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Sturm JJ, Ma C, McRackan TR, Schvartz-Leyzac KC. Frequency-to-Place Mismatch Impacts Cochlear Implant Quality of Life, But Not Speech Recognition. Laryngoscope 2024; 134:2898-2905. [PMID: 38214299 PMCID: PMC11078615 DOI: 10.1002/lary.31264] [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: 04/25/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/13/2024]
Abstract
OBJECTIVE To retrospectively compare frequency-place mismatch among adult cochlear implant (CI) recipients with lateral wall (LW) and perimodiolar/Mid Scala (PM/MS) arrays, and to quantify the impact of these factors on early post-activation (3 months) speech recognition abilities and CI-specific quality of life. METHODS One hundred and twenty-six adult participants were separated into two groups: (1) 83 participants who underwent CI with a PM/MS array and 43 patients who underwent CI with a LW array. All participants completed the Cochlear Implant Quality of Life Profile (CIQOL-35 Profile) instrument. Angular insertion depth and semitone mismatch, which contribute to frequency-place mismatch, were assessed using post-operative CT scans. Word and speech recognition in quiet were determined using the Consonant-Nucleus-Consonant (CNC) and the AzBio tests, respectively (n = 82 patients). RESULTS LW arrays were more deeply inserted and exhibited less semitone mismatch compared to PM/MS arrays. No significant relationship was found between semitone mismatch and early post-operative speech perception scores for either PM/MS or LW arrays. However, greater degrees of semitone mismatch were associated with lower CIQOL-35 profile scores for PM/MS arrays. CONCLUSIONS AND RELEVANCE The results of this study indicate that both the degree of frequency-place mismatch, and its impact on CI-specific quality of life, vary by CI array design. LEVEL OF EVIDENCE 4 Laryngoscope, 134:2898-2905, 2024.
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Affiliation(s)
- Joshua J Sturm
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, U.S.A
| | - Cheng Ma
- Department of Otolaryngology-Head and Neck Surgery, Penn State College of Medicine, Hershey, Pennsylvania, U.S.A
| | - Theodore R McRackan
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, U.S.A
| | - Kara C Schvartz-Leyzac
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, U.S.A
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Chai B, Holland ML, Camposeo EL, King K, Schvartz-Leyzac KC. Patient and Device Factors Contributing to Electrically Evoked Stapedial Reflex Thresholds in Cochlear Implanted Adults. Audiol Neurootol 2024; 29:263-270. [PMID: 38342083 PMCID: PMC11305975 DOI: 10.1159/000535058] [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: 06/04/2023] [Accepted: 10/22/2023] [Indexed: 02/13/2024] Open
Abstract
INTRODUCTION Optimal cochlear implant (CI) outcomes are due to, at least in part, appropriate device programming. Objective measures, such as electrically evoked stapedial reflex thresholds (ESRTs), can be used to more accurately set programming levels. However, underlying factors that contribute to ESRT levels are not well understood. The objective of the current study was to analyze how demographic variables of patient sex and age, along with CI electrode location, influence ESRTs in adult CI recipients. METHODS A single institution retrospective review was performed. Electronic medical records, CI programming records, and clinic database of postoperative computerized tomography were reviewed to gather information regarding patient demographics, ESRTs, and electrode array metrics including medial-lateral distance and scalar location. Linear mixed models were constructed to determine how demographic variables and electrode position influence ESRTs recorded in 138 adult CI recipients. RESULTS ESRTs were significantly affected by recipient age, with older listeners demonstrating higher ESRT levels. On average, males had higher ESRT levels when compared to females. In a subset of the study sample, ESRT levels increased with increasing medial-lateral distance; however, there was not a statistically significant effect of electrode type (lateral/straight arrays compared to perimodiolar arrays). ESRTs were not affected by scalar location. DISCUSSION/CONCLUSIONS The results suggest that key demographic and electrode position characteristics influence the level of ESRTs in adult CI recipients. While ESRTs are widely used to assist with CI programming, underlying factors are not well understood. The significant factors of aging and sex could be due to middle ear mechanics or neural health differences. However, further data are needed to better understand these associations.
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Affiliation(s)
- Brianna Chai
- Department of Otolaryngology- Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Mary Laing Holland
- Department of Otolaryngology- Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Elizabeth L Camposeo
- Department of Otolaryngology- Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Kaylene King
- Department of Otolaryngology- Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Kara C Schvartz-Leyzac
- Department of Otolaryngology- Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
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Anderson SR, Burg E, Suveg L, Litovsky RY. Review of Binaural Processing With Asymmetrical Hearing Outcomes in Patients With Bilateral Cochlear Implants. Trends Hear 2024; 28:23312165241229880. [PMID: 38545645 PMCID: PMC10976506 DOI: 10.1177/23312165241229880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 04/01/2024] Open
Abstract
Bilateral cochlear implants (BiCIs) result in several benefits, including improvements in speech understanding in noise and sound source localization. However, the benefit bilateral implants provide among recipients varies considerably across individuals. Here we consider one of the reasons for this variability: difference in hearing function between the two ears, that is, interaural asymmetry. Thus far, investigations of interaural asymmetry have been highly specialized within various research areas. The goal of this review is to integrate these studies in one place, motivating future research in the area of interaural asymmetry. We first consider bottom-up processing, where binaural cues are represented using excitation-inhibition of signals from the left ear and right ear, varying with the location of the sound in space, and represented by the lateral superior olive in the auditory brainstem. We then consider top-down processing via predictive coding, which assumes that perception stems from expectations based on context and prior sensory experience, represented by cascading series of cortical circuits. An internal, perceptual model is maintained and updated in light of incoming sensory input. Together, we hope that this amalgamation of physiological, behavioral, and modeling studies will help bridge gaps in the field of binaural hearing and promote a clearer understanding of the implications of interaural asymmetry for future research on optimal patient interventions.
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Affiliation(s)
- Sean R. Anderson
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical School, Aurora, CO, USA
| | - Emily Burg
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lukas Suveg
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Ruth Y. Litovsky
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, USA
- Department of Surgery, Division of Otolaryngology, University of Wisconsin-Madison, Madison, WI, USA
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Cychosz M, Xu K, Fu QJ. Effects of spectral smearing on speech understanding and masking release in simulated bilateral cochlear implants. PLoS One 2023; 18:e0287728. [PMID: 37917727 PMCID: PMC10621938 DOI: 10.1371/journal.pone.0287728] [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] [Received: 02/10/2023] [Accepted: 06/11/2023] [Indexed: 11/04/2023] Open
Abstract
Differences in spectro-temporal degradation may explain some variability in cochlear implant users' speech outcomes. The present study employs vocoder simulations on listeners with typical hearing to evaluate how differences in degree of channel interaction across ears affects spatial speech recognition. Speech recognition thresholds and spatial release from masking were measured in 16 normal-hearing subjects listening to simulated bilateral cochlear implants. 16-channel sine-vocoded speech simulated limited, broad, or mixed channel interaction, in dichotic and diotic target-masker conditions, across ears. Thresholds were highest with broad channel interaction in both ears but improved when interaction decreased in one ear and again in both ears. Masking release was apparent across conditions. Results from this simulation study on listeners with typical hearing show that channel interaction may impact speech recognition more than masking release, and may have implications for the effects of channel interaction on cochlear implant users' speech recognition outcomes.
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Affiliation(s)
- Margaret Cychosz
- Department of Linguistics, University of California, Los Angeles, Los Angeles, CA, United States of America
| | - Kevin Xu
- Department of Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States of America
| | - Qian-Jie Fu
- Department of Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States of America
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Tóth TF, Németh A, Bakó P, Révész P, Gerlinger I, Szanyi I. Matching the pitch perception of the cochlear implanted ear with the contralateral ear in patients with single-sided deafness: a novel approach. Eur Arch Otorhinolaryngol 2023; 280:4851-4859. [PMID: 37133499 PMCID: PMC10562495 DOI: 10.1007/s00405-023-08002-z] [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: 11/17/2022] [Accepted: 04/26/2023] [Indexed: 05/04/2023]
Abstract
PURPOSE Single-sided deaf patients following cochlear implantation often compare the sound quality of their implanted ear with normal hearing. The interaural differences can result in dissatisfaction with speech comprehension and reduced time of usage of the speech processor; hence, prolonging auditory adaptation time. The proposed calibration method presented in this study demonstrates how the frequency distribution of the cochlear implant can be set to adequately approximate the pitch perception of the contralateral normal hearing ear towards improving speech intelligibility in a noisy environment. METHODS In 12 postlingual single-sided deaf patients, subjective interaural pitch-matching was carried out to determine new central frequencies for the reallocation of the frequency bands of their speech processor (CP910, CP950 or CP1000, Cochlear, Australia). The patients were asked to compare the pitch of the tones presented to their normal hearing ear to the pitch of individual channels of their cochlear implant (CI522 or CI622, Cochlear, Australia). A third-degree polynomial curve was fit to the acquired matching frequencies to create the new frequency allocation table. Audiological measurements (free-field aided thresholds, speech reception thresholds, and monosyllabic word recognition score) in noise, together with a Speech, Spatial and Qualities of Hearing Scale (SSQ12) questionnaire (short version of the original SSQ) results were evaluated prior to the pitch-matching procedure, and again, 2 weeks later. RESULTS The free-field aided thresholds of the patients showed no greater shift than ± 5 dB following the procedure; however, their monosyllabic word recognition score in noise improved significantly (mean - 9.58%, SD 4.98%, matched pairs t test comparison: p < 0.001). The results of the SSQ12 questionnaire also showed significant improvement in speech intelligibility, sound localization, and sound quality (mean 0.96 points, SD 0.45 points, matched pairs t test comparison: p < 0.001). CONCLUSIONS Matching the pitch perception of the implanted cochlea with the sensation of the normal hearing contralateral ear, resulted in significant changes in the quality of hearing in patients with single-sided deafness. It is plausible the procedure can usher positive results in bimodal patients or following sequential bilateral cochlear implantation.
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Affiliation(s)
- Tamás Ferenc Tóth
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary.
| | - Adrienne Németh
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary
| | - Péter Bakó
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary
| | - Péter Révész
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary
| | - Imre Gerlinger
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary
| | - István Szanyi
- Department of Otorhinolaryngology and Head Neck Surgery, Medical School, University of Pécs, 2. Munkácsy M. Str., Pécs, 7621, Hungary
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Andren KG, Duffin K, Ryan MT, Riley CA, Tolisano AM. Postoperative optimization of cochlear implantation for single sided deafness and asymmetric hearing loss: a systematic review. Cochlear Implants Int 2023; 24:342-353. [PMID: 37490782 DOI: 10.1080/14670100.2023.2239512] [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] [Indexed: 07/27/2023]
Abstract
OBJECTIVE Identify and evaluate the effectiveness of methods for improving postoperative cochlear implant (CI) hearing performance in subjects with single-sided deafness (SSD) and asymmetric hearing loss (AHL). DATA SOURCES Embase, PubMed, Scopus. REVIEW METHODS Systematic review and narrative synthesis. English language studies of adult CI recipients with SSD and AHL reporting a postoperative intervention and comparative audiometric data pertaining to speech in noise, speech in quiet and sound localization were included. RESULTS 32 studies met criteria for full text review and 6 (n = 81) met final inclusion criteria. Interventions were categorized as: formal auditory training, programming techniques, or hardware optimization. Formal auditory training (n = 10) found no objective improvement in hearing outcomes. Experimental CI maps did not improve audiologic outcomes (n = 9). Programed CI signal delays to improve synchronization demonstrated improved sound localization (n = 12). Hardware optimization, including multidirectional (n = 29) and remote (n = 11) microphones, improved sound localization and speech in noise, respectively. CONCLUSION Few studies meeting inclusion criteria and small sample sizes highlight the need for further study. Formal auditory training did not appear to improve hearing outcomes. Programming techniques, such as CI signal delay, and hardware optimization, such as multidirectional and remote microphones, show promise to improve outcomes for SSD and AHL CI users.
