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
Neurosciences
Michaela Mueller, Hongmei Hu, Mathias Dietz, Barbara Beiderbeck, Dardo N. Ferreiro, Michael Pecka
Summary: The ability to localize a sound source is crucial for communication and navigation, and hearing impairments can negatively affect sound localization. Cochlear implants have been successful in restoring many hearing capabilities, but sound localization with bilateral cochlear implants remains poor. This study investigates the reasons behind this and finds that electrical stimulation from cochlear implants alters the input statistics of the binaural processing stage, leading to diminished ITD sensitivity. A computational model predicts that electrical stimulation affects spatial sensitivity, making adjacent source locations inseparable. The findings suggest that the temporal hyper-precision of inputs induced by electrical stimulation may be a central problem underlying the reduced ITD sensitivity in cochlear implant users.
FRONTIERS IN NEUROSCIENCE
(2023)
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
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
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
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
Audiology & Speech-Language Pathology
Carol A. Sammeth, Andrew D. Brown, Nathaniel T. Greene, Daniel J. Tollin
Summary: The binaural interaction component (BIC) of the auditory brainstem response (ABR) is a biomarker of binaural processing abilities. This study examined the effect of interaural frequency mismatch (IFM) on BIC and behavioral interaural time difference (ITD) sensitivity in normal adult human subjects. Results showed that IFM had significant effects on BIC amplitudes and elevated ITD discrimination thresholds. The study also found that combinations of ITD, IFM, and sound level were bound by the empirically-measured BIC.
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
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
Maike Klingel, Bernhard Laback
Summary: This study investigated the feasibility of changing binaural-cue weights through training and found that ILD reweighting requires high frequencies while ITD reweighting requires low frequencies. Additionally, binaural-cue reweighting demonstrates some degree of generalization.
Article
Audiology & Speech-Language Pathology
Griet Mertens, Ellen Andries, Charis Clement, Ellen Cochet, Anouk Hofkens-Van den Brandt, Laure Jacquemin, Iris Joossen, Hanne Vermeersch, Marc Jan-Willem Lammers, Vincent Van Rompaey, Olivier Vanderveken
Summary: A retrospective study investigated the frequency of bimodal stimulation and its clinical benefit among cochlear implant (CI) users. The study found that bimodal stimulation was more frequently used and provided better auditory benefits compared to unilateral use. It was recommended that CI recipients continue using contralateral hearing aids after CI surgery.
INTERNATIONAL JOURNAL OF AUDIOLOGY
(2023)
Article
Neurosciences
Jianxin Bao, Segun Light Jegede, John W. Hawks, Bethany Dade, Qiang Guan, Samantha Middaugh, Ziyu Qiu, Anna Levina, Tsung-Heng Tsai
Summary: This study investigates the feasibility of using curvature quantification to detect cochlear synaptic loss. The results demonstrate that curvature measurement is more sensitive and consistent in identifying cochlear synaptic loss in mice compared to amplitude and latency measurements. Furthermore, different types of ear disorders show distinct changes in curvature profiles.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2022)
Article
Audiology & Speech-Language Pathology
Robert T. Dwyer, Chen Chen, Phillipp Hehrmann, Nichole C. Dwyer, Rene H. Gifford
Summary: Synchronizing the AGC can improve spatial hearing abilities of individuals with bilateral cochlear implants by better preserving ILD cues, but simply restoring the ILD cue alone is not enough to bridge the large performance gap between BiCI listeners and normal-hearing listeners on static and dynamic spatial hearing measures.
Article
Audiology & Speech-Language Pathology
Carol A. Sammeth, Nathaniel T. Greene, Andrew D. Brown, Daniel J. Tollin
Summary: The study aims to investigate the prevalence of BIC in normal-hearing young adults, the effects of interaural time differences (ITDs) on BIC, and the relationship between BIC and behavioral ITD discrimination acuity. The results show that while BIC can be observed in most subjects under specific conditions, its presence varies as ITDs increase or subjects' states change.
Article
Neurosciences
Kenneth E. Hancock, Yoojin Chung, Martin F. McKinney, Bertrand Delgutte
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2017)
Article
Neurosciences
Sridhar Srinivasan, Bernhard Laback, Piotr Majdak, Bertrand Delgutte
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2018)
Article
Neurosciences
Brian D. Buechel, Kenneth E. Hancock, Yoojin Chung, Bertrand Delgutte
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2018)
Article
Neurosciences
Yoojin Chung, Brian D. Buechel, Woongsang Sunwoo, Joseph D. Wagner, Bertrand Delgutte
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2019)
Article
Neurosciences
Yaqing Su, Bertrand Delgutte
JOURNAL OF NEUROPHYSIOLOGY
(2019)
Article
Neurosciences
Yaqing Su, Bertrand Delgutte
JOURNAL OF NEUROSCIENCE
(2020)
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
Yaqing Su, Yoojin Chung, Dan F. M. Goodman, Kenneth E. Hancock, Bertrand Delgutte
Summary: The study revealed neural mechanisms differences in pitch perception of irregular sounds between rabbits with normal hearing and those with cochlear implants. IC neurons showed tuning of firing rate to average pulse rate and differences in synchronized responses to periodic and irregular pulse trains in both groups of rabbits.
JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY
(2021)
Article
Neurosciences
Joseph D. Wagner, Alice Gelman, Kenneth E. Hancock, Yoojin Chung, Bertrand Delgutte
Summary: This study investigates rabbits' ability to discriminate complex tones without fundamental frequency (F0) and shows that rabbits can use either spectral or temporal cues to perceive pitch. The findings suggest that the role of spectral cues in pitch perception by animals may have been underestimated in previous studies focusing on low frequencies.
JOURNAL OF NEUROPHYSIOLOGY
(2022)
Article
Neurosciences
Kenneth E. Hancock, Bertrand Delgutte
Summary: Dichotic pitches, such as the Huggins pitch and the binaural edge pitch, are perceptual illusions created by binaural interactions. In this study, scientists investigated the neural responses of binaural neurons in the auditory midbrain and found that these neurons encode the frequency of dichotic pitches through specific features in their firing rates. These findings provide physiological evidence for the neural mechanisms underlying dichotic pitches.
JOURNAL OF NEUROPHYSIOLOGY
(2023)
Article
Neurosciences
Oded Barzelay, Stephen David, Bertrand Delgutte
Summary: Reverberation, which is commonly observed in everyday acoustic environments, can degrade binaural cues and envelope modulations and affect speech perception. However, both humans and animals can accurately perceive reverberant stimuli in most daily situations. In this study, neural responses to reverberant and non-reverberant speech stimuli were recorded in the inferior colliculus of rabbits, and it was found that high-quality spectrogram reconstruction can be obtained in moderate reverberation but deteriorates in severe reverberation.