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Xie D, Luo J, Chao X, Li J, Liu X, Fan Z, Wang H, Xu L. Relationship Between the Ability to Detect Frequency Changes or Temporal Gaps and Speech Perception Performance in Post-lingual Cochlear Implant Users. Front Neurosci 2022; 16:904724. [PMID: 35757528 PMCID: PMC9213807 DOI: 10.3389/fnins.2022.904724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/17/2022] [Indexed: 12/03/2022] Open
Abstract
Previous studies, using modulation stimuli, on the relative effects of frequency resolution and time resolution on CI users’ speech perception failed to reach a consistent conclusion. In this study, frequency change detection and temporal gap detection were used to investigate the frequency resolution and time resolution of CI users, respectively. Psychophysical and neurophysiological methods were used to simultaneously investigate the effects of frequency and time resolution on speech perception in post-lingual cochlear implant (CI) users. We investigated the effects of psychophysical results [frequency change detection threshold (FCDT), gap detection threshold (GDT)], and acoustic change complex (ACC) responses (evoked threshold, latency, or amplitude of ACC induced by frequency change or temporal gap) on speech perception [recognition rate of monosyllabic words, disyllabic words, sentences in quiet, and sentence recognition threshold (SRT) in noise]. Thirty-one adult post-lingual CI users of Mandarin Chinese were enrolled in the study. The stimuli used to induce ACCs to frequency changes were 800-ms pure tones (fundamental frequency was 1,000 Hz); the frequency change occurred at the midpoint of the tones, with six percentages of frequency changes (0, 2, 5, 10, 20, and 50%). Temporal silences with different durations (0, 5, 10, 20, 50, and 100 ms) were inserted in the middle of the 800-ms white noise to induce ACCs evoked by temporal gaps. The FCDT and GDT were obtained by two 2-alternative forced-choice procedures. The results showed no significant correlation between the CI hearing threshold and speech perception in the study participants. In the multiple regression analysis of the influence of simultaneous psychophysical measures and ACC responses on speech perception, GDT significantly predicted every speech perception index, and the ACC amplitude evoked by the temporal gap significantly predicted the recognition of disyllabic words in quiet and SRT in noise. We conclude that when the ability to detect frequency changes and the temporal gap is considered simultaneously, the ability to detect frequency changes may have no significant effect on speech perception, but the ability to detect temporal gaps could significantly predict speech perception.
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Affiliation(s)
- Dianzhao Xie
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jianfen Luo
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xiuhua Chao
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jinming Li
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xianqi Liu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zhaomin Fan
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Lei Xu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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Cabrera L, Lau BK. The development of auditory temporal processing during the first year of life. HEARING, BALANCE AND COMMUNICATION 2022; 20:155-165. [PMID: 36111124 PMCID: PMC9473293 DOI: 10.1080/21695717.2022.2029092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
OBJECTIVES The processing of auditory temporal information is important for the extraction of voice pitch, linguistic information, as well as the overall temporal structure of speech. However, many aspects of its early development remain poorly understood. This paper reviews the development of auditory temporal processing during the first year of life when infants are acquiring their native language. METHODS First, potential mechanisms of neural immaturity are discussed in the context of neurophysiological studies. Next, what is known about infant auditory capabilities is considered with a focus on psychophysical studies involving non-speech stimuli to investigate the perception of temporal fine structure and envelope cues. This is followed by a review of studies involving speech stimuli, including those that present vocoded signals as a method of degrading the spectro-temporal information available to infant listeners. RESULTS/CONCLUSION This review suggests that temporal resolution may be well developed in the first postnatal months, but that the ability to use and process the temporal information in an efficient way along the entire auditory pathway is longer to develop. Those findings have crucial implications for the development of language abilities, especially for infants with hearing impairment who are using cochlear implants.
