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Alemu RZ, Gorodensky J, Gill S, Cushing SL, Papsin BC, Gordon KA. Binaural responses to a speech syllable are altered in children with hearing loss: Evidence from the frequency-following response. Hear Res 2024; 450:109068. [PMID: 38936172 DOI: 10.1016/j.heares.2024.109068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/14/2024] [Accepted: 06/11/2024] [Indexed: 06/29/2024]
Abstract
BACKGROUND & RATIONALE In prior work using non-speech stimuli, children with hearing loss show impaired perception of binaural cues and no significant change in cortical responses to bilateral versus unilateral stimulation. Aims of the present study were to: 1) identify bilateral responses to envelope and spectral components of a speech syllable using the frequency-following response (FFR), 2) determine if abnormalities in the bilateral FFR occur in children with hearing loss, and 3) assess functional consequences of abnormal bilateral FFR responses on perception of binaural timing cues. METHODS A single-syllable speech stimulus (/dα/) was presented to each ear individually and bilaterally. Participants were 9 children with normal hearing (MAge = 12.1 ± 2.5 years) and 6 children with bilateral hearing loss who were experienced bilateral hearing aid users (MAge = 14.0 ± 2.6 years). FFR temporal and spectral peak amplitudes were compared between listening conditions and groups using linear mixed model regression analyses. Behavioral sensitivity to binaural cues were measured by lateralization responses as coming from the right or left side of the head. RESULTS Both temporal and spectral peaks in FFR responses increased in amplitude in the bilateral compared to unilateral listening conditions in children with normal hearing. These measures of "bilateral advantage" were reduced in the group of children with bilateral hearing loss and associated with decreased sensitivity to interaural timing differences. CONCLUSION This study is the first to show that bilateral responses in both temporal and spectral domains can be measured in children using the FFR and is altered in children with hearing loss with consequences to binaural hearing.
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Affiliation(s)
- R Z Alemu
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - J Gorodensky
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada
| | - S Gill
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada
| | - S L Cushing
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology-Head & Neck Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - B C Papsin
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology-Head & Neck Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - K A Gordon
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology-Head & Neck Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
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Hu H, Ewert SD, Kollmeier B, Vickers D. Rate dependent neural responses of interaural-time-difference cues in fine-structure and envelope. PeerJ 2024; 12:e17104. [PMID: 38680894 PMCID: PMC11055513 DOI: 10.7717/peerj.17104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/22/2024] [Indexed: 05/01/2024] Open
Abstract
Advancements in cochlear implants (CIs) have led to a significant increase in bilateral CI users, especially among children. Yet, most bilateral CI users do not fully achieve the intended binaural benefit due to potential limitations in signal processing and/or surgical implant positioning. One crucial auditory cue that normal hearing (NH) listeners can benefit from is the interaural time difference (ITD), i.e., the time difference between the arrival of a sound at two ears. The ITD sensitivity is thought to be heavily relying on the effective utilization of temporal fine structure (very rapid oscillations in sound). Unfortunately, most current CIs do not transmit such true fine structure. Nevertheless, bilateral CI users have demonstrated sensitivity to ITD cues delivered through envelope or interaural pulse time differences, i.e., the time gap between the pulses delivered to the two implants. However, their ITD sensitivity is significantly poorer compared to NH individuals, and it further degrades at higher CI stimulation rates, especially when the rate exceeds 300 pulse per second. The overall purpose of this research thread is to improve spatial hearing abilities in bilateral CI users. This study aims to develop electroencephalography (EEG) paradigms that can be used with clinical settings to assess and optimize the delivery of ITD cues, which are crucial for spatial hearing in everyday life. The research objective of this article was to determine the effect of CI stimulation pulse rate on the ITD sensitivity, and to characterize the rate-dependent degradation in ITD perception using EEG measures. To develop protocols for bilateral CI studies, EEG responses were obtained from NH listeners using sinusoidal-amplitude-modulated (SAM) tones and filtered clicks with changes in either fine structure ITD (ITDFS) or envelope ITD (ITDENV). Multiple EEG responses were analyzed, which included the subcortical auditory steady-state responses (ASSRs) and cortical auditory evoked potentials (CAEPs) elicited by stimuli onset, offset, and changes. Results indicated that acoustic change complex (ACC) responses elicited by ITDENV changes were significantly smaller or absent compared to those elicited by ITDFS changes. The ACC morphologies evoked by ITDFS changes were similar to onset and offset CAEPs, although the peak latencies were longest for ACC responses and shortest for offset CAEPs. The high-frequency stimuli clearly elicited subcortical ASSRs, but smaller than those evoked by lower carrier frequency SAM tones. The 40-Hz ASSRs decreased with increasing carrier frequencies. Filtered clicks elicited larger ASSRs compared to high-frequency SAM tones, with the order being 40 > 160 > 80> 320 Hz ASSR for both stimulus types. Wavelet analysis revealed a clear interaction between detectable transient CAEPs and 40-Hz ASSRs in the time-frequency domain for SAM tones with a low carrier frequency.
