1
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Hu H, Klug J, Dietz M. Simulation of ITD-Dependent Single-Neuron Responses Under Electrical Stimulation and with Amplitude-Modulated Acoustic Stimuli. J Assoc Res Otolaryngol 2022; 23:535-550. [PMID: 35334001 PMCID: PMC9437183 DOI: 10.1007/s10162-021-00823-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022] Open
Abstract
Interaural time difference (ITD) sensitivity with cochlear implant stimulation is remarkably similar to envelope ITD sensitivity using conventional acoustic stimulation. This holds true for human perception, as well as for neural response rates recorded in the inferior colliculus of several mammalian species. We hypothesize that robust excitatory-inhibitory (EI) interaction is the dominant mechanism. Therefore, we connected the same single EI-model neuron to either a model of the normal acoustic auditory periphery or to a model of the electrically stimulated auditory nerve. The model captured most features of the experimentally obtained response properties with electric stimulation, such as the shape of rate-ITD functions, the dependence on stimulation level, and the pulse rate or modulation-frequency dependence. Rate-ITD functions with high-rate, amplitude-modulated electric stimuli were very similar to their acoustic counterparts. Responses obtained with unmodulated electric pulse trains most resembled acoustic filtered clicks. The fairly rapid decline of ITD sensitivity at rates above 300 pulses or cycles per second is correctly simulated by the 3.1-ms time constant of the inhibitory post-synaptic conductance. As the model accounts for these basic properties, it is expected to help in understanding and quantifying the binaural hearing abilities with electric stimulation when integrated in bigger simulation frameworks.
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Affiliation(s)
- Hongmei Hu
- Department of Medical Physics and Acoustics and Cluster of Excellence "Hearing4all", University of Oldenburg, 26129, Oldenburg, Germany.
| | - Jonas Klug
- Department of Medical Physics and Acoustics and Cluster of Excellence "Hearing4all", University of Oldenburg, 26129, Oldenburg, Germany
| | - Mathias Dietz
- Department of Medical Physics and Acoustics and Cluster of Excellence "Hearing4all", University of Oldenburg, 26129, Oldenburg, Germany
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2
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Gordon KA, Papsin BC, Papaioannou V, Cushing SL. The Importance of Access to Bilateral Hearing through Cochlear Implants in Children. Semin Hear 2021; 42:381-388. [PMID: 34912166 PMCID: PMC8660169 DOI: 10.1055/s-0041-1739371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Children with hearing loss require early access to sound in both ears to support their development. In this article, we describe barriers to providing bilateral hearing and developmental consequences of delays during early sensitive periods. Barriers include late identification of hearing loss in one or both ears and delayed access to intervention with hearing devices such as cochlear implants. Effects of delayed bilateral input on the auditory pathways and brain are discussed as well as behavioral effects on speech perception and other developmental outcomes including language and academics. Evidence for these effects has supported an evolution in cochlear implant candidacy in children that was started with unilateral implantation in children with profound deafness bilaterally to bilateral implantation to implantation of children with asymmetric hearing loss including children with single-side deafness. Opportunities to enhance the developmental benefits of bilateral hearing in children with hearing loss are also discussed including efforts to improve binaural/spatial hearing and consideration of concurrent vestibular deficits which are common in children with hearing loss.
