The effect of permutations of time samples in the speech waveform on intelligibility.

This paper describes the effect of two types of temporal permutations of the speech waveform on speech intelligibility. Using an overlap-add procedure with triangular-shaped windows for frame lengths of 1/8 to 2048 ms, the temporal order of the speech samples within each frame was subjected to either of two types of permutations: time-reversal or randomization. For both permutations, speech intelligibility tests expectantly show 100% intelligibility for the very short frame lengths containing only a few speech samples.

Cognitive abilities relate to self-reported hearing disability.

Purpose: In this explorative study, the authors investigated the relationship between auditory and cognitive abilities and self-reported hearing disability.

Method: Thirty-two adults with mild to moderate hearing loss completed the Amsterdam Inventory for Auditory Disability and Handicap (AIADH; Kramer, Kapteyn, Festen, & Tobi, 1996) and performed the Text Reception Threshold (TRT; Zekveld, George, Kramer, Goverts, & Houtgast, 2007) test as well as tests of spatial working memory (SWM) and visual sustained attention. Regression analyses examined the predictive value of age, hearing thresholds (pure-tone averages [PTAs]), speech perception in noise (speech reception thresholds in noise [SRTNs]), and the cognitive tests for the 5 AIADH factors.

Evaluation of the preliminary auditory profile test battery in an international multi-centre study.

Objective: This paper describes the composition and international multi-centre evaluation of a battery of tests termed the preliminary auditory profile. It includes measures of loudness perception, listening effort, speech perception, spectral and temporal resolution, spatial hearing, self-reported disability and handicap, and cognition. Clinical applicability and comparability across different centres are investigated.

On the use of the distortion-sensitivity approach in examining the role of linguistic abilities in speech understanding in noise.

Purpose: Researchers have used the distortion-sensitivity approach in the psychoacoustical domain to investigate the role of auditory processing abilities in speech perception in noise (van Schijndel, Houtgast, & Festen, 2001; Goverts & Houtgast, 2010). In this study, the authors examined the potential applicability of the distortion-sensitivity approach for investigating the role of linguistic abilities in speech understanding in noise.

Method: The authors applied the distortion-sensitivity approach by measuring the processing of visually presented masked text in a condition with manipulated syntactic, lexical, and semantic cues and while using the Text Reception Threshold (George et al.

The binaural intelligibility level difference in hearing-impaired listeners: the role of supra-threshold deficits.

Reduced binaural performance of hearing-impaired listeners may not only be caused by raised hearing thresholds (reduced audibility), but also by supra-threshold coding deficits in signal cues. This question was investigated in the present study using binaural intelligibility level difference (BILD) comparisons: the improvement of speech-reception threshold scores for N(0)S(π) relative to N(0)S(0) presentation conditions. Investigated was what types of supra-threshold deficits play a role in reducing BILDs in hearing-impaired subjects.

Measuring the effects of reverberation and noise on sentence intelligibility for hearing-impaired listeners.

Purpose: The Speech Transmission Index (STI; Houtgast, Steeneken, & Plomp, 1980; Steeneken & Houtgast, 1980) is commonly used to quantify the adverse effects of reverberation and stationary noise on speech intelligibility for normal-hearing listeners. Duquesnoy and Plomp (1980) showed that the STI can be applied for presbycusic listeners, relating speech reception thresholds (SRTs) in various reverberant conditions to a fixed, subject-dependent STI value. The current study aims at extending their results to a wider range of hearing-impaired listeners.

On the significance of phase in the short term Fourier spectrum for speech intelligibility.

This paper investigates the significance of the magnitude or the phase in the short term Fourier spectrum for speech intelligibility as a function of the time-window length. For a wide range of window lengths (1/16-2048 ms), two hybrid signals were obtained by a cross-wise combination of the magnitude and phase spectra of speech and white noise. Speech intelligibility data showed the significance of the phase spectrum for longer windows (>256 ms) and for very short windows (<4 ms), and that of the magnitude spectrum for medium-range window lengths.

Measuring cognitive factors in speech comprehension: the value of using the Text Reception Threshold test as a visual equivalent of the SRT test.

The ability to comprehend speech in noise is influenced by bottom-up auditory and top-down cognitive capacities. Separate examination of these capacities is relevant for various purposes. Speech-Reception-Threshold (SRT) tests measure an individual's ability to comprehend speech.

The concept of signal-to-noise ratio in the modulation domain and speech intelligibility.

A new concept is proposed that relates to intelligibility of speech in noise. The concept combines traditional estimations of signal-to-noise ratios (S/N) with elements from the modulation transfer function model, which results in the definition of the signal-to-noise ratio in the modulation domain: the (SN)(mod). It is argued that this (SN)(mod), quantifying the strength of speech modulations relative to a floor of spurious modulations arising from the speech-noise interaction, is the key factor in relation to speech intelligibility.

The influence of age, hearing, and working memory on the speech comprehension benefit derived from an automatic speech recognition system.

Objective: The aim of the current study was to examine whether partly incorrect subtitles that are automatically generated by an Automatic Speech Recognition (ASR) system, improve speech comprehension by listeners with hearing impairment. In an earlier study (Zekveld et al. 2008), we showed that speech comprehension in noise by young listeners with normal hearing improves when presenting partly incorrect, automatically generated subtitles.

User evaluation of a communication system that automatically generates captions to improve telephone communication.

This study examined the subjective benefit obtained from automatically generated captions during telephone-speech comprehension in the presence of babble noise. Short stories were presented by telephone either with or without captions that were generated offline by an automatic speech recognition (ASR) system. To simulate online ASR, the word accuracy (WA) level of the captions was 60% or 70% and the text was presented delayed to the speech.