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Affiliation(s)
- Laurianne Cabrera
- Université de Paris, INCC UMR 8002, CNRS, 45 rue des saints-pères, F-75006 Paris, France
| | - Bonnie K Lau
- Department of Otolaryngology - Head & Neck Surgery, University of Washington, 1701 NE Columbia Rd, Box 257923, Seattle, WA 98195
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Varnet L, Léger AC, Boucher S, Bonnet C, Petit C, Lorenzi C. Contributions of Age-Related and Audibility-Related Deficits to Aided Consonant Identification in Presbycusis: A Causal-Inference Analysis. Front Aging Neurosci 2021; 13:640522. [PMID: 33732140 PMCID: PMC7956988 DOI: 10.3389/fnagi.2021.640522] [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] [Received: 12/11/2020] [Accepted: 02/08/2021] [Indexed: 12/05/2022] Open
Abstract
The decline of speech intelligibility in presbycusis can be regarded as resulting from the combined contribution of two main groups of factors: (1) audibility-related factors and (2) age-related factors. In particular, there is now an abundant scientific literature on the crucial role of suprathreshold auditory abilities and cognitive functions, which have been found to decline with age even in the absence of audiometric hearing loss. However, researchers investigating the direct effect of aging in presbycusis have to deal with the methodological issue that age and peripheral hearing loss covary to a large extent. In the present study, we analyzed a dataset of consonant-identification scores measured in quiet and in noise for a large cohort (n = 459, age = 42-92) of hearing-impaired (HI) and normal-hearing (NH) listeners. HI listeners were provided with a frequency-dependent amplification adjusted to their audiometric profile. Their scores in the two conditions were predicted from their pure-tone average (PTA) and age, as well as from their Extended Speech Intelligibility Index (ESII), a measure of the impact of audibility loss on speech intelligibility. We relied on a causal-inference approach combined with Bayesian modeling to disentangle the direct causal effects of age and audibility on intelligibility from the indirect effect of age on hearing loss. The analysis revealed that the direct effect of PTA on HI intelligibility scores was 5 times higher than the effect of age. This overwhelming effect of PTA was not due to a residual audibility loss despite amplification, as confirmed by a ESII-based model. More plausibly, the marginal role of age could be a consequence of the relatively little cognitively-demanding task used in this study. Furthermore, the amount of variance in intelligibility scores was smaller for NH than HI listeners, even after accounting for age and audibility, reflecting the presence of additional suprathreshold deficits in the latter group. Although the non-sense-syllable materials and the particular amplification settings used in this study potentially restrict the generalization of the findings, we think that these promising results call for a wider use of causal-inference analysis in audiology, e.g., as a way to disentangle the influence of the various cognitive factors and suprathreshold deficits associated to presbycusis.
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Affiliation(s)
- Léo Varnet
- Laboratoire des Systèmes Perceptifs, UMR CNRS 8248, Département d'Études Cognitives, École normale supérieure, Université Paris Sciences & Lettres, Paris, France
| | - Agnès C. Léger
- Manchester Centre for Audiology and Deafness, Division of Human Communication, Development & Hearing, School of Health Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Sophie Boucher
- Complexité du Vivant, Sorbonne Universités, Université Pierre et Marie Curie, Université Paris VI, Paris, France
- Institut de l'Audition, Institut Pasteur, INSERM, Paris, France
- Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Crystel Bonnet
- Complexité du Vivant, Sorbonne Universités, Université Pierre et Marie Curie, Université Paris VI, Paris, France
- Institut de l'Audition, Institut Pasteur, INSERM, Paris, France
| | - Christine Petit
- Institut de l'Audition, Institut Pasteur, INSERM, Paris, France
- Collège de France, Paris, France
| | - Christian Lorenzi
- Laboratoire des Systèmes Perceptifs, UMR CNRS 8248, Département d'Études Cognitives, École normale supérieure, Université Paris Sciences & Lettres, Paris, France
