Effects of hearing loss, age, noise exposure, and listening skills on envelope regularity discrimination.

The envelope regularity discrimination (ERD) test assesses the ability to discriminate irregular from regular amplitude modulation (AM). The measured threshold is called the irregularity index (II). It was hypothesized that the II at threshold should be almost unaffected by the loudness recruitment that is associated with cochlear hearing loss because the effect of recruitment is similar to multiplying the AM depth by a certain factor, and II values depend on the amount of envelope irregularity relative to the baseline modulation depth. To test this hypothesis, the ERD test was administered to 60 older adults with varying degrees of hearing loss, using carrier frequencies of 1 and 4 kHz. The II values for the two carrier frequencies were highly correlated, indicating that the ERD test was measuring a consistent characteristic of each subject. The II values at 1 and 4 kHz were not significantly correlated with the audiometric thresholds at the corresponding frequencies, consistent with the hypothesis. The II values at 4 kHz were significantly positively correlated with age. There was an unexpected negative correlation between II values and a measure of noise exposure. This is argued to reflect the confounding effects of listening skills.

Improving hearing-aid gains based on automatic speech recognition.

This study provides proof of concept that automatic speech recognition (ASR) can be used to improve hearing aid (HA) fitting. A signal-processing chain consisting of a HA simulator, a hearing-loss simulator, and an ASR system normalizing the intensity of input signals was used to find HA-gain functions yielding the highest ASR intelligibility scores for individual audiometric profiles of 24 listeners with age-related hearing loss. Significantly higher aided speech intelligibility scores and subjective ratings of speech pleasantness were observed when the participants were fitted with ASR-established gains than when fitted with the gains recommended by the CAM2 fitting rule.

Developmental Effects in the "Vocale Rapide dans le Bruit" Speech-in-Noise Identification Test: Reference Performances of Normal-Hearing Children and Adolescents.

PURPOSE: The main objective of this study was to assess the existence of developmental effects on the performance of the Vocale Rapide dans le Bruit (VRB) speech-in-noise (SIN) identification test that was recently developed for the French language and to collect reference scores for children and adolescents. METHOD: Seventy-two native French speakers, aged 10-20 years, participated in the study. Each participant listened and repeated four lists of eight sentences, each containing three key words to be scored. The sentences were presented in free field at different signal-to-noise ratios (SNRs) using a four-talker babble noise. The SNR yielding 50% of correct repetitions of key words (SNR50) was recorded for each list. RESULTS: A strong relationship between age and SNR50 was found, better performance occurring with increasing age (average drop in SNR50 per year: 0.34 dB). Large differences (Cohen's d ≥ 1.2) were observed between the SNR50 achieved by 10- to 13-year-old participants and those of adults. For participants aged 14-15 years, the difference fell just above the 5% level of significance. No effects of hearing thresholds or level of education were observed. CONCLUSIONS: The study confirms the existence of developmental effects on SIN identification performance as measured using the VRB test and provides reference data for taking into account these effects during clinical practice. Explanations as to why age effects perdure during adolescence are discussed.

Using Automatic Speech Recognition to Optimize Hearing-Aid Time Constants.

Automatic speech recognition (ASR), when combined with hearing-aid (HA) and hearing-loss (HL) simulations, can predict aided speech-identification performances of persons with age-related hearing loss. ASR can thus be used to evaluate different HA configurations, such as combinations of insertion-gain functions and compression thresholds, in order to optimize HA fitting for a given person. The present study investigated whether, after fixing compression thresholds and insertion gains, a random-search algorithm could be used to optimize time constants (i.e., attack and release times) for 12 audiometric profiles. The insertion gains were either those recommended by the CAM2 prescription rule or those optimized using ASR, while compression thresholds were always optimized using ASR. For each audiometric profile, the random-search algorithm was used to vary time constants with the aim to maximize ASR performance. A HA simulator and a HL simulator simulator were used, respectively, to amplify and to degrade speech stimuli according to the input audiogram. The resulting speech signals were fed to an ASR system for recognition. For each audiogram, 1,000 iterations of the random-search algorithm were used to find the time-constant configuration yielding the highest ASR score. To assess the reproducibility of the results, the random search algorithm was run twice. Optimizing the time constants significantly improved the ASR scores when CAM2 insertion gains were used, but not when using ASR-based gains. Repeating the random search yielded similar ASR scores, but different time-constant configurations.

OPRA-RS: A Hearing-Aid Fitting Method Based on Automatic Speech Recognition and Random Search.

Hearing-aid (HA) prescription rules (such as NAL-NL2, DSL-v5, and CAM2) are used by HA audiologists to define initial HA settings (e.g., insertion gains, IGs) for patients. This initial fitting is later individually adjusted for each patient to improve clinical outcomes in terms of speech intelligibility and listening comfort. During this fine-tuning stage, speech-intelligibility tests are often carried out with the patient to assess the benefits associated with different HA settings. As these tests tend to be time-consuming and performance on them depends on the patient's level of fatigue and familiarity with the test material, only a limited number of HA settings can be explored. Consequently, it is likely that a suboptimal fitting is used for the patient. Recent studies have shown that automatic speech recognition (ASR) can be used to predict the effects of IGs on speech intelligibility for patients with age-related hearing loss (ARHL). The aim of the present study was to extend this approach by optimizing, in addition to IGs, compression thresholds (CTs). However, increasing the number of parameters to be fitted increases exponentially the number of configurations to be assessed. To limit the number of HA settings to be tested, three random-search (RS) genetic algorithms were used. The resulting new HA fitting method, combining ASR and RS, is referred to as "objective prescription rule based on ASR and random search" (OPRA-RS). Optimal HA settings were computed for 12 audiograms, representing average and individual audiometric profiles typical for various levels of ARHL severity, and associated ASR performances were compared to those obtained with the settings recommended by CAM2. Each RS algorithm was run twice to assess its reliability. For all RS algorithms, ASR scores obtained with OPRA-RS were significantly higher than those associated with CAM2. Each RS algorithm converged on similar optimal HA settings across repetitions. However, significant differences were observed between RS algorithms in terms of maximum ASR performance and processing costs. These promising results open the way to the use of ASR and RS algorithms for the fine-tuning of HAs with potential speech-intelligibility benefits for the patient.

