Measuring the Long-Term SNRs of Static and Adaptive Compression Amplification Techniques for Speech in Noise

2013 ◽  
Vol 24 (08) ◽  
pp. 671-683 ◽  
Author(s):  
Ying-Hui Lai ◽  
Pei-Chun Li ◽  
Kuen-Shian Tsai ◽  
Woei-Chyn Chu ◽  
Shuenn-Tsong Young
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
High Frequency Hearing Loss ◽  
Digital Hearing Aids ◽  
Speech In Noise ◽  
Dynamic Range Compression ◽  
Adaptive Compression

Background: Multichannel wide-dynamic-range compression (WDRC) is a widely adopted amplification scheme in modern digital hearing aids. It attempts to provide individuals with loudness recruitment with superior speech intelligibility and greater listening comfort over a wider range of input levels. However, recent surveys have shown that compression processing (operating in the nonlinear regime) usually reduces the long-term signal-to-noise ratio (SNR). Purpose: The purpose of this study was to determine the long-term SNR in an adaptive compression-ratio (CR) amplification scheme called adaptive wide-dynamic-range compression (AWDRC), and to determine whether this concept is better than static WDRC amplification at improving the long-term SNR for speech in noise. Design and Study Sample: AWDRC uses the input short-term dynamic range to adjust the CR to maximize audibility and comfort. Various methods for evaluating the long-term SNR were used to observe the relationship between the CR and output SNR performance in AWDRC for seven typical audiograms, and to compare the results with those for static WDRC amplification. Results: The results showed that the variation of the CR in AWDRC amplification can maintain the comfort and audibility of the output sound. In addition, the average long-term SNR improved by 0.1–5.5 dB for a flat hearing loss, by 0.2–3.4 dB for a reverse sloping hearing loss, by 1.4–4.8 dB for a high-frequency hearing loss, and by 0.3–5.7 dB for a mild-to-moderate-sloping high-frequency hearing loss relative to static WDRC amplification. The output long-term SNR differed significantly (p < .001) between static WDRC and AWDRC amplification. Conclusions: The results of this study show that AWDRC, which uses the characteristics of the input signal to adaptively adjust the CR, provides better long-term SNR performance than static WDRC amplification.

scholarly journals Real-World Performance of a Reverse-Horn Vent

2005 ◽  
Vol 16 (09) ◽  
pp. 653-661
Author(s):  
Francis Kuk ◽  
Denise Keenan ◽  
Chi-Chuen Lau ◽  
Nick Dinulescu ◽  
Richard Cortez ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
High Frequency ◽  
Objective Measures ◽  
Subjective Ratings ◽  
High Frequency Hearing Loss ◽  
Speech In Noise ◽  
Objective Performance ◽  
Occlusion Effect

The present study compared differences in subjective and objective performance in completely-in-the-canal (CIC) hearing aids with conventional uniform 1.5 mm parallel vents and another with a reverse horn vent where the diameter increased from 1.5 mm on the lateral faceplate to 3 mm on the medial opening of the hearing aid. Nine hearing-impaired persons with a high-frequency hearing loss participated. The test battery included unaided in situ thresholds, amount of available gain before feedback, speech in quiet, speech in noise (HINT), subjective ratings of hollowness and tolerance, objective measures of the occlusion effect, and real-ear aided response. Results showed less available gain before feedback but less occlusion effect for subjective ratings and objective measures with the reverse horn vent. This type of vent design may be useful to increase the effective vent diameter of custom (including CIC) 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.

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.

scholarly journals Long‐term outcomes of cochlear implantation in patients with high‐frequency hearing loss

2018 ◽  
Vol 128 (8) ◽  
pp. 1939-1945 ◽  
Author(s):  
J. Thomas Roland ◽  
Bruce J. Gantz ◽  
Susan B. Waltzman ◽  
Aaron J. Parkinson
Keyword(s):  
Hearing Loss ◽  
Cochlear Implantation ◽  
High Frequency ◽  
Long Term Outcomes ◽  
High Frequency Hearing Loss

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.