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Affiliation(s)
- Karen A Gordon
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Canada.,Department of Communication Disorders, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Toronto, Canada
| | - Blake C Papsin
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Toronto, Canada
| | - Vicky Papaioannou
- Department of Communication Disorders, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Toronto, Canada
| | - Sharon L Cushing
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology, The Hospital for Sick Children, Toronto, Canada.,Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Toronto, Canada
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3
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Dieudonné B, Van Wilderode M, Francart T. Temporal quantization deteriorates the discrimination of interaural time differences. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:815. [PMID: 32873012 DOI: 10.1121/10.0001759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Cochlear implants (CIs) often replace acoustic temporal fine structure by a fixed-rate pulse train. If the pulse timing is arbitrary (that is, not based on the phase information of the acoustic signal), temporal information is quantized by the pulse period. This temporal quantization is probably imperceptible with current clinical devices. However, it could result in large temporal jitter for strategies that aim to improve bilateral and bimodal CI users' perception of interaural time differences (ITDs), such as envelope enhancement. In an experiment with 16 normal-hearing listeners, it is shown that such jitter could deteriorate ITD perception for temporal quantization that corresponds to the often-used stimulation rate of 900 pulses per second (pps): the just-noticeable difference in ITD with quantization was 177 μs as compared to 129 μs without quantization. For smaller quantization step sizes, no significant deterioration of ITD perception was found. In conclusion, the binaural system can only average out the effect of temporal quantization to some extent, such that pulse timing should be well-considered. As this psychophysical procedure was somewhat unconventional, different procedural parameters were compared by simulating a number of commonly used two-down one-up adaptive procedures in Appendix B.
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Affiliation(s)
- Benjamin Dieudonné
- Experimental Oto-rhino-laryngology, Department of Neurosciences, Katholieke Universiteit (KU) Leuven-University of Leuven, Herestraat 49 bus 721, Leuven, 3000, Belgium
| | - Mira Van Wilderode
- Experimental Oto-rhino-laryngology, Department of Neurosciences, Katholieke Universiteit (KU) Leuven-University of Leuven, Herestraat 49 bus 721, Leuven, 3000, Belgium
| | - Tom Francart
- Experimental Oto-rhino-laryngology, Department of Neurosciences, Katholieke Universiteit (KU) Leuven-University of Leuven, Herestraat 49 bus 721, Leuven, 3000, Belgium
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4
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Williges B, Wesarg T, Jung L, Geven LI, Radeloff A, Jürgens T. Spatial Speech-in-Noise Performance in Bimodal and Single-Sided Deaf Cochlear Implant Users. Trends Hear 2020; 23:2331216519858311. [PMID: 31364496 PMCID: PMC6669847 DOI: 10.1177/2331216519858311] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This study compared spatial speech-in-noise performance in two cochlear implant (CI) patient groups: bimodal listeners, who use a hearing aid contralaterally to support their impaired acoustic hearing, and listeners with contralateral normal hearing, i.e., who were single-sided deaf before implantation. Using a laboratory setting that controls for head movements and that simulates spatial acoustic scenes, speech reception thresholds were measured for frontal speech-in-stationary noise from the front, the left, or the right side. Spatial release from masking (SRM) was then extracted from speech reception thresholds for monaural and binaural listening. SRM was found to be significantly lower in bimodal CI than in CI single-sided deaf listeners. Within each listener group, the SRM extracted from monaural listening did not differ from the SRM extracted from binaural listening. In contrast, a normal-hearing control group showed a significant improvement in SRM when using two ears in comparison to one. Neither CI group showed a binaural summation effect; that is, their performance was not improved by using two devices instead of the best monaural device in each spatial scenario. The results confirm a "listening with the better ear" strategy in the two CI patient groups, where patients benefited from using two ears/devices instead of one by selectively attending to the better one. Which one is the better ear, however, depends on the spatial scenario and on the individual configuration of hearing loss.
