Validating a phase-inversion procedure to assess the signal-to-noise ratios at the output of hearing aids with wide-dynamic-range compression

Purpose The purpose of this study was to examine the effects of varying wide dynamic range compression (WDRC) release time on intelligibility and clarity of reverberant speech. The study also considered the role of individual working memory. Method Thirty older listeners with mild to moderately-severe sloping sensorineural hearing loss participated. Individuals were divided into high and low working memory groups on the basis of the results of a reading span test. Participants listened binaurally to sentence stimuli simulated at a range of reverberation conditions and WDRC release times using a high compression ratio. Outcome measures included objective intelligibility and subjective clarity ratings. Results Speech intelligibility and clarity ratings both decreased as a function of reverberation. The low working memory group demonstrated a greater decrease in intelligibility with increasing amounts of reverberation than the high working memory group. Both groups, regardless of working memory, had higher speech intelligibility and clarity ratings with longer WDRC release times. WDRC release time had a larger effect on speech intelligibility under more reverberant conditions. Conclusions Reverberation significantly affects speech intelligibility, particularly for individuals with lower working memory. In addition, longer release times in hearing aids may improve listener speech intelligibility and clarity in reverberant environments.

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Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing Strategies on Consonant Recognition

Journal of the American Academy of Audiology ◽

10.3766/jaaa.14057 ◽

2015 ◽

Vol 26 (07) ◽

pp. 607-614 ◽

Cited By ~ 1

Author(s):

Patrick Plyler ◽

Mark Hedrick ◽

Brittany Rinehart ◽

Rebekah Tripp

Keyword(s):

Hearing Aids ◽

Repeated Measures ◽

Dynamic Range ◽

Hearing Aid ◽

Previous Experience ◽

Wide Dynamic Range ◽

Dynamic Range Compression ◽

Processing Strategies ◽

Hearing Aid Use ◽

Subjective Preference

Background: Both wide dynamic range compression (WDRC) and ChannelFree (CF) processing strategies in hearing aids were designed to improve listener comfort and consonant identification, yet few studies have actually compared them. Purpose: To determine whether CF processing provides equal or better consonant identification and subjective preference than WDRC. Research Design: A repeated-measures randomized design was used in which each participant identified consonants from prerecorded nonsense vowel–consonant–vowel syllables in three conditions: unaided, aided using CF processing, and aided using WDRC processing. For each of the three conditions, syllables were presented in quiet and in a speech-noise background. Participants were also asked to rate the two processing schemes according to overall preference, preference in quiet and noise, and sound quality. Study Sample: Twenty adults (seven females; mean age 69.7 yr) with ≥1 yr of hearing aid use participated. Ten participants had previous experience wearing aids with WDRC, and 10 had previous experience with CF processing. Participants were tested with both WDRC and CF processing. Data Collection and Analysis: Number of consonants correct were measured and used as the dependent variable in analyses of variance with subsequent post hoc testing. For subjective preference, a listener rating form was employed with subsequent χ2 analysis. Results: Overall results showed that signal-processing strategy did not significantly affect consonant identification or subjective preference, nor did previous hearing aid use influence results. Listeners with audiometric slopes exceeding 11 dB per octave, however, preferred CF processing and performed better in noise with CF processing. Conclusion: CF processing is a viable alternative to WDRC for listeners with more severely sloping audiometric contours.

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Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing in Open Canal Hearing Instruments

Journal of the American Academy of Audiology ◽

10.3766/jaaa.24.2.6 ◽

2013 ◽

Vol 24 (02) ◽

pp. 126-137 ◽

Cited By ~ 3

Author(s):

Patrick N. Plyler ◽

Monika Bertges Reber ◽

Amanda Kovach ◽

Elisabeth Galloway ◽

Elizabeth Humphrey

Keyword(s):

Signal Processing ◽

Hearing Loss ◽

Hearing Aids ◽

Repeated Measures ◽

Dynamic Range ◽

Wide Dynamic Range ◽

Repeated Measures Design ◽

Dynamic Range Compression ◽

Processing Strategies ◽

Hearing Instruments

Background: Multichannel wide dynamic range compression (WDRC) and ChannelFree processing have similar goals yet differ significantly in terms of signal processing. Multichannel WDRC devices divide the input signal into separate frequency bands; a separate level is determined within each frequency band; and compression in each band is based on the level within each band. ChannelFree processing detects the wideband level, and gain adjustments are based on the wideband signal level and adjusted up to 20,000 times per second. Although both signal processing strategies are currently available in hearing aids, it is unclear if differences in these signal processing strategies affect the performance and/or preference of the end user. Purpose: The purpose of the research was to determine the effects of multichannel wide dynamic range compression and ChannelFree processing on performance and/or preference of listeners using open-canal hearing instruments. Research Design: An experimental study in which subjects were exposed to a repeated measures design was utilized. Study Sample: Fourteen adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Data Collection and Analysis: Participants completed two 5 wk trial periods for each signal processing strategy. Probe microphone, behavioral and subjective measures were conducted unaided and aided at the end of each trial period. Results: Behavioral and subjective results for both signal processing strategies were significantly better than unaided results; however, behavioral and subjective results were not significantly different between the signal processing strategies. Conclusions: Multichannel WDRC and ChannelFree processing are both effective signal processing strategies that provide significant benefit for hearing instrument users. Overall preference between the strategies may be related to the degree of hearing loss of the user, high-frequency in-situ levels, and/or acceptance of background noise.

