Influence of noise type on speech reception thresholds across four languages measured with matrix sentence tests

The evaluation of auditory processing skills and late latencies in children with ventilation tube history

OBJECTIVE

(s): This study aims to evaluate the changes in temporal auditory processing skills in children who underwent bilateral ventilation tube insertion (VTI) due to Otitis Media with Effusion (OME) and the effect of these changes on speech comprehension in noisy environments.

METHODS

This is a case-control study. In total, 60 children were included in the study in two groups. The control group included 30 children aged 11 to 15, who had normal hearing thresholds and normal immitancemetric evaluation, and were not diagnosed with OME. The study group included 30 children, aged 11-15 who underwent bilateral VTI surgery after their diagnosis of OME during the ages of 3-10 and currently had normal hearing thresholds and normal immitancemetric values. Each group underwent the Turkish Matrix Test (TMT), Random Gap Detection Test (RGDT), Frequency Pattern Test (FPT), Duration Pattern Test (DPT), and Cortical Auditory Evoked Potential Test (CAEP).

RESULTS

When the temporal processing tests (FPT, DPT, RGDT) were compared, a significant difference was obtained between the study group and the control group (p < 0.05). With the TMT, significantly lower scores were obtained in the study group compared to the control group (p < 0.01). In addition, the latency values in the cortical auditory evoked potential test were longer in the study group compared to the control group, but these results were not statistically significant (p > 0.05).

CONCLUSION

As a result of the study, it is concluded that the central auditory processing skills were affected in children with a history of bilateral VTI due to OME. Temporal processing tests, Turkish Matrix Test and Cortical Auditory Evoked Potential tests can be recommended as reliable and easily applicable tests, together with traditional hearing test methods in children with a history of OME, in order to evaluate comprehension skills in classroom noise.

Evaluation of the American English Matrix Test with Cochlear Implant Recipients

OBJECTIVE

Currently, the variety of speech recognition tests used to evaluate cochlear implant (CI) recipients makes it difficult to compare results, especially across languages. The Matrix Test limits contextual cues and is available in multiple languages, including American English. The current study investigated test format and noise type for the American English Matrix Test (AMT) and compared results to AzBio sentence scores in adult CI recipients.

DESIGN

Fifteen experienced CI recipients were administered the AMT in fixed- and adaptive-level formats and AzBio sentences in a fixed-level format. Testing in noise used the AMT-specific noise and 4-talker babble.

RESULTS

Ceiling effects were present for all AMT fixed-level conditions and AzBio sentences in quiet. Group mean AzBio scores were poorer than AMT scores. Noise type affected performance regardless of format; 4-talker babble was more challenging.

CONCLUSIONS

The limited number of word choices in each category likely aided listeners performance for the AMT compared to AzBio sentences. The use of the AMT in the designed adaptive-level format would allow effective evaluation and comparison of CI performance internationally. A test battery with the AMT may also benefit from including AzBio sentences in 4-talker babble to reflect performance during listening challenges.

A standardised test to evaluate audio-visual speech intelligibility in French

Objective

Lipreading, which plays a major role in the communication of the hearing impaired, lacked a French standardised tool. Our aim was to create and validate an audio-visual (AV) version of the French Matrix Sentence Test (FrMST).

Design

Video recordings were created by dubbing the existing audio files.

Sample

Thirty-five young, normal-hearing participants were tested in auditory and visual modalities alone (Ao, Vo) and in AV conditions, in quiet, noise, and open and closed-set response formats.

Results

Lipreading ability (Vo) ranged from 1 % to 77%-word comprehension. The absolute AV benefit was 9.25 dB SPL in quiet and 4.6 dB SNR in noise. The response format did not influence the results in the AV noise condition, except during the training phase. Lipreading ability and AV benefit were significantly correlated.

Conclusions

The French video material achieved similar AV benefits as those described in the literature for AV MST in other languages. For clinical purposes, we suggest targeting SRT80 to avoid ceiling effects, and performing two training lists in the AV condition in noise, followed by one AV list in noise, one Ao list in noise and one Vo list, in a randomised order, in open or close set-format.

