameters, including those characterizing frequency selectivity, are fine-tuned by minimizing waveform prediction errors across numerous masking conditions, yielding robust estimates. RESULTS The method was applied to click-evoked CAPs at the round window of anesthetized chinchillas using notched-noise maskers with various notch widths and attenuations. The estimated quality factor Q10 as a function of center frequency is shown to closely match the average quality factor obtained from AN fiber tuning curves, without the need for an empirical correction factor. CONCLUSION This study establishes a moderately invasive method for estimating cochlear frequency selectivity with potential applicability to other animal species or humans. Beyond the estimation of frequency selectivity, the proposed model proved to be remarkably accurate in fitting forward-masked CAP responses and could be extended to study more complex aspects of cochlear signal processing (e.g., compressive nonlinearities).
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Affiliation(s)
- François Deloche
- Department of Speech, Language, and Hearing Sciences, Purdue University, 715 Clinic Drive, West Lafayette, 47907, IN, USA.
| | - Satyabrata Parida
- Department of Speech, Language, and Hearing Sciences, Purdue University, 715 Clinic Drive, West Lafayette, 47907, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, 47907, IN, USA
| | - Andrew Sivaprakasam
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, 47907, IN, USA
| | - Michael G Heinz
- Department of Speech, Language, and Hearing Sciences, Purdue University, 715 Clinic Drive, West Lafayette, 47907, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, 47907, IN, USA
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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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Zhang Y, Wang Y, Zhen Z, Zhang J, Zeng Z, Zhong Z, Wang Q. The role of electrocochleography and the caloric test in predicting short-term recurrence of benign paroxysmal positional vertigo. Front Neurol 2023; 14:1225857. [PMID: 37681006 PMCID: PMC10480563 DOI: 10.3389/fneur.2023.1225857] [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: 05/20/2023] [Accepted: 08/04/2023] [Indexed: 09/09/2023] Open
Abstract
Objective The study aimed to assess the value of physiological tests for evaluating inner ear function in predicting the short-term recurrence of benign paroxysmal positional vertigo (BPPV). Materials and methods The clinical information of all idiopathic BPPV patients who were treated in our clinic between February 2021 and December 2022 were reviewed. All patients included in the study had completed audiology examinations including pure tone audiometry, electrocochleography (EcochG), auditory brainstem response, and vestibular function examination such as the vestibular caloric test. The relationships between the results of the above tests and short-term recurrent BPPV were analyzed. Results A total of 96 patients with unilateral idiopathic BPPV were included for analysis. The numbers of non-recurrent patients and recurrent patients were 57 (59.4%) and 39 (40.6%), respectively. Only the results of EcochG and the caloric test showed significant differences between non-recurrent and recurrent patients (both P < 0.05). The results of these two tests were also found to be independently predictive of short-term recurrence (both P < 0.05). The non-recurrence rate for patients with normal results in both tests reached up to 78.3%, which was significantly higher than that for patients with abnormal results in both tests, 28.6% (P < 0.05). Conclusion Endolymphatic hydrops and canal paresis were independent risk factors for short-term recurrent BPPV. Additional treatments should be considered to reduce the recurrence rate, including dehydration treatment and vestibular rehabilitation.
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Affiliation(s)
| | | | | | | | | | - Zhen Zhong
- Department of Otolaryngology, Head and Neck Surgery, Peking University First Hospital, Beijing, China
| | - Quangui Wang
- Department of Otolaryngology, Head and Neck Surgery, Peking University First Hospital, Beijing, China
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Hakizimana P. The summating potential polarity encodes the ear health condition. Cell Mol Life Sci 2023; 80:163. [PMID: 37225973 DOI: 10.1007/s00018-023-04809-5] [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: 01/18/2023] [Revised: 05/10/2023] [Accepted: 05/14/2023] [Indexed: 05/26/2023]
Abstract
The summating potential (SP), the DC potential which, along with the AC response, is produced when the hair cells convert the vibrational mechanical energy of sound into electrical signals, is the most enigmatic of the cochlear potentials because its polarity and function have remained elusive for more than seven decades. Despite the tremendous socioeconomic consequences of noise-induced hearing loss and the profound physiological importance of understanding how loud noise exposure impairs the hair cell receptor activation, the relationship between the SP and noise-induced hearing impairment remains poorly characterized. Here, I show that in normally hearing ears, the SP polarity is positive and its amplitude relative to the AC response grows exponentially across frequencies, and becomes negative and decreases exponentially across frequencies following noise-induced hearing injury. Since the SP is thought to be generated by K+ outflow down the gradient through the hair cell basolateral K+ channels, the SP polarity switch to negative values is consistent with a noise-induced shift in the operating point of the hair cells.
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Affiliation(s)
- Pierre Hakizimana
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, 581 83, Linköping, Sweden.