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Affiliation(s)
- Kristofer G Andren
- Department of Otolaryngology - Head & Neck Surgery, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX, USA
| | - Kevin Duffin
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Matthew T Ryan
- Department of Otolaryngology - Head & Neck Surgery, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Charles A Riley
- Department of Otolaryngology - Head & Neck Surgery, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Anthony M Tolisano
- Department of Otolaryngology - Head & Neck Surgery, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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Liu Z, Fan Y, Lou A, Noble JH. Super-resolution segmentation network for inner-ear tissue segmentation. SIMULATION AND SYNTHESIS IN MEDICAL IMAGING : ... INTERNATIONAL WORKSHOP, SASHIMI ..., HELD IN CONJUNCTION WITH MICCAI ..., PROCEEDINGS. SASHIMI (WORKSHOP) 2023; 14288:11-20. [PMID: 38560492 PMCID: PMC10979466 DOI: 10.1007/978-3-031-44689-4_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cochlear implants (CIs) are considered the standard-of-care treatment for profound sensory-based hearing loss. Several groups have proposed computational models of the cochlea in order to study the neural activation patterns in response to CI stimulation. However, most of the current implementations either rely on high-resolution histological images that cannot be customized for CI users or CT images that lack the spatial resolution to show cochlear structures. In this work, we propose to use a deep learning-based method to obtain μCT level tissue labels using patient CT images. Experiments showed that the proposed super-resolution segmentation architecture achieved very good performance on the inner-ear tissue segmentation. Our best-performing model (0.871) outperformed the UNet (0.746), VNet (0.853), nnUNet (0.861), TransUNet (0.848), and SRGAN (0.780) in terms of mean dice score.
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Affiliation(s)
- Ziteng Liu
- Dept. of Computer Science, Vanderbilt University
| | - Yubo Fan
- Dept. of Computer Science, Vanderbilt University
| | - Ange Lou
- Dept. of Computer Science, Vanderbilt University
| | - Jack H Noble
- Dept. of Computer Science, Vanderbilt University
- Dept. of Electrical and Computer Engineering, Vanderbilt University
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8
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Fan Y, Wang J, Zhao Y, Li R, Liu H, Labadie RF, Noble JH, Dawant BM. A Unified Deep-Learning-Based Framework for Cochlear Implant Electrode Array Localization. MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION : MICCAI ... INTERNATIONAL CONFERENCE ON MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION 2023; 14228:376-385. [PMID: 38559808 PMCID: PMC10976972 DOI: 10.1007/978-3-031-43996-4_36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cochlear implants (CIs) are neuroprosthetics that can provide a sense of sound to people with severe-to-profound hearing loss. A CI contains an electrode array (EA) that is threaded into the cochlea during surgery. Recent studies have shown that hearing outcomes are correlated with EA placement. An image-guided cochlear implant programming technique is based on this correlation and utilizes the EA location with respect to the intracochlear anatomy to help audiologists adjust the CI settings to improve hearing. Automated methods to localize EA in postoperative CT images are of great interest for large-scale studies and for translation into the clinical workflow. In this work, we propose a unified deep-learning-based framework for automated EA localization. It consists of a multi-task network and a series of postprocessing algorithms to localize various types of EAs. The evaluation on a dataset with 27 cadaveric samples shows that its localization error is slightly smaller than the state-of-the-art method. Another evaluation on a large-scale clinical dataset containing 561 cases across two institutions demonstrates a significant improvement in robustness compared to the state-of-the-art method. This suggests that this technique could be integrated into the clinical workflow and provide audiologists with information that facilitates the programming of the implant leading to improved patient care.
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Affiliation(s)
- Yubo Fan
- Department of Computer Science, Vanderbilt University, Nashville, TN 37235, USA
| | - Jianing Wang
- Digital Technology and Innovation, Siemens Healthineers, Princeton, NJ 08540, USA
| | - Yiyuan Zhao
- Digital and Automation, Siemens Healthineers, Malvern, PA 19355, USA
| | - Rui Li
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Han Liu
- Department of Computer Science, Vanderbilt University, Nashville, TN 37235, USA
| | - Robert F Labadie
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jack H Noble
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Benoit M Dawant
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
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Wagner L, Plontke SK, Rahne T. An analysis of the spread of electric field within the cochlea for different devices including custom-made electrodes for subtotal cochleoectomy. PLoS One 2023; 18:e0287216. [PMID: 37682960 PMCID: PMC10490913 DOI: 10.1371/journal.pone.0287216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 06/01/2023] [Indexed: 09/10/2023] Open
Abstract
OBJECTIVE Cochlear implants (CIs) can restore hearing not only in patients with profound hearing loss and deafness, but also in patients following tumour removal of intra-cochlear schwannomas. In such cases, design and placement differ from conventional electrode insertion, in which the cochlea remains filled with fluid. Despite these technical and surgical differences, previous studies have tended to show positive results in speech perception in tumour patients. The purpose of this study is to retrospectively evaluate the ability to predict speech recognition outcomes using individual electric field spreads and to investigate worldwide unique tumour cases. STUDY DESIGN In a retrospective analysis in a university tertiary center electric field spreads were compared between two groups of electrode designs implanted between 2009 and 2020 i.e., between lateral wall electrodes and custom-made perimodiolar electrode carriers from the same company. The voltage gradients were analysed and grouped with speech recognition results. RESULTS Differences in electrical field spreads were found between lateral wall electrodes and the custom-made perimodiolar electrodes, whereas a significant influence of electric fields on scores in speech recognition cannot be demonstrated. CONCLUSION Prediction of speech recognition outcome based on electric field propagation results seems not feasible. Significant differences in field spread between electrode arrays can be clearly demonstrated. This observation and its relevance to hearing treatment and speech recognition should therefore be further investigated in upcoming studies.
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Affiliation(s)
- Luise Wagner
- Department of Otorhinolaryngology and Halle Hearing and Implant Center, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Stefan K. Plontke
- Department of Otorhinolaryngology and Halle Hearing and Implant Center, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Torsten Rahne
- Department of Otorhinolaryngology and Halle Hearing and Implant Center, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
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Banalagay RA, Labadie RF, Noble JH. Validation of active shape model techniques for intracochlear anatomy segmentation in computed tomography images. J Med Imaging (Bellingham) 2023; 10:044003. [PMID: 37476645 PMCID: PMC10355218 DOI: 10.1117/1.jmi.10.4.044003] [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: 09/12/2022] [Revised: 05/28/2023] [Accepted: 06/20/2023] [Indexed: 07/22/2023] Open
Abstract
Purpose Cochlear implants (CIs) have been shown to be highly effective restorative devices for patients suffering from severe-to-profound hearing loss. Hearing outcomes with CIs depend on electrode positions with respect to intracochlear anatomy. Intracochlear anatomy can only be directly visualized using high-resolution modalities, such as micro-computed tomography (μ CT ), which cannot be used in vivo. However, active shape models (ASM) have been shown to be robust and effective for segmenting intracochlear anatomy in large scale datasets of patient computed tomographies (CTs). We present an extended dataset of μ CT specimens and aim to evaluate the ASM's performance more comprehensively than has been previously possible. Approach Using a dataset of 16 manually segmented cochlea specimens on μ CTs , we found parameters that optimize mean CT segmentation performance and then evaluate the effect of library size on the ASM. The optimized ASM was further evaluated on a clinical dataset of 134 CT images to assess method reliability. Results Optimized parameters lead to mean CT segmentation performance to 0.36 mm point-to-point error, 0.10 mm surface error, and 0.83 Dice score. Larger library sizes provide diminishing returns on segmentation performance and total variance captured by the ASM. We found our method to be clinically reliable with the main performance limitation that was found to be the candidate search process rather than model representation. Conclusions We have presented a comprehensive validation of the ASM for use in intracochlear anatomy segmentation. These results are critical to understand the limitations of the method for clinical use and for future development.
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Affiliation(s)
- Rueben A. Banalagay
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
| | - Robert F. Labadie
- Medical University of South Carolina, Department of Otolaryngology—Head & Neck Surgery, Charleston, South Carolina, United States
| | - Jack H. Noble
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
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Berg KA, Chen C, Noble JH, Dawant BM, Dwyer RT, Labadie RF, Gifford RH. Effects of the Number of Channels and Channel Stimulation Rate on Speech Recognition and Sound Quality Using Precurved Electrode Arrays. Am J Audiol 2023; 32:403-416. [PMID: 37249492 PMCID: PMC10468116 DOI: 10.1044/2023_aja-22-00032] [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] [Received: 02/04/2022] [Revised: 06/16/2022] [Accepted: 02/05/2023] [Indexed: 05/31/2023] Open
Abstract
PURPOSE This study investigated the relationship between the number of active electrodes, channel stimulation rate, and their interaction on speech recognition and sound quality measures while controlling for electrode placement. Cochlear implant (CI) recipients with precurved electrode arrays placed entirely within scala tympani and closer to the modiolus were hypothesized to be able to utilize more channels and possibly higher stimulation rates to achieve better speech recognition performance and sound quality ratings than recipients in previous studies. METHOD Participants included seven postlingually deafened adult CI recipients with Advanced Bionics Mid-Scala electrode arrays confirmed to be entirely within scala tympani using postoperative computerized tomography. Twelve conditions were tested using four, eight, 12, and 16 electrodes and channel stimulation rates of 600 pulse per second (pps), 1,200 pps, and each participant's maximum allowable rate (1,245-4,800 pps). Measures of speech recognition and sound quality were acutely assessed. RESULTS For the effect of channels, results showed no significant improvements beyond eight channels for all measures. For the effect of channel stimulation rate, results showed no significant improvements with higher rates, suggesting that 600 pps was sufficient for maximum speech recognition performance and sound quality ratings. However, across all conditions, there was a significant relationship between mean electrode-to-modiolus distance and all measures, suggesting that a lower mean electrode-to-modiolus distance was correlated with higher speech recognition scores and sound quality ratings. CONCLUSION These findings suggest that even well-placed precurved electrode array recipients may not be able to take advantage of more than eight channels or higher channel stimulation rates (> 600 pps), but that closer electrode array placement to the modiolus correlates with better outcomes for these recipients.
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Affiliation(s)
- Katelyn A. Berg
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Chen Chen
- Research and Technology, Advanced Bionics, LLC, Valencia, CA
| | - Jack H. Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN
| | - Benoit M. Dawant
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN
| | - Robert T. Dwyer
- Research and Technology, Advanced Bionics, LLC, Valencia, CA
| | - Robert F. Labadie
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston
| | - René H. Gifford
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
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12
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Sander KL, Warren SE, Mendel LL. Survey of selective electrode deactivation attitudes and practices by cochlear implant audiologists. Cochlear Implants Int 2023; 24:167-175. [PMID: 36732065 DOI: 10.1080/14670100.2023.2166571] [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] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The purpose of this study was to explore clinician attitudes regarding selective electrode deactivation and to investigate the primary methodology used to identify poorly encoded electrodes, deactivate identified electrodes, and measure outcomes. METHODS An online survey consisting of 32 questions was administered to certified clinical and research cochlear implant (CI) audiologists. Questions asked participants about their demographic information, device programming patterns, and attitudes regarding selective electrode deactivation. RESULTS Fifty-four audiologists completed the survey. When asked whether they believed selectively deactivating poorly encoded electrodes could improve speech perception outcomes, 43% of respondents selected 'Probably Yes,' 39% selected 'Definitely Yes,' and 18% selected 'Might or Might Not.' Of those who reported deactivating electrodes as part of CI programming, various methodology was reported to identify and deactivate poorly encoding electrodes and evaluate effectiveness of deactivation. General reasons against deactivation were also reported. DISCUSSION CI audiologists generally believed selective electrode deactivation could be used to improve speech perception outcomes for patients; however, few reported implementing selective electrode deactivation in practice. Among those who do perform selective electrode deactivation, the reported methodology was highly variable. CONCLUSION These findings support the need for clinical practice guidelines to assist audiologists in performing selective electrode deactivation.