Evaluating the Relative Perceptual Salience of Linguistic and Emotional Prosody in Quiet and Noisy Contexts

How people recognize linguistic and emotional prosody in different listening conditions is essential for understanding the complex interplay between social context, cognition, and communication. The perception of both lexical tones and emotional prosody depends on prosodic features including pitch, intensity, duration, and voice quality. However, it is unclear which aspect of prosody is perceptually more salient and resistant to noise. This study aimed to investigate the relative perceptual salience of emotional prosody and lexical tone recognition in quiet and in the presence of multi-talker babble noise. Forty young adults randomly sampled from a pool of native Mandarin Chinese with normal hearing listened to monosyllables either with or without background babble noise and completed two identification tasks, one for emotion recognition and the other for lexical tone recognition. Accuracy and speed were recorded and analyzed using generalized linear mixed-effects models. Compared with emotional prosody, lexical tones were more perceptually salient in multi-talker babble noise. Native Mandarin Chinese participants identified lexical tones more accurately and quickly than vocal emotions at the same signal-to-noise ratio. Acoustic and cognitive dissimilarities between linguistic prosody and emotional prosody may have led to the phenomenon, which calls for further explorations into the underlying psychobiological and neurophysiological mechanisms.

Influence of Age on Speech Recognition in Noise and Hearing Effort in Listeners with Age-Related Hearing Loss

The aim of this study was to measure how age affects the speech recognition threshold (SRT50) of the Oldenburg Sentence Test (OLSA) and the listening effort at the corresponding signal-to-noise ratio (SNRcut). The study also investigated the effect of the spatial configuration of sound sources and noise signals on SRT50 and SNRcut. To achieve this goal, the study used olnoise and icra5 noise presented from one or more spatial locations from the front and back. Ninety-nine participants with age-related hearing loss in the 18-80 years age range, specifically in the 18-30, 31-40, 41-50, 51-60, 61-70, and 71-80 age groups, participated in this study. Speech recognition and listening effort in noise were measured and compared between the different age groups, different spatial sound configurations and noise signals. Speech recognition in noise decreased with age and became significant from the age group of 50-51. The decrease in SRT50 with age was greater for icra5 noise than for olnoise. For all age groups, SRT50 and SNRcut were better for icra5 noise than for olnoise. The measured age-related reference data for SRT50 and SNRcut can be used in further studies in listeners with age-related hearing loss and hearing aid or implant users.

Thoughts on the potential to compensate a hearing loss in noise

Background: The effect of hearing impairment on speech perception was described by Plomp (1978) as a sum of a loss of class A, due to signal attenuation, and a loss of class D, due to signal distortion. While a loss of class A can be compensated by linear amplification, a loss of class D, which severely limits the benefit of hearing aids in noisy listening conditions, cannot. The hearing loss of class D is assumed to be the main reason why not few users of hearing aids keep complaining about the limited benefit of their devices in noisy environments. Working compensation strategies against it are unknown.

Methods: Recently, in an approach to model human speech recognition by means of a re-purposed automatic speech recognition (ASR) system, the loss of class D was explained by introducing a level uncertainty which reduces the individual accuracy of spectro-temporal signal levels. Based on this finding, an implementation of a patented dynamic range manipulation scheme (PLATT) is proposed which aims to mitigate the effect of increased level uncertainty on speech recognition in noise by expanding spectral modulation patterns in the range of 2 to 4 ERB. This compensation approach is objectively evaluated regarding the benefit in speech recognition thresholds in noise using the ASR-based speech recognition model. Recommendations for an evaluation with human listeners are derived.

Results: The objective evaluation suggests that approximately half of the class D loss due to an increased level uncertainty might be compensable. To measure the effect with human listeners, an experiment needs to be carefully designed to prevent the confusion class A and D loss compensations.

Conclusions: A working compensation strategy for the class D loss could provide previously unexploited potential for relief. Evidence has to be provided in experiments with human listeners.

Evaluation of Speech Recognition Skills in Different Noises with the Turkish Matrix Sentence Test in Hearing Aid Users

Objective:

This study aimed to analyze the effectiveness of the Turkish matrix sentence test in evaluating the speech recognition performance of hearing aid users under different noise conditions.

Methods:

Speech recognition performance of 42 individuals, 20 to 65 years of age (mean 49.1±14 years) with bilateral sensorineural hearing loss was measured in noise with the Turkish matrix sentence test without a background noise and with headphones. Additionally, the participants’ speech recognition thresholds were measured with a matrix test while wearing their hearing aid under three different listening conditions in which the phases of speech and noise stimuli were changed with constant and fluctuating noise.