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Alamri Y, Jennings SG. Computational modeling of the human compound action potential. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2376. [PMID: 37092943 PMCID: PMC10119875 DOI: 10.1121/10.0017863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 03/21/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
The auditory nerve (AN) compound action potential (CAP) is an important tool for assessing auditory disorders and monitoring the health of the auditory periphery during surgical procedures. The CAP has been mathematically conceptualized as the convolution of a unit response (UR) waveform with the firing rate of a population of AN fibers. Here, an approach for predicting experimentally recorded CAPs in humans is proposed, which involves the use of human-based computational models to simulate AN activity. CAPs elicited by clicks, chirps, and amplitude-modulated carriers were simulated and compared with empirically recorded CAPs from human subjects. In addition, narrowband CAPs derived from noise-masked clicks and tone bursts were simulated. Many morphological, temporal, and spectral aspects of human CAPs were captured by the simulations for all stimuli tested. These findings support the use of model simulations of the human CAP to refine existing human-based models of the auditory periphery, aid in the design and analysis of auditory experiments, and predict the effects of hearing loss, synaptopathy, and other auditory disorders on the human CAP.
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Affiliation(s)
- Yousef Alamri
- Department of Biomedical Engineering, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
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Jwair S, Ramekers D, Thomeer HGXM, Versnel H. Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs. Front Neurosci 2023; 17:978230. [PMID: 36845413 PMCID: PMC9945226 DOI: 10.3389/fnins.2023.978230] [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: 06/25/2022] [Accepted: 01/09/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction Electrocochleography (ECochG) is increasingly used in cochlear implant (CI) surgery, in order to monitor the effect of insertion of the electrode array aiming to preserve residual hearing. However, obtained results are often difficult to interpret. Here we aim to relate changes in ECochG responses to acute trauma induced by different stages of cochlear implantation by performing ECochG at multiple time points during the procedure in normal-hearing guinea pigs. Materials and methods Eleven normal-hearing guinea pigs received a gold-ball electrode that was fixed in the round-window niche. ECochG recordings were performed during the four steps of cochlear implantation using the gold-ball electrode: (1) Bullostomy to expose the round window, (2) hand-drilling of 0.5-0.6 mm cochleostomy in the basal turn near the round window, (3) insertion of a short flexible electrode array, and (4) withdrawal of electrode array. Acoustical stimuli were tones varying in frequency (0.25-16 kHz) and sound level. The ECochG signal was primarily analyzed in terms of threshold, amplitude, and latency of the compound action potential (CAP). Midmodiolar sections of the implanted cochleas were analyzed in terms of trauma to hair cells, modiolar wall, osseous spiral lamina (OSL) and lateral wall. Results Animals were assigned to cochlear trauma categories: minimal (n = 3), moderate (n = 5), or severe (n = 3). After cochleostomy and array insertion, CAP threshold shifts increased with trauma severity. At each stage a threshold shift at high frequencies (4-16 kHz) was accompanied with a threshold shift at low frequencies (0.25-2 kHz) that was 10-20 dB smaller. Withdrawal of the array led to a further worsening of responses, which probably indicates that insertion and removal trauma affected the responses rather than the mere presence of the array. In two instances, CAP threshold shifts were considerably larger than threshold shifts of cochlear microphonics, which could be explained by neural damage due to OSL fracture. A change in amplitudes at high sound levels was strongly correlated with threshold shifts, which is relevant for clinical ECochG performed at one sound level. Conclusion Basal trauma caused by cochleostomy and/or array insertion should be minimized in order to preserve the low-frequency residual hearing of CI recipients.
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Affiliation(s)
- Saad Jwair
- Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands,UMC Utrecht Brain Center, Utrecht University, Utrecht, Netherlands
| | - Dyan Ramekers
- Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands,UMC Utrecht Brain Center, Utrecht University, Utrecht, Netherlands
| | - Hans G. X. M. Thomeer
- Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands,UMC Utrecht Brain Center, Utrecht University, Utrecht, Netherlands
| | - Huib Versnel
- Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands,UMC Utrecht Brain Center, Utrecht University, Utrecht, Netherlands,*Correspondence: Huib Versnel,
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Chen J, Jennings SG. Temporal Envelope Coding of the Human Auditory Nerve Inferred from Electrocochleography: Comparison with Envelope Following Responses. J Assoc Res Otolaryngol 2022; 23:803-814. [PMID: 35948693 PMCID: PMC9789235 DOI: 10.1007/s10162-022-00865-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 07/12/2022] [Indexed: 01/06/2023] Open
Abstract
Neural coding of the slow amplitude fluctuations of sound (i.e., temporal envelope) is thought to be essential for speech understanding; however, such coding by the human auditory nerve is poorly understood. Here, neural coding of the temporal envelope by the human auditory nerve is inferred from measurements of the compound action potential in response to an amplitude modulated carrier (CAPENV) for modulation frequencies ranging from 20 to 1000 Hz. The envelope following response (EFR) was measured simultaneously with CAPENV from active electrodes placed on the high forehead and tympanic membrane, respectively. Results support the hypothesis that phase locking to higher modulation frequencies (> 80 Hz) will be stronger for CAPENV, compared to EFR, consistent with the upper-frequency limits of phase locking for auditory nerve fibers compared to auditory brainstem/cortex neurons. Future work is needed to determine the extent to which (1) CAPENV is a useful tool for studying how temporal processing of the auditory nerve is affected by aging, hearing loss, and noise-induced cochlear synaptopathy and (2) CAPENV reveals the relationship between auditory nerve temporal processing and perception of the temporal envelope.
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Affiliation(s)
- Jessica Chen
- Department of Communication Sciences and Disorders, The University of Utah, 390 South BEHS 1201, Salt Lake City, UT, USA
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, The University of Utah, 390 South BEHS 1201, Salt Lake City, UT, USA.
