scholarly journals Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users

2015 ◽  
Vol 26 (06) ◽  
pp. 572-581 ◽  
Author(s):  
Stanley Sheft ◽  
Min-Yu Cheng ◽  
Valeriy Shafiro
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Stimulus Duration ◽  
Frequency Modulation ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Normal Hearing ◽  
Signal To Noise ◽  
Common Basis ◽  
Low Rate

Background: Past work has shown that low-rate frequency modulation (FM) may help preserve signal coherence, aid segmentation at word and syllable boundaries, and benefit speech intelligibility in the presence of a masker. Purpose: This study evaluated whether difficulties in speech perception by cochlear implant (CI) users relate to a deficit in the ability to discriminate among stochastic low-rate patterns of FM. Research Design: This is a correlational study assessing the association between the ability to discriminate stochastic patterns of low-rate FM and the intelligibility of speech in noise. Study Sample: Thirteen postlingually deafened adult CI users participated in this study. Data Collection and Analysis: Using modulators derived from 5-Hz lowpass noise applied to a 1-kHz carrier, thresholds were measured in terms of frequency excursion both in quiet and with a speech-babble masker present, stimulus duration, and signal-to-noise ratio in the presence of a speech-babble masker. Speech perception ability was assessed in the presence of the same speech-babble masker. Relationships were evaluated with Pearson product–moment correlation analysis with correction for family-wise error, and commonality analysis to determine the unique and common contributions across psychoacoustic variables to the association with speech ability. Results: Significant correlations were obtained between masked speech intelligibility and three metrics of FM discrimination involving either signal-to-noise ratio or stimulus duration, with shared variance among the three measures accounting for much of the effect. Compared to past results from young normal-hearing adults and older adults with either normal hearing or a mild-to-moderate hearing loss, mean FM discrimination thresholds obtained from CI users were higher in all conditions. Conclusions: The ability to process the pattern of frequency excursions of stochastic FM may, in part, have a common basis with speech perception in noise. Discrimination of differences in the temporally distributed place coding of the stimulus could serve as this common basis for CI users.

Effect of Synchronized Linked Band Selection on Speech Intelligibility of Bilateral Cochlear Implant Users

2020 ◽  
Author(s):  
Tom Gajęcki ◽  
Waldo Nogueira
Keyword(s):  
Electrical Stimulation ◽  
Cochlear Implant ◽  
Background Noise ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Normal Hearing ◽  
Band Selection ◽  
Signal To Noise ◽  
Intelligibility Test ◽  
Bilateral Cochlear Implant

Normal hearing listeners have the ability to exploit the audio input perceived by each ear to extract target information in challenging listening scenarios. Bilateral cochlear implant (BiCI) users, however, do not benefit as much as normal hearing listeners do from a bilateral input. In this study, we investigate the effect that bilaterally linked band selection, bilaterally synchronized electrical stimulation and ideal binary masks (IdBMs) have on the ability of 10 BiCIs to understand speech in background noise. The performance was assessed through a sentence-based speech intelligibility test, in a scenario where the speech signal was presented from the front and the interfering noise from one side. The linked band selection relies on the most favorable signal-to-noise-ratio (SNR) ear, which will select the bands to be stimulated for both CIs. Results show that no benefit from adding a second CI to the most favorable SNR side was achieved for any of the tested bilateral conditions. However, when using both devices, speech perception results show that performing linked band selection, besides delivering bilaterally synchronized electrical stimulation, leads to an improvement compared to standard clinical setups. Moreover, the outcomes of this work show that by applying IdBMs, subjects achieve speech intelligibility scores similar to the ones without background noise.

scholarly journals Logatome Discrimination in Cochlear Implant Users: Subjective Tests Compared to the Mismatch Negativity

2010 ◽  
Vol 10 ◽  
pp. 329-339 ◽  
Author(s):  
Torsten Rahne ◽  
Michael Ziese ◽  
Dorothea Rostalski ◽  
Roland Mühler
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Mismatch Negativity ◽  
Speech Intelligibility ◽  
Event Related Potentials ◽  
Normal Hearing ◽  
Discrimination Test ◽  
Speech Database ◽  
Automated Speech Recognition ◽  
Related Potentials