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Affiliation(s)
- Kara L Sander
- Department of Communication Sciences and Disorders, University of Memphis, Memphis, TN, USA
| | - Sarah E Warren
- Department of Communication Sciences and Disorders, University of Memphis, Memphis, TN, USA
| | - Lisa Lucks Mendel
- Department of Communication Sciences and Disorders, University of Memphis, Memphis, TN, USA
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13
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Warren SE, Atcherson SR. Evaluation of a clinical method for selective electrode deactivation in cochlear implant programming. Front Hum Neurosci 2023; 17:1157673. [PMID: 37063101 PMCID: PMC10101326 DOI: 10.3389/fnhum.2023.1157673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/09/2023] [Indexed: 03/31/2023] Open
Abstract
BackgroundCochlear implants are a neural prosthesis used to restore the perception of hearing in individuals with severe-to-profound hearing loss by stimulating the auditory nerve with electrical current through a surgically implanted electrode array. The integrity of the interface between the implanted electrode array and the auditory nerve contributes to the variability in outcomes experienced by cochlear implant users. Strategies to identify and eliminate poorly encoding electrodes have been found to be effective in improving outcomes with the device, but application is limited in a clinical setting.ObjectiveThe purpose of this study was to evaluate a clinical method used to identify and selectively deactivate cochlear implants (CI) electrodes related to poor electrode-neural interface.MethodsThirteen adult CI users participated in a pitch ranking task to identify indiscriminate electrode pairs. Electrodes associated with indiscriminate pairs were selectively deactivated, creating an individualized experimental program. Speech perception was evaluated in the baseline condition and with the experimental program before and after an acclimation period. Participant preference responses were recorded at each visit.ResultsStatistically significant improvements using the experimental program were found in at least one measure of speech perception at the individual level in four out of 13 participants when tested before acclimation. Following an acclimation period, ten out of 13 participants demonstrated statistically significant improvements in at least one measure of speech perception. Statistically significant improvements were found with the experimental program at the group level for both monosyllabic words (p = 0.006) and sentences in noise (p = 0.020). Additionally, ten participants preferred the experimental program prior to the acclimation period and eleven preferred the experimental program following the acclimation period.ConclusionResults from this study suggest that electrode deactivation may yield improvement in speech perception following an acclimation period. A majority of CI users in our study reported a preference for the experimental program. This method proved to be a suitable clinical strategy for identifying and deactivating poorly encoding electrodes in adult CI users.
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Affiliation(s)
- Sarah E. Warren
- Cochlear Implant Research Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, TN, United States
- Department of Audiology, Arkansas Children’s Hospital, Little Rock, AR, United States
- Department of Audiology and Speech Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
- *Correspondence: Sarah E. Warren,
| | - Samuel R. Atcherson
- Department of Audiology and Speech Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
- Department of Otolaryngology–Head and Neck Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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14
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Schvartz-Leyzac KC, Colesa DJ, Swiderski DL, Raphael Y, Pfingst BE. Cochlear Health and Cochlear-implant Function. J Assoc Res Otolaryngol 2023; 24:5-29. [PMID: 36600147 PMCID: PMC9971430 DOI: 10.1007/s10162-022-00882-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 11/24/2022] [Indexed: 01/06/2023] Open
Abstract
The cochlear implant (CI) is widely considered to be one of the most innovative and successful neuroprosthetic treatments developed to date. Although outcomes vary, CIs are able to effectively improve hearing in nearly all recipients and can substantially improve speech understanding and quality of life for patients with significant hearing loss. A wealth of research has focused on underlying factors that contribute to success with a CI, and recent evidence suggests that the overall health of the cochlea could potentially play a larger role than previously recognized. This article defines and reviews attributes of cochlear health and describes procedures to evaluate cochlear health in humans and animal models in order to examine the effects of cochlear health on performance with a CI. Lastly, we describe how future biologic approaches can be used to preserve and/or enhance cochlear health in order to maximize performance for individual CI recipients.
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Affiliation(s)
- Kara C Schvartz-Leyzac
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, Charleston, SC, 29425, USA
| | - Deborah J Colesa
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Donald L Swiderski
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Yehoash Raphael
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Bryan E Pfingst
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA.
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15
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Image-Guided Cochlear Implant Programming: A Systematic Review and Meta-analysis. Otol Neurotol 2022; 43:e924-e935. [PMID: 35973035 DOI: 10.1097/mao.0000000000003653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To review studies evaluating clinically implemented image-guided cochlear implant programing (IGCIP) and to determine its effect on cochlear implant (CI) performance. DATA SOURCES PubMed, EMBASE, and Google Scholar were searched for English language publications from inception to August 1, 2021. STUDY SELECTION Included studies prospectively compared intraindividual CI performance between an image-guided experimental map and a patient's preferred traditional map. Non-English studies, cadaveric studies, and studies where imaging did not directly inform programming were excluded. DATA EXTRACTION Seven studies were identified for review, and five reported comparable components of audiological testing and follow-up times appropriate for meta-analysis. Demographic, speech, spectral modulation, pitch accuracy, and quality-of-life survey data were collected. Aggregate data were used when individual data were unavailable. DATA SYNTHESIS Audiological test outcomes were evaluated as standardized mean change (95% confidence interval) using random-effects meta-analysis with raw score standardization. Improvements in speech and quality-of-life measures using the IGCIP map demonstrated nominal effect sizes: consonant-nucleus-consonant words, 0.15 (-0.12 to 0.42); AzBio quiet, 0.09 (-0.05 to 0.22); AzBio +10 dB signal-noise ratio, 0.14 (-0.01 to 0.30); Bamford-Kowel-Bench sentence in noise, -0.11 (-0.35 to 0.12); Abbreviated Profile of Hearing Aid Benefit, -0.14 (-0.28 to 0.00); and Speech Spatial and Qualities of Hearing Scale, 0.13 (-0.02 to 0.28). Nevertheless, 79% of patients allowed to keep their IGCIP map opted for continued use after the investigational period. CONCLUSION IGCIP has potential to precisely guide CI programming. Nominal effect sizes for objective outcome measures fail to reflect subjective benefits fully given discordance with the percentage of patients who prefer to maintain their IGCIP map.
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16
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Application of Signals with Rippled Spectra as a Training Approach for Speech Intelligibility Improvements in Cochlear Implant Users. J Pers Med 2022; 12:jpm12091426. [PMID: 36143210 PMCID: PMC9503413 DOI: 10.3390/jpm12091426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/19/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
In cochlear implant (CI) users, the discrimination of sound signals with rippled spectra correlates with speech discrimination. We suggest that rippled-spectrum signals could be a basis for training CI users to improve speech intelligibility. Fifteen CI users participated in the study. Ten of them used the software for training (the experimental group), and five did not (the control group). Software based on the phase reversal discrimination of rippled spectra was used. The experimental group was also tested for speech discrimination using phonetic material based on polysyllabic balanced speech material. An improvement in the discrimination of the rippled spectrum was observed in all CI users from the experimental group. There was no significant improvement in the control group. The result of the speech discrimination test showed that the percentage of recognized words increased after training in nine out of ten CI users. For five CI users who participated in the training program, the data on word recognition were also obtained earlier (at least eight months before training). The increase in the percentage of recognized words was greater after training compared to the period before training. The results allow the suggestion that sound signals with rippled spectra could be used not only for testing rehabilitation results after CI but also for training CI users to discriminate sounds with complex spectra.
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17
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Ding AS, Lu A, Li Z, Galaiya D, Ishii M, Siewerdsen JH, Taylor RH, Creighton FX. Statistical Shape Model of the Temporal Bone Using Segmentation Propagation. Otol Neurotol 2022; 43:e679-e687. [PMID: 35761465 PMCID: PMC10072910 DOI: 10.1097/mao.0000000000003554] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Automated image registration techniques can successfully determine anatomical variation in human temporal bones with statistical shape modeling. BACKGROUND There is a lack of knowledge about inter-patient anatomical variation in the temporal bone. Statistical shape models (SSMs) provide a powerful method for quantifying variation of anatomical structures in medical images but are time-intensive to manually develop. This study presents SSMs of temporal bone anatomy using automated image-registration techniques. METHODS Fifty-three cone-beam temporal bone CTs were included for SSM generation. The malleus, incus, stapes, bony labyrinth, and facial nerve were automatically segmented using 3D Slicer and a template-based segmentation propagation technique. Segmentations were then used to construct SSMs using MATLAB. The first three principal components of each SSM were analyzed to describe shape variation. RESULTS Principal component analysis of middle and inner ear structures revealed novel modes of anatomical variation. The first three principal components for the malleus represented variability in manubrium length (mean: 4.47 mm; ±2-SDs: 4.03-5.03 mm) and rotation about its long axis (±2-SDs: -1.6° to 1.8° posteriorly). The facial nerve exhibits variability in first and second genu angles. The bony labyrinth varies in the angle between the posterior and superior canals (mean: 88.9°; ±2-SDs: 83.7°-95.7°) and cochlear orientation (±2-SDs: -4.0° to 3.0° anterolaterally). CONCLUSIONS SSMs of temporal bone anatomy can inform surgeons on clinically relevant inter-patient variability. Anatomical variation elucidated by these models can provide novel insight into function and pathophysiology. These models also allow further investigation of anatomical variation based on age, BMI, sex, and geographical location.
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Affiliation(s)
- Andy S. Ding
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Alexander Lu
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Zhaoshuo Li
- Department of Computer Science, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Deepa Galaiya
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Masaru Ishii
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jeffrey H. Siewerdsen
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
- Department of Computer Science, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Russell H. Taylor
- Department of Computer Science, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Francis X. Creighton
- Department of Otolaryngology – Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Berg KA, Noble JH, Dawant BM, Dwyer RT, Labadie RF, Gifford RH. Speech recognition as a function of the number of channels for Mid-Scala electrode array recipients. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:67. [PMID: 35931512 PMCID: PMC9984239 DOI: 10.1121/10.0012163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This study investigated the number of channels needed for maximum speech understanding and sound quality in 15 adult cochlear implant (CI) recipients with Advanced Bionics (AB) Mid-Scala electrode arrays completely within scala tympani. In experiment I, CI programs used a continuous interleaved sampling (CIS)-based strategy and 4-16 active electrodes. In experiment II, CI programs used an n-of-m strategy featuring 16 active electrodes with either 8- or 12-maxima. Speech understanding and sound quality measures were assessed. For CIS programs, participants demonstrated performance gains using up to 4-10 electrodes on speech measures and sound quality ratings. For n-of-m programs, there was no significant effect of maxima, suggesting 8-maxima is sufficient for this sample's maximum performance and sound quality. These results are largely consistent with previous studies using straight electrode arrays [e.g., Fishman, Shannon, and Slattery (1997). J. Speech Lang. Hear. Res. 40, 1201-1215; Friesen, Shannon, Baskent, and Wang (2001). J. Acoust. Soc. Am. 110, 1150-1163; Shannon, Cruz, and Galvin (2011). Audiol. Neurotol. 16, 113-123; Berg, Noble, Dawant, Dwyer, Labadie, and Gifford (2020). J. Acoust. Soc. Am. 147, 3646-3656] and in contrast with recent studies looking at cochlear precurved electrode arrays [e.g., Croghan, Duran, and Smith (2017). J. Acoust. Soc. Am. 142, EL537-EL543; Berg, Noble, Dawant, Dwuer, Labadie, and Gifford (2019b). J. Acoust. Soc. Am. 145, 1556-1564], which found continuous improvements up to 16 independent channels. These findings suggest that Mid-Scala electrode array recipients demonstrate similar channel independence to straight electrode arrays rather than other manufacturer's precurved electrode arrays.