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Cabrera L, Varnet L, Buss E, Rosen S, Lorenzi C. Development of temporal auditory processing in childhood: Changes in efficiency rather than temporal-modulation selectivity. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:2415. [PMID: 31672005 DOI: 10.1121/1.5128324] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/16/2019] [Indexed: 05/22/2023]
Abstract
The ability to detect amplitude modulation (AM) is essential to distinguish the spectro-temporal features of speech from those of a competing masker. Previous work shows that AM sensitivity improves until 10 years of age. This may relate to the development of sensory factors (tuning of AM filters, susceptibility to AM masking) or to changes in processing efficiency (reduction in internal noise, optimization of decision strategies). To disentangle these hypotheses, three groups of children (5-11 years) and one of young adults completed psychophysical tasks measuring thresholds for detecting sinusoidal AM (with a rate of 4, 8, or 32 Hz) applied to carriers whose inherent modulations exerted different amounts of AM masking. Results showed that between 5 and 11 years, AM detection thresholds improved and that susceptibility to AM masking slightly increased. However, the effects of AM rate and carrier were not associated with age, suggesting that sensory factors are mature by 5 years. Subsequent modelling indicated that reducing internal noise by a factor 10 accounted for the observed developmental trends. Finally, children's consonant identification thresholds in noise related to some extent to AM sensitivity. Increased efficiency in AM detection may support better use of temporal information in speech during childhood.
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Affiliation(s)
- Laurianne Cabrera
- Department of Speech, Hearing and Phonetic Sciences, University College London, Chandler House, 2 Wakefield Street, WC1N 1PF, London, United Kingdom
| | - Léo Varnet
- Laboratoire des Systèmes Perceptifs, Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, 29 Rue d'Ulm, 75005, Paris, France
| | - Emily Buss
- Department of Otolaryngology/Head and Neck Surgery, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Stuart Rosen
- Department of Speech, Hearing and Phonetic Sciences, University College London, Chandler House, 2 Wakefield Street, WC1N 1PF, London, United Kingdom
| | - Christian Lorenzi
- Laboratoire des Systèmes Perceptifs, Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, 29 Rue d'Ulm, 75005, Paris, France
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Temporal Sensitivity Measured Shortly After Cochlear Implantation Predicts 6-Month Speech Recognition Outcome. Ear Hear 2019; 40:27-33. [PMID: 29697465 DOI: 10.1097/aud.0000000000000588] [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
OBJECTIVES Psychoacoustic tests assessed shortly after cochlear implantation are useful predictors of the rehabilitative speech outcome. While largely independent, both spectral and temporal resolution tests are important to provide an accurate prediction of speech recognition. However, rapid tests of temporal sensitivity are currently lacking. Here, we propose a simple amplitude modulation rate discrimination (AMRD) paradigm that is validated by predicting future speech recognition in adult cochlear implant (CI) patients. DESIGN In 34 newly implanted patients, we used an adaptive AMRD paradigm, where broadband noise was modulated at the speech-relevant rate of ~4 Hz. In a longitudinal study, speech recognition in quiet was assessed using the closed-set Freiburger number test shortly after cochlear implantation (t0) as well as the open-set Freiburger monosyllabic word test 6 months later (t6). RESULTS Both AMRD thresholds at t0 (r = -0.51) and speech recognition scores at t0 (r = 0.56) predicted speech recognition scores at t6. However, AMRD and speech recognition at t0 were uncorrelated, suggesting that those measures capture partially distinct perceptual abilities. A multiple regression model predicting 6-month speech recognition outcome with deafness duration and speech recognition at t0 improved from adjusted R = 0.30 to adjusted R = 0.44 when AMRD threshold was added as a predictor. CONCLUSIONS These findings identify AMRD thresholds as a reliable, nonredundant predictor above and beyond established speech tests for CI outcome. This AMRD test could potentially be developed into a rapid clinical temporal-resolution test to be integrated into the postoperative test battery to improve the reliability of speech outcome prognosis.