This paper describes a logatome discrimination test for the assessment of speech perception in cochlear implant users (CI users), based on a multilingual speech database, the Oldenburg Logatome Corpus, which was originally recorded for the comparison of human and automated speech recognition. The logatome discrimination task is based on the presentation of 100 logatome pairs (i.e., nonsense syllables) with balanced representations of alternating “vowel-replacement” and “consonant-replacement” paradigms in order to assess phoneme confusions. Thirteen adult normal hearing listeners and eight adult CI users, including both good and poor performers, were included in the study and completed the test after their speech intelligibility abilities were evaluated with an established sentence test in noise. Furthermore, the discrimination abilities were measured electrophysiologically by recording the mismatch negativity (MMN) as a component of auditory event-related potentials. The results show a clear MMN response only for normal hearing listeners and CI users with good performance, correlating with their logatome discrimination abilities. Higher discrimination scores for vowel-replacement paradigms than for the consonant-replacement paradigms were found. We conclude that the logatome discrimination test is well suited to monitor the speech perception skills of CI users. Due to the large number of available spoken logatome items, the Oldenburg Logatome Corpus appears to provide a useful and powerful basis for further development of speech perception tests for CI users.

scholarly journals Evaluation of an Adaptive Dynamic Compensation System in Cochlear Implant Listeners

2020 ◽  
Vol 24 ◽  
pp. 233121652097034
Author(s):  
Florian Langner ◽  
Andreas Büchner ◽  
Waldo Nogueira
Keyword(s):  
Signal Processing ◽  
Cochlear Implant ◽  
Speech Intelligibility ◽  
Discrimination Task ◽  
Signal To Noise Ratio ◽  
Compensation System ◽  
Signal To Noise ◽  
Dynamic Compensation ◽  
Front End ◽  
Noise Ratio

Cochlear implant (CI) sound processing typically uses a front-end automatic gain control (AGC), reducing the acoustic dynamic range (DR) to control the output level and protect the signal processing against large amplitude changes. It can also introduce distortions into the signal and does not allow a direct mapping between acoustic input and electric output. For speech in noise, a reduction in DR can result in lower speech intelligibility due to compressed modulations of speech. This study proposes to implement a CI signal processing scheme consisting of a full acoustic DR with adaptive properties to improve the signal-to-noise ratio and overall speech intelligibility. Measurements based on the Short-Time Objective Intelligibility measure and an electrodogram analysis, as well as behavioral tests in up to 10 CI users, were used to compare performance with a single-channel, dual-loop, front-end AGC and with an adaptive back-end multiband dynamic compensation system (Voice Guard [VG]). Speech intelligibility in quiet and at a +10 dB signal-to-noise ratio was assessed with the Hochmair–Schulz–Moser sentence test. A logatome discrimination task with different consonants was performed in quiet. Speech intelligibility was significantly higher in quiet for VG than for AGC, but intelligibility was similar in noise. Participants obtained significantly better scores with VG than AGC in the logatome discrimination task. The objective measurements predicted significantly better performance estimates for VG. Overall, a dynamic compensation system can outperform a single-stage compression (AGC + linear compression) for speech perception in quiet.

scholarly journals Hearing in Noise: The Importance of Coding Strategies—Normal-Hearing Subjects and Cochlear Implant Users

2019 ◽  
Vol 9 (4) ◽  
pp. 734 ◽  
Author(s):  
Pierre-Antoine Cucis ◽  
Christian Berger-Vachon ◽  
Ruben Hermann ◽  
Fabien Millioz ◽  
Eric Truy ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Channel Coding ◽  
Signal To Noise Ratio ◽  
Normal Hearing ◽  
Signal To Noise ◽  
Sound Coding ◽  
Coding Schemes ◽  
Channel Strategy ◽  
Hearing In Noise ◽  
Common Signal

Two schemes are mainly used for coding sounds in cochlear implants: Fixed-Channel and Channel-Picking. This study aims to determine the speech audiometry scores in noise of people using either type of sound coding scheme. Twenty normal-hearing and 45 cochlear implant subjects participated in this experiment. Both populations were tested by using dissyllabic words mixed with cocktail-party noise. A cochlear implant simulator was used to test the normal-hearing subjects. This simulator separated the sound into 20 spectral channels and the eight most energetic were selected to simulate the Channel-Picking strategy. For normal-hearing subjects, we noticed higher scores with the Fixed-Channel strategy than with the Channel-Picking strategy in the mid-range signal-to-noise ratios (0 to +6 dB). For cochlear implant users, no differences were found between the two coding schemes but we could see a slight advantage for the Fixed-Channel strategies over the Channel-Picking strategies. For both populations, a difference was observed for the signal-to-noise ratios at 50% of the maximum recognition plateau in favour of the Fixed-Channel strategy. To conclude, in the most common signal-to-noise ratio conditions, a Fixed-Channel coding strategy may lead to better recognition percentages than a Channel-Picking strategy. Further studies are indicated to confirm this.