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A Method of Wide Dynamic Range Compression Based on Curve Compression Applying on Hearing Aids

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.719-720.1074 ◽

2015 ◽

Vol 719-720 ◽

pp. 1074-1081

Author(s):

Xiang Xiang Luo ◽

Zhao Yang Guo ◽

Zhi Liang Zhao ◽

Feng Jie Xue ◽

Xin An Wang

Keyword(s):

Hearing Aids ◽

Background Noise ◽

Dynamic Range ◽

Wide Dynamic Range ◽

Compression Technique ◽

High Frequency Signal ◽

Theoretical Simulation ◽

Dynamic Range Compression ◽

Curve Compression ◽

Linear Compression

Recently, there is a growing trend to investigate wide dynamic range compression technique with the development of hearing aids. However, existing methods used to enhance expected speech as well as the background noise and classical linear compression can’t achieve the requirements of hearing impaired individuals’ reaction to the loudness compensation flexibly. To cope with the problems, this paper proposes a new approach to suppress the enhanced background noise and to dismiss abnormal sound caused by severe jittering from high frequency signal. What’s more, a scheme of curve compression is introduced to improve the loudness amplifying flexibility instead of conventional linear compression. Both the theoretical simulation and testing on cellphone hearing aid APP based on android system prove the proposed method can improve the performance of speech enhancement and provide more choices to strength sound with the curve compression ratio.

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A Comparison of the Aided Performance and Benefit Provided by a Linear and a Two-Channel Wide Dynamic Range Compression Hearing Aid

Journal of Speech Language and Hearing Research ◽

10.1044/jslhr.4201.65 ◽

1999 ◽

Vol 42 (1) ◽

pp. 65-79 ◽

Cited By ~ 29

Author(s):

Larry E. Humes ◽

Laurel Christensen ◽

Tara Thomas ◽

Fred H. Bess ◽

Andrea Hedley-Williams ◽

...

Keyword(s):

Outcome Measures ◽

Hearing Aids ◽

Dynamic Range ◽

Hearing Aid ◽

Self Report ◽

Volume Control ◽

Listening Effort ◽

Wide Dynamic Range ◽

Dynamic Range Compression ◽

Monosyllabic Words

The aided performance and benefit achieved with linear and two-channel wide dynamic range compression (WDRC) in-the-canal (ITC) hearing aids were established in 55 individuals. Study participants had been wearing either linear or adaptive-frequency-response (Bass Increase at Low Levels, BILL) ITC hearing aids for approximately one year before participation in this study. Outcome measures included aided performance and objective benefit in quiet and noise at a variety of speech levels (50, 60, and 75 dB SPL), at various levels of babble background (quiet, signal-to-babble ratios of +5 and +10 dB), and for various types of test materials (monosyllabic words and sentences in connected speech). Several subjective measures of aided performance (sound-quality judgments and magnitude estimates of listening effort) and relative benefit (improvement in listening effort and the Hearing Aid Performance Inventory, HAPI) were also obtained. Finally, self-report measures of hearing-aid use were also obtained using daily logs. Participants completed all outcome measures for the linear ITC hearing aids first, following 2 months of usage, and then repeated all outcome measures for the WDRC instruments after a subsequent 2-month period of use. In general, although both types of hearing aids demonstrated significant benefit, the results indicated that the WDRC instruments were superior to the linear devices for many of the outcome measures. This tended to be the case most frequently when low speech levels were used. Many of the performance differences between devices most likely can be ascribed to differences in gain, and prescriptive approaches (DSL[i/o] vs. NAL-R), for the fixed volume control testing performed in this study.

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Loudness and Satisfaction Ratings for Hearing Aid Users

Journal of the American Academy of Audiology ◽

10.3766/jaaa.20.4.7 ◽

2009 ◽

Vol 20 (04) ◽

pp. 272-282 ◽

Cited By ~ 8

Author(s):

Peter J. Blamey ◽

Lois F.A. Martin

Keyword(s):

Hearing Aids ◽

Dynamic Range ◽

Hearing Aid ◽

Strong Relationship ◽

Impaired Hearing ◽

Soft Or ◽

Wide Dynamic Range ◽

Dynamic Range Compression ◽

Hearing Thresholds ◽

Comfortable Loudness

Background: Hearing aids amplify low-intensity sounds to make them audible while keeping high-intensity sounds at an acceptable loudness for listeners with impaired hearing. Purpose: The purpose of this analysis was to assess loudness and satisfaction at the same time using a combined loudness and satisfaction questionnaire to rate 18 everyday environmental sounds. Research Design: Ten sets of data from four studies, covering three conditions, were analyzed. The three conditions were unaided, wide dynamic range compression (WDRC), and adaptive dynamic range optimization (ADRO®). In total, there were 61 subjects giving over 3,000 pairs of ratings for loudness and satisfaction. Results: The analysis found a strong relationship between loudness and satisfaction ratings for this set of listeners and conditions. The maximum satisfaction ratings corresponded to sounds with “comfortable” loudness ratings. Satisfaction was lowest for sounds that were “uncomfortably loud.” Sounds that were very soft or inaudible also received low satisfaction ratings unless the sounds were expected to be soft, such as the sound of one's own breathing. Conclusions: Hearing aid fittings that place most sounds at a comfortable level are likely to be more satisfactory than hearing aid fittings that produce more sounds close to hearing thresholds or discomfort levels. Aided conditions gave higher loudness and satisfaction ratings than the unaided condition, and the ADRO hearing aids gave significantly higher satisfaction ratings than the WDRC hearing aids.

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