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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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15
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Objective Detection of Tinnitus Based on Electrophysiology. Brain Sci 2022; 12:brainsci12081086. [PMID: 36009149 PMCID: PMC9406100 DOI: 10.3390/brainsci12081086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/29/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022] Open
Abstract
Tinnitus, a common disease in the clinic, is associated with persistent pain and high costs to society. Several aspects of tinnitus, such as the pathophysiology mechanism, effective treatment, objective detection, etc., have not been elucidated. Any change in the auditory pathway can lead to tinnitus. At present, there is no clear and unified mechanism to explain tinnitus, and the hypotheses regarding its mechanism include auditory plasticity theory, cortical reorganization theory, dorsal cochlear nucleus hypothesis, etc. Current theories on the mechanism of tinnitus mainly focus on the abnormal activity of the central nervous system. Unfortunately, there is currently a lack of objective diagnostic methods for tinnitus. Developing a method that can detect tinnitus objectively is crucial, only in this way can we identify whether the patient really suffers from tinnitus in the case of cognitive impairment or medical disputes and the therapeutic effect of tinnitus. Electrophysiological investigations have prompted the development of an objective detection of tinnitus by potentials recorded in the auditory pathway. However, there is no objective indicator with sufficient sensitivity and specificity to diagnose tinnitus at present. Based on recent findings of studies with various methods, possible electrophysiological approaches to detect the presence of tinnitus have been summarized. We analyze the change of neural activity throughout the auditory pathway in tinnitus subjects and in patients with tinnitus of varying severity to find available parameters in these methods, which is helpful to further explore the feasibility of using electrophysiological methods for the objective detection of tinnitus.
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16
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Henslee AM, Kaufmann CR, Andrick MD, Reineke PT, Tejani VD, Hansen MR. Development and Characterization of an Electrocochleography-Guided Robotics-Assisted Cochlear Implant Array Insertion System. Otolaryngol Head Neck Surg 2022; 167:334-340. [PMID: 34609909 PMCID: PMC9969559 DOI: 10.1177/01945998211049210] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Electrocochleography (ECochG) is increasingly being used during cochlear implant (CI) surgery to detect and mitigate insertion-related intracochlear trauma, where a drop in ECochG signal has been shown to correlate with a decline in hearing outcomes. In this study, an ECochG-guided robotics-assisted CI insertion system was developed and characterized that provides controlled and consistent electrode array insertions while monitoring and adapting to real-time ECochG signals. STUDY DESIGN Experimental research. SETTING A research laboratory and animal testing facility. METHODS A proof-of-concept benchtop study evaluated the ability of the system to detect simulated ECochG signal changes and robotically adapt the insertion. Additionally, the ECochG-guided insertion system was evaluated in a pilot in vivo sheep study to characterize the signal-to-noise ratio and amplitude of ECochG recordings during robotics-assisted insertions. The system comprises an electrode array insertion drive unit, an extracochlear recording electrode module, and a control console that interfaces with both components and the surgeon. RESULTS The system exhibited a microvolt signal resolution and a response time <100 milliseconds after signal change detection, indicating that the system can detect changes and respond faster than a human. Additionally, animal results demonstrated that the system was capable of recording ECochG signals with a high signal-to-noise ratio and sufficient amplitude. CONCLUSION An ECochG-guided robotics-assisted CI insertion system can detect real-time drops in ECochG signals during electrode array insertions and immediately alter the insertion motion. The system may provide a surgeon the means to monitor and reduce CI insertion-related trauma beyond manual insertion techniques for improved CI hearing outcomes.
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Affiliation(s)
| | | | | | | | - Viral D. Tejani
- iotaMotion, Inc, Iowa City, Iowa, USA,Department of Otolaryngology–Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
| | - Marlan R. Hansen
- iotaMotion, Inc, Iowa City, Iowa, USA,Department of Otolaryngology–Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
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17
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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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18
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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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Cheng FY, Xu C, Gold L, Smith S. Rapid Enhancement of Subcortical Neural Responses to Sine-Wave Speech. Front Neurosci 2022; 15:747303. [PMID: 34987356 PMCID: PMC8721138 DOI: 10.3389/fnins.2021.747303] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/02/2021] [Indexed: 01/15/2023] Open
Abstract
The efferent auditory nervous system may be a potent force in shaping how the brain responds to behaviorally significant sounds. Previous human experiments using the frequency following response (FFR) have shown efferent-induced modulation of subcortical auditory function online and over short- and long-term time scales; however, a contemporary understanding of FFR generation presents new questions about whether previous effects were constrained solely to the auditory subcortex. The present experiment used sine-wave speech (SWS), an acoustically-sparse stimulus in which dynamic pure tones represent speech formant contours, to evoke FFRSWS. Due to the higher stimulus frequencies used in SWS, this approach biased neural responses toward brainstem generators and allowed for three stimuli (/bɔ/, /bu/, and /bo/) to be used to evoke FFRSWSbefore and after listeners in a training group were made aware that they were hearing a degraded speech stimulus. All SWS stimuli were rapidly perceived as speech when presented with a SWS carrier phrase, and average token identification reached ceiling performance during a perceptual training phase. Compared to a control group which remained naïve throughout the experiment, training group FFRSWS amplitudes were enhanced post-training for each stimulus. Further, linear support vector machine classification of training group FFRSWS significantly improved post-training compared to the control group, indicating that training-induced neural enhancements were sufficient to bolster machine learning classification accuracy. These results suggest that the efferent auditory system may rapidly modulate auditory brainstem representation of sounds depending on their context and perception as non-speech or speech.
