Article
Neurosciences
Woongsang Sunwoo, Bertrand Delgutte, Yoojin Chung
Summary: The study found that chronic bilateral CI stimulation during development can partially reverse the impact of early-onset deafness on ITD sensitivity, restoring the level of neural sensitivity in rabbits. However, the stimulation did not improve temporal coding in early-deaf rabbits.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Neurosciences
Maike Klingel, Bernhard Laback
Summary: The study explores the impact of visual reinforcement training on ITD cues for CI listeners, showing a slight increase in perceptual contribution of ITDs for 100-pps stimuli but limited impact for 300-pps stimuli. Additionally, adding azimuth-dependent ITDs to stimuli containing ILDs increased the extent of lateralization across both stimulus types. These findings suggest that training and incorporating robustly encoded low-rate ITD cues may enhance sound localization with future CI systems.
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2022)
Article
Psychology, Multidisciplinary
Alexandra Annemarie Ludwig, Sylvia Meuret, Rolf-Dieter Battmer, Marc Schoenwiesner, Michael Fuchs, Arne Ernst
Summary: Spatial hearing is crucial in real life but deteriorates in participants with severe sensorineural hearing loss or single-sided deafness. This study investigated sound localization ability in participants with single-sided deafness using a unilateral cochlear implant (CI). Results showed that CI can largely restore sound localization ability in participants, with some difficulties remaining at frontal locations and on the CI side. Improved speech understanding in noise was observed with CI, particularly when sound localization was also enhanced.
FRONTIERS IN PSYCHOLOGY
(2021)
Article
Audiology & Speech-Language Pathology
Snandan Sharma, Lucas H. M. Mens, Ad F. M. Snik, A. John van Opstal, Marc M. M. van Wanrooij
Summary: Many cochlear implant users with binaural residual (acoustic) hearing benefit from combining electric and acoustic stimulation (EAS) in the implanted ear with acoustic amplification in the other. However, their hearing is generally asymmetric for mid- and high-frequency sounds, perturbing or even abolishing binaural cues. A study investigated the effect of frequency-dependent binaural asymmetry in hearing thresholds on sound localization by bimodal EAS listeners. The results showed that sound-localization performance was poor in general, with biases towards the better hearing ear.
Article
Acoustics
T. Fischer, C. Schmid, M. Kompis, G. Mantokoudis, M. Caversaccio, W. Wimmer
Summary: The study found that bilateral cochlear implant users showed significantly improved ITD discrimination for 250Hz pure-tone stimuli when using a coding strategy that preserved TFS, but this sensitivity did not extend to broadband stimuli or sound field spatial hearing tests.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Review
Audiology & Speech-Language Pathology
Tom Gajecki, Waldo Nogueira
Summary: Enhancing interaural level differences (ILDs) coding can improve sound localization accuracy for bilateral cochlear implant (BiCI) users, especially at narrow azimuths. Additionally, linking band selection can enhance left/right discrimination accuracy at larger azimuths, benefiting some BiCI participants.
Article
Neurosciences
Joshua G. W. Bernstein, Kenneth K. Jensen, Olga A. Stakhovskaya, Jack H. Noble, Michael Hoa, H. Jeffery Kim, Robert Shih, Elizabeth Kolberg, Miranda Cleary, Matthew J. Goupell
Summary: The study investigates whether plasticity-reorganization of central neural pathways can compensate for peripheral interaural place mismatch in individuals with bilateral cochlear implants and single-sided deafness. While binaural processing did not show adaptation to mismatch, there was evidence of adaptation in pitch perception towards specific electrode frequencies. Results suggest that reducing interaural place mismatch and potentially improving binaural processing by reprogramming the cochlear implant frequency allocation would be better done using CT scan than pitch information.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Multidisciplinary Sciences
Erin Glennon, Silvana Valtcheva, Angela Zhu, Youssef Z. Wadghiri, Mario A. Svirsky, Robert C. Froemke
Summary: Cochlear implants (CIs) are neuroprosthetic devices that can provide hearing to deaf people. The time taken for hearing to be restored and perceptual accuracy after long-term CI use remain highly variable. This study suggests that the neuromodulator noradrenaline from the brainstem locus coeruleus (LC) plays a role in CI-related neuroplasticity.
Article
Audiology & Speech-Language Pathology
J. Seebacher, A. Franke-Trieger, V Weichbold, O. Galvan, J. Schmutzhard, P. Zorowka, K. Stephan
Summary: This study investigated the objective localisation of low- and high-frequency sounds in single-sided deaf cochlear implant users. The results showed that the users had the best sound localisation for high-frequency sounds, while their ability to localise low-frequency sounds was limited.
