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

2013 ◽  
Vol 24 (02) ◽  
pp. 126-137 ◽  
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.

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

2015 ◽  
Vol 26 (07) ◽  
pp. 607-614 ◽  
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.

A Digital Processing Strategy to Optimize Hearing Aid Outputs Directly

2004 ◽  
Vol 15 (10) ◽  
pp. 716-728 ◽  
Author(s):  
Peter J. Blamey ◽  
Lois F.A. Martin ◽  
Hayley J. Fiket
Keyword(s):  
Hearing Loss ◽  
Confidence Interval ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Digital Processing ◽  
Second Phase ◽  
Open Platform ◽  
Dynamic Range Compression ◽  
Hearing Instruments ◽  
Amplification Strategy

A new amplification strategy (ADRO™), based on 64 independently operating channels, was compared with a nine-channel wide dynamic range compression strategy (WDRC). Open-platform in-the-ear hearing instruments were configured either with ADRO or the manufacturer's WDRC strategy. Twenty-two subjects with mild to moderate hearing loss took home the ADRO or WDRC hearing aids. After three weeks' acclimatization, the aids were evaluated using monosyllables in quiet at 50 to 65 dB SPL and sentences in eight-talker babble. The acclimatization and evaluation were repeated in the second phase of the balanced reverse-block blind experimental design. The ADRO program showed a statistically significant mean advantage of 7.85% word score (95% confidence interval 3.19% to 12.51%; p = 0.002) and 6.41% phoneme score for the monosyllables in quiet (95% confidence interval 2.03% to 10.79%; p = 0.006). A statistically significant advantage of 7.25% was also found for the ADRO program in background noise (95% confidence interval 1.95% to 12.55%; p = 0.010). The results are consistent with earlier data for listeners with moderate to severe hearing loss.

A 1-Channel 3-Band Wide Dynamic Range Compression Chip for Vibration Transducer of Implantable Hearing Aids

2014 ◽  
Vol 24 (1) ◽  
pp. 1009-1017 ◽  
Author(s):  
DongWook Kim ◽  
KiWoong Seong ◽  
MyoungNam Kim ◽  
JinHo Cho ◽  
JyungHyun Lee
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Vibration Transducer ◽  
Implantable Hearing Aids

Effect of Slow-Acting Wide Dynamic Range Compression on Measures of Intelligibility and Ratings of Speech Quality in Simulated-Loss Listeners

2005 ◽  
Vol 48 (3) ◽  
pp. 702-714 ◽  
Author(s):  
Peninah S. Rosengard ◽  
Karen L. Payton ◽  
Louis D. Braida
Keyword(s):  
Hearing Loss ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Speech Quality ◽  
Subjective Ratings ◽  
Subjective Measures ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Amplitude Compression ◽  
Moderate Hearing Loss

The purpose of this study was twofold: (a) to determine the extent to which 4-channel, slow-acting wide dynamic range amplitude compression (WDRC) can counteract the perceptual effects of reduced auditory dynamic range and (b) to examine the relation between objective measures of speech intelligibility and categorical ratings of speech quality for sentences processed with slow-acting WDRC. Multiband expansion was used to simulate the effects of elevated thresholds and loudness recruitment in normal hearing listeners. While some previous studies have shown that WDRC can improve both speech intelligibility and quality, others have found no benefit. The current experiment shows that moderate amounts of compression can provide a small but significant improvement in speech intelligibility, relative to linear amplification, for simulated-loss listeners with small dynamic ranges (i.e., flat, moderate hearing loss). This benefit was found for speech at conversational levels, both in quiet and in a background of babble. Simulated-loss listeners with large dynamic ranges (i.e., sloping, mild-to-moderate hearing loss) did not show any improvement. Comparison of speech intelligibility scores and subjective ratings of intelligibility showed that listeners with simulated hearing loss could accurately judge the overall intelligibility of speech. However, in all listeners, ratings of pleasantness decreased as the compression ratio increased. These findings suggest that subjective measures of speech quality should be used in conjunction with either objective or subjective measures of speech intelligibility to ensure that participant-selected hearing aid parameters optimize both comfort and intelligibility.