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Affiliation(s)
- Fan-Yin Cheng
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Can Xu
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Lisa Gold
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Spencer Smith
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
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20
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Carcagno S, Plack CJ. Relations between speech-reception, psychophysical temporal processing, and subcortical electrophysiological measures of auditory function in humans. Hear Res 2022; 417:108456. [PMID: 35149333 PMCID: PMC8935383 DOI: 10.1016/j.heares.2022.108456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 01/05/2022] [Accepted: 01/27/2022] [Indexed: 11/04/2022]
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21
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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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22
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Curthoys IS, Grant JW, Pastras CJ, Fröhlich L, Brown DJ. Similarities and Differences Between Vestibular and Cochlear Systems - A Review of Clinical and Physiological Evidence. Front Neurosci 2021; 15:695179. [PMID: 34456671 PMCID: PMC8397526 DOI: 10.3389/fnins.2021.695179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/12/2021] [Indexed: 12/04/2022] Open
Abstract
The evoked response to repeated brief stimuli, such as clicks or short tone bursts, is used for clinical evaluation of the function of both the auditory and vestibular systems. One auditory response is a neural potential - the Auditory Brainstem Response (ABR) - recorded by surface electrodes on the head. The clinical analogue for testing the otolithic response to abrupt sounds and vibration is the myogenic potential recorded from tensed muscles - the vestibular evoked myogenic potential (VEMP). VEMPs have provided clinicians with a long sought-after tool - a simple, clinically realistic indicator of the function of each of the 4 otolithic sensory regions. We review the basic neural evidence for VEMPs and discuss the similarities and differences between otolithic and cochlear receptors and afferents. VEMPs are probably initiated by sound or vibration selectively activating afferent neurons with irregular resting discharge originating from the unique type I receptors at a specialized region of the otolithic maculae (the striola). We review how changes in VEMP responses indicate the functional state of peripheral vestibular function and the likely transduction mechanisms allowing otolithic receptors and afferents to trigger such very short latency responses. In section "ELECTROPHYSIOLOGY" we show how cochlear and vestibular receptors and afferents have many similar electrophysiological characteristics [e.g., both generate microphonics, summating potentials, and compound action potentials (the vestibular evoked potential, VsEP)]. Recent electrophysiological evidence shows that the hydrodynamic changes in the labyrinth caused by increased fluid volume (endolymphatic hydrops), change the responses of utricular receptors and afferents in a way which mimics the changes in vestibular function attributed to endolymphatic hydrops in human patients. In section "MECHANICS OF OTOLITHS IN VEMPS TESTING" we show how the major VEMP results (latency and frequency response) follow from modeling the physical characteristics of the macula (dimensions, stiffness etc.). In particular, the structure and mechanical operation of the utricular macula explains the very fast response of the type I receptors and irregular afferents which is the very basis of VEMPs and these structural changes of the macula in Menière's Disease (MD) predict the upward shift of VEMP tuning in these patients.
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Affiliation(s)
- Ian S. Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW, Australia
| | - John Wally Grant
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States
| | - Christopher J. Pastras
- The Menière’s Research Laboratory, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Laura Fröhlich
- Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Daniel J. Brown
- School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, WA, Australia
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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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24
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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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25
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He B, Zhang F, Zheng H, Sun X, Chen J, Chen J, Liu Y, Wang L, Wang W, Li S, Yang J, Duan M. The Correlation of a 2D Volume-Referencing Endolymphatic-Hydrops Grading System With Extra-Tympanic Electrocochleography in Patients With Definite Ménière's Disease. Front Neurol 2021; 11:595038. [PMID: 33551957 PMCID: PMC7856148 DOI: 10.3389/fneur.2020.595038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/16/2020] [Indexed: 01/18/2023] Open
Abstract
Background: Although magnetic resonance imaging (MRI) of the membranous labyrinth and electrocochleography (ECochG) have been used to diagnose endolymphatic hydrops (ELH) in patients with Ménière's disease (MD), the relationship between imaging and ECochG is not well-documented. Objectives: This study evaluates the ELH using 3D-FLAIR MRI and extra-tympanic ECochG (ET-ECochG) and correlates the results from 3D-FLAIR MRI to those from ET-ECochG. Materials and Methods: 3D-FLAIR MRI images of 50 patients were assessed using a 2D volume-referencing grading system (VR scores, relative scores according to the known volumes of the cochlea, vestibule, and semicircular canals). Forty healthy subjects were included and compared to 51 definite MD ears of 50 patients while analyzing the ET-ECochG, which used a self-made bronze foil electrode. The amplitude ratio of the summating potential (SP) to the action potential (AP) (SP/AP) and the area ratio of SP to AP (Asp/Aap) were collected. Relative ELH grade scores were then correlated to ET-ECochG (SP/AP, Asp/Aap). Results: The VR scores showed a better correlation (r = 0.88) with the pure tone average (PTA), disease duration, and vertigo frequency of MD than the Bernaerts scores (grading the cochlea and vestibule separately) (r = 0.22). The SP/AP and Asp/Aap of the unilateral MD patients were statistically comparable to those measured in contralateral ears and the results between the definite MD ears with healthy ears were statistically comparable (p < 0.05). In a ROC analysis Asp/Aap (area under curve, AUC 0.98) significantly (p = 0.01) outperformed SP/AP (AUC 0.91). The total score of ELH, vestibular ELH, and cochlear ELH were also correlated with SP/AP and Asp/Aap. The strongest correlation was found between the Asp/Aap and cochlear ELH (r = 0.60). Conclusion: The 2D volume-referencing grading system was more meaningful than the Bernaerts scores. A correlation was found between ELH revealed by 3D-FLAIR MRI and the SP/AP of ET-ECochG in evaluating definite MD patients. The Asp/Aap appeared a more sensitive and reliable parameter than SP/AP for diagnosing the ELH of the membranous labyrinth.