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Affiliation(s)
- Ben Williges
- 1 Medical Physics and Cluster of Excellence "Hearing4all," Carl von Ossietzky University of Oldenburg, Germany
| | - Thomas Wesarg
- 2 Department of Otorhinolaryngology - Head and Neck Surgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Germany
| | - Lorenz Jung
- 2 Department of Otorhinolaryngology - Head and Neck Surgery, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Germany
| | - Leontien I Geven
- 3 Department of Otorhinolaryngology, Head and Neck Surgery, Carl von Ossietzky University of Oldenburg, Germany
| | - Andreas Radeloff
- 3 Department of Otorhinolaryngology, Head and Neck Surgery, Carl von Ossietzky University of Oldenburg, Germany
| | - Tim Jürgens
- 1 Medical Physics and Cluster of Excellence "Hearing4all," Carl von Ossietzky University of Oldenburg, Germany.,4 Institute of Acoustics, University of Applied Sciences Lübeck, Germany
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5
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Williges B, Jürgens T, Hu H, Dietz M. Coherent Coding of Enhanced Interaural Cues Improves Sound Localization in Noise With Bilateral Cochlear Implants. Trends Hear 2019; 22:2331216518781746. [PMID: 29956589 PMCID: PMC6048749 DOI: 10.1177/2331216518781746] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Bilateral cochlear implant (BCI) users only have very limited spatial hearing
abilities. Speech coding strategies transmit interaural level differences (ILDs)
but in a distorted manner. Interaural time difference (ITD) information
transmission is even more limited. With these cues, most BCI users can coarsely
localize a single source in quiet, but performance quickly declines in the
presence of other sound. This proof-of-concept study presents a novel signal
processing algorithm specific for BCIs, with the aim to improve sound
localization in noise. The core part of the BCI algorithm duplicates a
monophonic electrode pulse pattern and applies quasistationary natural or
artificial ITDs or ILDs based on the estimated direction of the dominant source.
Three experiments were conducted to evaluate different algorithm variants:
Experiment 1 tested if ITD transmission alone enables BCI subjects to lateralize
speech. Results showed that six out of nine BCI subjects were able to lateralize
intelligible speech in quiet solely based on ITDs. Experiments 2 and 3 assessed
azimuthal angle discrimination in noise with natural or modified ILDs and ITDs.
Angle discrimination for frontal locations was possible with all variants,
including the pure ITD case, but for lateral reference angles, it was only
possible with a linearized ILD mapping. Speech intelligibility in noise,
limitations, and challenges of this interaural cue transmission approach are
discussed alongside suggestions for modifying and further improving the BCI
algorithm.
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Affiliation(s)
- Ben Williges
- 1 Medizinische Physik and Cluster of Excellence "Hearing4all," Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Tim Jürgens
- 1 Medizinische Physik and Cluster of Excellence "Hearing4all," Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.,2 Institute of Acoustics, University of Applied Sciences Lübeck, Lübeck, Germany
| | - Hongmei Hu
- 1 Medizinische Physik and Cluster of Excellence "Hearing4all," Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Mathias Dietz
- 1 Medizinische Physik and Cluster of Excellence "Hearing4all," Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.,3 National Centre for Audiology, School of Communication Sciences and Disorders, Western University, London, Ontario, Canada
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6
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Corrective binaural processing for bilateral cochlear implant patients. PLoS One 2018; 13:e0187965. [PMID: 29351279 PMCID: PMC5774684 DOI: 10.1371/journal.pone.0187965] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/30/2017] [Indexed: 11/19/2022] Open
Abstract
Although bilateral cochlear implant users receive input to both ears, they nonetheless have relatively poor localization abilities in the horizontal plane. This is likely because of the two binaural cues, they have good sensitivity to interaural differences of level (inter-aural level differences, or ILDs), but not those of time (inter-aural time differences; ITDs). Here, localization performance is assessed in six bilateral cochlear implant patients when instantaneous ITDs are measured and converted to ILDs, a strategy that results in larger-than-typical ILDs. The added ILDs are corrective, in that they are derived from individual listener performance across both frequency and azimuth, so that they are small where a listener performs well, and increase as performance deviates from ideal. Results show significantly improved localization performance as a result of this strategy, with two of the six listeners achieving levels of performance typically observed in NH listeners.