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Affiliation(s)
- Katelyn A Berg
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
| | - Jack H Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, USA
| | - Benoit M Dawant
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, USA
| | - Robert T Dwyer
- Advanced Bionics, 28515 Westinghouse Place, Valencia, California 91355, USA
| | - Robert F Labadie
- Department of Otolaryngology, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
| | - René H Gifford
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
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19
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Arjmandi MK, Jahn KN, Arenberg JG. Single-Channel Focused Thresholds Relate to Vowel Identification in Pediatric and Adult Cochlear Implant Listeners. Trends Hear 2022; 26:23312165221095364. [PMID: 35505617 PMCID: PMC9073113 DOI: 10.1177/23312165221095364] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Speech recognition outcomes are highly variable among pediatric and adult cochlear implant (CI) listeners. Although there is some evidence that the quality of the electrode-neuron interface (ENI) contributes to this large variability in auditory perception, its relationship with speech outcomes is not well understood. Single-channel auditory detection thresholds measured in response to focused electrical fields (i.e., focused thresholds) are sensitive to properties of ENI quality, including electrode-neuron distance, intracochlear resistance, and neural health. In the present study, focused thresholds and speech perception abilities were assessed in 15 children and 21 adult CI listeners. Focused thresholds were measured for all active electrodes using a fast sweep procedure. Speech perception performance was evaluated by assessing listeners’ ability to identify vowels presented in /h-vowel-d/ context. Consistent with prior literature, focused thresholds were lower for children than for adults, but vowel identification did not differ significantly across age groups. Higher across-array average focused thresholds, which may indicate a relatively poor ENI quality, were associated with poorer vowel identification scores in both children and adults. Adult CI listeners with longer durations of deafness had higher focused thresholds. Findings from this study demonstrate that poor-quality ENIs may contribute to reduced speech outcomes for pediatric and adult CI listeners. Estimates of ENI quality (e.g., focused thresholds) may assist in developing customized programming interventions that serve to improve the transmission of spectral cues that are important in vowel identification.
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Affiliation(s)
- Meisam K Arjmandi
- Department of Otolaryngology - Head and Neck Surgery, 1811Harvard Medical School, Boston, MA, USA.,Eaton-Peabody Laboratories, 1866Massachusetts Eye and Ear, Boston, MA, USA.,Audiology Division, 1866Massachusetts Eye and Ear, Boston, MA, USA
| | - Kelly N Jahn
- Department of Otolaryngology - Head and Neck Surgery, 1811Harvard Medical School, Boston, MA, USA.,Eaton-Peabody Laboratories, 1866Massachusetts Eye and Ear, Boston, MA, USA.,Department of Speech, Language, and Hearing, University of Texas at Dallas, Richardson, TX, USA
| | - Julie G Arenberg
- Department of Otolaryngology - Head and Neck Surgery, 1811Harvard Medical School, Boston, MA, USA.,Eaton-Peabody Laboratories, 1866Massachusetts Eye and Ear, Boston, MA, USA.,Audiology Division, 1866Massachusetts Eye and Ear, Boston, MA, USA
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20
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Heshmat A, Sajedi S, Schrott-Fischer A, Rattay F. Polarity Sensitivity of Human Auditory Nerve Fibers Based on Pulse Shape, Cochlear Implant Stimulation Strategy and Array. Front Neurosci 2021; 15:751599. [PMID: 34955717 PMCID: PMC8692583 DOI: 10.3389/fnins.2021.751599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022] Open
Abstract
Neural health is of great interest to determine individual degeneration patterns for improving speech perception in cochlear implant (CI) users. Therefore, in recent years, several studies tried to identify and quantify neural survival in CI users. Among all proposed techniques, polarity sensitivity is a promising way to evaluate the neural status of auditory nerve fibers (ANFs) in CI users. Nevertheless, investigating neural health based on polarity sensitivity is a challenging and complicated task that involves various parameters, and the outcomes of many studies show contradictory results of polarity sensitivity behavior. Our computational study benefits from an accurate three-dimensional finite element model of a human cochlea with realistic human ANFs and determined ANF degeneration pattern of peripheral part with a diminishing of axon diameter and myelination thickness based on degeneration levels. In order to see how different parameters may impact the polarity sensitivity behavior of ANFs, we investigated polarity behavior under the application of symmetric and asymmetric pulse shapes, monopolar and multipolar CI stimulation strategies, and a perimodiolar and lateral CI array system. Our main findings are as follows: (1) action potential (AP) initiation sites occurred mainly in the peripheral site in the lateral system regardless of stimulation strategies, pulse polarities, pulse shapes, cochlear turns, and ANF degeneration levels. However, in the perimodiolar system, AP initiation sites varied between peripheral and central processes, depending on stimulation strategies, pulse shapes, and pulse polarities. (2) In perimodiolar array, clusters formed in threshold values based on cochlear turns and degeneration levels for multipolar strategies only when asymmetric pulses were applied. (3) In the perimodiolar array, a declining trend in polarity (anodic threshold/cathodic threshold) with multipolar strategies was observed between intact or slight degenerated cases and more severe degenerated cases, whereas in the lateral array, cathodic sensitivity was noticed for intact and less degenerated cases and anodic sensitivity for cases with high degrees of degeneration. Our results suggest that a combination of asymmetric pulse shapes, focusing more on multipolar stimulation strategies, as well as considering the distances to the modiolus wall, allows us to distinguish the degeneration patterns of ANFs across the cochlea.
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Affiliation(s)
- Amirreza Heshmat
- Institute for Analysis and Scientific Computing, Vienna University of Technology, Vienna, Austria.,Laboratory for Inner Ear Biology, Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Sogand Sajedi
- Institute for Analysis and Scientific Computing, Vienna University of Technology, Vienna, Austria
| | - Anneliese Schrott-Fischer
- Laboratory for Inner Ear Biology, Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Frank Rattay
- Institute for Analysis and Scientific Computing, Vienna University of Technology, Vienna, Austria
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21
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Fan Y, Zhang D, Banalagay R, Wang J, Noble JH, Dawant BM. Hybrid active shape and deep learning method for the accurate and robust segmentation of the intracochlear anatomy in clinical head CT and CBCT images. J Med Imaging (Bellingham) 2021; 8:064002. [PMID: 34853805 DOI: 10.1117/1.jmi.8.6.064002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 11/08/2021] [Indexed: 11/14/2022] Open
Abstract
Purpose: Robust and accurate segmentation methods for the intracochlear anatomy (ICA) are a critical step in the image-guided cochlear implant programming process. We have proposed an active shape model (ASM)-based method and a deep learning (DL)-based method for this task, and we have observed that the DL method tends to be more accurate than the ASM method while the ASM method tends to be more robust. Approach: We propose a DL-based U-Net-like architecture that incorporates ASM segmentation into the network. A quantitative analysis is performed on a dataset that consists of 11 cochlea specimens for which a segmentation ground truth is available. To qualitatively evaluate the robustness of the method, an experienced expert is asked to visually inspect and grade the segmentation results on a clinical dataset made of 138 image volumes acquired with conventional CT scanners and of 39 image volumes acquired with cone beam CT (CBCT) scanners. Finally, we compare training the network (1) first with the ASM results, and then fine-tuning it with the ground truth segmentation and (2) directly with the specimens with ground truth segmentation. Results: Quantitative and qualitative results show that the proposed method increases substantially the robustness of the DL method while having only a minor detrimental effect (though not significant) on its accuracy. Expert evaluation of the clinical dataset shows that by incorporating the ASM segmentation into the DL network, the proportion of good segmentation cases increases from 60/177 to 119/177 when training only with the specimens and increases from 129/177 to 151/177 when pretraining with the ASM results. Conclusions: A hybrid ASM and DL-based segmentation method is proposed to segment the ICA in CT and CBCT images. Our results show that combining DL and ASM methods leads to a solution that is both robust and accurate.
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Affiliation(s)
- Yubo Fan
- Vanderbilt University, Department of Computer Science, Nashville, Tennessee, United States
| | | | - Rueben Banalagay
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
| | - Jianing Wang
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
| | - Jack H Noble
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
| | - Benoit M Dawant
- Vanderbilt University, Department of Electrical and Computer Engineering, Nashville, Tennessee, United States
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22
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Inner-ear augmented metal artifact reduction with simulation-based 3D generative adversarial networks. Comput Med Imaging Graph 2021; 93:101990. [PMID: 34607275 DOI: 10.1016/j.compmedimag.2021.101990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 09/08/2021] [Accepted: 09/18/2021] [Indexed: 11/21/2022]
Abstract
Metal Artifacts creates often difficulties for a high quality visual assessment of post-operative imaging in computed tomography (CT). A vast body of methods have been proposed to tackle this issue, but these methods were designed for regular CT scans and their performance is usually insufficient when imaging tiny implants. In the context of post-operative high-resolution CT imaging, we propose a 3D metal artifact reduction algorithm based on a generative adversarial neural network. It is based on the simulation of physically realistic CT metal artifacts created by cochlea implant electrodes on preoperative images. The generated images serve to train a 3D generative adversarial networks for artifacts reduction. The proposed approach was assessed qualitatively and quantitatively on clinical conventional and cone beam CT of cochlear implant postoperative images. These experiments show that the proposed method outperforms other general metal artifact reduction approaches.
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23
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Carlyon RP, Goehring T. Cochlear Implant Research and Development in the Twenty-first Century: A Critical Update. J Assoc Res Otolaryngol 2021; 22:481-508. [PMID: 34432222 PMCID: PMC8476711 DOI: 10.1007/s10162-021-00811-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 08/02/2021] [Indexed: 12/22/2022] Open
Abstract
Cochlear implants (CIs) are the world's most successful sensory prosthesis and have been the subject of intense research and development in recent decades. We critically review the progress in CI research, and its success in improving patient outcomes, from the turn of the century to the present day. The review focuses on the processing, stimulation, and audiological methods that have been used to try to improve speech perception by human CI listeners, and on fundamental new insights in the response of the auditory system to electrical stimulation. The introduction of directional microphones and of new noise reduction and pre-processing algorithms has produced robust and sometimes substantial improvements. Novel speech-processing algorithms, the use of current-focusing methods, and individualised (patient-by-patient) deactivation of subsets of electrodes have produced more modest improvements. We argue that incremental advances have and will continue to be made, that collectively these may substantially improve patient outcomes, but that the modest size of each individual advance will require greater attention to experimental design and power. We also briefly discuss the potential and limitations of promising technologies that are currently being developed in animal models, and suggest strategies for researchers to collectively maximise the potential of CIs to improve hearing in a wide range of listening situations.
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Affiliation(s)
- Robert P Carlyon
- Cambridge Hearing Group, MRC Cognition & Brain Sciences Unit, University of Cambridge, Cambridge, CB2 7EF, UK.
| | - Tobias Goehring
- Cambridge Hearing Group, MRC Cognition & Brain Sciences Unit, University of Cambridge, Cambridge, CB2 7EF, UK
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24
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Geraldine Zuniga M, Lenarz T, Rau TS. Hydraulic insertions of cochlear implant electrode arrays into the human cadaver cochlea: preliminary findings. Eur Arch Otorhinolaryngol 2021; 279:2827-2835. [PMID: 34390390 PMCID: PMC9072458 DOI: 10.1007/s00405-021-06979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 07/02/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES (1) To evaluate the feasibility of a non-invasive, novel, simple insertion tool to perform automated, slow insertions of cochlear implant electrode arrays (EA) into a human cadaver cochlea; (2) to estimate the handling time required by our tool. METHODS Basic science study conducted in an experimental OR. Two previously anonymized human cadaver heads, three commercially available EAs, and our novel insertion tool were used for the experiments. Our tool operates as a hydraulic actuator that delivers an EA at continuous velocities slower than manually feasible. INTERVENTION(S) the human cadaver heads were prepared with a round-window approach for CI surgery in a standard fashion. Twelve EA insertion trials using our tool involved: non-invasive fixation of the tool to the head; directing the tool to the round window and EA mounting onto the tool; automated EA insertion at approximately 0.1 mm/s driven by hydraulic actuation. Outcome measurement(s): handling time of the tool; post-insertion cone-beam CT scans to provide intracochlear evaluation of the EA insertions. RESULTS Our insertion tool successfully inserted an EA into the human cadaver cochlea (n = 12) while being attached to the human cadaver head in a non-invasive fashion. Median time to set up the tool was 8.8 (7.2-9.4) min. CONCLUSION The first insertions into the human cochlea using our novel, simple insertion tool were successful without the need for invasive fixation. The tool requires < 10 min to set up, which is clinically acceptable. Future assessment of intracochlear trauma is needed to support its safety profile for clinical translation.