INTERNATIONAL JOURNAL OF AUDIOLOGY
(2023)
Article
Audiology & Speech-Language Pathology
William O. Gray, Paul G. Mayo, Matthew J. Goupell, Andrew D. Brown
Summary: Empirical measurements of binaural cue transmission via bilateral cochlear implants (BiCIs) revealed that asymmetric spectral peak-picking may degrade binaural cues, particularly envelope ITD cues, for source locations away from the midline. Additionally, pulse amplitude saturation due to nonlinear level mapping resulted in smaller ILDs at higher presentation levels. Furthermore, variation in transmitted envelope ITDs due to independent left and right processor clocks was observed, suggesting potential avenues for improvement of BiCI technology.
Article
Audiology & Speech-Language Pathology
Hannah E. Staisloff, Justin M. Aronoff
Summary: This study investigated the optimal electrode pairings for bilateral cochlear implants (CIs) among seven users, finding systematic differences in pairing based on the cue measured, particularly at the basal end of the electrode array. The results suggest that improvements in binaural tasks using optimally paired electrodes may be tied to the specific percept being measured.
Article
Otorhinolaryngology
Monika Koertje, Timo Stoever, Uwe Baumann, Tobias Weissgerber
Summary: This study investigated the impact of interaural delay on sensitivity to interaural level differences (ILDs) in normal hearing subjects and cochlear implant (CI) users. ILD sensitivity was measured in both groups using different interaural delays induced by hearing devices. The results showed that ILD sensitivity significantly decreased with increasing interaural delays in the normal hearing group, but no significant effect was found in the CI group. Further studies are needed to verify the potential benefits of temporal matching for ILD processing and sound localization in CI patients.
EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY
(2023)
Article
Acoustics
Ria Ghosh, John H. L. Hansen
Summary: While cochlear implant (CI) users struggle with identifying speakers and sound location, bilateral and bimodal assisted hearing is gaining popularity to improve hearing abilities and speech intelligibility. This study demonstrates the use of a custom-made CI research platform - CCi-MOBILE for bilateral implant algorithm processing, allowing researchers to test the accuracy of bilateral CI processing in real-time naturalistic environments.
IEEE-ACM TRANSACTIONS ON AUDIO SPEECH AND LANGUAGE PROCESSING
(2023)
Article
Audiology & Speech-Language Pathology
Kenneth K. Jensen, Stefano Cosentino, Joshua G. W. Bernstein, Olga A. Stakhovskaya, Matthew J. Goupell
Summary: Bias effects in interaural pitch-comparison tasks for bilateral cochlear-implant listeners were compared using three methods, with ranking showing the least susceptibility to biases and emerging as the optimal approach.
Article
Acoustics
Hongmei Hu, Sebastian A. Ausili, Ben Williges, Jonas Klug, Rebecca C. Felsheim, Deborah Vickers, Mathias Dietz
Summary: Bilateral cochlear implants greatly improve spatial hearing acuity for CI users, but there are still gaps compared to normal-hearing listeners. Multiple factors, including degraded cues and impaired neurons, limit the binaural hearing with CIs. Computer models can help quantify these factors, but the combination of models often does not provide a comprehensive simulation of perception.
Article
Audiology & Speech-Language Pathology
Martin Klein-Hennig, Mathias Dietz, Volker Hohmann
Article
Audiology & Speech-Language Pathology
Mathias Dietz, Jean-Hugues Lestang, Piotr Majdak, Richard M. Stern, Torsten Marquardt, Stephan D. Ewert, William M. Hartmann, Dan P. M. Goodman
Article
Acoustics
Jonas Klug, Lisa Schmors, Go Ashida, Mathias Dietz
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2020)
Article
Neurosciences
Andrew Brughera, Jason Mikiel-Hunter, Mathias Dietz, David McAlpine
Summary: This study investigates the mechanism behind the emphasis of ITD cues in early-arriving sound in the auditory process, revealing a higher ITD transmission weight in 600 Hz sound. The model experiments suggest that adaptation and binaural coincidence detection within MSO neurons play crucial roles in this process.