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Affiliation(s)
- Hongmei Hu
- SOUND Lab, Cambridge Hearing Group, Department of Clinical Neuroscience, Cambridge University, Cambridge, United Kingdom
- Department of Medical Physics and Acoustics, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Stephan D. Ewert
- Department of Medical Physics and Acoustics, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Birger Kollmeier
- Department of Medical Physics and Acoustics, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Deborah Vickers
- SOUND Lab, Cambridge Hearing Group, Department of Clinical Neuroscience, Cambridge University, Cambridge, United Kingdom
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Lerud KD, Hancock R, Skoe E. A high-density EEG and structural MRI source analysis of the frequency following response to missing fundamental stimuli reveals subcortical and cortical activation to low and high frequency stimuli. Neuroimage 2023; 279:120330. [PMID: 37598815 DOI: 10.1016/j.neuroimage.2023.120330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 07/29/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023] Open
Abstract
Pitch is a perceptual rather than physical phenomenon, important for spoken language use, musical communication, and other aspects of everyday life. Auditory stimuli can be designed to probe the relationship between perception and physiological responses to pitch-evoking stimuli. One technique for measuring physiological responses to pitch-evoking stimuli is the frequency following response (FFR). The FFR is an electroencephalographic (EEG) response to periodic auditory stimuli. The FFR contains nonlinearities not present in the stimuli, including correlates of the amplitude envelope of the stimulus; however, these nonlinearities remain undercharacterized. The FFR is a composite response reflecting multiple neural and peripheral generators, and their contributions to the scalp-recorded FFR vary in ill-understood ways depending on the electrode montage, stimulus, and imaging technique. The FFR is typically assumed to be generated in the auditory brainstem; there is also evidence both for and against a cortical contribution to the FFR. Here a methodology is used to examine the FFR correlates of pitch and the generators of the FFR to stimuli with different pitches. Stimuli were designed to tease apart biological correlates of pitch and amplitude envelope. FFRs were recorded with 256-electrode EEG nets, in contrast to a typical FFR setup which only contains a single active electrode. Structural MRI scans were obtained for each participant to co-register with the electrode locations and constrain a source localization algorithm. The results of this localization shed light on the generating mechanisms of the FFR, including providing evidence for both cortical and subcortical auditory sources.
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Affiliation(s)
- Karl D Lerud
- University of Maryland College Park, Institute for Systems Research, 20742, United States of America.
| | - Roeland Hancock
- Yale University, Wu Tsai Institute, 06510, United States of America
| | - Erika Skoe
- University of Connecticut, Department of Speech, Language, and Hearing Sciences, Cognitive Sciences Program, 06269, United States of America
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Xu C, Cheng FY, Medina S, Eng E, Gifford R, Smith S. Objective discrimination of bimodal speech using frequency following responses. Hear Res 2023; 437:108853. [PMID: 37441879 DOI: 10.1016/j.heares.2023.108853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/03/2023] [Accepted: 07/08/2023] [Indexed: 07/15/2023]
Abstract
Bimodal hearing, in which a contralateral hearing aid is combined with a cochlear implant (CI), provides greater speech recognition benefits than using a CI alone. Factors predicting individual bimodal patient success are not fully understood. Previous studies have shown that bimodal benefits may be driven by a patient's ability to extract fundamental frequency (f0) and/or temporal fine structure cues (e.g., F1). Both of these features may be represented in frequency following responses (FFR) to bimodal speech. Thus, the goals of this study were to: 1) parametrically examine neural encoding of f0 and F1 in simulated bimodal speech conditions; 2) examine objective discrimination of FFRs to bimodal speech conditions using machine learning; 3) explore whether FFRs are predictive of perceptual bimodal benefit. Three vowels (/ε/, /i/, and /ʊ/) with identical f0 were manipulated by a vocoder (right ear) and low-pass filters (left ear) to create five bimodal simulations for evoking FFRs: Vocoder-only, Vocoder +125 Hz, Vocoder +250 Hz, Vocoder +500 Hz, and Vocoder +750 Hz. Perceptual performance on the BKB-SIN test was also measured using the same five configurations. Results suggested that neural representation of f0 and F1 FFR components were enhanced with increasing acoustic bandwidth in the simulated "non-implanted" ear. As spectral differences between vowels emerged in the FFRs with increased acoustic bandwidth, FFRs were more accurately classified and discriminated using a machine learning algorithm. Enhancement of f0 and F1 neural encoding with increasing bandwidth were collectively predictive of perceptual bimodal benefit on a speech-in-noise task. Given these results, FFR may be a useful tool to objectively assess individual variability in bimodal hearing.
