Preferred Strength of Noise Reduction for Normally Hearing and Hearing-Impaired Listeners.

Preference for noise reduction (NR) strength differs between individuals. The purpose of this study was (1) to investigate whether hearing loss influences this preference, (2) to find the number of distinct settings required to classify participants in similar groups based on their preference for NR strength, and (3) to estimate the number of paired comparisons needed to predict to which preference group a participant belongs. A paired comparison paradigm was used in which participants listened to pairs of speech-in-noise stimuli processed by NR with 10 different strength settings.

Individual Listener Preference for Strength of Single-Microphone Noise-Reduction; Trade-off Between Noise Tolerance and Signal Distortion Tolerance.

There are large interindividual variations in preference for strength of noise-reduction (NR). It is hypothesized that each individual's tolerance for background noise on one hand and signal distortions on the other hand form this preference. We aim to visualize and analyze this so-called trade-off between noise attenuation and signal quality.

Measuring the Influence of Noise Reduction on Listening Effort in Hearing-Impaired Listeners Using Response Times to an Arithmetic Task in Noise.

Single microphone noise reduction (NR) in hearing aids can provide a subjective benefit even when there is no objective improvement in speech intelligibility. A possible explanation lies in a reduction of listening effort. Previously, we showed that response times (a proxy for listening effort) to an auditory-only dual-task were reduced by NR in normal-hearing (NH) listeners.

Measuring Auditory Fitness in Locomotive Engineers: Development and Validation of a Signal Detection Test.

Objectives: To perform their job safely and effectively, locomotive engineers are required to detect auditory warning signals in the noisy work setting of a train cabin. Based on audio recordings of Dutch train cabins, we have developed a task and job-specific test for assessing the engineer's ability to detect the two acoustic warning signals for the Dutch situation. The aim of this study was to evaluate the reliability, agreement, and construct validity of this test.

Detectability of auditory warning signals in the ambient noise of Dutch train cabins.

Locomotive engineers need to detect auditory warning signals for safe and effective job performance. We measured the levels and spectra of the warning signals and noises present in Dutch train cabins to evaluate the effectiveness of these signals. Audio-recordings were made in six train types during normal operation.

Subjective evaluation of single microphone noise reduction with different time constants.

Previous studies on single microphone noise reduction (NR) in hearing aids (HAs) have shown that some NR algorithms provide beneficial effects in terms of listener preference. To improve HA user satisfaction, we are interested in characteristics that determine preferences for NR, and in the inter-individual variability. The aim of this study was to test if dynamic properties of NR influence listener preference.

The Influence of Noise Reduction on Speech Intelligibility, Response Times to Speech, and Perceived Listening Effort in Normal-Hearing Listeners.

Single-microphone noise reduction leads to subjective benefit, but not to objective improvements in speech intelligibility. We investigated whether response times (RTs) provide an objective measure of the benefit of noise reduction and whether the effect of noise reduction is reflected in rated listening effort. Twelve normal-hearing participants listened to digit triplets that were either unprocessed or processed with one of two noise-reduction algorithms: an ideal binary mask (IBM) and a more realistic minimum mean square error estimator (MMSE).

Acoustical and Perceptual Comparison of Noise Reduction and Compression in Hearing Aids.

Purpose: Noise reduction and dynamic-range compression are generally applied together in hearing aids but may have opposite effects on amplification. This study evaluated the acoustical and perceptual effects of separate and combined processing of noise reduction and compression.

Design: Recordings of the output of 4 hearing aids for speech in babble noise at +4 dB signal-to-noise ratio were used in 3 experiments: (a) acoustical measurements to determine the influence of processing on speech and noise levels; (b) perceptual measurements to determine the detectability of processing differences for 16 listeners with hearing impairment; and (c) perceptual measurements to determine the effect of processing on speech intelligibility, noise annoyance, speech naturalness, and overall preference.

Optimization of the Dutch matrix test by random selection of sentences from a preselected subset.

Matrix tests are available for speech recognition testing in many languages. For an accurate measurement, a steep psychometric function of the speech materials is required. For existing tests, it would be beneficial if it were possible to further optimize the available materials by increasing the function's steepness.

Effects of noise reduction on speech intelligibility, perceived listening effort, and personal preference in hearing-impaired listeners.

This study evaluates the perceptual effects of single-microphone noise reduction in hearing aids. Twenty subjects with moderate sensorineural hearing loss listened to speech in babble noise processed via noise reduction from three different linearly fitted hearing aids. Subjects performed (a) speech-intelligibility tests, (b) listening-effort ratings, and (c) paired-comparison ratings on noise annoyance, speech naturalness, and overall preference.

Detection threshold for sound distortion resulting from noise reduction in normal-hearing and hearing-impaired listeners.

Hearing-aid noise reduction should reduce background noise, but not disturb the target speech. This objective is difficult because noise reduction suffers from a trade-off between the amount of noise removed and signal distortion. It is unknown if this important trade-off differs between normal-hearing (NH) and hearing-impaired (HI) listeners.

Investigation into the applicability and optimization of the Dutch matrix sentence test for use with cochlear implant users.

Objective: Matrix sentence tests use words from a fixed word matrix to compose syntactically equivalent, but semantically unpredictable sentences. These tests are suitable for monitoring performance of cochlear implant (CI) users by repeated speech intelligibility testing. This study evaluates the Dutch matrix sentence test in CI users in quiet and in noise.

Development of a Dutch matrix sentence test to assess speech intelligibility in noise.

Objective: A Dutch matrix sentence test was developed and evaluated. A matrix test is a speech-in-noise test based on a closed speech corpus of sentences derived from words from fixed categories. An example is "Mark gives five large flowers.

Using response time to speech as a measure for listening effort.

Objective: Speech signals that do not differ in intelligibility might differ in listening effort. This study aimed to investigate the effect of background noise on response time to intelligible speech.

Design: We added various amounts of stationary noise to spoken digit triplets and measured the influence of noise on the response time for both an identification and an arithmetic task: Task 1 'identify the final digit in a triplet', and Task 2 'calculate the sum of the initial and the final digits in a triplet.

Perceptual effects of noise reduction by time-frequency masking of noisy speech.

Time-frequency masking is a method for noise reduction that is based on the time-frequency representation of a speech in noise signal. Depending on the estimated signal-to-noise ratio (SNR), each time-frequency unit is either attenuated or not. A special type of a time-frequency mask is the ideal binary mask (IBM), which has access to the real SNR (ideal).

Perceptual effects of noise reduction with respect to personal preference, speech intelligibility, and listening effort.

Objectives: Most modern hearing aids use noise reduction to increase listening comfort in noisy environments. However, it is unclear whether perceptual effects (e.g.

A method to remove differences in frequency response between commercial hearing aids to allow direct comparison of the sound quality of hearing-aid features.

Goal: We want to remove differences in frequency response between different commercial hearing aids so that we can compare the sound quality of signal processing features from different hearing-aid in a future paired-comparison set-up. More specifically, we want to control for the confounding effects of the linear hearing aid response when evaluating nonlinear processing. This article presents a control procedure and evaluates its effectiveness.

Multicenter evaluation of signal enhancement algorithms for hearing aids.

In the framework of the European HearCom project, promising signal enhancement algorithms were developed and evaluated for future use in hearing instruments. To assess the algorithms' performance, five of the algorithms were selected and implemented on a common real-time hardware/software platform. Four test centers in Belgium, The Netherlands, Germany, and Switzerland perceptually evaluated the algorithms.