Perception of Prosody in Hearing-Impaired Individuals and Users of Hearing Assistive Devices: An Overview of Recent Advances.

Purpose: Prosody perception is an essential component of speech communication and social interaction through which both linguistic and emotional information are conveyed. Considering the importance of the auditory system in processing prosody-related acoustic features, the aim of this review article is to review the effects of hearing impairment on prosody perception in children and adults. It also assesses the performance of hearing assistive devices in restoring prosodic perception.

The effect of hearing protection worn by talker and/or target listener on speech production in quiet and noise.

Speech production while wearing hearing protectors poses significant challenges due to their occlusion effect and disruption of the Lombard effect. An experiment was conducted with 24 individuals as they read a list of 12 sentences in open ears and while wearing an earmuff in quiet and in four different noises [pink, International Female Fluctuating Masker (IFFM), speech-spectrum noise (SSnoise), and helicopter] at two levels (70 and 85 dBA). An acoustic manikin, fitted or not with an identical protector, served as the target listener.

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms.

Objective: This study explored the effects of hearing protection devices (HPDs) and head protection on the ability of normal-hearing individuals to localize reverse alarms in background noise.

Background: Among factors potentially contributing to accidents involving heavy vehicles, reverse alarms can be difficult to localize in space, leading to errors in identifying the source of danger. Previous studies have shown that traditional tonal alarms are more difficult to localize than broadband alarms.

Development of the Canadian Digit Triplet Test in English and French.

The Canadian Digit Triplet Test was developed in English and French, the official languages of Canada. Four versions were developed on a common software platform using recordings produced by two fluent bilinguals, one male and one female, following procedures recommended by international guidelines. Phase I of test development focused on homogenizing digit recognition across tokens and positions within the triplets for young adults with normal hearing (n = 48).

Effects of hearing loss and language proficiency on speech intelligibility over radio transmission with tactical communication devices.

Study the effects of hearing loss and language proficiency in a speech task over radio transmission. Four TCAPS device conditions (2 models × 2 talk-through modes) were investigated with the Modified Rhyme Test (MRT) conducted in talker-listener pairs immersed in 85-dBA noise. Speech quality ratings and preferred radio volume levels were also collected.

Development of hearing standards for Ontario's Constable Selection System.

Develop valid and defensible hearing standards for Ontario constables to ensure safe and efficient operations. Research involved three steps: (1) identification of hearing critical (HC) tasks, (2) characterisation of real-world noise environments where these tasks are performed (3) and establishment of screening criteria and protocols for determining fitness for duty. Three panels of subject matter experts (SMEs) from different Ontario police services participated in Steps 1 and 3.

An indirect calculation method for estimating occupational sound exposure from communication headsets.

Measurement of noise exposure from communication headsets is challenging due to the need for specialized equipment, methods, and training. Canadian standard Z107.56-13 [(2013).

Evidence-Based Occupational Hearing Screening I: Modeling the Effects of Real-World Noise Environments on the Likelihood of Effective Speech Communication.

Objectives: The objectives of this study were to (1) identify essential hearing-critical job tasks for public safety and law enforcement personnel; (2) determine the locations and real-world noise environments where these tasks are performed; (3) characterize each noise environment in terms of its impact on the likelihood of effective speech communication, considering the effects of different levels of vocal effort, communication distances, and repetition; and (4) use this characterization to define an objective normative reference for evaluating the ability of individuals to perform essential hearing-critical job tasks in noisy real-world environments.

Design: Data from five occupational hearing studies performed over a 17-year period for various public safety agencies were analyzed. In each study, job task analyses by job content experts identified essential hearing-critical tasks and the real-world noise environments where these tasks are performed.

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

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.

Effects of Early- and Late-Arriving Room Reflections on the Speech-Evoked Auditory Brainstem Response.

Background: Room reverberation alters the acoustical properties of the speech signals reaching our ears, affecting speech understanding. Therefore, it is important to understand the consequences of reverberation on auditory processing. In perceptual studies, the direct sound and early reflections of reverberated speech have been found to constitute useful energy, whereas the late reflections constitute detrimental energy.

Self-masking and overlap-masking from reverberation using the speech-evoked auditory brainstem response.

This study introduces an improved method to investigate the effects of reverberation using the speech-evoked auditory brainstem response (ABR) that more realistically captures the influence of self- and overlap-masking induced by room reverberation. Speech-evoked ABR was measured under three acoustic scenarios: anechoic, mild reverberation with dominance of early reflections, and severe reverberation with dominance of late reverberation. Responses were significantly weaker and had longer latencies with severe reverberation relative to anechoic and mild reverberation.

Detection and reaction thresholds for reverse alarms in noise with and without passive hearing protection.

Objective: To measure masked detection and reaction thresholds for two reverse alarms (tonal and broadband) and compare results to available standards and psychoacoustic criteria for setting alarm levels.

Design: Alarm detection and reaction thresholds were adaptively measured in 80-dBA background noises without hearing protection (Experiment 1), and with a passive earmuff-style hearing protection device (HPD) (Experiment 2).

Study Sample: Twenty-four young adults with normal hearing in each experimental group.

Comparison of direct measurement methods for headset noise exposure in the workplace.

The measurement of noise exposure from communication headsets poses a methodological challenge. Although several standards describe methods for general noise measurements in occupational settings, these are not directly applicable to noise assessments under communication headsets. For measurements under occluded ears, specialized methods have been specified by the International Standards Organization (ISO 11904) such as the microphone in a real ear and manikin techniques.

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Objective: To investigate the effects of hearing protection on speech recognition in noise.

Design: Computational study using a speech recognition model that was previously empirically validated.

Study Sample: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.

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

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.

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.

Improving hearing aid fitting using the speech-evoked auditory brainstem response.

Measuring brain responses to speech may help improve the process of hearing aid fitting, especially in young children. Speech-evoked auditory brainstem responses (sABR) may be particularly useful because they provide a spectro-temporal representation of auditory neural activity in response to speech. However, use of the sABR in evaluating hearing aid performance has not been explored.

Differences in shimmer across formant regions.

Objectives: Objective acoustic measures used to analyze phonatory dysfunction include shimmer and jitter. These measures are limited in that they do not take into account auditory processing. However, previous studies have indicated that shimmer may be processed differently along the tonotopic axis of the ear and, in particular, may be perceptually and physiologically significant around the third and fourth formants.

Evaluation of auditory functions for Royal Canadian Mounted Police officers.

Background: Auditory fitness for duty (AFFD) testing is an important element in an assessment of workers' ability to perform job tasks safely and effectively. Functional hearing is particularly critical to job performance in law enforcement. Most often, assessment is based on pure-tone detection thresholds; however, its validity can be questioned and challenged in court.

Speech perception in noise: exploring the effect of linguistic context in children with and without auditory processing disorder.

Objective: The objective of this study was to investigate whether the speech perception problems in noise of children with auditory processing disorder (APD) stem from an auditory or a higher order dysfunction.

Design: A repeated measures design comparing the sentence key word recognition scores of children with APD and a control group was used. Four sentence lists from the Test de phrases dans le bruit (TPB) were presented with a babble masker at four different signal-to-noise ratios.

Adaptive environment classification system for hearing aids.

An adaptive sound classification framework is proposed for hearing aid applications. The long-term goal is to develop fully trainable instruments in which both the acoustical environments encountered in daily life and the hearing aid settings preferred by the user in each environmental class could be learned. Two adaptive classifiers are described, one based on minimum distance clustering and one on Bayesian classification.

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.

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.