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Affiliation(s)
- Can Xu
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, 2504A Whitis Ave. (A1100), Austin 78712-0114, TX, USA
| | - Fan-Yin Cheng
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, 2504A Whitis Ave. (A1100), Austin 78712-0114, TX, USA
| | - Sarah Medina
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, 2504A Whitis Ave. (A1100), Austin 78712-0114, TX, USA
| | - Erica Eng
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, 2504A Whitis Ave. (A1100), Austin 78712-0114, TX, USA
| | - René Gifford
- Department of Speech, Language, and Hearing Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Spencer Smith
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, 2504A Whitis Ave. (A1100), Austin 78712-0114, TX, USA.
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So W, Smith SB. Comparison of two cortical measures of binaural hearing acuity. Int J Audiol 2021; 60:875-884. [PMID: 33345686 PMCID: PMC8244817 DOI: 10.1080/14992027.2020.1860260] [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: 08/04/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Multiple studies have demonstrated binaural hearing deficits in the aging and those with hearing loss. Consequently, there is great interest in developing efficient clinical tests of binaural hearing acuity to improve diagnostic assessments and to assist clinicians when fitting binaural hearing aids and/or cochlear implants. DESIGN Two cortical measures of interaural phase difference sensitivity, the acoustic change complex (ACC) and interaural phase modulation following response (IPM-FR), were compared on three metrics using five different stimulus interaural phase differences (IPDs; 0°, ±22.5°, ±45°, ±67.5° and ±90°). These metrics were scalp topography, time-to-detect, and input-output characteristics. STUDY SAMPLE Ten young, normal-hearing listeners. RESULTS Scalp topography qualitatively differed between ACC and IPM-FR. The IPM-FR demonstrated better time-to-detect performance on smaller (±22.5° and ±45°) but not larger (67.5°, and ±90°) IPDs. Input-output characteristics of each response were similar. CONCLUSIONS The IPM-FR may be a faster and more efficient tool for assessing neural sensitivity to subtle IPD changes. However, the ACC may be useful for research or clinical questions concerned with the topographic representation of binaural cues.
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Affiliation(s)
- Won So
- Department of Communication Sciences and Disorders, The University of Texas at Austin, Austin, TX, USA
| | - Spencer B Smith
- Department of Communication Sciences and Disorders, The University of Texas at Austin, Austin, TX, USA
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Xu N, Luo L, Chen L, Ding Y, Li L. Different binaural processing of the envelope component and the temporal fine structure component of a narrowband noise in rat inferior colliculus. Hear Res 2021; 411:108354. [PMID: 34583218 DOI: 10.1016/j.heares.2021.108354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/29/2021] [Accepted: 09/15/2021] [Indexed: 11/18/2022]
Abstract
Complex broadband sounds are decomposed by peripheral auditory filters into a series of relatively narrowband signals, each with a slowly varying envelope (ENV) and a rapidly fluctuating temporal fine structure (TFS). ENV and TFS information at the bilateral ears contribute differentially to auditory perception. However, whether the difference could attribute to mechanisms of binaural integration remains an open question. As a potential neural correlate, subsets of neurons in the central nucleus of the inferior colliculus (ICC) are known to integrate binaural information with binaural inhibition or binaural summation. Therefore, we recorded the frequency-following responses (FFRs) to the ENV and TFS components of narrowband noises in the ICC of anesthetized rats and examined changes in FFR amplitude and stimulus-response coherence under various sound-delivery settings. We showed that binaural FFRENV was predominantly elicited by contralateral inputs and inhibited by ipsilateral inputs, exhibiting a "binaural-inhibition" like property. On the other hand, binaural FFRTFS received a balanced contribution from both sides, echoing the "binaural-summation" mechanism. What is more, binaural FFRENV was significantly correlated with contralateral-evoked but not ipsilateral-evoked FFRENV, while binaural FFRTFS correlated with both contralateral- and ipsilateral-evoked FFRTFS. Overall, these results suggest distinct binaural processing of ENV and TFS information at the midbrain level.
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Affiliation(s)
- Na Xu
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100080, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China.
| | - Lu Luo
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100080, China; School of Psychology, Beijing Sport University, Beijing 100084, China
| | - Liangjie Chen
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100080, China
| | - Yu Ding
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100080, China; Division of Sports Science and physical education, Tsinghua University, Beijing 100084, China
| | - Liang Li
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100080, China; Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing 100871, China; Beijing Institute for Brain Disorders, Beijing 100096, China.
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