scholarly journals Effects of Compression on Speech Acoustics, Intelligibility, and Sound Quality

2002 ◽  
Vol 6 (4) ◽  
pp. 131-165 ◽  
Author(s):  
Pamela E. Souza
Keyword(s):  
Speech Perception ◽  
Time Use ◽  
Hearing Aids ◽  
Speech Signal ◽  
Speech Intelligibility ◽  
Sound Quality ◽  
Speech Quality ◽  
Speech Acoustics ◽  
Clinical Procedures ◽  
Digitally Programmable

The topic of compression has been discussed quite extensively in the last 20 years (eg, Braida et al., 1982; Dillon, 1996 , 2000 ; Dreschler, 1992 ; Hickson, 1994 ; Kuk, 2000 and 2002; Kuk and Ludvigsen, 1999 ; Moore, 1990 ; Van Tasell, 1993 ; Venema, 2000 ; Verschuure et al., 1996; Walker and Dillon, 1982 ). However, the latest comprehensive update by this journal was published in 1996 ( Kuk, 1996 ). Since that time, use of compression hearing aids has increased dramatically, from half of hearing aids dispensed only 5 years ago to four out of five hearing aids dispensed today ( Strom, 2002b ). Most of today's digital and digitally programmable hearing aids are compression devices ( Strom, 2002a ). It is probable that within a few years, very few patients will be fit with linear hearing aids. Furthermore, compression has increased in complexity, with greater numbers of parameters under the clinician's control. Ideally, these changes will translate to greater flexibility and precision in fitting and selection. However, they also increase the need for information about the effects of compression amplification on speech perception and speech quality. As evidenced by the large number of sessions at professional conferences on fitting compression hearing aids, clinicians continue to have questions about compression technology and when and how it should be used. How does compression work? Who are the best candidates for this technology? How should adjustable parameters be set to provide optimal speech recognition? What effect will compression have on speech quality? These and other questions continue to drive our interest in this technology. This article reviews the effects of compression on the speech signal and the implications for speech intelligibility, quality, and design of clinical procedures.

scholarly journals Listener Performance with a Novel Hearing Aid Frequency Lowering Technique

2017 ◽  
Vol 28 (09) ◽  
pp. 810-822 ◽  
Author(s):  
Benjamin J. Kirby ◽  
Judy G. Kopun ◽  
Meredith Spratford ◽  
Clairissa M. Mollak ◽  
Marc A. Brennan ◽  
...  
Keyword(s):  
Signal Processing ◽  
Hearing Loss ◽  
Speech Perception ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Quality ◽  
Processing Strategy ◽  
Listening Effort ◽  
At Home

AbstractSloping hearing loss imposes limits on audibility for high-frequency sounds in many hearing aid users. Signal processing algorithms that shift high-frequency sounds to lower frequencies have been introduced in hearing aids to address this challenge by improving audibility of high-frequency sounds.This study examined speech perception performance, listening effort, and subjective sound quality ratings with conventional hearing aid processing and a new frequency-lowering signal processing strategy called frequency composition (FC) in adults and children.Participants wore the study hearing aids in two signal processing conditions (conventional processing versus FC) at an initial laboratory visit and subsequently at home during two approximately six-week long trials, with the order of conditions counterbalanced across individuals in a double-blind paradigm.Children (N = 12, 7 females, mean age in years = 12.0, SD = 3.0) and adults (N = 12, 6 females, mean age in years = 56.2, SD = 17.6) with bilateral sensorineural hearing loss who were full-time hearing aid users.Individual performance with each type of processing was assessed using speech perception tasks, a measure of listening effort, and subjective sound quality surveys at an initial visit. At the conclusion of each subsequent at-home trial, participants were retested in the laboratory. Linear mixed effects analyses were completed for each outcome measure with signal processing condition, age group, visit (prehome versus posthome trial), and measures of aided audibility as predictors.Overall, there were few significant differences in speech perception, listening effort, or subjective sound quality between FC and conventional processing, effects of listener age, or longitudinal changes in performance. Listeners preferred FC to conventional processing on one of six subjective sound quality metrics. Better speech perception performance was consistently related to higher aided audibility.These results indicate that when high-frequency speech sounds are made audible with conventional processing, speech recognition ability and listening effort are similar between conventional processing and FC. Despite the lack of benefit to speech perception, some listeners still preferred FC, suggesting that qualitative measures should be considered when evaluating candidacy for this signal processing strategy.