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Archer-Boyd AW, Southwell RV, Deeks JM, Turner RE, Carlyon RP. Development and validation of a spectro-temporal processing test for cochlear-implant listeners. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:2983. [PMID: 30522311 PMCID: PMC6805218 DOI: 10.1121/1.5079636] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 11/01/2018] [Indexed: 06/06/2023]
Abstract
Psychophysical tests of spectro-temporal resolution may aid the evaluation of methods for improving hearing by cochlear implant (CI) listeners. Here the STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is described and validated. Like speech, the test requires both spectral and temporal processing to perform well. Listeners discriminate between complexes of sine sweeps which increase or decrease in frequency; difficulty is controlled by changing the stimulus spectro-temporal density. Care was taken to minimize extraneous cues, forcing listeners to perform the task only on the direction of the sweeps. Vocoder simulations with normal hearing listeners showed that the STRIPES test was sensitive to the number of channels and temporal information fidelity. An evaluation with CI listeners compared a standard processing strategy with one having very wide filters, thereby spectrally blurring the stimulus. Psychometric functions were monotonic for both strategies and five of six participants performed better with the standard strategy. An adaptive procedure revealed significant differences, all in favour of the standard strategy, at the individual listener level for six of eight CI listeners. Subsequent measures validated a faster version of the test, and showed that STRIPES could be performed by recently implanted listeners having no experience of psychophysical testing.
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Affiliation(s)
- Alan W. Archer-Boyd
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Rosy V. Southwell
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - John M. Deeks
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Richard E. Turner
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
| | - Robert P. Carlyon
- MRC Cognition & Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom
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Brochier T, McKay C, McDermott H. Encoding speech in cochlear implants using simultaneous amplitude and rate modulation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:2042. [PMID: 30404505 DOI: 10.1121/1.5055989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 09/10/2018] [Indexed: 06/08/2023]
Abstract
To improve speech perception for cochlear implant (CI) users, it is essential to improve the transmission of temporal envelopes. The most common speech processors deliver temporal envelopes via the CI using fixed-rate amplitude modulated (AM) pulse trains. Psychophysical studies suggest that rate modulation (RM) and AM are perceived by a shared temporal integration mechanism, but the potential for them to constructively combine to encode temporal envelopes has yet to be explored. In this experiment, a speech processing strategy called amplitude and rate temporal modulation was developed to encode speech temporal envelopes with simultaneous AM and RM. The strategy was tested for perception of clean speech at 60 and 40 dBA, and 60 dBA speech in noise (+10 dB SNR). The amount of RM was varied and the amount of AM was held constant to determine whether the addition of RM could enhance the perception of temporal envelopes and improve speech understanding. At the lowest RM amount, speech scores were poorest for all speech conditions. For 60 dBA clean speech and speech in noise, speech scores were significantly better at the highest RM amounts, suggesting that RM combined with AM can be used to enhance perception of temporal envelopes.
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Affiliation(s)
- Tim Brochier
- Department of Medical Bionics, University of Melbourne, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Colette McKay
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Hugh McDermott
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
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Brochier T, McKay C, McDermott H. Rate modulation detection thresholds for cochlear implant users. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:1214. [PMID: 29495682 DOI: 10.1121/1.5025048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The perception of temporal amplitude modulations is critical for speech understanding by cochlear implant (CI) users. The present study compared the ability of CI users to detect sinusoidal modulations of the electrical stimulation rate and current level, at different presentation levels (80% and 40% of the dynamic range) and modulation frequencies (10 and 100 Hz). Rate modulation detection thresholds (RMDTs) and amplitude modulation detection thresholds (AMDTs) were measured and compared to assess whether there was a perceptual advantage to either modulation method. Both RMDTs and AMDTs improved with increasing presentation level and decreasing modulation frequency. RMDTs and AMDTs were correlated, indicating that a common processing mechanism may underlie the perception of rate modulation and amplitude modulation, or that some subject-dependent factors affect both types of modulation detection.