Modulation detection interference for asynchronous presentation of masker and target in listeners with normal and impaired hearing.

Purpose: The sensitivity to sinusoidal amplitude modulations (SAMs) is reduced when other modulated maskers are presented simultaneously at a distant frequency (also referred to as modulation detection interference [MDI]). This article describes the results of onset differences between masker and target as a parameter.

Method: Carrier frequencies were 1 kHz (target: 625 ms, 8 Hz SAM) and 2 kHz (masker: 625 ms, 8 Hz SAM; modulation depth = 1) presented at 25 dB SL for listeners with impaired hearing (n = 8) and at 25 dB SL and 50 dB SL for listeners with normal hearing (n = 6).

The combined effects of reverberation and nonstationary noise on sentence intelligibility.

Listening conditions in everyday life typically include a combination of reverberation and nonstationary background noise. It is well known that sentence intelligibility is adversely affected by these factors. To assess their combined effects, an approach is introduced which combines two methods of predicting speech intelligibility, the extended speech intelligibility index (ESII) and the speech transmission index.

The benefit obtained from visually displayed text from an automatic speech recognizer during listening to speech presented in noise.

Objectives: The aim of this study was to evaluate the benefit that listeners obtain from visually presented output from an automatic speech recognition (ASR) system during listening to speech in noise.

Design: Auditory-alone and audiovisual speech reception thresholds (SRTs) were measured. The SRT is defined as the speech-to-noise ratio at which 50% of the test sentences are reproduced correctly.

On the auditory and cognitive functions that may explain an individual's elevation of the speech reception threshold in noise.

It is generally recognized that poor results of speech-in-noise tests by hearing-impaired persons cannot be fully explained by the elevated pure-tone hearing threshold. Plomp has shown, among others, that an additional factor has to be taken into account, often referred to in general terms as distortion. In an attempt to specify auditory and cognitive functions which may underlie this distortion, various studies on this topic originating from Plomp's research group are reviewed, as well as other relevant studies which provide quantitative data on the correlations between various types of auditory or cognitive tests (the predictor tests) and speech-in-noise tests.

A detailed study on the effects of noise on speech intelligibility.

A wavelet representation of speech was used to display the instantaneous amplitude and phase within 14 octave frequency bands, representing the envelope and the carrier within each band. Adding stationary noise alters the wavelet pattern, which can be understood as a combination of three simultaneously occurring subeffects: two effects on the wavelet levels (one systematic and one stochastic) and one effect on the wavelet phases. Specific types of signal processing were applied to speech, which allowed each effect to be either included or excluded.

Audiovisual perception of speech in noise and masked written text.

Objective: The aim of this study was to examine the support obtained from degraded visual information in the comprehension of speech in noise.

Design: We presented sentences auditorily (speech reception threshold test), visually (text reception threshold test), and audiovisually. Presenting speech in noise and masked written text enabled the quantification and systematic variation of the amount of information presented in both modalities.

The development of the text reception threshold test: a visual analogue of the speech reception threshold test.

Purpose: In this study, the authors aimed to develop a visual analogue of the widely used Speech Reception Threshold (SRT; R. Plomp & A. M.

Auditory and nonauditory factors affecting speech reception in noise by older listeners.

Speech reception thresholds (SRTs) for sentences were determined in stationary and modulated background noise for two age-matched groups of normal-hearing (N = 13) and hearing-impaired listeners (N = 21). Correlations were studied between the SRT in noise and measures of auditory and nonauditory performance, after which stepwise regression analyses were performed within both groups separately. Auditory measures included the pure-tone audiogram and tests of spectral and temporal acuity.

Recognition of digits in different types of noise by normal-hearing and hearing-impaired listeners.

The objective of the study was to examine the ability to understand digits in different types of noise. Adaptive speech-in-noise tests were developed that measure the speech-reception-threshold (SRTn) i.e.

Factors affecting masking release for speech in modulated noise for normal-hearing and hearing-impaired listeners.

The Speech Reception Threshold for sentences in stationary noise and in several amplitude-modulated noises was measured for 8 normal-hearing listeners, 29 sensorineural hearing-impaired listeners, and 16 normal-hearing listeners with simulated hearing loss. This approach makes it possible to determine whether the reduced benefit from masker modulations, as often observed for hearing-impaired listeners, is due to a loss of signal audibility, or due to suprathreshold deficits, such as reduced spectral and temporal resolution, which were measured in four separate psychophysical tasks. Results show that the reduced masking release can only partly be accounted for by reduced audibility, and that, when considering suprathreshold deficits, the normal effects associated with a raised presentation level should be taken into account.

Occupational performance: comparing normally-hearing and hearing-impaired employees using the Amsterdam Checklist for Hearing and Work.

This study compares the occupational performance of employees with and without hearing impairment, and aims to identify occupational difficulties specifically related to hearing loss. The Amsterdam Checklist for Hearing and Work was administered to 150 hearing-impaired employees and 60 normally-hearing colleagues. A multivariate analysis of variance was performed to test group effects, and to examine differences between means.

Measurements and calculations on the simple up-down adaptive procedure for speech-in-noise tests.

The simple up-down adaptive procedure is a common method for measuring speech reception thresholds. It is used by the Dutch speech-in-noise telephone screening test [National Hearing test; Smits and Houtgast Ear Hear. 26, 89-95 (2005)].

Speech reception thresholds in noise and self-reported hearing disability in a general adult population.

Objective: The principal objective of this study was to describe speech reception thresholds in noise (SRTTn, i.e., the signal-to-noise ratio corresponding to 50% intelligibility) and self-reported hearing disability in a general adult population.