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Affiliation(s)
- M Geraldine Zuniga
- Department of Otolaryngology and Cluster of Excellence Hearing4all, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Thomas Lenarz
- Department of Otolaryngology and Cluster of Excellence Hearing4all, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thomas S Rau
- Department of Otolaryngology and Cluster of Excellence Hearing4all, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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Jahn KN, Arenberg JG. Identifying Cochlear Implant Channels With Relatively Poor Electrode-Neuron Interfaces Using the Electrically Evoked Compound Action Potential. Ear Hear 2021; 41:961-973. [PMID: 31972772 PMCID: PMC10443089 DOI: 10.1097/aud.0000000000000844] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The primary objective of this study was to quantify local (within ear) and global (between ear) variation in the cochlear implant (CI) electrode-neuron interface (ENI) using the electrically evoked compound action potential (ECAP). We tested the hypothesis that, within an ear, ECAP measures can be used to identify channels with presumed good and poor ENIs, which may be influenced by a combination of spiral ganglion neuron (SGN) density, electrode position, and cochlear resistivity. We also hypothesized that ECAP responses would reflect age-related differences in the global quality of the ENI between younger and older listeners who theoretically differ in SGN density. DESIGN Data were obtained from 18 implanted ears (13 individuals) with Advanced Bionics HiRes 90K devices. Six participants (8 ears) were adolescents or young adults (age range: 14-32 years), and 7 participants (10 ears) were older adults (age range: 54-88 years). In each ear, single-channel auditory detection thresholds were measured on channels 2 through 15 in response to a spatially focused electrode configuration (steered quadrupolar; focusing coefficient = 0.9). ECAP amplitudes, amplitude growth function (AGF) slopes, and thresholds were assessed on a subset of channels in each ear in response to three interphase gaps (0, 7, and 30 µs). ECAP peak amplitudes were assessed on all channels between 2 and 15. AGFs and ECAP thresholds were measured on the two nonadjacent channels with the lowest and highest focused behavioral thresholds in each ear. ECAP responses were compared across low- and high-threshold channels and between younger and older CI listeners. RESULTS Channels that were estimated to interface poorly with the auditory nerve (i.e., high-focused-threshold channels) had steeper ECAP AGF slopes, smaller dynamic ranges, and higher ECAP thresholds than channels with low focused thresholds. Younger listeners had steeper ECAP AGF slopes and larger ECAP peak amplitudes than older listeners. Moreover, younger listeners showed greater interphase gap sensitivity for ECAP amplitude than older listeners. CONCLUSIONS ECAP responses may be used to quantify both local (within ear) and global (between ear) variation in the quality of the ENI. Results of this study support future investigation into the use of ECAP responses in site-selection CI programming strategies. The present results also support a growing body of evidence suggesting that adolescents and young adults with CIs may have denser populations of functional SGNs relative to older adults. Potential differences in global SGN integrity between younger and older listeners warrant investigation of optimal CI programming interventions based on their divergent hearing histories.
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Affiliation(s)
- Kelly N. Jahn
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA 02114, USA
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114, USA
| | - Julie G. Arenberg
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA 02114, USA
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114, USA
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Xu K, Willis S, Gopen Q, Fu QJ. Effects of Spectral Resolution and Frequency Mismatch on Speech Understanding and Spatial Release From Masking in Simulated Bilateral Cochlear Implants. Ear Hear 2021; 41:1362-1371. [PMID: 32132377 DOI: 10.1097/aud.0000000000000865] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Due to interaural frequency mismatch, bilateral cochlear-implant (CI) users may be less able to take advantage of binaural cues that normal-hearing (NH) listeners use for spatial hearing, such as interaural time differences and interaural level differences. As such, bilateral CI users have difficulty segregating competing speech even when the target and competing talkers are spatially separated. The goal of this study was to evaluate the effects of spectral resolution, tonotopic mismatch (the frequency mismatch between the acoustic center frequency assigned to CI electrode within an implanted ear relative to the expected spiral ganglion characteristic frequency), and interaural mismatch (differences in the degree of tonotopic mismatch in each ear) on speech understanding and spatial release from masking (SRM) in the presence of competing talkers in NH subjects listening to bilateral vocoder simulations. DESIGN During testing, both target and masker speech were presented in five-word sentences that had the same syntax but were not necessarily meaningful. The sentences were composed of five categories in fixed order (Name, Verb, Number, Color, and Clothes), each of which had 10 items, such that multiple sentences could be generated by randomly selecting a word from each category. Speech reception thresholds (SRTs) for the target sentence presented in competing speech maskers were measured. The target speech was delivered to both ears and the two speech maskers were delivered to (1) both ears (diotic masker), or (2) different ears (dichotic masker: one delivered to the left ear and the other delivered to the right ear). Stimuli included the unprocessed speech and four 16-channel sine-vocoder simulations with different interaural mismatch (0, 1, and 2 mm). SRM was calculated as the difference between the diotic and dichotic listening conditions. RESULTS With unprocessed speech, SRTs were 0.3 and -18.0 dB for the diotic and dichotic maskers, respectively. For the spectrally degraded speech with mild tonotopic mismatch and no interaural mismatch, SRTs were 5.6 and -2.0 dB for the diotic and dichotic maskers, respectively. When the tonotopic mismatch increased in both ears, SRTs worsened to 8.9 and 2.4 dB for the diotic and dichotic maskers, respectively. When the two ears had different tonotopic mismatch (e.g., there was interaural mismatch), the performance drop in SRTs was much larger for the dichotic than for the diotic masker. The largest SRM was observed with unprocessed speech (18.3 dB). With the CI simulations, SRM was significantly reduced to 7.6 dB even with mild tonotopic mismatch but no interaural mismatch; SRM was further reduced with increasing interaural mismatch. CONCLUSIONS The results demonstrate that frequency resolution, tonotopic mismatch, and interaural mismatch have differential effects on speech understanding and SRM in simulation of bilateral CIs. Minimizing interaural mismatch may be critical to optimize binaural benefits and improve CI performance for competing speech, a typical listening environment. SRM (the difference in SRTs between diotic and dichotic maskers) may be a useful clinical tool to assess interaural frequency mismatch in bilateral CI users and to evaluate the benefits of optimization methods that minimize interaural mismatch.
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Affiliation(s)
- Kevin Xu
- Department of Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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Helpard L, Li H, Rohani SA, Zhu N, Rask-Andersen H, Agrawal S, Ladak HM. An Approach for Individualized Cochlear Frequency Mapping Determined from 3D Synchrotron Radiation Phase-Contrast Imaging. IEEE Trans Biomed Eng 2021; 68:3602-3611. [PMID: 33983877 DOI: 10.1109/tbme.2021.3080116] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Cochlear implants are traditionally programmed to stimulate according to a generalized frequency map, where individual anatomic variability is not considered when selecting the centre frequency of stimulation of each implant electrode. However, high variability in cochlear size and spatial frequency distributions exist among individuals. Generalized cochlear implant frequency maps can result in large pitch perception errors and reduced hearing outcomes for cochlear implant recipients. The objective of this work was to develop an individualized frequency mapping technique for the human cochlea to allow for patient-specific cochlear implant stimulation. METHODS Ten cadaveric human cochleae were scanned using synchrotron radiation phase-contrast imaging (SR-PCI) combined with computed tomography (CT). For each cochlea, ground truth angle-frequency measurements were obtained in three-dimensions using the SR-PCI CT data. Using an approach designed to minimize perceptual error in frequency estimation, an individualized frequency function was determined to relate angular depth to frequency within the cochlea. RESULTS The individualized frequency mapping function significantly reduced pitch errors in comparison to the current gold standard generalized approach. CONCLUSION AND SIGNIFICANCE This paper presents for the first time a cochlear frequency map which can be individualized using only the angular length of cochleae. This approach can be applied in the clinical setting and has the potential to revolutionize cochlear implant programming for patients worldwide.
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Schvartz-Leyzac KC, Zwolan TA, Pfingst BE. Using the electrically-evoked compound action potential (ECAP) interphase gap effect to select electrode stimulation sites in cochlear implant users. Hear Res 2021; 406:108257. [PMID: 34020316 DOI: 10.1016/j.heares.2021.108257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/25/2021] [Accepted: 04/19/2021] [Indexed: 10/21/2022]
Abstract
Studies in cochlear implanted animals show that the IPG Effect for ECAP growth functions (i.e., the magnitude of the change in ECAP amplitude growth function (AGF) slope or peak amplitude when the interphase gap (IPG) is increased) can be used to estimate the densities of spiral ganglion neurons (SGNs) near the electrode stimulation and recording sites. In humans, the same ECAP IPG Effect measures correlate with speech recognition performance. The present study examined the efficacy of selecting electrode sites for stimulation based on the IPG Effect, in order to improve performance of CI users on speech recognition tasks. We measured the ECAP IPG Effect for peak amplitude in adult (>18 years old) CI users (N= 18 ears), and created experimental programs to stimulate electrodes with either the highest or lowest ECAP IPG Effect for peak amplitude. Subjects also listened to a program without any electrodes deactivated. In a subset of subject ears (11/18), we compared performance differences between the experimental programs to post-operative computerized tomography (CT) scans to examine underlying factors that might contribute to the efficacy of an electrode site-selection approach. For sentences-in-noise, average performance was better when subjects listened to the experimental program that stimulated electrodes with the highest rather than the lowest IPG Effect for ECAP peak amplitude. A similar pattern was noted for transmission and perception of consonant place cues in a consonant recognition task. However, on average, performance when listening to a program with higher IPG Effect values was equal to that when listening with all electrodes activated. Results also suggest that scalar location (scala tympani or vestibuli) should be considered when using an ECAP-based electrode site-selection procedure to optimize CI performance.
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Affiliation(s)
- Kara C Schvartz-Leyzac
- Kresge Hearing Research Institute, Department of Otolaryngology, Michigan Medicine, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5616, United States; Hearing Rehabilitation Center, Department of Otolaryngology, Michigan Medicine, 475 W. Market Place, Building 1, Suite A, Ann Arbor, MI 48108, United States.
| | - Teresa A Zwolan
- Hearing Rehabilitation Center, Department of Otolaryngology, Michigan Medicine, 475 W. Market Place, Building 1, Suite A, Ann Arbor, MI 48108, United States
| | - Bryan E Pfingst
- Kresge Hearing Research Institute, Department of Otolaryngology, Michigan Medicine, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5616, United States
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Archer-Boyd AW, Goehring T, Carlyon RP. The Effect of Free-Field Presentation and Processing Strategy on a Measure of Spectro-Temporal Processing by Cochlear-Implant Listeners. Trends Hear 2021; 24:2331216520964281. [PMID: 33305696 PMCID: PMC7734493 DOI: 10.1177/2331216520964281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is a psychophysical test of spectro-temporal resolution developed for cochlear-implant (CI) listeners. Previously, the test has been strictly controlled to minimize the introduction of extraneous, nonspectro-temporal cues. Here, the effect of relaxing many of those controls was investigated to ascertain the generalizability of the STRIPES test. Preemphasis compensation was removed from the STRIPES stimuli, the test was presented over a loudspeaker at a level similar to conversational speech and above the automatic gain control threshold of the CI processor, and listeners were tested using the everyday setting of their clinical devices. There was no significant difference in STRIPES thresholds measured across conditions for the 10 CI listeners tested. One listener obtained higher (better) thresholds when listening with their clinical processor. An analysis of longitudinal results showed excellent test–retest reliability of STRIPES over multiple listening sessions with similar conditions. Overall, the results show that the STRIPES test is robust to extraneous cues, and that thresholds are reliable over time. It is sufficiently robust for use with different processing strategies, free-field presentation, and in nonresearch settings.