Results:

Speech-recognition thresholds were better in fluctuating noise than in constant noise in all listening conditions, and this difference was statistically significant (p=0.02). In both types of noise, speech-recognition thresholds of bilateral hearing aid users (n=29) were lower (better) than those of unilateral hearing aid users (n=13) under three different listening conditions, but there was no statistically significant difference (p=0.67). Speech-recognition thresholds without hearing aids were statistically higher (worse) than those obtained with hearing aids (p=0.001).

Conclusion:

Since the Turkish matrix sentence test gives useful results, this test can be used in the diagnosis, follow-up, and rehabilitation planning of hearing aid users. We observed that speech intelligibility was better, although there were differences among those with hearing loss when the speech test was conducted in fluctuating background noise with the Turkish matrix sentence test.

Improved Speech in Noise Perception in the Elderly After 6 Months of Musical Instruction

Understanding speech in background noise poses a challenge in daily communication, which is a particular problem among the elderly. Although musical expertise has often been suggested to be a contributor to speech intelligibility, the associations are mostly correlative. In the present multisite study conducted in Germany and Switzerland, 156 healthy, normal-hearing elderly were randomly assigned to either piano playing or music listening/musical culture groups. The speech reception threshold was assessed using the International Matrix Test before and after a 6 month intervention. Bayesian multilevel modeling revealed an improvement of both groups over time under binaural conditions. Additionally, the speech reception threshold of the piano group decreased during stimuli presentation to the left ear. A right ear improvement only occurred in the German piano group. Furthermore, improvements were predominantly found in women. These findings are discussed in the light of current neuroscientific theories on hemispheric lateralization and biological sex differences. The study indicates a positive transfer from musical training to speech processing, probably supported by the enhancement of auditory processing and improvement of general cognitive functions.

Inference of the distortion component of hearing impairment from speech recognition by predicting the effect of the attenuation component

OBJECTIVE

A model-based determination of the average supra-threshold ("distortion") component of hearing impairment which limits the benefit of hearing aid amplification.

DESIGN

Published speech recognition thresholds (SRTs) were predicted with the framework for auditory discrimination experiments (FADE), which simulates recognition processes, the speech intelligibility index (SII), which exploits frequency-dependent signal-to-noise ratios (SNR), and a modified SII with a hearing-loss-dependent band importance function (PAV). Their attenuation-component-based prediction errors were interpreted as estimates of the distortion component.

STUDY SAMPLE

Unaided SRTs of 315 hearing-impaired ears measured with the German matrix sentence test in stationary noise.

RESULTS

Overall, the models showed root-mean-square errors (RMSEs) of 7 dB, but for steeply sloping hearing loss FADE and PAV were more accurate (RMSE = 9 dB) than the SII (RMSE = 23 dB). Prediction errors of FADE and PAV increased linearly with the average hearing loss. The consideration of the distortion component estimate significantly improved the accuracy of FADE's and PAV's predictions.

CONCLUSIONS

The supra-threshold distortion component-estimated by prediction errors of FADE and PAV-seems to increase with the average hearing loss. Accounting for a distortion component improves the model predictions and implies a need for effective compensation strategies for supra-threshold processing deficits with increasing audibility loss.

DARF: A data-reduced FADE version for simulations of speech recognition thresholds with real hearing aids

Developing and selecting hearing aids is a time consuming process which is simplified by using objective models. Previously, the framework for auditory discrimination experiments (FADE) accurately simulated benefits of hearing aid algorithms with root mean squared prediction errors below 3 dB. One FADE simulation requires several hours of (un)processed signals, which is obstructive when the signals have to be recorded. We propose and evaluate a data-reduced FADE version (DARF) which facilitates simulations with signals that cannot be processed digitally, but that can only be recorded in real-time. DARF simulates one speech recognition threshold (SRT) with about 30 min of recorded and processed signals of the (German) matrix sentence test. Benchmark experiments were carried out to compare DARF and standard FADE exhibiting small differences for stationary maskers (1 dB), but larger differences with strongly fluctuating maskers (5 dB). Hearing impairment and hearing aid algorithms seemed to reduce the differences. Hearing aid benefits were simulated in terms of speech recognition with three pairs of real hearing aids in silence (≥8 dB), in stationary and fluctuating maskers in co-located (stat. 2 dB; fluct. 6 dB), and spatially separated speech and noise signals (stat. ≥8 dB; fluct. 8 dB). The simulations were plausible in comparison to data from literature, but a comparison with empirical data is still open. DARF facilitates objective SRT simulations with real devices with unknown signal processing in real environments. Yet, a validation of DARF for devices with unknown signal processing is still pending since it was only tested with three similar devices. Nonetheless, DARF could be used for improving as well as for developing or model-based fitting of hearing aids.