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Affiliation(s)
- Baihui He
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Fan Zhang
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Hui Zheng
- Department of Radiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiayu Sun
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Junmin Chen
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jianyong Chen
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yupeng Liu
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lu Wang
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Wei Wang
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Shuna Li
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jun Yang
- Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Maoli Duan
- Department of Otolaryngology Head and Neck and Neurotology and Audiology, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
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26
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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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27
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Kim JS. Electrocochleography in Cochlear Implant Users with Residual Acoustic Hearing: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E7043. [PMID: 32993065 PMCID: PMC7579537 DOI: 10.3390/ijerph17197043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/18/2020] [Accepted: 09/24/2020] [Indexed: 11/16/2022]
Abstract
(1) Objectives: This study reviews the use of electrocochleography (ECoG) as a tool for assessing the response of the peripheral auditory system and monitoring hearing preservation in the growing population of cochlear implant (CI) users with preserved hearing in the implanted ear. (2) Methods: A search was conducted in PubMed and CINAHL databases up to August 2020 to locate articles related to the ECoG measured during or after the cochlear implant (CI) surgery for monitoring purposes. Non-English articles, animal studies, literature reviews and editorials, case reports, and conference papers were excluded. The quality of studies was evaluated using the National Institute of Health (NIH) "Study Quality Assessment Tool for Case Series Studies". (3) Results: A total 30 articles were included for the systematic review. A total of 21 articles were intraoperative ECoG studies, while seven articles were postoperative studies. Two studies were conducted ECoG both during and after the surgery. Intraoperative ECoG studies focused on monitoring changes in ECoG response amplitudes during and/or after electrode insertion and predicting the scalar location of the electrode array. Postoperative ECoG studies focused on using the ECoG measurements to estimate behavioral audiometric thresholds and monitor pathophysiological changes related to delayed onset hearing loss postimplant. (4) Conclusions: ECoG is feasible to provide real-time feedback intraoperatively and has a potential clinical value to monitor the status of hearing preservation postoperatively in this CI population with residual acoustic hearing.
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Affiliation(s)
- Jeong-Seo Kim
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA 52242, USA
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28
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Postoperative Intracochlear Electrocochleography in Pediatric Cochlear Implant Recipients: Association to Audiometric Thresholds and Auditory Performance. Ear Hear 2020; 41:1135-1143. [DOI: 10.1097/aud.0000000000000833] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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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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30
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Barnes JH, Yin LX, Saoji AA, Carlson ML. Electrocochleography in cochlear implantation: Development, applications, and future directions. World J Otorhinolaryngol Head Neck Surg 2020; 7:94-100. [PMID: 33997718 PMCID: PMC8103527 DOI: 10.1016/j.wjorl.2020.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 11/26/2022] Open
Affiliation(s)
- Jason H Barnes
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, USA
| | - Linda X Yin
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, USA
| | - Aniket A Saoji
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, USA
| | - Matthew L Carlson
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, USA
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31
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Lorens A, Walkowiak A, Polak M, Kowalczuk A, Furmanek M, Skarzynski H, Obrycka A. Cochlear Microphonics in Hearing Preservation Cochlear Implantees. J Int Adv Otol 2020; 15:345-351. [PMID: 31846910 DOI: 10.5152/iao.2019.6334] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The intracochlear electrocochleography (ECoG) could be recorded directly from the cochlear implant (CI) electrode in CI recipients with residual hearing. The primary objective of this study is to identify the most sensitive frequency to record cochlear microphonics (CM) in CI users with a wide degree of hearing abilities and deep electrode insertion. The secondary objective is to identify the optimum location within the cochlea to record intracochlear potentials. MATERIALS AND METHODS CMs were recorded from the CI electrodes in eight females and eight males implanted with CIs Pulsar, Concerto, or Sonata, Med-El Corp. RESULTS Among the tone pips of various frequencies, 1k or 500 Hz were the most sensitive for CI users. The most sensitive place in the cochlea to record the CM potentials depended on the tone frequency used. The deeper into the cochlea the mean maximum CM peak-to-peak amplitude was measured, the lower the stimulating tone frequency was. CONCLUSION The most optimal recording parameters identified for intracochlear CM recording can be useful for intraoperative and postoperative monitoring of cochlear health in CI users with residual hearing.