Peaks in the Frequency Response of Hearing Aids: Evaluation of the Effects on Speech Intelligibility and Sound Quality

1996 ◽  
Vol 39 (2) ◽  
pp. 239-250 ◽  
Author(s):  
Ronald A. van Buuren ◽  
Joost M. Festen ◽  
Tammo Houtgast
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Rating Scale ◽  
Sound Quality ◽  
Normal Hearing ◽  
Reference Frequency ◽  
Impaired Hearing ◽  
Speech Spectrum ◽  
Series Of Experiments

In a series of experiments, we introduced peaks of 10, 20, and 30 dB, in various combinations, onto a smooth reference frequency response. For each of the conditions, we evaluated speech intelligibility in noise, using a test as developed by Plomp and Mimpen (1979), and sound quality (for both speech and music), using a rating-scale procedure. We performed the experiments with 26 listeners with sensorineurally impaired hearing and 10 listeners with normal hearing. Signal processing was accomplished digitally; for each listener, the stimuli were filtered and subsequently amplified so that the average speech spectrum was well above the threshold of hearing at all frequencies. The results show that, as a result of the introduction of peaks onto the frequency response, speech intelligibility is affected more for the listeners with impaired hearing than for those with normal hearing. Sound-quality judgments tend to be less different between the listener groups. Conditions with 30-dB peaks especially show serious effects on both speech intelligibility and sound quality.

A Comparison of Personal Sound Amplification Products and Hearing Aids in Ecologically Relevant Test Environments

2018 ◽  
Vol 27 (4) ◽  
pp. 581-593 ◽  
Author(s):  
Lisa Brody ◽  
Yu-Hsiang Wu ◽  
Elizabeth Stangl
Keyword(s):  
Speech Recognition ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Best Practice ◽  
Hearing Aid ◽  
Recognition Performance ◽  
Sound Quality ◽  
Listening Effort ◽  
Speech Intelligibility Index ◽  
Sound Amplification

Purpose The aim of this study was to compare the benefit of self-adjusted personal sound amplification products (PSAPs) to audiologist-fitted hearing aids based on speech recognition, listening effort, and sound quality in ecologically relevant test conditions to estimate real-world effectiveness. Method Twenty-five older adults with bilateral mild-to-moderate hearing loss completed the single-blinded, crossover study. Participants underwent aided testing using 3 PSAPs and a traditional hearing aid, as well as unaided testing. PSAPs were adjusted based on participant preference, whereas the hearing aid was configured using best-practice verification protocols. Audibility provided by the devices was quantified using the Speech Intelligibility Index (American National Standards Institute, 2012). Outcome measures assessing speech recognition, listening effort, and sound quality were administered in ecologically relevant laboratory conditions designed to represent real-world speech listening situations. Results All devices significantly improved Speech Intelligibility Index compared to unaided listening, with the hearing aid providing more audibility than all PSAPs. Results further revealed that, in general, the hearing aid improved speech recognition performance and reduced listening effort significantly more than all PSAPs. Few differences in sound quality were observed between devices. All PSAPs improved speech recognition and listening effort compared to unaided testing. Conclusions Hearing aids fitted using best-practice verification protocols were capable of providing more aided audibility, better speech recognition performance, and lower listening effort compared to the PSAPs tested in the current study. Differences in sound quality between the devices were minimal. However, because all PSAPs tested in the study significantly improved participants' speech recognition performance and reduced listening effort compared to unaided listening, PSAPs could serve as a budget-friendly option for those who cannot afford traditional amplification.

scholarly journals Binaural Signal Processing in Hearing Aids

2021 ◽  
Vol 42 (03) ◽  
pp. 206-223
Author(s):  
Peter Derleth ◽  
Eleftheria Georganti ◽  
Matthias Latzel ◽  
Gilles Courtois ◽  
Markus Hofbauer ◽  
...  
Keyword(s):  
Signal Processing ◽  
Hearing Impairment ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Sound Quality ◽  
The Body ◽  
Technological Advances ◽  
Reverberant Environments ◽  
Left And Right ◽  
Algorithmic Approaches

AbstractFor many years, clinicians have understood the advantages of listening with two ears compared with one. In addition to improved speech intelligibility in quiet, noisy, and reverberant environments, binaural versus monaural listening improves perceived sound quality and decreases the effort listeners must expend to understand a target voice of interest or to monitor a multitude of potential target voices. For most individuals with bilateral hearing impairment, the body of evidence collected across decades of research has also found that the provision of two compared with one hearing aid yields significant benefit for the user. This article briefly summarizes the major advantages of binaural compared with monaural hearing, followed by a detailed description of the related technological advances in modern hearing aids. Aspects related to the communication and exchange of data between the left and right hearing aids are discussed together with typical algorithmic approaches implemented in modern hearing aids.

