Véronique Vaillancourt

Adaptation of the HINT (hearing in noise test) for adult Canadian Francophone populations

The HINT provides an efficient and reliable method of assessing speech intelligibility in quiet and in noise by using an adaptive strategy to measure speech reception thresholds for sentences, thus avoiding ceiling and floor effects that plague traditional measures performed at fixed presentation levels. A strong need for such a test within the Canadian Francophone population, led us to develop a French version of the HINT. Here we describe the development of this test. The Canadian French version is composed of 240-recorded sentences, equated for intelligibility, and cast into 12 phonemically balanced 20-sentence lists. Average headphone SRTs, measured with 36 adult Canadian Francophone native speakers with normal hearing, were 16.4 dBA in quiet, −3.0 dBA SNR in a 65 dBA noise front condition and −11.4 dBA SNR in a 65 dBA noise side condition. Reliability was established by means of within-subjects standard deviation of repeated SRT measurements over different lists and yielded values of 2.2 and 1.1 dB for the quiet and noise conditions, respectively.

Establishment of age-specific normative data for the canadian French version of the hearing in noise test for children.

Objectives: A Canadian French version of the Hearing in Noise Test (HINT) has been developed to assess children’s ability to recognize speech in noise. To avoid testing a large number of children in each clinical test site to establish soundfield norms, a protocol based on the use of correction factors has been proposed and validated in the current study. More specifically, the objective of this study was to provide a protocol for the establishment of age-specific normative data for the Canadian French HINT for children to facilitate its clinical use and allow comparing an individual child’s performance with that of age-matched normal hearing children. Using the proposed protocol, a limited number of normal hearing adults are tested in each HINT condition to correct the adult headphone norms for the soundfield in question, and the correction factors established in the current study are then applied to generate age-specific soundfield norms. Mean adult performance values obtained in a given soundfield are entered into the HINT software, which automatically derives the soundfield adult norms, age-specific children norms, and percentile rankings. Design: Speech reception thresholds (SRT) for sentences were measured in 70 native French-speaking subjects to establish mean performances across various age groups, and correction factors were calculated by comparing performance in each age group with adult performance. To validate the normalization protocol, 28 additional subjects were tested in a new soundfield. The correction factors were applied to adult performance (N = 15) and the resulting predicted scores were compared with measured performance in a group of 9-yr olds (N = 13). Results: Statistical analyses indicate that SRTs decrease with age and reach adult values in older children (12-yr olds). Correction factors are therefore provided for children 6 to 12 yrs old. Spatial separation advantage, the improvement in SRT when speech and noise are spatially separated, also improves with age. The correction factors were effective in predicting mean SRTs for a previously untested age group in all HINT conditions apart from the quiet condition. The difference between predicted and measured performances was less than 0.5 dB for the noise conditions but exceeded 4 dB in the quiet condition. The reliability of SRT measures was determined, with an overall within-subjects SD of repeated measurements of 0.7 dB for the noise front condition. No learning effect was found in the current data. Conclusions: Correction factors can be used to predict performance on the HINT in a group of normal-hearing children in all HINT conditions, apart from quiet. Findings of the current study concur with the literature on age effects in auditory processing abilities, where performance on a variety of auditory tasks has been demonstrated to increase with age to reach adult-like values in adolescence or past 10 yrs.

Comparison of sound propagation and perception of three types of backup alarms with regards to worker safety

A technology of backup alarms based on the use of a broadband signal has recently gained popularity in many countries. In this study, the performance of this broadband technology is compared to that of a conventional tonal alarm and a multi-tone alarm from a worker-safety standpoint. Field measurements of sound pressure level patterns behind heavy vehicles were performed in real work environments and psychoacoustic measurements (sound detection thresholds, equal loudness, perceived urgency and sound localization) were carried out in the laboratory with human subjects. Compared with the conventional tonal alarm, the broadband alarm generates a much more uniform sound field behind vehicles, is easier to localize in space and is judged slighter louder at representative alarm levels. Slight advantages were found with the tonal alarm for sound detection and for perceived urgency at low levels, but these benefits observed in laboratory conditions would not overcome the detrimental effects associated with the large and abrupt variations in sound pressure levels (up to 15-20 dB within short distances) observed in the field behind vehicles for this alarm, which are significantly higher than those obtained with the broadband alarm. Performance with the multi-tone alarm generally fell between that of the tonal and broadband alarms on most measures.

Functionally-based screening criteria for hearing-critical jobs based on the Hearing in Noise Test.

Effective communication is a crucial requirement in many workplaces to ensure safe and effective operations. Often, critical verbal communications are carried out in noise, which can be very challenging, particularly for individuals with hearing loss. Diagnostic measures of hearing, such as the audiogram, are not adequate to make accurate predictions of speech intelligibility in real-world environments for specific workers, and thus are not generally suitable as a basis for making employment decisions. Instead, the Hearing in Noise Test (HINT) has been identified and validated for use in predicting speech intelligibility in a wide range of communication environments. The approach to validation of the HINT takes into account the expected voice level of the talker, the communication distance between the talker and the listener, and a statistical model of speech intelligibility in real-world occupational noises. For each hearing-critical task, a HINT screening threshold score is derived upon specification of the minimum level of performance required of the workers. The HINT is available in several languages, so the tools developed are applicable in a wide range of settings, including multilingual workplaces.