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Affiliation(s)
- Alan W Archer-Boyd
- Cambridge Hearing Group, MRC Cognition and Brain Sciences Unit, 2152University of Cambridge, Cambridge, United Kingdom
| | - Tobias Goehring
- Cambridge Hearing Group, MRC Cognition and Brain Sciences Unit, 2152University of Cambridge, Cambridge, United Kingdom
| | - Robert P Carlyon
- Cambridge Hearing Group, MRC Cognition and Brain Sciences Unit, 2152University of Cambridge, Cambridge, United Kingdom
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Berg KA, Noble JH, Dawant BM, Dwyer RT, Labadie RF, Gifford RH. Speech recognition as a function of the number of channels for an array with large inter-electrode distances. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:2752. [PMID: 33940865 PMCID: PMC8062138 DOI: 10.1121/10.0004244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 05/28/2023]
Abstract
This study investigated the number of channels available to cochlear implant (CI) recipients for maximum speech understanding and sound quality for lateral wall electrode arrays-which result in large electrode-to-modiolus distances-featuring the greatest inter-electrode distances (2.1-2.4 mm), the longest active lengths (23.1-26.4 mm), and the fewest number of electrodes commercially available. Participants included ten post-lingually deafened adult CI recipients with MED-EL electrode arrays (FLEX28 and STANDARD) entirely within scala tympani. Electrode placement and scalar location were determined using computerized tomography. The number of channels was varied from 4 to 12 with equal spatial distribution across the array. A continuous interleaved sampling-based strategy was used. Speech recognition, sound quality ratings, and a closed-set vowel recognition task were measured acutely for each electrode condition. Participants did not demonstrate statistically significant differences beyond eight channels at the group level for almost all measures. However, several listeners showed considerable improvements from 8 to 12 channels for speech and sound quality measures. These results suggest that channel interaction caused by the greater electrode-to-modiolus distances of straight electrode arrays could be partially compensated for by a large inter-electrode distance or spacing.
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Affiliation(s)
- Katelyn A Berg
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
| | - Jack H Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, USA
| | - Benoit M Dawant
- Department of Electrical Engineering and Computer Science, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, USA
| | - Robert T Dwyer
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
| | - Robert F Labadie
- Department of Otolaryngology, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
| | - René H Gifford
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA
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Dillon MT, Canfarotta MW, Buss E, Hopfinger J, O'Connell BP. Effectiveness of Place-based Mapping in Electric-Acoustic Stimulation Devices. Otol Neurotol 2021; 42:197-202. [PMID: 33885267 PMCID: PMC8787166 DOI: 10.1097/mao.0000000000002965] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The default mapping procedure for electric-acoustic stimulation (EAS) devices uses the cochlear implant recipient's unaided detection thresholds in the implanted ear to derive the acoustic settings and assign the lowest frequency filter of electric stimulation. Individual differences for speech recognition with EAS may be due to discrepancies between the electric frequency filters of individual electrode contacts and the cochlear place of stimulation, known as a frequency-to-place mismatch. Frequency-to-place mismatch of greater than 1/2 octave has been demonstrated in up to 60% of EAS users. Aligning the electric frequency filters via a place-based mapping procedure using postoperative imaging may improve speech recognition with EAS. METHODS Masked sentence recognition was evaluated for normal-hearing subjects (n = 17) listening with vocoder simulations of EAS, using a place-based map and a default map. Simulation parameters were based on audiometric and imaging data from a representative 24-mm electrode array recipient and EAS user. The place-based map aligned electric frequency filters with the cochlear place frequency, which introduced a gap between the simulated acoustic and electric output. The default map settings were derived from the clinical programming software and provided the full speech frequency range. RESULTS Masked sentence recognition was significantly better for simulated EAS with the place-based map as compared with the default map. CONCLUSION The simulated EAS place-based map supported better performance than the simulated EAS default map. This indicates that individualizing maps may improve performance in EAS users by helping them achieve better asymptotic performance earlier and mitigate the need for acclimatization.
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Affiliation(s)
- Margaret T Dillon
- Department of Otolaryngology/Head and Neck Surgery, School of Medicine
- Division of Speech & Hearing, Department of Allied Health Sciences
| | | | - Emily Buss
- Department of Otolaryngology/Head and Neck Surgery, School of Medicine
| | - Joseph Hopfinger
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, North Carolina
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Abstract
INTRODUCTION Cochlear implants (CIs) are biomedical devices that restore sound perception for people with severe-to-profound sensorineural hearing loss. Most postlingually deafened CI users are able to achieve excellent speech recognition in quiet environments. However, current CI sound processors remain limited in their ability to deliver fine spectrotemporal information, making it difficult for CI users to perceive complex sounds. Limited access to complex acoustic cues such as music, environmental sounds, lexical tones, and voice emotion may have significant ramifications on quality of life, social development, and community interactions. AREAS COVERED The purpose of this review article is to summarize the literature on CIs and music perception, with an emphasis on music training in pediatric CI recipients. The findings have implications on our understanding of noninvasive, accessible methods for improving auditory processing and may help advance our ability to improve sound quality and performance for implantees. EXPERT OPINION Music training, particularly in the pediatric population, may be able to continue to enhance auditory processing even after performance plateaus. The effects of these training programs appear generalizable to non-trained musical tasks, speech prosody and, emotion perception. Future studies should employ rigorous control groups involving a non-musical acoustic intervention, standardized auditory stimuli, and the provision of feedback.
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Affiliation(s)
- Nicole T Jiam
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco School of Medicine , San Francisco, CA, USA
| | - Charles Limb
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco School of Medicine , San Francisco, CA, USA
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Auditory Nerve Fiber Health Estimation Using Patient Specific Cochlear Implant Stimulation Models. ACTA ACUST UNITED AC 2020. [PMID: 33884380 DOI: 10.1007/978-3-030-59520-3_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Cochlear implants (CIs) restore hearing using an array of electrodes implanted in the cochlea to directly stimulate auditory nerve fibers (ANFs). Hearing outcomes with CIs are dependent on the health of the ANFs. In this research, we developed an approach to estimate the health of ANFs using patient-customized, image-based computational models of CI stimulation. Our stimulation models build on a previous model-based solution to estimate the intra-cochlear electric field (EF) created by the CI. Herein, we propose to use the estimated EF to drive ANF models representing 75 nerve bundles along the length of the cochlea. We propose a method to detect the neural health of the ANF models by optimizing neural health parameters to minimize the sum of squared differences between simulated and the physiological measurements available via patients' CIs. The resulting health parameters provide an estimate of the health of ANF bundles. Experiments with 8 subjects show promising model prediction accuracy, with excellent agreement between neural stimulation responses that are clinically measured and those that are predicted by our parameter optimized models. These results suggest our modeling approach may provide an accurate estimation of ANF health for CI users.
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Goehring T, Arenberg JG, Carlyon RP. Using Spectral Blurring to Assess Effects of Channel Interaction on Speech-in-Noise Perception with Cochlear Implants. J Assoc Res Otolaryngol 2020; 21:353-371. [PMID: 32519088 PMCID: PMC7445227 DOI: 10.1007/s10162-020-00758-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/21/2020] [Indexed: 01/07/2023] Open
Abstract
Cochlear implant (CI) listeners struggle to understand speech in background noise. Interactions between electrode channels due to current spread increase the masking of speech by noise and lead to difficulties with speech perception. Strategies that reduce channel interaction therefore have the potential to improve speech-in-noise perception by CI listeners, but previous results have been mixed. We investigated the effects of channel interaction on speech-in-noise perception and its association with spectro-temporal acuity in a listening study with 12 experienced CI users. Instead of attempting to reduce channel interaction, we introduced spectral blurring to simulate some of the effects of channel interaction by adjusting the overlap between electrode channels at the input level of the analysis filters or at the output by using several simultaneously stimulated electrodes per channel. We measured speech reception thresholds in noise as a function of the amount of blurring applied to either all 15 electrode channels or to 5 evenly spaced channels. Performance remained roughly constant as the amount of blurring applied to all channels increased up to some knee point, above which it deteriorated. This knee point differed across listeners in a way that correlated with performance on a non-speech spectro-temporal task, and is proposed here as an individual measure of channel interaction. Surprisingly, even extreme amounts of blurring applied to 5 channels did not affect performance. The effects on speech perception in noise were similar for blurring at the input and at the output of the CI. The results are in line with the assumption that experienced CI users can make use of a limited number of effective channels of information and tolerate some deviations from their everyday settings when identifying speech in the presence of a masker. Furthermore, these findings may explain the mixed results by strategies that optimized or deactivated a small number of electrodes evenly distributed along the array by showing that blurring or deactivating one-third of the electrodes did not harm speech-in-noise performance.
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Affiliation(s)
- Tobias Goehring
- Cambridge Hearing Group, Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK.
| | - Julie G Arenberg
- Massachusetts Eye and Ear, Harvard Medical School, 243 Charles St, Boston, MA, 02114, USA
| | - Robert P Carlyon
- Cambridge Hearing Group, Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
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Auditory performance of post-lingually deafened adult cochlear implant recipients using electrode deactivation based on postoperative cone beam CT images. Eur Arch Otorhinolaryngol 2020; 278:977-986. [PMID: 32588169 DOI: 10.1007/s00405-020-06156-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/18/2020] [Indexed: 01/04/2023]
Abstract
PURPOSE The use of image processing techniques to estimate the position of intra-cochlear electrodes has enabled the creation of personalized maps to meet the individual stimulation needs of cochlear implant (CI) recipients. The aim of this study was to evaluate a novel technique of electrode deactivation based on postoperative cone beam computed tomography (CBCT) images in post-lingually deafened adult CI recipients. METHODS Based on postoperative CBCT images, the positioning of the electrodes was estimated in relation to the modiolus in 14 ears of 13 post-lingually deafened adult CI recipients. The electrodes sub-optimally positioned or involved in kinking and tip fold-over were deactivated. Speech perception scores in silence and in noise were obtained from subjects using the standard map and were followed up 4 weeks after image-based electrode deactivation reprogramming technique (IBEDRT). The participants selected their preferred map after 4 weeks of IBEDRT use. RESULTS There were statistically significant improvements in the speech recognition tests in silence and noise when comparing IBEDRT performance to the standard map. All participants elected the IBEDRT as their new preferred map. CONCLUSIONS IBEDRT is a promising technique for fitting CI recipients and minimizing channel interaction increased by the positioning of the electrodes sub-optimally placed, thereby improving their auditory performance. We propose a novel electrode deactivation technique based on postoperative CBCT imaging, with a limited number of deactivated electrodes and a low-dosing scanning which could be applied for clinical routine.
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Angular Electrode Insertion Depth and Speech Perception in Adults With a Cochlear Implant: A Systematic Review. Otol Neurotol 2020; 40:900-910. [PMID: 31135680 PMCID: PMC6641467 DOI: 10.1097/mao.0000000000002298] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objective: By discussing the design, findings, strengths, and weaknesses of available studies investigating the influence of angular insertion depth on speech perception, we intend to summarize the current status of evidence; and using evidence based conclusions, possibly contribute to the determination of the optimal cochlear implant (CI) electrode position. Data Sources: Our search strategy yielded 10,877 papers. PubMed, Ovid EMBASE, Web of Science, and the Cochrane Library were searched up to June 1, 2018. Both keywords and free-text terms, related to patient population, predictive factor, and outcome measurements were used. There were no restrictions in languages or year of publication. Study Selection: Seven articles were included in this systematic review. Articles eligible for inclusion: (a) investigated cochlear implantation of any CI system in adults with post-lingual onset of deafness and normal cochlear anatomy; (b) investigated the relationship between angular insertion depth and speech perception; (c) measured angular insertion depth on imaging; and (d) measured speech perception at, or beyond 1-year post-activation. Data Extraction and Synthesis: In included studies; quality was judged low-to-moderate and risk of bias, evaluated using a Quality-in-Prognostic-Studies-tool (QUIPS), was high. Included studies were too heterogeneous to perform meta-analyses, therefore, effect estimates of the individual studies are presented. Six out of seven included studies found no effect of angular insertion depth on speech perception. Conclusion: All included studies are characterized by methodological flaws, and therefore, evidence-based conclusions regarding the influence of angular insertion depth cannot be drawn to date.