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Affiliation(s)
- Tim Brochier
- Department of Medical Bionics, University of Melbourne, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Colette McKay
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Hugh McDermott
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
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Waechter SM, Lopez Valdes A, Simoes-Franklin C, Viani L, Reilly RB. Depth matters - Towards finding an objective neurophysiological measure of behavioral amplitude modulation detection based on neural threshold determination. Hear Res 2017; 359:13-22. [PMID: 29291949 DOI: 10.1016/j.heares.2017.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 11/29/2022]
Abstract
With increasing numbers undergoing intervention for hearing impairment at a young age, the clinical need for objective assessment tools of auditory discrimination abilities is growing. Amplitude modulation (AM) sensitivity has been known to be an important factor for speech recognition particularly among cochlear implant (CI) users. It therefore would be useful to develop objective measures of AM detection for future clinical assessment of CI users; this study aimed to verify the feasibility of a neurophysiological approach studying a cohort of normal-hearing participants. The mismatch waveform (MMW) was evaluated as a potential objective measure of AM detection for a low modulation rate (8 Hz). This study also explored the relationship between behavioral AM detection and speech-in-noise recognition. The following measures were obtained for 15 young adults with no known hearing impairment: (1) psychoacoustic sinusoidal AM detection ability for a modulation rate of 8 Hz; (2) neural AM detection thresholds estimated from morphology weighted cortical auditory evoked potentials elicited to various AM depths; and (3) AzBio sentence scores for speech-in-noise recognition. No significant correlations were found between speech recognition and behavioral AM detection measures. Individual neural thresholds were obtained from MMW data and showed significant positive correlations with behavioral AM detection thresholds. Neural thresholds estimated from morphology weighted MMWs provide a novel, objective approach for assessing low-rate AM detection. The findings of this study encourage the continued investigation of the MMW as a neural correlate of low-rate AM detection in larger normal-hearing cohorts and subsequently in clinical cohorts such as cochlear implant users.
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Affiliation(s)
- Saskia M Waechter
- Trinity Centre for Bioengineering, Trinity College, The University of Dublin, Dublin 2, Ireland; School of Engineering, Trinity College, The University of Dublin, Dublin 2, Ireland
| | - Alejandro Lopez Valdes
- Trinity Centre for Bioengineering, Trinity College, The University of Dublin, Dublin 2, Ireland; School of Engineering, Trinity College, The University of Dublin, Dublin 2, Ireland
| | - Cristina Simoes-Franklin
- Trinity Centre for Bioengineering, Trinity College, The University of Dublin, Dublin 2, Ireland; National Cochlear Implant Program, Beaumont Hospital, Dublin 9, Ireland; School of Medicine, Trinity College, The University of Dublin, Dublin 2, Ireland
| | - Laura Viani
- National Cochlear Implant Program, Beaumont Hospital, Dublin 9, Ireland; Royal College of Surgeons in Ireland, Dublin 2, Ireland; School of Medicine, Trinity College, The University of Dublin, Dublin 2, Ireland
| | - Richard B Reilly
- Trinity Centre for Bioengineering, Trinity College, The University of Dublin, Dublin 2, Ireland; School of Engineering, Trinity College, The University of Dublin, Dublin 2, Ireland; Royal College of Surgeons in Ireland, Dublin 2, Ireland; School of Medicine, Trinity College, The University of Dublin, Dublin 2, Ireland.