Fitting and Verification of Frequency Modulation Systems on Children with Normal Hearing

2014 ◽  
Vol 25 (06) ◽  
pp. 529-540 ◽  
Author(s):  
Erin C. Schafer ◽  
Danielle Bryant ◽  
Katie Sanders ◽  
Nicole Baldus ◽  
Katherine Algier ◽  
...  
Keyword(s):  
Speech Recognition ◽  
Frequency Modulation ◽  
Auditory Processing ◽  
Signal To Noise Ratio ◽  
Recognition Performance ◽  
Normal Hearing ◽  
Signal To Noise ◽  
The Real ◽  
Hearing Sensitivity ◽  
Speech Recognition In Noise

Background: Several recent investigations support the use of frequency modulation (FM) systems in children with normal hearing and auditory processing or listening disorders such as those diagnosed with auditory processing disorders, autism spectrum disorders, attention-deficit hyperactivity disorder, Friedreich ataxia, and dyslexia. The American Academy of Audiology (AAA) published suggested procedures, but these guidelines do not cite research evidence to support the validity of the recommended procedures for fitting and verifying nonoccluding open-ear FM systems on children with normal hearing. Documenting the validity of these fitting procedures is critical to maximize the potential FM-system benefit in the abovementioned populations of children with normal hearing and those with auditory-listening problems. Purpose: The primary goal of this investigation was to determine the validity of the AAA real-ear approach to fitting FM systems on children with normal hearing. The secondary goal of this study was to examine speech-recognition performance in noise and loudness ratings without and with FM systems in children with normal hearing sensitivity. Research Design: A two-group, cross-sectional design was used in the present study. Study Sample: Twenty-six typically functioning children, ages 5–12 yr, with normal hearing sensitivity participated in the study. Intervention: Participants used a nonoccluding open-ear FM receiver during laboratory-based testing. Data Collection and Analysis: Participants completed three laboratory tests: (1) real-ear measures, (2) speech recognition performance in noise, and (3) loudness ratings. Four real-ear measures were conducted to (1) verify that measured output met prescribed-gain targets across the 1000–4000 Hz frequency range for speech stimuli, (2) confirm that the FM-receiver volume did not exceed predicted uncomfortable loudness levels, and (3 and 4) measure changes to the real-ear unaided response when placing the FM receiver in the child’s ear. After completion of the fitting, speech recognition in noise at a –5 signal-to-noise ratio and loudness ratings at a +5 signal-to-noise ratio were measured in four conditions: (1) no FM system, (2) FM receiver on the right ear, (3) FM receiver on the left ear, and (4) bilateral FM system. Results: The results of this study suggested that the slightly modified AAA real-ear measurement procedures resulted in a valid fitting of one FM system on children with normal hearing. On average, prescriptive targets were met for 1000, 2000, 3000, and 4000 Hz within 3 dB, and maximum output of the FM system never exceeded and was significantly lower than predicted uncomfortable loudness levels for the children. There was a minimal change in the real-ear unaided response when the open-ear FM receiver was placed into the ear. Use of the FM system on one or both ears resulted in significantly better speech recognition in noise relative to a no-FM condition, and the unilateral and bilateral FM receivers resulted in a comfortably loud signal when listening in background noise. Conclusions: Real-ear measures are critical for obtaining an appropriate fit of an FM system on children with normal hearing.

Effects of Speech Rate, Background Noise, and Simulated Hearing Loss on Speech Rate Judgment and Speech Intelligibility in Young Listeners

2009 ◽  
Vol 20 (01) ◽  
pp. 028-039 ◽  
Author(s):  
Elizabeth M. Adams ◽  
Robert E. Moore
Keyword(s):  
Hearing Loss ◽  
Research Design ◽  
Background Noise ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Speech Rate ◽  
Normal Hearing ◽  
Moderate Correlation ◽  
Signal To Noise ◽  
Noise Ratio