Development of the Everyday Conversational Sentences in Noise test

To capture the demands of real-world listening, laboratory-based speech-in-noise tasks must better reflect the types of speech and environments listeners encounter in everyday life. This article reports the development of original sentence materials that were produced spontaneously with varying vocal efforts. These sentences were extracted from conversations between a talker pair (female/male) communicating in different realistic acoustic environments to elicit normal, raised and loud vocal efforts. In total, 384 sentences were extracted to provide four equivalent lists of 16 sentences at the three efforts for the two talkers. The sentences were presented to 32 young, normally hearing participants in stationary noise at five signal-to-noise ratios from -8 to 0 dB in 2 dB steps. Psychometric functions were fitted for each sentence, revealing an average 50% speech reception threshold (SRT₅₀) of -5.2 dB, and an average slope of 17.2%/dB. Sentences were then level-normalised to adjust their individual SRT₅₀ to the mean (-5.2 dB). The sentences may be combined with realistic background noise to provide an assessment method that better captures the perceptual demands of everyday communication.

Individual Aided Speech-Recognition Performance and Predictions of Benefit for Listeners With Impaired Hearing Employing FADE

The benefit in speech-recognition performance due to the compensation of a hearing loss can vary between listeners, even if unaided performance and hearing thresholds are similar. To accurately predict the individual performance benefit due to a specific hearing device, a prediction model is proposed which takes into account hearing thresholds and a frequency-dependent suprathreshold component of impaired hearing. To test the model, the German matrix sentence test was performed in unaided and individually aided conditions in quiet and in noise by 18 listeners with different degrees of hearing loss. The outcomes were predicted by an individualized automatic speech-recognition system where the individualization parameter for the suprathreshold component of hearing loss was inferred from tone-in-noise detection thresholds. The suprathreshold component was implemented as a frequency-dependent multiplicative noise (mimicking level uncertainty) in the feature-extraction stage of the automatic speech-recognition system. Its inclusion improved the root-mean-square prediction error of individual speech-recognition thresholds (SRTs) from 6.3 dB to 4.2 dB and of individual benefits in SRT due to common compensation strategies from 5.1 dB to 3.4 dB. The outcome predictions are highly correlated with both the corresponding observed SRTs (R2 = .94) and the benefits in SRT (R2 = .89) and hence might help to better understand-and eventually mitigate-the perceptual consequences of as yet unexplained hearing problems, also discussed in the context of hidden hearing loss.

The effect of speech material on the band importance function for Mandarin Chinese

Speech material influences the relative contributions of different frequency regions to intelligibility for English. In the current study, whether a similar effect of speech material is present for Mandarin Chinese was investigated. Speech recognition was measured using three speech materials in Mandarin, including disyllabic words, nonsense sentences, and meaningful sentences. These materials differed from one another in terms of the amount of contextual information and word frequency. The band importance function (BIF), as defined under the Speech Intelligibility Index (SII) framework, was used to quantify the contributions across frequency regions. The BIFs for the three speech materials were estimated from 16 adults who were native speakers of Mandarin. A Bayesian adaptive procedure was used to efficiently estimate the octave-frequency BIFs for the three materials for each listener. As the amount of contextual information increased, low-frequency bands (e.g., 250 and 500 Hz) became more important for speech recognition, consistent with English. The BIF was flatter for Mandarin than for comparable English speech materials. Introducing the language- and material-specific BIFs to the SII model led to improved predictions of Mandarin speech-recognition performance. Results suggested the necessity of developing material-specific BIFs for Mandarin.

Code-Switching in Highly Proficient Spanish/English Bilingual Adults: Impact on Masked Word Recognition

PURPOSE

The purpose of this study was to evaluate the impact of code-switching on Spanish/English bilingual listeners' speech recognition of English and Spanish words in the presence of competing speech-shaped noise.

METHOD

Participants were Spanish/English bilingual adults (N = 27) who were highly proficient in both languages. Target stimuli were English and Spanish words presented in speech-shaped noise at a -14-dB signal-to-noise ratio. There were 4 target conditions: (a) English only, (b) Spanish only, (c) mixed English, and (d) mixed Spanish. In the mixed-English condition, 75% of the words were in English, whereas 25% of the words were in Spanish. The percentages were reversed in the mixed-Spanish condition.