Effects of Coordinated Compression and Pinna Compensation Features on Horizontal Localization Performance in Hearing Aid Users

2015 ◽  
Vol 26 (01) ◽  
pp. 080-092 ◽  
Author(s):  
Petri Korhonen ◽  
Chi Lau ◽  
Francis Kuk ◽  
Denise Keenan ◽  
Jennifer Schumacher
Keyword(s):  
Repeated Measures ◽  
Horizontal Plane ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Hearing Impaired ◽  
Localization Accuracy ◽  
Repeated Measures Design ◽  
Dynamic Range Compression ◽  
Data Collection And Analysis ◽  
Localization Performance

Background: Hearing-impaired listeners localize sounds better unaided than aided. Wide dynamic range compression circuits operating independently at each ear in bilateral fittings, and microphone positions of different hearing aid styles, have been cited as a reason. Two hearing aid features, inter-ear coordinated compression (IE) and pinna compensation (PC), were developed to mitigate the compromised aided localization performance. Purpose: This study examined the effect of IE and PC on aided localization performance in the horizontal plane with hearing-impaired listeners. Research Design: A single-blind, repeated-measures design was used. Study Sample: A total of 10 experienced hearing aid users with bilaterally symmetrical sensorineural hearing loss who had previously participated in localization training were evaluated. Data Collection and Analysis: Localization performance was measured using 12 loudspeakers spaced 30° apart on the horizontal plane. Aided performance was evaluated using a behind-the-ear hearing aid at four settings: omnidirectional microphone (Omni), Omni microphone with the PC feature, Omni microphone with IE, and Omni microphone with the PC feature and IE together. In addition, unaided localization performance was measured. Results: Significant improvement in the localization accuracy was measured for sounds arriving from the back when comparing the PC with the Omni conditions. The use of IE reduced the magnitude of errors for some listeners for sounds originating from ±90°. The average reduction in the errors was 7.3°. Conclusions: This study confirmed that the use of the PC feature improved localization for sounds arriving from behind the listener. The use of IE may improve localization for some listeners for sounds arriving from the sides.

Fitting Wide Dynamic Range Compression Hearing Aids

1997 ◽  
Vol 6 (3) ◽  
pp. 19-28 ◽  
Author(s):  
George A. Lindley ◽  
Catherine V. Palmer
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression

scholarly journals Intelligibility and Clarity of Reverberant Speech: Effects of Wide Dynamic Range Compression Release Time and Working Memory

2016 ◽  
Vol 59 (6) ◽  
pp. 1543-1554 ◽  
Author(s):  
Paul N. Reinhart ◽  
Pamela E. Souza
Keyword(s):  
Working Memory ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Release Time ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Release Times ◽  
Memory Group ◽  
Reverberant Speech

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.

Effect of Compression Ratio on Speech Recognition and Speech-Quality Ratings With Wide Dynamic Range Compression Amplification

2000 ◽  
Vol 43 (2) ◽  
pp. 456-468 ◽  
Author(s):  
Kumiko T. Boike ◽  
Pamela E. Souza
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Compression Ratio ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Speech Quality ◽  
Control Group ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Quality Ratings

This project examined the effect of varying compression ratio on speech recognition and quality. Both listeners with mild-to-moderate sensorineural hearing loss and a control group of listeners with normal hearing participated. Test materials were sentences from the Connected Speech Test (R. M. Cox, G. C. Alexander, & C. Gilmore, 1987) which were digitally processed with linear amplification and wide dynamic range compression amplification with 3 compression ratios. Speech-recognition scores were obtained with sentences in quiet and in noise at a 10-dB signal-to-noise ratio for each amplification condition. Additionally, the participants rated each amplification condition in terms of clarity, pleasantness, ease of understanding, and overall impression. Results indicated that, for speech in quiet, compression ratio had no effect on speech-recognition scores; however, speech-quality ratings decreased as compression ratio increased. For speech in noise, both speech-recognition scores and ratings decreased with increasing compression ratio for the listeners with hearing loss. These results suggest that selection of compression ratio on the basis of speech-quality judgments does not compromise speech recognition.

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