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7
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Ashida G, Tollin DJ, Kretzberg J. Physiological models of the lateral superior olive. PLoS Comput Biol 2017; 13:e1005903. [PMID: 29281618 PMCID: PMC5744914 DOI: 10.1371/journal.pcbi.1005903] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 11/28/2017] [Indexed: 01/09/2023] Open
Abstract
In computational biology, modeling is a fundamental tool for formulating, analyzing and predicting complex phenomena. Most neuron models, however, are designed to reproduce certain small sets of empirical data. Hence their outcome is usually not compatible or comparable with other models or datasets, making it unclear how widely applicable such models are. In this study, we investigate these aspects of modeling, namely credibility and generalizability, with a specific focus on auditory neurons involved in the localization of sound sources. The primary cues for binaural sound localization are comprised of interaural time and level differences (ITD/ILD), which are the timing and intensity differences of the sound waves arriving at the two ears. The lateral superior olive (LSO) in the auditory brainstem is one of the locations where such acoustic information is first computed. An LSO neuron receives temporally structured excitatory and inhibitory synaptic inputs that are driven by ipsi- and contralateral sound stimuli, respectively, and changes its spike rate according to binaural acoustic differences. Here we examine seven contemporary models of LSO neurons with different levels of biophysical complexity, from predominantly functional ones (‘shot-noise’ models) to those with more detailed physiological components (variations of integrate-and-fire and Hodgkin-Huxley-type). These models, calibrated to reproduce known monaural and binaural characteristics of LSO, generate largely similar results to each other in simulating ITD and ILD coding. Our comparisons of physiological detail, computational efficiency, predictive performances, and further expandability of the models demonstrate (1) that the simplistic, functional LSO models are suitable for applications where low computational costs and mathematical transparency are needed, (2) that more complex models with detailed membrane potential dynamics are necessary for simulation studies where sub-neuronal nonlinear processes play important roles, and (3) that, for general purposes, intermediate models might be a reasonable compromise between simplicity and biological plausibility. Computational models help our understanding of complex biological systems, by identifying their key elements and revealing their operational principles. Close comparisons between model predictions and empirical observations ensure our confidence in a model as a building block for further applications. Most current neuronal models, however, are constructed to replicate only a small specific set of experimental data. Thus, it is usually unclear how these models can be generalized to different datasets and how they compare with each other. In this paper, seven neuronal models are examined that are designed to reproduce known physiological characteristics of auditory neurons involved in the detection of sound source location. Despite their different levels of complexity, the models generate largely similar results when their parameters are tuned with common criteria. Comparisons show that simple models are computationally more efficient and theoretically transparent, and therefore suitable for rigorous mathematical analyses and engineering applications including real-time simulations. In contrast, complex models are necessary for investigating the relationship between underlying biophysical processes and sub- and suprathreshold spiking properties, although they have a large number of unconstrained, unverified parameters. Having identified their advantages and drawbacks, these auditory neuron models may readily be used for future studies and applications.
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Affiliation(s)
- Go Ashida
- Cluster of Excellence "Hearing4all", Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Daniel J Tollin
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Jutta Kretzberg
- Cluster of Excellence "Hearing4all", Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
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8
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Dietz M, Lestang JH, Majdak P, Stern RM, Marquardt T, Ewert SD, Hartmann WM, Goodman DFM. A framework for testing and comparing binaural models. Hear Res 2017; 360:92-106. [PMID: 29208336 DOI: 10.1016/j.heares.2017.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/03/2017] [Accepted: 11/24/2017] [Indexed: 11/19/2022]
Abstract
Auditory research has a rich history of combining experimental evidence with computational simulations of auditory processing in order to deepen our theoretical understanding of how sound is processed in the ears and in the brain. Despite significant progress in the amount of detail and breadth covered by auditory models, for many components of the auditory pathway there are still different model approaches that are often not equivalent but rather in conflict with each other. Similarly, some experimental studies yield conflicting results which has led to controversies. This can be best resolved by a systematic comparison of multiple experimental data sets and model approaches. Binaural processing is a prominent example of how the development of quantitative theories can advance our understanding of the phenomena, but there remain several unresolved questions for which competing model approaches exist. This article discusses a number of current unresolved or disputed issues in binaural modelling, as well as some of the significant challenges in comparing binaural models with each other and with the experimental data. We introduce an auditory model framework, which we believe can become a useful infrastructure for resolving some of the current controversies. It operates models over the same paradigms that are used experimentally. The core of the proposed framework is an interface that connects three components irrespective of their underlying programming language: The experiment software, an auditory pathway model, and task-dependent decision stages called artificial observers that provide the same output format as the test subject.