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Affiliation(s)
- Artur Lorens
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
| | - Adam Walkowiak
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
| | | | - Aleksandra Kowalczuk
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
| | - Mariusz Furmanek
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
| | - Henryk Skarzynski
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
| | - Anita Obrycka
- Institute of Physiology and Pathology of Hearing, World Hearing Center, Kajetany, Poland
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Simpson MJ, Jennings SG, Margolis RH. Techniques for Obtaining High-quality Recordings in Electrocochleography. Front Syst Neurosci 2020; 14:18. [PMID: 32351368 PMCID: PMC7176302 DOI: 10.3389/fnsys.2020.00018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/18/2020] [Indexed: 11/17/2022] Open
Abstract
There are several technical challenges to obtaining high-quality recordings of cochlear potentials in human electrocochleography (ECochG). These challenges include electrical artifacts from devices such as acoustic transducers, biological artifacts from excessive myogenic and electroencephalographic potentials, and issues associated with the placement of a tympanic membrane (TM) electrode on the eardrum. This article presents approaches for dealing with these challenges for ECochG measurement using a TM electrode. Emphasis is placed on eliminating stimulus artifact, optimizing the placement of the electrode, and comparing a custom-made electrode with a commercially-available electrode. This comparison revealed that the custom-made electrode results in greater subject comfort, superior ease of placing the electrode on the eardrum, and larger compound action potential (CAP) amplitudes.
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Affiliation(s)
- Michael J Simpson
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, United States
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, United States
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Sheppard A, Stocking C, Ralli M, Salvi R. A review of auditory gain, low-level noise and sound therapy for tinnitus and hyperacusis. Int J Audiol 2019; 59:5-15. [DOI: 10.1080/14992027.2019.1660812] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Adam Sheppard
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
| | - Christina Stocking
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
| | - Massimo Ralli
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, Rome, Italy
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
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34
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Obeidat FS, Lewis Bell S. Comparing the sensitivity and specificity of cervical vestibular-evoked myogenic potentials and electrocochleography in the diagnosis of Ménière’s disease. Int J Audiol 2019; 58:738-746. [DOI: 10.1080/14992027.2019.1627008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Faten Saeed Obeidat
- Hearing and Speech Sciences, Faculty of Rehabilitation Sciences, University of Jordan, Amman, Jordan
- Faculty of Engineering and the Environment, Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
| | - Steven Lewis Bell
- Faculty of Engineering and the Environment, Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
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35
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Ayub A, Qi L, Nunez DA. A systematic review and meta-analysis of extratympanic electrocochleography in Ménière's disease diagnosis. Int J Audiol 2019; 58:533-540. [PMID: 31066337 DOI: 10.1080/14992027.2019.1606947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: Determine whether a combination of electrocochleography determined summating/action potential (SP/AP) ratio and other audiological measurements has greater sensitivity and specificity than that achieved with electrocochleography SP/AP ratio alone in diagnosing definite Ménière's Disease. Design: Systematic review and meta-analysis. Study sample: Pubmed, Cochrane Library, and Web of Science were searched using search terms "electrocochleography", "ECochG, ,"ECoG", "Ménière's Disease", and "Idiopathic Endolymphatic Hydrops". Inclusion criteria were extratympanic electrocochleography methodology, English language publication between January 2002 and December 2017, and the 1995 American Academy of Otolaryngology and Head and Neck Surgery Ménière's disease diagnostic criteria. Five articles satisfied inclusion criteria and were sufficiently detailed for aggregate quantitative analysis of SP/AP ratio (315 subjects) and combination audiological measures (113 subjects). Results: The diagnostic sensitivity and specificity of the SP/AP amplitude ratio was 47.6% and 83.8% and of combination diagnostic measures 63.5% and 89.3%, respectively. Point estimates of sensitivity (p = 0.248) and specificity (p = 0.969) and the summary Receiver Operator Characteristic Curve (p = 0.407) were not statistically significant. Conclusion: Statistically, combination diagnostic measures do not result in greater accuracy of definite Ménière's disease diagnosis compared to the SP/AP amplitude ratio alone. However, given the small sample size further studies are recommended to arrive at a definitive conclusion.
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Affiliation(s)
- Aysha Ayub
- a Faculty of Science , University of British Columbia , Vancouver , Canada.,b Division of Otolaryngology Head and Neck Surgery, Department of Surgery , University of British Columbia , Vancouver , Canada
| | - Li Qi
- b Division of Otolaryngology Head and Neck Surgery, Department of Surgery , University of British Columbia , Vancouver , Canada.,c Neuro-Otology Clinic , Vancouver General Hospital , Vancouver , Canada.,d School of Audiology and Speech Sciences , University of British Columbia , Vancouver , Canada
| | - Desmond A Nunez
- b Division of Otolaryngology Head and Neck Surgery, Department of Surgery , University of British Columbia , Vancouver , Canada
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36
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Pappa AK, Hutson KA, Scott WC, Wilson JD, Fox KE, Masood MM, Giardina CK, Pulver SH, Grana GD, Askew C, Fitzpatrick DC. Hair cell and neural contributions to the cochlear summating potential. J Neurophysiol 2019; 121:2163-2180. [PMID: 30943095 DOI: 10.1152/jn.00006.2019] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The cochlear summating potential (SP) to a tone is a baseline shift that persists for the duration of the burst. It is often considered the most enigmatic of cochlear potentials because its magnitude and polarity vary across frequency and level and its origins are uncertain. In this study, we used pharmacology to isolate sources of the SP originating from the gerbil cochlea. Animals either had the full complement of outer and inner hair cells (OHCs and IHCs) and an intact auditory nerve or had systemic treatment with furosemide and kanamycin (FK) to remove the outer hair cells. Responses to tone bursts were recorded from the round window before and after the neurotoxin kainic acid (KA) was applied. IHC responses were then isolated from the post-KA responses in FK animals, neural responses were isolated from the subtraction of post-KA from pre-KA responses in NH animals, and OHC responses were isolated by subtraction of post-KA responses in FK animals from post-KA responses in normal hearing (NH) animals. All three sources contributed to the SP; OHCs with a negative polarity and IHCs and the auditory nerve with positive polarity. Thus the recorded SP in NH animals is a sum of contributions from different sources, contributing to the variety of magnitudes and polarities seen across frequency and intensity. When this information was applied to observations of the SP recorded from the round window in human cochlear implant subjects, a strong neural contribution to the SP was confirmed in humans as well as gerbils. NEW & NOTEWORTHY Of the various potentials produced by the cochlea, the summating potential (SP) is typically described as the most enigmatic. Using combinations of ototoxins and neurotoxins, we show contributions to the SP from the auditory nerve and from inner and outer hair cells, which differ in polarity and vary in size across frequency and level. This complexity of sources helps to explain the enigmatic nature of the SP.