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Brochier T, McDermott HJ, McKay CM. The effect of presentation level and stimulation rate on speech perception and modulation detection for cochlear implant users. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:4097. [PMID: 28618807 PMCID: PMC5457292 DOI: 10.1121/1.4983658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 04/26/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
In order to improve speech understanding for cochlear implant users, it is important to maximize the transmission of temporal information. The combined effects of stimulation rate and presentation level on temporal information transfer and speech understanding remain unclear. The present study systematically varied presentation level (60, 50, and 40 dBA) and stimulation rate [500 and 2400 pulses per second per electrode (pps)] in order to observe how the effect of rate on speech understanding changes for different presentation levels. Speech recognition in quiet and noise, and acoustic amplitude modulation detection thresholds (AMDTs) were measured with acoustic stimuli presented to speech processors via direct audio input (DAI). With the 500 pps processor, results showed significantly better performance for consonant-vowel nucleus-consonant words in quiet, and a reduced effect of noise on sentence recognition. However, no rate or level effect was found for AMDTs, perhaps partly because of amplitude compression in the sound processor. AMDTs were found to be strongly correlated with the effect of noise on sentence perception at low levels. These results indicate that AMDTs, at least when measured with the CP910 Freedom speech processor via DAI, explain between-subject variance of speech understanding, but do not explain within-subject variance for different rates and levels.
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Affiliation(s)
- Tim Brochier
- Department of Medical Bionics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Hugh J McDermott
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
| | - Colette M McKay
- The Bionics Institute, 384-388 Albert Street, East Melbourne, Victoria 3002, Australia
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Zheng Y, Escabí M, Litovsky RY. Spectro-temporal cues enhance modulation sensitivity in cochlear implant users. Hear Res 2017; 351:45-54. [PMID: 28601530 DOI: 10.1016/j.heares.2017.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 05/12/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
Although speech understanding is highly variable amongst cochlear implants (CIs) subjects, the remarkably high speech recognition performance of many CI users is unexpected and not well understood. Numerous factors, including neural health and degradation of the spectral information in the speech signal of CIs, likely contribute to speech understanding. We studied the ability to use spectro-temporal modulations, which may be critical for speech understanding and discrimination, and hypothesize that CI users adopt a different perceptual strategy than normal-hearing (NH) individuals, whereby they rely more heavily on joint spectro-temporal cues to enhance detection of auditory cues. Modulation detection sensitivity was studied in CI users and NH subjects using broadband "ripple" stimuli that were modulated spectrally, temporally, or jointly, i.e., spectro-temporally. The spectro-temporal modulation transfer functions of CI users and NH subjects was decomposed into spectral and temporal dimensions and compared to those subjects' spectral-only and temporal-only modulation transfer functions. In CI users, the joint spectro-temporal sensitivity was better than that predicted by spectral-only and temporal-only sensitivity, indicating a heightened spectro-temporal sensitivity. Such an enhancement through the combined integration of spectral and temporal cues was not observed in NH subjects. The unique use of spectro-temporal cues by CI patients can yield benefits for use of cues that are important for speech understanding. This finding has implications for developing sound processing strategies that may rely on joint spectro-temporal modulations to improve speech comprehension of CI users, and the findings of this study may be valuable for developing clinical assessment tools to optimize CI processor performance.
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Affiliation(s)
- Yi Zheng
- Waisman Center, University of Wisconsin Madison, 1500 Highland Avenue, Madison, WI, 53705, USA
| | - Monty Escabí
- Biomedical Engineering, Electrical and Computer Engineering, University of Connecticut, 371 Fairfield Rd., U1157, Storrs, CT, 06269, USA
| | - Ruth Y Litovsky
- Waisman Center, University of Wisconsin Madison, 1500 Highland Avenue, Madison, WI, 53705, USA.