Purpose: To study the effect of noise on speech rate judgment and signal-to-noise ratio threshold (SNR50) at different speech rates (slow, preferred, and fast). Research Design: Speech rate judgment and SNR50 tasks were completed in a normal-hearing condition and a simulated hearing-loss condition. Study Sample: Twenty-four female and six male young, normal-hearing participants. Results: Speech rate judgment was not affected by background noise regardless of hearing condition. Results of the SNR50 task indicated that, as speech rate increased, performance decreased for both hearing conditions. There was a moderate correlation between speech rate judgment and SNR50 with the various speech rates, such that as judgment of speech rate increased from too slow to too fast, performance deteriorated. Conclusions: These findings can be used to support the need for counseling patients and their families about the potential advantages to using average speech rates or rates that are slightly slowed while conversing in the presence of background noise.

scholarly journals Evaluation of speech perception in noise in Kurd-Persian bilinguals

2019 ◽  
Author(s):  
Yones Lotfi ◽  
Jamileh Chupani ◽  
Mohanna Javanbakht ◽  
Enayatollah Bakhshi
Keyword(s):  
Nervous System ◽  
Speech Perception ◽  
Signal To Noise Ratio ◽  
Normal Hearing ◽  
Cognitive Factors ◽  
Signal To Noise ◽  
Speech Perception In Noise ◽  
Speech In Noise ◽  
Noise Test ◽  
Comparison Of The Results

Background and Aim: In most everyday sett­ings, speech is heard in the presence of com­peting sounds and speech perception in noise is affected by various factors, including cognitive factors. In this regard, bilingualism is a pheno­menon that changes cognitive and behavioral processes as well as the nervous system. This study aimed to evaluate speech perception in noise and compare differences in Kurd-Persian bilinguals versus Persian monolinguals. Methods: This descriptive-analytic study was performed on 92 students with normal hearing, 46 of whom were bilingual Kurd-Persian with a mean (SD) age of 22.73 (1.92) years, and 46 other Persian monolinguals with a mean (SD) age of 22.71 (2.28) years. They were examined by consonant-vowel in noise (CV in noise) test and quick speech in noise (Q-SIN) test. The obtained data were analyzed by SPSS 21. Results: The comparison of the results showed differences in both tests between bilingual and monolingual subjects. In both groups, the reduc­tion of signal-to-noise ratio led to lower scores, but decrease in CV in noise test in bilinguals was less than monolinguals (p < 0.001) and in the Q-SIN test, the drop in bilinguals’ score was  more than monolinguals (p = 0.002). Conclusion: Kurd-Persian bilinguals had a bet­ter performance in CV in noise test but had a worse performance in Q-SIN test than Persian monolinguals.

scholarly journals Interleaved Acoustic Environments: Impact of an Auditory Scene Classification Procedure on Speech Perception in Cochlear Implant Users

2021 ◽  
Vol 25 ◽  
pp. 233121652110141
Author(s):  
Anja Eichenauer ◽  
Uwe Baumann ◽  
Timo Stöver ◽  
Tobias Weissgerber
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Signal To Noise Ratio ◽  
Scene Classification ◽  
Signal To Noise ◽  
Acoustic Environment ◽  
The Mean ◽  
Noise Ratio ◽  
Acoustic Environments ◽  
The Impact

Clinical speech perception tests with simple presentation conditions often overestimate the impact of signal preprocessing on speech perception in complex listening environments. A new procedure was developed to assess speech perception in interleaved acoustic environments of different complexity that allows investigation of the impact of an automatic scene classification (ASC) algorithm on speech perception. The procedure was applied in cohorts of normal hearing (NH) controls and uni- and bilateral cochlear implant (CI) users. Speech reception thresholds (SRTs) were measured by means of a matrix sentence test in five acoustic environments that included different noise conditions (amplitude modulated and continuous), two spatial configurations, and reverberation. The acoustic environments were encapsulated in a randomized, mixed order single experimental run. Acoustic room simulation was played back with a loudspeaker auralization setup with 128 loudspeakers. 18 NH, 16 unilateral, and 16 bilateral CI users participated. SRTs were evaluated for each individual acoustic environment and as mean-SRT. Mean-SRTs improved by 2.4 dB signal-to-noise ratio for unilateral and 1.3 dB signal-to-noise ratio for bilateral CI users with activated ASC. Without ASC, the mean-SRT of bilateral CI users was 3.7 dB better than the SRT of unilateral CI users. The mean-SRT indicated significant differences, with NH group performing best and unilateral CI users performing worse with a difference of up to 13 dB compared to NH. The proposed speech test procedure successfully demonstrated that speech perception and benefit with ASC depend on the acoustic environment.

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