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Affiliation(s)
- Andrew K Pappa
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Kendall A Hutson
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - William C Scott
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - J David Wilson
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Kevin E Fox
- Campbell University School of Osteopathic Medicine, Lillington, North Carolina
| | - Maheer M Masood
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Christopher K Giardina
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Stephen H Pulver
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Gilberto D Grana
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Charles Askew
- Gene Therapy Center, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - Douglas C Fitzpatrick
- Department of Otolaryngology and Head and Neck Surgery, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
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37
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Abstract
The transduction process in the cochlea requires patent hair cells. Population responses that reflect this patency are the cochlear microphonic (CM) and summating potential (SP). They can be measured using electrocochleography (ECochG). The CM reflects the sound waveform in the form of outer hair cell (OHC) depolarization and hyperpolarization, and the SP reflects the average voltage difference of the OHC membrane potential for depolarization and hyperpolarization. The CM can be measured using ECochG or via the so-called otoacoustic emissions, using a sensitive microphone in the ear canal. Neural population responses are called the compound action potentials (CAPs), which by frequency selective masking can be decomposed into narrow-band action potentials (NAPs) reflecting CAPs evoked by activity from small cochlear regions. Presence of CM and absence of CAPs are the diagnostic hallmarks of auditory neuropathy. Increased and prolonged SPs are often found in Ménière's disease but are too often in the normal range to be diagnostic. When including NAP waveforms, Ménière's disease can be differentiated from vestibular schwannomas, which often feature overlapping symptoms such as dizziness, hearing loss, and tinnitus. The patency of the efferent system, particularly the olivocochlear bundle, can be tested using the suppressive effect of contralateral stimulation on the otoacoustic emission amplitude.
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Investigating peripheral sources of speech-in-noise variability in listeners with normal audiograms. Hear Res 2018; 371:66-74. [PMID: 30504092 DOI: 10.1016/j.heares.2018.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/25/2018] [Accepted: 11/19/2018] [Indexed: 12/19/2022]
Abstract
A current initiative in auditory neuroscience research is to better understand why some listeners struggle to perceive speech-in-noise (SIN) despite having normal hearing sensitivity. Various hypotheses regarding the physiologic bases of this disorder have been proposed. Notably, recent work has suggested that the site of lesion underlying SIN deficits in normal hearing listeners may be either in "sub-clinical" outer hair cell damage or synaptopathic degeneration at the inner hair cell-auditory nerve fiber synapse. In this study, we present a retrospective investigation of these peripheral sources and their relationship with SIN performance variability in one of the largest datasets of young normal-hearing listeners presented to date. 194 participants completed detailed case history questionnaires assessing noise exposure, SIN complaints, tinnitus, and hyperacusis. Standard and extended high frequency audiograms, distortion product otoacoustic emissions, click-evoked auditory brainstem responses, and SIN performance measures were also collected. We found that: 1) the prevalence of SIN deficits in normal hearing listeners was 42% when based on subjective report and 8% when based on SIN performance, 2) hearing complaints and hyperacusis were more common in listeners with self-reported noise exposure histories than controls, 3) neither extended high frequency thresholds nor compound action potential amplitudes differed between noise-exposed and control groups, 4) extended high frequency hearing thresholds and compound action potential amplitudes were not predictive of SIN performance. These results suggest an association between noise exposure and hearing complaints in young, normal hearing listeners; however, SIN performance variability is not explained by peripheral auditory function to the extent that these measures capture subtle physiologic differences between participants.