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George SS, Shivdasani MN, Fallon JB. Effect of current focusing on the sensitivity of inferior colliculus neurons to amplitude-modulated stimulation. J Neurophysiol 2016; 116:1104-16. [PMID: 27306672 DOI: 10.1152/jn.00126.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/15/2016] [Indexed: 11/22/2022] Open
Abstract
In multichannel cochlear implants (CIs), current is delivered to specific electrodes along the cochlea in the form of amplitude-modulated pulse trains, to convey temporal and spectral cues. Our previous studies have shown that focused multipolar (FMP) and tripolar (TP) stimulation produce more restricted neural activation and reduced channel interactions in the inferior colliculus (IC) compared with traditional monopolar (MP) stimulation, suggesting that focusing of stimulation could produce better transmission of spectral information. The present study explored the capability of IC neurons to detect modulated CI stimulation with FMP and TP stimulation compared with MP stimulation. The study examined multiunit responses of IC neurons in acutely deafened guinea pigs by systematically varying the stimulation configuration, modulation depth, and stimulation level. Stimuli were sinusoidal amplitude-modulated pulse trains (carrier rate of 120 pulses/s). Modulation sensitivity was quantified by measuring modulation detection thresholds (MDTs), defined as the lowest modulation depth required to differentiate the response of a modulated stimulus from an unmodulated one. Whereas MP stimulation showed significantly lower MDTs than FMP and TP stimulation (P values <0.05) at stimulation ≤2 dB above threshold, all stimulation configurations were found to have similar modulation sensitivities at 4 dB above threshold. There was no difference found in modulation sensitivity between FMP and TP stimulation. The present study demonstrates that current focusing techniques such as FMP and TP can adequately convey amplitude modulation and are comparable to MP stimulation, especially at higher stimulation levels, although there may be some trade-off between spectral and temporal fidelity with current focusing stimulation.
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Affiliation(s)
- Shefin S George
- The Bionics Institute, East Melbourne, Australia; and Department of Medical Bionics, University of Melbourne, Melbourne, Australia
| | - Mohit N Shivdasani
- The Bionics Institute, East Melbourne, Australia; and Department of Medical Bionics, University of Melbourne, Melbourne, Australia
| | - James B Fallon
- The Bionics Institute, East Melbourne, Australia; and Department of Medical Bionics, University of Melbourne, Melbourne, Australia
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Won JH, Moon IJ, Jin S, Park H, Woo J, Cho YS, Chung WH, Hong SH. Spectrotemporal Modulation Detection and Speech Perception by Cochlear Implant Users. PLoS One 2015; 10:e0140920. [PMID: 26485715 PMCID: PMC4617902 DOI: 10.1371/journal.pone.0140920] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 10/01/2015] [Indexed: 11/18/2022] Open
Abstract
Spectrotemporal modulation (STM) detection performance was examined for cochlear implant (CI) users. The test involved discriminating between an unmodulated steady noise and a modulated stimulus. The modulated stimulus presents frequency modulation patterns that change in frequency over time. In order to examine STM detection performance for different modulation conditions, two different temporal modulation rates (5 and 10 Hz) and three different spectral modulation densities (0.5, 1.0, and 2.0 cycles/octave) were employed, producing a total 6 different STM stimulus conditions. In order to explore how electric hearing constrains STM sensitivity for CI users differently from acoustic hearing, normal-hearing (NH) and hearing-impaired (HI) listeners were also tested on the same tasks. STM detection performance was best in NH subjects, followed by HI subjects. On average, CI subjects showed poorest performance, but some CI subjects showed high levels of STM detection performance that was comparable to acoustic hearing. Significant correlations were found between STM detection performance and speech identification performance in quiet and in noise. In order to understand the relative contribution of spectral and temporal modulation cues to speech perception abilities for CI users, spectral and temporal modulation detection was performed separately and related to STM detection and speech perception performance. The results suggest that that slow spectral modulation rather than slow temporal modulation may be important for determining speech perception capabilities for CI users. Lastly, test–retest reliability for STM detection was good with no learning. The present study demonstrates that STM detection may be a useful tool to evaluate the ability of CI sound processing strategies to deliver clinically pertinent acoustic modulation information.