Automated Methods of Assessing Hearing Aid Performance in Listeners With Impaired Hearing

1994 ◽  
Vol 3 (2) ◽  
pp. 14-19
Author(s):  
Todd W. Fortune
Keyword(s):  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Sound Quality ◽  
Impaired Hearing ◽  
Maximum Benefit ◽  
Degree Of Satisfaction ◽  
Behavioral Methods ◽  
Automated Methods ◽  
Over Time

The methods that have been described, although still under development, are intended to demonstrate that the issues of sound quality, speech intelligibility, and loudness may be addressed in a clinical setting in a reasonable amount of time. Being automated, these methods are relatively time-efficient, and may become more so as they are refined. Being database oriented, these methods make it easy to monitor individual clients over time, and also provide an efficient way to evaluate the success rate of individual circuits across listeners with similar hearing losses. Individually, these techniques provide only some of the information that may indicate whether a particular fitting may succeed. Taken together, these behavioral methods will provide a great deal of both subjective and objective information that will help the dispenser not only decide which of several hearing aids may be best for a user, but also how a given instrument may be adjusted to provide the maximum benefit. By including the formal assessment of sound quality, speech intelligibility, and loudness in the hearing aid evaluation, the needs of the user are more likely to be met, and the degree of satisfaction achieved is likely to be higher than if the evaluation consists solely of matching the real ear insertion response to a prescribed target.

Alaryngeal Speech Intelligibility and the Older Listener

1985 ◽  
Vol 50 (1) ◽  
pp. 60-65 ◽  
Author(s):  
John Greer Clark
Keyword(s):  
Speech Perception ◽  
Older Adult ◽  
Speech Signal ◽  
Speech Intelligibility ◽  
Speech Signals ◽  
Identification Performance ◽  
Alaryngeal Speech ◽  
Artificial Larynx ◽  
Tracheoesophageal Speech ◽  
Speech Identification

Past investigations of alaryngeal speech intelligibility have focused on comparative intelligibility as perceived by young normally hearing adults. However, the spouses and social companions of laryngectomees may have significantly different auditory capabilities compared to young listeners. This report presents a comparison of alaryngeal and laryngeal speech identification performance for a group of young normally hearing listeners and a group of older adult listeners representative of the age of the laryngectomee's social companions. The speech signals investigated included normal laryngeal speech, artificial larynx speech, traditional esophageal speech, and tracheoesophageal speech. The results obtained reveal not only differences in speech signals but also a difference in the proficiency of speech perception for the two groups, favoring the younger listeners. The results of the speech identification measures in the presence of auditory competition revealed greatest intelligibility for the artificial larynx speech signal and poorest for the tracheoesophageal speech signal.

scholarly journals Sound Quality Effects of an Adaptive Nonlinear Frequency Compression Processor with Normal-Hearing and Hearing-Impaired Listeners

2019 ◽  
Vol 30 (07) ◽  
pp. 552-563 ◽  
Author(s):  
Danielle Glista ◽  
Marianne Hawkins ◽  
Jonathan M. Vaisberg ◽  
Nazanin Pourmand ◽  
Vijay Parsa ◽  
...  
Keyword(s):  
Hearing Aids ◽  
Sound Quality ◽  
Normal Hearing ◽  
Speech Quality ◽  
Hearing Impaired ◽  
Nonlinear Frequency ◽  
Experimental Conditions ◽  
Frequency Compression ◽  
Test Conditions ◽  
Quality Ratings