RESULTS

Accuracy was poorer for the majority (75%) and minority (25%) languages in both mixed-language conditions compared with the corresponding single-language conditions. Results of a follow-up experiment suggest that this finding cannot be explained in terms of an increase in the number of possible response alternatives for each picture in the mixed-language condition relative to the single-language condition.

CONCLUSIONS

Results suggest a cost of language mixing on speech perception when bilingual listeners alternate between languages in noisy environments. In addition, the cost of code-switching on speech recognition in noise was similar for both languages in this group of highly proficient Spanish/English bilingual speakers. Differences in response-set size could not account for the poorer results in the mixed-language conditions.

[Characteristics, advantages, and limits of matrix tests]

BACKGROUND

Deterioration of communication abilities due to hearing problems is particularly relevant in listening situations with noise. Therefore, speech intelligibility tests in noise are required for audiological diagnostics and evaluation of hearing rehabilitation.

OBJECTIVE

This study analyzed the characteristics of matrix tests assessing the 50 % speech recognition threshold in noise. What are their advantages and limitations?

METHODS

Matrix tests are based on a matrix of 50 words (10 five-word sentences with same grammatical structure). In the standard setting, 20 sentences are presented using an adaptive procedure estimating the individual 50 % speech recognition threshold in noise. At present, matrix tests in 17 different languages are available.

RESULTS

A high international comparability of matrix tests exists. The German language matrix test (OLSA, male speaker) has a reference 50 % speech recognition threshold of -7.1 (± 1.1) dB SNR.

CONCLUSION

Before using a matrix test for the first time, the test person has to become familiar with the basic speech material using two training lists. Hereafter, matrix tests produce constant results even if repeated many times. Matrix tests are suitable for users of hearing aids and cochlear implants, particularly for assessment of benefit during the fitting process. Matrix tests can be performed in closed form and consequently with non-native listeners, even if the experimenter does not speak the test person's native language. Short versions of matrix tests are available for listeners with a shorter memory span, e.g., children.

Binaural masking release in symmetric listening conditions with spectro-temporally modulated maskers

Speech reception thresholds (SRTs) decrease as target and maskers are spatially separated (spatial release from masking, SRM). The current study systematically assessed how SRTs and SRM for a frontal target in a spatially symmetric masker configuration depend on spectro-temporal masker properties, the availability of short-time interaural level difference (ILD) and interaural time difference (ITD), and informational masking. Maskers ranged from stationary noise to single, interfering talkers and were modified by head-related transfer functions to provide: (i) different binaural cues (ILD, ITD, or both) and (ii) independent maskers in each ear ("infinite ILD"). Additionally, a condition was tested in which only information from short-time spectro-temporal segments of the ear with a favorable signal-to-noise ratio (better-ear glimpses) was presented. For noise-based maskers, ILD, ITD, and spectral changes related to masker location contributed similarly to SRM, while ILD cues played a larger role if temporal modulation was introduced. For speech maskers, glimpsing and perceived location contributed roughly equally and ITD contributed less. The "infinite ILD" condition might suggest better-ear glimpsing limitations resulting in a maximal SRM of 12 dB for maskers with low or absent informational masking. Comparison to binaural model predictions highlighted the importance of short-time processing and helped to clarify the contribution of the different binaural cues and mechanisms.

Development of equally intelligible Telugu sentence-lists to test speech recognition in noise

OBJECTIVE

To develop sentence lists in the Telugu language for the assessment of speech recognition threshold (SRT) in the presence of background noise through identification of the mean signal-to-noise ratio required to attain a 50% sentence recognition score (SRTn).

DESIGN

This study was conducted in three phases. The first phase involved the selection and recording of Telugu sentences. In the second phase, 20 lists, each consisting of 10 sentences with equal intelligibility, were formulated using a numerical optimisation procedure. In the third phase, the SRTn of the developed lists was estimated using adaptive procedures on individuals with normal hearing.

STUDY SAMPLE

A total of 68 native Telugu speakers with normal hearing participated in the study. Of these, 18 (including the speakers) performed on various subjective measures in first phase, 20 performed on sentence/word recognition in noise for second phase and 30 participated in the list equivalency procedures in third phase.

RESULTS

In all, 15 lists of comparable difficulty were formulated as test material. The mean SRTn across these lists corresponded to -2.74 (SD = 0.21).

CONCLUSIONS

The developed sentence lists provided a valid and reliable tool to measure SRTn in Telugu native speakers.