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Affiliation(s)
- Jong Ho Won
- Division of Ophthalmic and Ear, Nose and Throat Devices, Office of Device Evaluation, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Il Joon Moon
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
- * E-mail:
| | - Sunhwa Jin
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
| | - Heesung Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
| | - Jihwan Woo
- School of Electrical Engineering, Biomedical Engineering, University of Ulsan, Ulsan 680-749, Republic of Korea
| | - Yang-Sun Cho
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
| | - Won-Ho Chung
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
| | - Sung Hwa Hong
- Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 135-710, Republic of Korea
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Park MH, Won JH, Horn DL, Rubinstein JT. Acoustic temporal modulation detection in normal-hearing and cochlear implanted listeners: effects of hearing mechanism and development. J Assoc Res Otolaryngol 2015; 16:389-99. [PMID: 25790949 DOI: 10.1007/s10162-014-0499-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 11/10/2014] [Indexed: 11/28/2022] Open
Abstract
Temporal modulation detection ability matures over many years after birth and may be particularly sensitive to experience during this period. Profound hearing loss during early childhood might result in greater perceptual deficits than a similar loss beginning in adulthood. We tested this idea by measuring performance in temporal modulation detection in profoundly deaf children and adults fitted with cochlear implants (CIs). At least two independent variables could constrain temporal modulation detection performance in children with CIs: altered encoding of modulation information due to the CI-auditory nerve interface, and atypical development of central processing of sound information provided by CIs. The effect of altered encoding was investigated by testing subjects with one of two different hearing mechanisms (normal hearing vs. CI) and the effect of atypical development was studied by testing two different age groups. All subjects were tested for their ability to detect acoustic temporal modulations of sound amplitude. A comparison of the slope, or cutoff frequency, of the temporal modulation transfer functions (TMTFs) among the four subject groups revealed that temporal resolution was mainly constrained by hearing mechanism: normal-hearing listeners could detect smaller amplitude modulations at high modulation frequencies than CI users. In contrast, a comparison of the height of the TMTFs revealed a significant interaction between hearing mechanism and age group on overall sensitivity to temporal modulation: sensitivity was significantly poorer in children with CIs, relative to the other three groups. Results suggest that there is an age-specific vulnerability of intensity discrimination or non-sensory factors, which subsequently affects sensitivity to temporal modulation in prelingually deaf children who use CIs.
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Affiliation(s)
- Min-Hyun Park
- Department of Otorhinolaryngology, Boramae Medical Center, Seoul Metropolitan Government - Seoul National University, Seoul, 156-707, Korea
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Oxenham AJ, Kreft HA. Speech perception in tones and noise via cochlear implants reveals influence of spectral resolution on temporal processing. Trends Hear 2014; 18:18/0/2331216514553783. [PMID: 25315376 PMCID: PMC4227666 DOI: 10.1177/2331216514553783] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Under normal conditions, human speech is remarkably robust to degradation by noise and other distortions. However, people with hearing loss, including those with cochlear implants, often experience great difficulty in understanding speech in noisy environments. Recent work with normal-hearing listeners has shown that the amplitude fluctuations inherent in noise contribute strongly to the masking of speech. In contrast, this study shows that speech perception via a cochlear implant is unaffected by the inherent temporal fluctuations of noise. This qualitative difference between acoustic and electric auditory perception does not seem to be due to differences in underlying temporal acuity but can instead be explained by the poorer spectral resolution of cochlear implants, relative to the normally functioning ear, which leads to an effective smoothing of the inherent temporal-envelope fluctuations of noise. The outcome suggests an unexpected trade-off between the detrimental effects of poorer spectral resolution and the beneficial effects of a smoother noise temporal envelope. This trade-off provides an explanation for the long-standing puzzle of why strong correlations between speech understanding and spectral resolution have remained elusive. The results also provide a potential explanation for why cochlear-implant users and hearing-impaired listeners exhibit reduced or absent masking release when large and relatively slow temporal fluctuations are introduced in noise maskers. The multitone maskers used here may provide an effective new diagnostic tool for assessing functional hearing loss and reduced spectral resolution.
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Affiliation(s)
- Andrew J Oxenham
- Department of Psychology, University of Minnesota, Minneapolis, MN, USA Department of Otolaryngology, University of Minnesota, Minneapolis, MN, USA
| | - Heather A Kreft
- Department of Otolaryngology, University of Minnesota, Minneapolis, MN, USA
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