AbstractFrequency lowering (FL) technology offers a means of improving audibility of high-frequency sounds. For some listeners, the benefit of such technology can be accompanied by a perceived degradation in sound quality, depending on the strength of the FL setting.The studies presented in this article investigate the effect of a new type of FL signal processing for hearing aids, adaptive nonlinear frequency compression (ANFC), on subjective speech quality.Listener ratings of sound quality were collected for speech stimuli processed with systematically varied fitting parameters.Study 1 included 40 normal-hearing (NH) adult and child listeners. Study 2 included 11 hearing-impaired (HI) adult and child listeners. HI listeners were fitted with laboratory-worn hearing aids for use during listening tasks.Speech quality ratings were assessed across test conditions consisting of various strengths of static nonlinear frequency compression (NFC) and ANFC speech. Test conditions included those that were fine-tuned on an individual basis per hearing aid fitting and conditions that were modified to intentionally alter the sound quality of the signal.Listeners rated speech quality using the MUlti Stimulus test with Hidden Reference and Anchor (MUSHRA) test paradigm. Ratings were analyzed for reliability and to compare results across conditions.Results show that interrater reliability is high for both studies, indicating that NH and HI listeners from both adult and child age groups can reliably complete the MUSHRA task. Results comparing sound quality ratings across experimental conditions suggest that both the NH and HI listener groups rate the stimuli intended to have poor sound quality (e.g., anchors and the strongest available parameter settings) as having below-average sound quality ratings. A different trend in the results is reported when considering the other experimental conditions across the listener groups in the studies. Speech quality ratings measured with NH listeners improve as the strength of ANFC decreases, with a range of bad to good ratings reported, on average. Speech quality ratings measured with HI listeners are similar and above-average for many of the experimental stimuli, including those with fine-tuned NFC and ANFC parameters.Overall, HI listeners provide similar sound quality ratings when comparing static and adaptive forms of frequency compression, especially when considering the individualized parameter settings. These findings suggest that a range in settings may result in above-average sound quality for adults and children with hearing impairment. Furthermore, the fitter should fine-tune FL parameters for each individual listener, regardless of type of FL technology.

scholarly journals The Effects of Manufacturer’s Prefit and Real-Ear Fitting on the Predicted Speech Perception of Children with Severe to Profound Hearing Loss

2019 ◽  
Vol 30 (05) ◽  
pp. 346-356 ◽  
Author(s):  
Tian Kar Quar ◽  
Cila Umat ◽  
Yong Yee Chew
Keyword(s):  
Hearing Loss ◽  
Speech Perception ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
High Input ◽  
Profound Hearing Loss ◽  
High Frequency Region ◽  
Cross Sectional ◽  
Significant Difference

AbstractThe use of probe microphone measures in hearing aid verification is often neglected or not fully used by practitioners. Some practitioners rely on simulated gain and output provided by manufacturer's fitting software to verify hearing aids.This study aims to evaluate the effectiveness of manufacturer’s prefit procedure in matching the prescribed real-ear targets. It also aims to study its correlated impact on the predicted speech perception in children with severe and profound hearing loss.This cross-sectional experiment was carried out by measuring the output of hearing aids based on prefit versus real-ear at low-, moderate-, and high-input levels. The predicted speech perception for different hearing aid fittings was determined based on the Speech Intelligibility Index (SII).Sixteen children (28 ears) aged between 4 and 7 yr, with severe to profound sensorineural hearing loss took part in the study.Two different types of hearing aids (Phonak and Unitron) were programmed based on their respective manufacturers’ Desired Sensation Levels (DSL) v5 Child procedure. The hearing aids were then verified using coupler-based measurements and individual real-ear-to-coupler differences. The prefit outputs were compared with the DSL v5 Child–prescribed outputs at low-, moderate-, and high-input levels. The hearing aids were then adjusted to closely match the prescribed output. The SIIs were calculated for the fittings before and after adjustment.Sixty four percent of fittings that were based on the prefit procedure achieved the optimal fit-to-targets, with less than 5-dB RMS deviations from the DSL v5 Child targets. After adjusting the hearing aids to attempt to meet the DSL v5 Child targets, 75% of the ears tested achieved the optimal fit-to-targets. On average, hearing aid outputs generated by the manufacturer’s prefit procedure had good and reasonable agreement with the DSL v5 Child–prescribed outputs at low- and mid-frequencies. Nonetheless, at 4000 Hz, the hearing aid output mostly fell below the DSL v5 Child–prescribed outputs. This was still the case even after the hearing aid was adjusted to attempt to match with the targets. At low input level, some prefit outputs were found to be higher than the prescribed outputs. The deviations of prefit outputs from the prescribed outputs were dependent on the type of hearing aid and input levels. There was no significant difference between the SII calculated for fittings based on the prefit and adjusted fit.Prefit procedure tends to produce outputs that were below the DSL v5 Child–prescribed outputs, with the largest mean difference at 4000 Hz. Even though the hearing aid gains were adjusted to attempt to match with the targets, the outputs were still below the targets. The limitations of hearing aids to match the DSL v5 Child targets at high-frequency region have resulted in no improvement in the children’s predicted speech perception.

Sign in / Sign up

Export Citation Format

Share Document