Senescent Decline in Verbal-Emotion Identification by Older Hearing-Impaired Listeners - Do Hearing Aids Help?

PURPOSE: To assess the ability of older-adult hearing-impaired (OHI) listeners to identify verbal expressions of emotions, and to evaluate whether hearing-aid (HA) use improves identification performance in those listeners. METHODS: Twenty-nine OHI listeners, who were experienced bilateral-HA users, participated in the study. They listened to a 20-sentence-long speech passage rendered with six different emotional expressions ("happiness", "pleasant surprise", "sadness", "anger", "fear", and "neutral"). The task was to identify the emotion portrayed in each version of the passage. Listeners completed the task twice in random order, once unaided, and once wearing their own bilateral HAs. Seventeen young-adult normal-hearing (YNH) listeners were also tested unaided as controls. RESULTS: Most YNH listeners (89.2%) correctly identified emotions compared to just over half of the OHI listeners (58.7%). Within the OHI group, verbal emotion identification was significantly correlated with age, but not with audibility-related factors. The number of OHI listeners who were able to correctly identify the different emotions did not significantly change when HAs were worn (54.8%). CONCLUSION: In line with previous investigations using shorter speech stimuli, there were clear age differences in the recognition of verbal emotions, with OHI listeners showing a significant reduction in unaided verbal-emotion identification performance that progressively declined with age across older adulthood. Rehabilitation through HAs did not provide compensation for the impaired ability to perceive emotions carried by speech sounds.

Vocal Problems in Sports and Fitness Instructors: A Study of Prevalence, Risk Factors, and Need for Prevention in France.

OBJECTIVES: Sports and fitness instructors (SFIs) are known for being a high-risk population for voice difficulties (VD). However, past studies have encountered various methodological difficulties in determining prevalence and risk factors for VD in SFIs, such as limited population, gender and selection biases, or poor statistical power, because VD were studied as a binary variable. The present research work addresses these issues and aims at studying the prevalence of vocal problems and risk factors in French SFIs, a population in which no such study was conducted yet. Another objective is to survey the French SFIs' habits and expectations regarding vocal prevention and care. STUDY DESIGN: This is a cross-sectional study. METHODS: Three hundred and twenty SFIs answered a questionnaire, whether in an online (n = 267) or a paper (n = 53) version. The questionnaire consisted of 31 items addressing self-reported vocal difficulties, supposed risk factors, and personal health-care history, followed by the Voice Handicap Index assessment. RESULTS: Prevalence of self-reported vocal difficulties is 55%. The Voice Handicap Index is significantly associated with gender, age, and variables related to work environment (noise and music) and habits (shouting, frequency of classes), as well as with daily sleeping time. Results also indicate that a minority of the SFIs (37%) received information on vocal difficulties, whereas a majority (80%) declares being interested in participating in prevention programs. CONCLUSIONS: This work confirms that SFIs are a high-risk population for VD, underlines the need for specific information programs in France, and provides relevant data for driving such preventive actions.

Automatic Speech Recognition Predicts Speech Intelligibility and Comprehension for Listeners With Simulated Age-Related Hearing Loss.

Purpose: The purpose of this article is to assess speech processing for listeners with simulated age-related hearing loss (ARHL) and to investigate whether the observed performance can be replicated using an automatic speech recognition (ASR) system. The long-term goal of this research is to develop a system that will assist audiologists/hearing-aid dispensers in the fine-tuning of hearing aids. Method: Sixty young participants with normal hearing listened to speech materials mimicking the perceptual consequences of ARHL at different levels of severity. Two intelligibility tests (repetition of words and sentences) and 1 comprehension test (responding to oral commands by moving virtual objects) were administered. Several language models were developed and used by the ASR system in order to fit human performances. Results: Strong significant positive correlations were observed between human and ASR scores, with coefficients up to .99. However, the spectral smearing used to simulate losses in frequency selectivity caused larger declines in ASR performance than in human performance. Conclusion: Both intelligibility and comprehension scores for listeners with simulated ARHL are highly correlated with the performances of an ASR-based system. In the future, it needs to be determined if the ASR system is similarly successful in predicting speech processing in noise and by older people with ARHL.

Relationship Between Speech Intelligibility and Speech Comprehension in Babble Noise.

PURPOSE: The authors investigated the relationship between the intelligibility and comprehension of speech presented in babble noise. METHOD: Forty participants listened to French imperative sentences (commands for moving objects) in a multitalker babble background for which intensity was experimentally controlled. Participants were instructed to transcribe what they heard and obey the commands in an interactive environment set up for this purpose. The former test provided intelligibility scores and the latter provided comprehension scores. RESULTS: Collected data revealed a globally weak correlation between intelligibility and comprehension scores (r = .35, p < .001). The discrepancy tended to grow as noise level increased. An analysis of standard deviations showed that variability in comprehension scores increased linearly with noise level, whereas higher variability in intelligibility scores was found for moderate noise level conditions. CONCLUSION: These results support the hypothesis that intelligibility scores are poor predictors of listeners' comprehension in real communication situations. Intelligibility and comprehension scores appear to provide different insights, the first measure being centered on speech signal transfer and the second on communicative performance. Both theoretical and practical implications for the use of speech intelligibility tests as indicators of speakers' performances are discussed.