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McClaskey CM, Dias JW, Dubno JR, Harris KC. Reliability of Measures of N1 Peak Amplitude of the Compound Action Potential in Younger and Older Adults. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2018; 61:2422-2430. [PMID: 30208403 PMCID: PMC6195041 DOI: 10.1044/2018_jslhr-h-18-0097] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/07/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
Purpose Human auditory nerve (AN) activity estimated from the amplitude of the first prominent negative peak (N1) of the compound action potential (CAP) is typically quantified using either a peak-to-peak measurement or a baseline-corrected measurement. However, the reliability of these 2 common measurement techniques has not been evaluated but is often assumed to be relatively poor, especially for older adults. To address this question, the current study (a) compared test-retest reliability of these 2 methods and (b) tested the extent to which measurement type affected the relationship between N1 amplitude and experimental factors related to the stimulus (higher and lower intensity levels) and participants (younger and older adults). Method Click-evoked CAPs were recorded in 24 younger (aged 18-30 years) and 20 older (aged 55-85 years) adults with clinically normal audiograms up to 3000 Hz. N1 peak amplitudes were estimated from peak-to-peak measurements (from N1 to P1) and baseline-corrected measurements for 2 stimulus levels (80 and 110 dB pSPL). Baseline-corrected measurements were made with 4 baseline windows. Each stimulus level was presented twice, and test-retest reliability of these 2 measures was assessed using the intraclass correlation coefficient. Linear mixed models were used to evaluate the extent to which age group and click level uniquely predicted N1 amplitude and whether the predictive relationships differed between N1 measurement techniques. Results Both peak-to-peak and baseline-corrected measurements of N1 amplitude were found to have good-to-excellent reliability, with intraclass correlation coefficient values > 0.60. As expected, N1 amplitudes were significantly larger for younger participants compared with older participants for both measurement types and were significantly larger in response to clicks presented at 110 dB pSPL than at 80 dB pSPL for both measurement types. Furthermore, the choice of baseline window had no significant effect on N1 amplitudes using the baseline-corrected method. Conclusions Our results suggest that measurements of AN activity can be robustly and reliably recorded in both younger and older adults using either peak-to-peak or baseline-corrected measurements of the N1 of the CAP. Peak-to-peak measurements yield larger N1 response amplitudes and are the default measurement type for many clinical systems, whereas baseline-corrected measurements are computationally simpler. Furthermore, the relationships between AN activity and stimulus- and participant-related variables were not affected by measurement technique, which suggests that these relationships can be compared across studies using different techniques for measuring the CAP N1.
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Patterns Seen During Electrode Insertion Using Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant. Otol Neurotol 2018; 38:1415-1420. [PMID: 28953607 DOI: 10.1097/mao.0000000000001559] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
HYPOTHESIS Intraoperative, intracochlear electrocochleography (ECochG) will provide a means to monitor cochlear hair cell and neural response during cochlear implant (CI) electrode insertion. Distinct patterns in the insertion track can be characterized. BACKGROUND Conventional CI surgery is performed without a means of actively monitoring cochlear hair cell and neural responses. Intracochlear ECochG obtained directly through the CI may be a source of such feedback. Understanding the patterns observed in the "insertion track" is an essential step toward refining intracochlear ECochG as a tool that can be used to assist in intraoperative decision making and prognostication of hearing preservation. METHODS Intracochlear ECochG was performed in 17 patients. During electrode insertion, a 50-ms tone burst acoustic stimulus was delivered with a frequency of 500 Hz at 110 dB SPL. The ECochG response was monitored from the apical-most electrode. The amplitude of the first harmonic was plotted and monitored in near real time by the audiologist-surgeon team during CI electrode insertion. RESULTS Three distinct patterns in first harmonic amplitude change were observed across subjects during insertion: Type A (52%), overall increase in amplitude from the beginning of insertion until completion; Type B (11%), a maximum amplitude at the beginning of insertion, with a decrease in amplitude as insertion progressed to completion; and Type C (35%), comparable amplitudes at the beginning and completion of the insertion with the maximum amplitude mid-insertion. CONCLUSION Three ECochG patterns were observed during electrode advancement into the cochlea. Ongoing and future work will broaden our scope of knowledge regarding the relationship among these patterns, the presence of cochlear trauma, and functional outcomes related to hearing preservation.
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Brown DJ, Pastras CJ, Curthoys IS. Electrophysiological Measurements of Peripheral Vestibular Function-A Review of Electrovestibulography. Front Syst Neurosci 2017; 11:34. [PMID: 28620284 PMCID: PMC5450778 DOI: 10.3389/fnsys.2017.00034] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022] Open
Abstract
Electrocochleography (EcochG), incorporating the Cochlear Microphonic (CM), the Summating Potential (SP), and the cochlear Compound Action Potential (CAP), has been used to study cochlear function in humans and experimental animals since the 1930s, providing a simple objective tool to assess both hair cell (HC) and nerve sensitivity. The vestibular equivalent of ECochG, termed here Electrovestibulography (EVestG), incorporates responses of the vestibular HCs and nerve. Few research groups have utilized EVestG to study vestibular function. Arguably, this is because stimulating the cochlea in isolation with sound is a trivial matter, whereas stimulating the vestibular system in isolation requires significantly more technical effort. That is, the vestibular system is sensitive to both high-level sound and bone-conducted vibrations, but so is the cochlea, and gross electrical responses of the inner ear to such stimuli can be difficult to interpret. Fortunately, several simple techniques can be employed to isolate vestibular electrical responses. Here, we review the literature underpinning gross vestibular nerve and HC responses, and we discuss the nomenclature used in this field. We also discuss techniques for recording EVestG in experimental animals and humans and highlight how EVestG is furthering our understanding of the vestibular system.
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Affiliation(s)
- Daniel J Brown
- Neurotology Laboratory, Sydney Medical School, The University of SydneySydney, NSW, Australia
| | - Christopher J Pastras
- Neurotology Laboratory, Sydney Medical School, The University of SydneySydney, NSW, Australia
| | - Ian S Curthoys
- Department of Psychology, The University of SydneySydney, NSW, Australia
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