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2021)
Article
Acoustics
Joerg Encke, Mathias Dietz
Summary: This study demonstrates that smaller bandwidths are needed to resolve phase ambiguity more effectively when handling differences in envelope fluctuation. By integrating cross-frequency information and binaural timing information conveyed within a single frequency channel, phase ambiguity can be better resolved.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Neurosciences
Hongmei Hu, Jonas Klug, Mathias Dietz
Summary: The sensitivity to interaural time difference (ITD) is similar for cochlear implant stimulation and conventional acoustic stimulation. This similarity is likely due to the dominant mechanism of robust excitatory-inhibitory (EI) interaction. By connecting a single EI-model neuron to models of the normal auditory periphery and electrically stimulated auditory nerve, the study was able to capture the response properties of electric stimulation and understand the binaural hearing abilities with electric stimulation.
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2022)
Article
Acoustics
Bernhard Eurich, Joerg Encke, Stephan D. Ewert, Mathias Dietz
Summary: Differences in interaural phase configuration can result in significant binaural unmasking, which can be reduced by interaural time difference (ITD) in masking noises. Adding a second noise with opposing ITD further decreases binaural unmasking. This study proposes a quantitative multi-channel model that explains this reduction by utilizing monaurally derived peripheral filter bandwidths and across-channel incoherence interference mechanism.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Biology
Joerg Encke, Mathias Dietz
Summary: A new sound localization model based on encoding temporal fluctuations within two hemispheric channels is capable of explaining a wide range of psychoacoustic experiments. The model suggests that binaural unmasking is achieved through the encoding of interaural differences in neuronal activity. By applying the model to numerous experiments, it successfully accounts for the majority of variance. This research is an important step towards a unified understanding of binaural unmasking and the encoding of interaural differences.
COMMUNICATIONS BIOLOGY
(2022)
Article
Acoustics
Jonas Klug, Mathias Dietz
Summary: In normal-hearing humans, the threshold of interaural time differences for pure tones increases dramatically above 1300Hz and becomes unmeasurable above 1400Hz. Published data only report thresholds at certain proportions correct but do not provide information about the decline of proportions correct or the sensitivity index d' with increasing frequencies. Behavioral data obtained with a constant stimulus procedure show that proportions correct were above 0.9 at 1300Hz and virtually no sensitivity was observed at 1500Hz.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Acoustics
Bernhard Eurich, Mathias Dietz
Summary: The perceptual organization of complex acoustic scenes requires fast binaural processing for accurate localization or lateralization. This study investigates the ability to detect rapid binaural oscillations and suggests a model with fast interaural phase difference encoding but a slower process of updating the internal representation of the masker interaural phase difference statistics to explain both fast and sluggish categories of experiments.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Acoustics
Jonas Klug, Joerg Encke, Mathias Dietz
Summary: The frequency dependence of phase locking in the auditory nerve impacts auditory coding mechanisms. The decline in phase locking as frequency increases is commonly explained by a low-pass filter. This study compares fitted low-pass filter parameters with the actual rate of phase locking decline, finding a consistent decline of 40 dB per decade, resembling a second order filter's asymptotic decline.
JASA EXPRESS LETTERS
(2023)
Article
Acoustics
Hongmei Hu, Sebastian A. Ausili, Ben Williges, Jonas Klug, Rebecca C. Felsheim, Deborah Vickers, Mathias Dietz
Summary: Bilateral cochlear implants greatly improve spatial hearing acuity for CI users, but there are still gaps compared to normal-hearing listeners. Multiple factors, including degraded cues and impaired neurons, limit the binaural hearing with CIs. Computer models can help quantify these factors, but the combination of models often does not provide a comprehensive simulation of perception.
Article
Audiology & Speech-Language Pathology
Sabrina H. Pieper, Noura Hamze, Stefan Brill, Sabine Hochmuth, Mats Exter, Marek Polak, Andreas Radeloff, Michael Buschermoehle, Mathias Dietz
Summary: When using a cochlear implant in one ear and acoustically listening in the other ear, the binaural benefits and spatial hearing abilities are generally poorer compared to other bilateral stimulation setups. Mismatch in latency, frequency, and level between the two ears can lead to perceptual consequences. Various strategies for compensating mismatch have been explored, but achieving comprehensive mismatch compensation is challenging.
Article
Acoustics
Mathias Dietz, Joerg Encke, Kristin Bracklo, Stephan D. Ewert
Summary: The study found that differences in interaural phase between noise and target tone can improve detection thresholds. The masking release for detecting an antiphasic tone in diotic noise decreases gradually with interaural time delay, attributed to reduced interaural coherence of the noise. Reducing noise bandwidth increases masking release for an 8-ms ITD, while wider bandwidth noises show no significant difference in masking release.
Article
Acoustics
Sven Herrmann, Mathias Dietz
Summary: The article discusses the complexity of relating experimental data to individual physiology or pathology, and proposes a likelihood-based fitting procedure to provide confidence intervals for model parameters.