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Affiliation(s)
- Mathias Dietz
- National Centre for Audiology, Western University, London, ON, Canada.
| | - Jean-Hugues Lestang
- Department of Electrical and Electronic Engineering, Imperial College London, London, United Kingdom
| | - Piotr Majdak
- Institut für Schallforschung, Österreichische Akademie der Wissenschaften, Wien, Austria
| | | | | | - Stephan D Ewert
- Medizinische Physik, Universität Oldenburg, Oldenburg, Germany
| | | | - Dan F M Goodman
- Department of Electrical and Electronic Engineering, Imperial College London, London, United Kingdom
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9
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Ehlers E, Goupell MJ, Zheng Y, Godar SP, Litovsky RY. Binaural sensitivity in children who use bilateral cochlear implants. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:4264. [PMID: 28618809 PMCID: PMC5464955 DOI: 10.1121/1.4983824] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 05/29/2023]
Abstract
Children who are deaf and receive bilateral cochlear implants (BiCIs) perform better on spatial hearing tasks using bilateral rather than unilateral inputs; however, they underperform relative to normal-hearing (NH) peers. This gap in performance is multi-factorial, including the inability of speech processors to reliably deliver binaural cues. Although much is known regarding binaural sensitivity of adults with BiCIs, less is known about how the development of binaural sensitivity in children with BiCIs compared to NH children. Sixteen children (ages 9-17 years) were tested using synchronized research processors. Interaural time differences and interaural level differences (ITDs and ILDs, respectively) were presented to pairs of pitch-matched electrodes. Stimuli were 300-ms, 100-pulses-per-second, constant-amplitude pulse trains. In the first and second experiments, discrimination of interaural cues (either ITDs or ILDs) was measured using a two-interval left/right task. In the third experiment, subjects reported the perceived intracranial position of ITDs and ILDs in a lateralization task. All children demonstrated sensitivity to ILDs, possibly due to monaural level cues. Children who were born deaf had weak or absent sensitivity to ITDs; in contrast, ITD sensitivity was noted in children with previous exposure to acoustic hearing. Therefore, factors such as auditory deprivation, in particular, lack of early exposure to consistent timing differences between the ears, may delay the maturation of binaural circuits and cause insensitivity to binaural differences.
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Affiliation(s)
- Erica Ehlers
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Matthew J Goupell
- Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742, USA
| | - Yi Zheng
- Beijing Advanced Innovation Center for Future Education, Beijing Normal University, Beijing 100875, China
| | - Shelly P Godar
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Ruth Y Litovsky
- University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, Wisconsin 53705, USA
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10
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Seeber BU, Bruce IC. The history and future of neural modeling for cochlear implants. NETWORK (BRISTOL, ENGLAND) 2016; 27:53-66. [PMID: 27726506 DOI: 10.1080/0954898x.2016.1223365] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This special issue of Network: Computation in Neural Systems on the topic of "Computational models of the electrically stimulated auditory system" incorporates review articles spanning a wide range of approaches to modeling cochlear implant stimulation of the auditory system. The purpose of this overview paper is to provide a historical context for the different modeling endeavors and to point toward how computational modeling could play a key role in the understanding, evaluation, and improvement of cochlear implants in the future.
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Affiliation(s)
- Bernhard U Seeber
- a Audio Information Processing, Department of Electrical and Computer Engineering , Technical University of Munich , Munich , Germany
| | - Ian C Bruce
- b Department of Electrical and Computer Engineering , McMaster University , Hamilton , Ontario , Canada
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