The Canadian French Hearing in Noise Test

English and French represent the two official languages of Canada. During the last census, 23.2% of Canadians identified French as their mother tongue (Statistics Canada, 2001). Unfortunately, until recently, there were no reliable, standardized, and efficient tools for the assessment of sentence-length speech intelligibility in noisy listening conditions to serve this segment of the Canadian population. This report summarizes the development of a Canadian French version of the HINT. A more detailed description can be found in Vaillancourt et al (2005).

The interaction of hearing loss and level-dependent hearing protection on speech recognition in noise

Abstract Objectives: To determine the effects of different control settings of level-dependent hearing protectors on speech recognition performance in interaction with hearing loss. Design: Controlled laboratory experiment with two level-dependent devices (Peltor® PowerCom Plus™ and Nacre QuietPro®) in two military noises. Study sample: Word recognition scores were collected in protected and unprotected conditions for 45 participants grouped into four hearing profile categories ranging from within normal limits to moderate-to-severe hearing loss. Results: When the level-dependent mode was switched off to simulate conventional hearing protection, there were large differences across hearing profile categories regarding the effects of wearing the devices on speech recognition in noise; participants with normal hearing showed little effect while participants in the most hearing-impaired category showed large decrements in scores compared to unprotected listening. Activating the level-dependent mode of the devices produced large speech recognition benefits over the passive mode at both low and high gain pass-through settings. The category of participants with the most impaired hearing benefitted the most from the level-dependent mode. Conclusions: The findings indicate that level-dependent hearing protection circuitry can provide substantial benefits in speech recognition performance in noise, compared to conventional passive protection, for individuals covering a wide range of hearing losses.

Quantifying the Lombard effect in different background noises

The Lombard effect of increasing one’s vocal effort in the presence of background noise has been quantified by Pearsons et al. (1977) as a 0.6‐dB increase in speech levels for each dB increase in the background noise up to a ceiling level. Lombard speech has also been investigated in other studies with variable results. This study reports data on the effect of different noises on (1) the slope of the function relating speech levels and noise levels and (2) the spectral structure of speech. Twenty normal‐hearing adults were asked to read aloud ten sentences from the hearing in noise test (HINT) to an experimenter seated 1 m away, in quiet and in various noises (white, speech spectrum, babble, and restaurant) presented in the sound field at 60 and 75 dBA. Preliminary findings show that increases in speech levels in natural environmental noises (restaurant and babble) most closely follow Pearsons’ data, with a slope of 0.6 dB. In contrast, artificial noises (speech spectrum and white) were associated with lower slopes (0.2 and 0.4 dB, respectively). Findings of this study could be useful in a wider context of modeling the complete speech communication process from talker to listener.

Evidence-based occupational hearing screening II: validation of a screening methodology using measures of functional hearing ability

Abstract Objective: Validate use of the Extended Speech Intelligibility Index (ESII) for prediction of speech intelligibility in non-stationary real-world noise environments. Define a means of using these predictions for objective occupational hearing screening for hearing-critical public safety and law enforcement jobs. Design: Analyses of predicted and measured speech intelligibility in recordings of real-world noise environments were performed in two studies using speech recognition thresholds (SRTs) and intelligibility measures. ESII analyses of the recordings were used to predict intelligibility. Noise recordings were made in prison environments and at US Army facilities for training ground and airborne forces. Speech materials included full bandwidth sentences and bandpass filtered sentences that simulated radio transmissions. Study sample: A total of 22 adults with normal hearing (NH) and 15 with mild–moderate hearing impairment (HI) participated in the two studies. Results: Average intelligibility predictions for individual NH and HI subjects were accurate in both studies (r2 ≥ 0.94). Pooled predictions were slightly less accurate (0.78 ≤ r2 ≤ 0.92). Conclusions: An individual’s SRT and audiogram can accurately predict the likelihood of effective speech communication in noise environments with known ESII characteristics, where essential hearing-critical tasks are performed. These predictions provide an objective means of occupational hearing screening.

Speech intelligibility in military noise for normal-hearing and hearing-impaired listeners using level-dependent tactical hearing protectors

The effects of two tactical headsets with level-dependent hearing protection capabilities on face-to-face speech intelligibility in military noise were investigated. Devices were the Nacre QuietPro and the Peltor Powercom Plus. Noises recorded from light-artillery vehicles in the Canadian Forces were reproduced in a simulation room at 80-95 dBA. Over 45 subjects covering a wide range of hearing profiles were tested using sentences from the Hearing-In-Noise Test. When used as passive devices with the electronics powered off, the devices performed as expected from conventional protectors having the same amount of attenuation. In this mode, there were large performance differences among subject groups in terms of the effects of wearing the devices compared to unprotected listening. When used in active talk-through (or surround) mode, both devices showed large intelligibility benefits over the passive mode and demonstrated a level of performance often exceeding that in unprotected listening. The subject group...

A statistical model for prediction of functional hearing abilities in real‐world noise environments

Many tasks require functional hearing abilities such as speech communication, sound localization, and sound detection, and are performed in challenging noisy environments. Individuals who must perform these tasks and whose functional hearing abilities are impaired by hearing loss may constitute safety risks to themselves and others. We have developed and validated in two languages (American English and Canadian French) statistical techniques based on Plomps (1986) speech reception threshold model of speech communication handicap. These techniques predict functional hearing ability using the statistical characteristics of the real‐world noise environments where the tasks are performed together with the communication task parameters. The techniques will be used by the Department of Fisheries and Oceans Canada to screen individuals who are required to perform hearing‐critical public safety tasks. This presentation will summarize the three years of field and laboratory work culminating in the implementation o...