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Assessing Cochlear Implant Insertion Angle From an Intraoperative X-ray Using a Rotating 3D Helical Scala Tympani Model. Otol Neurotol 2020; 41:e686-e694. [DOI: 10.1097/mao.0000000000002638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
OBJECTIVES The Quick Spectral Modulation Detection (QSMD) test provides a quick and clinically implementable spectral resolution estimate for cochlear implant (CI) users. However, the original QSMD software (QSMD(MySound)) has technical and usability limitations that prevent widespread distribution and implementation. In this article, we introduce a new software package EasyQSMD, which is freely available software with the goal of both simplifying and standardizing spectral resolution measurements. DESIGN QSMD was measured for 20 CI users using both software packages. RESULTS No differences between the two software packages were detected, and based on the 95% confidence interval of the difference between tests, the difference between the tests is expected to be <2% points. The average test duration was under 4 minutes. CONCLUSIONS EasyQSMD is considered functionally equivalent to QSMD(MySound) providing a clinically feasible and quick estimate of spectral resolution for CI users.
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Zhang D, Wang J, Noble JH, Dawant BM. HeadLocNet: Deep convolutional neural networks for accurate classification and multi-landmark localization of head CTs. Med Image Anal 2020; 61:101659. [PMID: 32062157 PMCID: PMC7959656 DOI: 10.1016/j.media.2020.101659] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 01/19/2023]
Abstract
Cochlear implants (CIs) are used to treat subjects with hearing loss. In a CI surgery, an electrode array is inserted into the cochlea to stimulate auditory nerves. After surgery, CIs need to be programmed. Studies have shown that the cochlea-electrode spatial relationship derived from medical images can guide CI programming and lead to significant improvement in hearing outcomes. We have developed a series of algorithms to segment the inner ear anatomy and localize the electrodes. But, because clinical head CT images are acquired with different protocols, the field of view and orientation of the image volumes vary greatly. As a consequence, visual inspection and manual image registration to an atlas image are needed to document their content and to initialize intensity-based registration algorithms used in our processing pipeline. For large-scale evaluation and deployment of our methods these steps need to be automated. In this article we propose to achieve this with a deep convolutional neural network (CNN) that can be trained end-to-end to classify a head CT image in terms of its content and to localize landmarks. The detected landmarks can then be used to estimate a point-based registration with the atlas image in which the same landmark set's positions are known. We achieve 99.5% classification accuracy and an average localization error of 3.45 mm for 7 landmarks located around each inner ear. This is better than what was achieved with earlier methods we have proposed for the same tasks.
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Affiliation(s)
- Dongqing Zhang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA.
| | - Jianing Wang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jack H Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Benoit M Dawant
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA.
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Comparison of Skull Radiograph and Computed Tomography Measurements of Cochlear Implant Insertion Angles. Otol Neurotol 2020; 40:e298-e303. [PMID: 30741910 DOI: 10.1097/mao.0000000000002121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Measurement of the angular depth of insertion (aDOI) of cochlear implant electrode arrays has numerous clinical and research applications. Plain-film radiographs are easily obtained intraoperatively and have been described as a means to calculate aDOI. CT imaging with 3D reformatting can also be used for this measurement, but is less conveniently obtained and requires higher radiation doses, a particular concern in pediatrics. The extent to which plain-film and 3D CT image-based measurements are representative of the true position of the electrode within the cochlea is unknown. METHODS Cochlear implantation was performed on 10 cadaveric temporal bones. Five bones were implanted with perimodiolar electrodes (Contour Advance TM, Cochlear, Sydney, Australia) and five were implanted with lateral wall electrodes (Slim Straight, Cochlear). The insertion depths of the electrodes were varied. Each bone was imaged with a radiograph and CT. aDOI was measured for each bone in each imaging modality by a neurotologist and a neuroradiologist. To obtain a 'gold standard' estimate of aDOI, the implanted temporal bones were embedded in an epoxy resin and methodically sectioned at 100 μm intervals; histologic images were captured at each interval. A 3D stack of the images was compounded, and a MATLAB script used to calculate aDOI of the most apical electrode. Measurements in the three modalities (radiograph, CT, and histology) were then compared. RESULTS The average aDOI across all bones was similar for all modalities: 423° for radiographs, 425° for CT scans, and 427° for histology, indicating that neither imaging modality resulted in large systematic errors. Using the histology-measured angles as a reference, the average error for CT-based measures (regardless of whether the error was in the positive or negative direction) was 12°, and that for radiograph-based measures was 15°. This small difference (12 vs 15° error) was not statistically significant. CONCLUSION Based on this cadaveric temporal bone model, both radiographs and CTs can provide reasonably accurate aDOI measurements. In this small sample, and as expected, the CT-based estimates were more accurate than the radiograph-based measurements. However, the difference was small and not statistically significant. Thus, the use of plain radiographs to calculate aDOI seems judicious whenever it is desired to prevent unnecessary radiation exposure and expense.
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Abstract
OBJECTIVE Cochlear implant (CI) users struggle with pitch perception, particularly for polyphonic stimuli. Tripolar (TP) stimulation has been proposed as a way to mitigate the broad spread of neural excitation observed in traditional monopolar (MP) stimulation, thereby potentially improving perception of polyphony. STUDY DESIGN Prospective cohort study. SETTING Tertiary academic center. PATIENTS Eleven postlingually deafened adults with Advanced Bionics HiRes 90K CIs. INTERVENTION(S) We performed pitch ranking and polyphonic pitch detection testing under MP and TP configurations. To assess pitch ranking, users were asked to identify the higher pitch between two notes. In polyphonic pitch detection, users were asked to distinguish between single-pitch tones and two-pitch tones. Two-pitch stimuli consisted of one pitch of three base frequencies (392, 523, 740 Hz) and a second pitch between 1 and 12 semitones above the base frequency. MAIN OUTCOME MEASURE Pitch performance was analyzed as a function of current delivery mode (tripolar vs. monopolar), with smaller semitone interval pitch resolution indicating better performance. RESULTS In pitch ranking tasks, TP configuration did not confer an advantage over MP stimulation. In polyphonic perception, however, tripolar stimulation improved performance in lower frequencies and resulted in statistically significant (p < 0.05) improvement at the highest base frequency, 740 Hz. CONCLUSIONS These data suggest that TP configuration may confer an advantage in the perception of polyphonic pitch, which may not be observed in monophonic pitch ranking tasks. Since music is typically polyphonic, such data offer approaches toward improving perception of real-world musical stimuli.
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Wess JM, Spencer NJ, Bernstein JGW. Counting or discriminating the number of voices to assess binaural fusion with single-sided vocoders. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:446. [PMID: 32006956 PMCID: PMC7043860 DOI: 10.1121/10.0000511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
For single-sided deafness cochlear-implant (SSD-CI) listeners, different peripheral representations for electric versus acoustic stimulation, combined with interaural frequency mismatch, might limit the ability to perceive bilaterally presented speech as a single voice. The assessment of binaural fusion often relies on subjective report, which requires listeners to have some understanding of the perceptual phenomenon of object formation. Two experiments explored whether binaural fusion could instead be assessed using judgments of the number of voices in a mixture. In an SSD-CI simulation, normal-hearing listeners were presented with one or two "diotic" voices (i.e., unprocessed in one ear and noise-vocoded in the other) in a mixture with additional monaural voices. In experiment 1, listeners reported how many voices they heard. Listeners generally counted the diotic speech as two separate voices, regardless of interaural frequency mismatch. In experiment 2, listeners identified which of two mixtures contained diotic speech. Listeners performed significantly better with interaurally frequency-matched than with frequency-mismatched stimuli. These contrasting results suggest that listeners experienced partial fusion: not enough to count the diotic speech as one voice, but enough to detect its presence. The diotic-speech detection task (experiment 2) might provide a tool to evaluate fusion and optimize frequency mapping for SSD-CI patients.
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Affiliation(s)
- Jessica M Wess
- National Military Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland 20889, USA
| | - Nathaniel J Spencer
- Air Force Research Laboratory, Wright Patterson Air Force Base, Ohio 45433, USA
| | - Joshua G W Bernstein
- National Military Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland 20889, USA
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Kreft HA, DeVries LA, Arenberg JG, Oxenham AJ. Comparing Rapid and Traditional Forward-Masked Spatial Tuning Curves in Cochlear-Implant Users. Trends Hear 2019; 23:2331216519851306. [PMID: 31134842 PMCID: PMC6540501 DOI: 10.1177/2331216519851306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A rapid forward-masked spatial tuning curve measurement procedure, based on Bekesy tracking, was adapted and evaluated for use with cochlear implants. Twelve postlingually-deafened adult cochlear-implant users participated. Spatial tuning curves using the new procedure and using a traditional forced-choice adaptive procedure resulted in similar estimates of parameters. The Bekesy-tracking method was almost 3 times faster than the forced-choice procedure, but its test-retest reliability was significantly poorer. Although too time-consuming for general clinical use, the new method may have some benefits in individual cases, where identifying electrodes with poor spatial selectivity as candidates for deactivation is deemed necessary.
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Affiliation(s)
- Heather A Kreft
- 1 Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - Lindsay A DeVries
- 2 Department Hearing and Speech Sciences, University of Maryland, College Park, MD, USA
| | - Julie G Arenberg
- 3 Department of Otolaryngology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Andrew J Oxenham
- 1 Department of Psychology, University of Minnesota, Minneapolis, MN, USA
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Abstract
HYPOTHESIS Using patient-customized cochlear measurements obtained from preoperative computed tomography (CT) scans to guide insertion of cochlear implant (CI) electrode arrays will lead to more optimal intracochlear positioning. BACKGROUND Cochlear duct length is highly variable ranging from 25.26 to 35.46 mm, yet CI electrode arrays are treated as one size fits most. We sought to investigate the impact of patient-customized insertion plans on final location of electrode arrays. METHODS Twenty cadaveric temporal bone specimens were CT scanned and randomly divided into groups A and B. Group A specimens had an optimal customized insertion plan generated including entry site (e.g., round window versus extended round window), entry vector based on anatomical landmarks (e.g., hug posterior aspect of facial recess and angle 1 mm inferior to stapes), depth to begin advancing off stylet, and final insertion depth. Suboptimal plans were chosen for group B by selecting an approach that was normal yet predicted to result in poor final electrode location. One surgeon, blinded as to group, carried out the CI insertions following which the electrode array was fixed using superglue and the specimen CT scanned to allow assessment of final electrode location. RESULTS Average perimodiolar distances for groups A and B were 0.51 and 0.60 mm, respectively. For group A, full scala tympani insertion was achieved in all specimens while in group B, 4 of 10 specimens had scalar translocation. CONCLUSION Patient customized cochlear implant insertion techniques achieved better positioning of electrode arrays in this study and have potential for improving electrode positioning in patients.
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Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports. Otol Neurotol 2019; 39:e325-e331. [PMID: 29738386 DOI: 10.1097/mao.0000000000001818] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To quantify and compare the number of cochlear implant (CI) electrodes found to be extracochlear on postoperative computerized tomography (CT) scans, the number of basal electrodes deactivated during standard CI mapping (without knowledge of the postoperative CT scan), and the extent of electrode insertion noted by the surgeon. STUDY DESIGN Retrospective. SETTING Academic Medical Center. METHODS Two hundred sixty-two patients underwent standard cochlear implantation and postoperative temporal bone CT scanning. Scans were analyzed to determine the number of extracochlear electrodes. Standard CI programming had been completed without knowledge of the extracochlear electrodes identified on the CT. These standard CI maps were reviewed to record the number of deactivated basal electrodes. Lastly, each operative report was reviewed to record the extent of reported electrode insertion. RESULTS 13.4% (n = 35) of CIs were found to have at least one electrode outside of the cochlea on the CT scan. Review of CI mapping indicated that audiologists had deactivated extracochlear electrodes in 60% (21) of these cases. Review of operative reports revealed that surgeons correctly indicated the number of extracochlear electrodes in 6% (2) of these cases. CONCLUSIONS Extracochlear electrodes were correctly identified audiologically in 60% of cases and in surgical reports in 6% of cases; however, it is possible that at least a portion of these cases involved postoperative electrode migration. Given these findings, postoperative CT scans can provide information regarding basal electrode location, which could help improve programming accuracy, associated frequency allocation, and audibility with appropriate deactivation of extracochlear electrodes.
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Evaluation of Intracochlear Position of a Slim Modiolar Electrode Array, by Using Different Radiological Analyses. Otol Neurotol 2019; 40:S10-S17. [PMID: 31225817 DOI: 10.1097/mao.0000000000002213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The radiological analysis following a cochlear implantation offers insight into the audiological outcomes of cochlear implant recipients. The wrapping factor (WF) is the most common radiological analysis measuring the modiolar position and depth of insertion of an electrode array. New measurements like the intracochlear position index (ICPI) or the homogeneity factor (HF) can offer more accurate information regarding the electrode's intracochlear position. We have also studied a new method to calculate the WF, by normalizing it with a new methodology (WFn). OBJECTIVES To analyze and compare the results of the WF, ICPI, HF, and WFn obtained using a cone beam computer tomography (CBCT) with the histological analysis on temporal bone. MATERIAL A perimodiolar electrode array (Nucleus Slim CI532) was inserted in three temporal bones. A perfect insertion was performed in the first temporal bone, according to the correct specifications. In the second specimen, a slightly over-inserted electrode was analyzed and in the third specimen a completely over-inserted electrode array was studied. METHOD A CBCT was performed following the implantations and then, a histological analysis with slices perpendicular to the cochlea axis (modiolus). Each measurement was made 10 times by 10 experts (radiologist and otologist) with a total amount of 600 measurements (100 for each data, 3 CBCT and 3 histology). A t test statistical analysis was performed to compare the measurements between CBCT and histology. RESULTS It was observed that the ICPI and the HF correctly identify the three different insertions. Regarding the WF no significant difference in the two over-inserted specimens was found. The ICPI was the only measurement that shows no statistical difference between the CBCT and the histology, so it was considered the most accurate method. Finally, the WF shows a statistical difference between the CBCT and the histology in all cases, indicating the poor value of the radiological method. The WFn analysis includes the modiolar wall length in the measurement. This improves the final result as it reduces the error induced by the size of the cochlea. CONCLUSION The ICPI and the HF provide better radiological information than the WF, regarding the intracochlear position of the electrode array. The most relevant difference is that the ICPI, HF, and WFn include modiolar and lateral wall dimensions, thereby using the diameter of the cochlear duct for the analysis.
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Goehring T, Archer-Boyd A, Deeks JM, Arenberg JG, Carlyon RP. A Site-Selection Strategy Based on Polarity Sensitivity for Cochlear Implants: Effects on Spectro-Temporal Resolution and Speech Perception. J Assoc Res Otolaryngol 2019; 20:431-448. [PMID: 31161338 PMCID: PMC6646483 DOI: 10.1007/s10162-019-00724-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 05/08/2019] [Indexed: 01/04/2023] Open
Abstract
Thresholds of asymmetric pulses presented to cochlear implant (CI) listeners depend on polarity in a way that differs across subjects and electrodes. It has been suggested that lower thresholds for cathodic-dominant compared to anodic-dominant pulses reflect good local neural health. We evaluated the hypothesis that this polarity effect (PE) can be used in a site-selection strategy to improve speech perception and spectro-temporal resolution. Detection thresholds were measured in eight users of Advanced Bionics CIs for 80-pps, triphasic, monopolar pulse trains where the central high-amplitude phase was either anodic or cathodic. Two experimental MAPs were then generated for each subject by deactivating the five electrodes with either the highest or the lowest PE magnitudes (cathodic minus anodic threshold). Performance with the two experimental MAPs was evaluated using two spectro-temporal tests (Spectro-Temporal Ripple for Investigating Processor EffectivenesS (STRIPES; Archer-Boyd et al. in J Acoust Soc Am 144:2983–2997, 2018) and Spectral-Temporally Modulated Ripple Test (SMRT; Aronoff and Landsberger in J Acoust Soc Am 134:EL217–EL222, 2013)) and with speech recognition in quiet and in noise. Performance was also measured with an experimental MAP that used all electrodes, similar to the subjects’ clinical MAP. The PE varied strongly across subjects and electrodes, with substantial magnitudes relative to the electrical dynamic range. There were no significant differences in performance between the three MAPs at group level, but there were significant effects at subject level—not all of which were in the hypothesized direction—consistent with previous reports of a large variability in CI users’ performance and in the potential benefit of site-selection strategies. The STRIPES but not the SMRT test successfully predicted which strategy produced the best speech-in-noise performance on a subject-by-subject basis. The average PE across electrodes correlated significantly with subject age, duration of deafness, and speech perception scores, consistent with a relationship between PE and neural health. These findings motivate further investigations into site-specific measures of neural health and their application to CI processing strategies.
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Affiliation(s)
- Tobias Goehring
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK.
| | - Alan Archer-Boyd
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - John M Deeks
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - Julie G Arenberg
- Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42nd St., Seattle, WA, 98105, USA
| | - Robert P Carlyon
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
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Chakravorti S, Noble JH, Gifford RH, Dawant BM, O’Connell B, Wang J, Labadie RF. Further Evidence of the Relationship Between Cochlear Implant Electrode Positioning and Hearing Outcomes. Otol Neurotol 2019; 40:617-624. [PMID: 31083083 PMCID: PMC6788798 DOI: 10.1097/mao.0000000000002204] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Postoperative imaging studies by numerous groups have revealed that final cochlear implant (CI) electrode position impacts audiological outcomes with scalar location consistently shown to be a significant factor. Modiolar proximity has been less extensively studied, and findings regarding the effect of insertion depth have been inconsistent. METHODS Using previously developed automated algorithms, we determined CI electrode position in an Institutional Review Board-approved database of 220 CI ears. Generalized linear models (GLM) were used to analyze the relationship between audiological outcomes and factors including age, duration of CI use, device type, and electrode position. RESULTS For precurved arrays, GLM revealed that scalar position, modiolar proximity, base insertion depth, and sex were significant factors for Consonant-Nucleus-Consonant (CNC) words (R = 0.43, p < 0.001, n = 92 arrays), while scalar position, modiolar proximity, age, and postlingual onset of deafness were significant for Bamford-Kawal-Bench Sentences in Noise (BKB-SIN) (R = 0.51, p < 0.001, n = 85) scores. Other factors were not significant in the final model after controlling for these variables. For straight arrays, we found the insertion depth, postlingual deafness, and length of CI use to be highly significant (R = 0.47, p < 0.001) factors for CNC words (91 arrays), while for BKB-SIN scores the most significant (R = 0.47, p < 0.001) factors were insertion depth, younger age, and postlingual deafness (89 arrays). CONCLUSION Our results confirm the significance of electrode positioning in audiological outcomes. The most significant positional predictors of outcome for precurved arrays were full scala tympani (ST) insertion and the modiolar distance, while for the lateral wall arrays the depth of insertion was the most significant factor.
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Affiliation(s)
- Srijata Chakravorti
- Department of Electrical Engineering and Computer Science, Vanderbilt University
| | - Jack H. Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University
- Vanderbilt Bill Wilkerson Center, Department of Hearing and Speech Sciences, Vanderbilt University Medical Center
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center
| | - René H. Gifford
- Vanderbilt Bill Wilkerson Center, Department of Hearing and Speech Sciences, Vanderbilt University Medical Center
| | - Benoit M. Dawant
- Department of Electrical Engineering and Computer Science, Vanderbilt University
| | - Brendan O’Connell
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center
| | - Jianing Wang
- Department of Electrical Engineering and Computer Science, Vanderbilt University
| | - Robert F. Labadie
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center
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Jahn KN, Arenberg JG. Evaluating Psychophysical Polarity Sensitivity as an Indirect Estimate of Neural Status in Cochlear Implant Listeners. J Assoc Res Otolaryngol 2019; 20:415-430. [PMID: 30949879 PMCID: PMC6646612 DOI: 10.1007/s10162-019-00718-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/12/2019] [Indexed: 01/04/2023] Open
Abstract
The physiological integrity of spiral ganglion neurons is presumed to influence cochlear implant (CI) outcomes, but it is difficult to measure neural health in CI listeners. Modeling data suggest that, when peripheral processes have degenerated, anodic stimulation may be a more effective neural stimulus than cathodic stimulation. The primary goal of the present study was to evaluate the emerging theory that polarity sensitivity reflects neural health in CI listeners. An ideal in vivo estimate of neural integrity should vary independently of other factors known to influence the CI electrode-neuron interface, such as electrode position and tissue impedances. Thus, the present analyses quantified the relationships between polarity sensitivity and (1) electrode position estimated via computed tomography imaging, (2) intracochlear resistance estimated via electrical field imaging, and (3) focused (steered quadrupolar) behavioral thresholds, which are believed to reflect a combination of local neural health, electrode position, and intracochlear resistance. Eleven adults with Advanced Bionics devices participated. To estimate polarity sensitivity, electrode-specific behavioral thresholds in response to monopolar, triphasic pulses where the central high-amplitude phase was either anodic (CAC) or cathodic (ACA) were measured. The polarity effect was defined as the difference in threshold response to the ACA compared to the CAC stimulus. Results indicated that the polarity effect was not related to electrode-to-modiolus distance, electrode scalar location, or intracochlear resistance. Large, positive polarity effects, which may indicate SGN degeneration, were associated with relatively high focused behavioral thresholds. The polarity effect explained a significant portion of the variation in focused thresholds, even after controlling for electrode position and intracochlear resistance. Overall, these results provide support for the theory that the polarity effect may reflect neural integrity in CI listeners. Evidence from this study supports further investigation into the use of polarity sensitivity for optimizing individual CI programming parameters.
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Affiliation(s)
- Kelly N Jahn
- Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42nd St., Seattle, WA, 98105, USA.
| | - Julie G Arenberg
- Massachusetts Eye and Ear, 243 Charles St., Boston, MA, 02114, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA
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Abstract
Supplemental Digital Content is available in the text. Objectives: The standard, monopolar (MP) electrode configuration used in commercially available cochlear implants (CI) creates a broad electrical field, which can lead to unwanted channel interactions. Use of more focused configurations, such as tripolar and phased array, has led to mixed results for improving speech understanding. The purpose of the present study was to assess the efficacy of a physiologically inspired configuration called dynamic focusing, using focused tripolar stimulation at low levels and less focused stimulation at high levels. Dynamic focusing may better mimic cochlear excitation patterns in normal acoustic hearing, while reducing the current levels necessary to achieve sufficient loudness at high levels. Design: Twenty postlingually deafened adult CI users participated in the study. Speech perception was assessed in quiet and in a four-talker babble background noise. Speech stimuli were closed-set spondees in noise, and medial vowels at 50 and 60 dB SPL in quiet and in noise. The signal to noise ratio was adjusted individually such that performance was between 40 and 60% correct with the MP strategy. Subjects were fitted with three experimental strategies matched for pulse duration, pulse rate, filter settings, and loudness on a channel-by-channel basis. The strategies included 14 channels programmed in MP, fixed partial tripolar (σ = 0.8), and dynamic partial tripolar (σ at 0.8 at threshold and 0.5 at the most comfortable level). Fifteen minutes of listening experience was provided with each strategy before testing. Sound quality ratings were also obtained. Results: Speech perception performance for vowel identification in quiet at 50 and 60 dB SPL and for spondees in noise was similar for the three tested strategies. However, performance on vowel identification in noise was significantly better for listeners using the dynamic focusing strategy. Sound quality ratings were similar for the three strategies. Some subjects obtained more benefit than others, with some individual differences explained by the relation between loudness growth and the rate of change from focused to broader stimulation. Conclusions: These initial results suggest that further exploration of dynamic focusing is warranted. Specifically, optimizing such strategies on an individual basis may lead to improvements in speech perception for more adult listeners and improve how CIs are tailored. Some listeners may also need a longer period of time to acclimate to a new program.
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