Effect of a Single-Channel Wide Dynamic Range Compression Circuit on Perception of Stop Consonant Place of Articulation

2000 ◽  
Vol 43 (5) ◽  
pp. 1174-1184 ◽  
Author(s):  
Mark S. Hedrick ◽  
Tracie Rice
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Dynamic Range ◽  
Single Channel ◽  
Hearing Aid ◽  
Category Boundary ◽  
Frequency Region ◽  
Wide Dynamic Range ◽  
Place Of Articulation ◽  
Dynamic Range Compression

Previous studies have shown that altering the amplitude of a consonant in a specific frequency region relative to an adjacent vowel's amplitude in the same frequency region will affect listeners' perception of the consonant place of articulation. Hearing aids with single-channel, fast-acting wide dynamic range compression (WDRC) alter the overall consonant-vowel (CV) intensity ratio by increasing consonant energy. Perhaps one reason WDRC has had limited success in improving speech recognition performance is that the natural amplitude balances between consonant and vowel are altered in crucial frequency regions, thus disturbing the aforementioned amplitude cue for determining place of articulation. The current study investigated the effect of a WDRC circuit on listeners' perception of place of articulation when the relative amplitude of consonant and vowel was manipulated. The stimuli were a continuum of synthetic CV syllables stripped of all place cues except relative consonant amplitudes. Acoustic analysis of the CVs before and after hearing aid processing showed a predictable increase in high-frequency energy, particularly for the burst of the consonant. Alveolar bursts had more high-frequency energy than labial bursts. Twenty-five listeners with normal hearing and 5 listeners with sensorineural hearing loss labeled the consonant sound of the CV syllables in unaided form and after the syllables were recorded through a hearing aid with single-channel WDRC. There were significantly more listeners who were unable to produce a category boundary when labeling the aided stimuli. Of those listeners who did yield a category boundary for both aided and unaided stimuli, there were significantly more alveolar responses for the aided condition. These results can be explained by the acoustic analyses of the aided stimuli.

scholarly journals Temporal Resolution With a Prescriptive Fitting Formula

2013 ◽  
Vol 22 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Marc A. Brennan ◽  
Frederick J. Gallun ◽  
Pamela E. Souza ◽  
G. Christopher Stecker
Keyword(s):  
Hearing Loss ◽  
Temporal Resolution ◽  
Dynamic Range ◽  
Gap Detection ◽  
Linear Amplification ◽  
Wide Dynamic Range ◽  
Detection Thresholds ◽  
Dynamic Range Compression ◽  
Fitting Method ◽  
Moderate Hearing Loss

Purpose Authors of previous work using laboratory-based paradigms documented that wide dynamic range compression (WDRC) may improve gap detection compared to linear amplification. The purpose of this study was to measure temporal resolution using WDRC fit with compression ratios set for each listener's hearing loss. Method Nineteen adults with mild-to-moderate hearing loss fitted with WDRC or linear amplification set to a prescriptive fitting method participated in this study. Subjects detected amplitude modulations and gaps. Two types of noise carrier were used: narrowband (1995–2005 Hz) and broadband (100–8000 Hz). Results Small differences between WDRC and linear amplification were observed in the measures of temporal resolution. Modulation detection thresholds worsened by a mean of 0.7 dB with WDRC compared to linear amplification. This reduction was observed for both carrier types. Gap detection thresholds did not differ between the 2 amplification conditions. Conclusions WDRC set using a prescriptive fitting method with individualized compression ratios had a small but statistically significant effect on measures of modulation thresholds. Differences were not observed between the two amplification conditions for the measures of gap detection. These findings contrast with previous work using fixed compression ratios, suggesting that the effect of the fitting method on the compression ratio should be considered when attempting to generalize the effect of WDRC on temporal resolution to the clinical setting.

Sign in / Sign up

Export Citation Format

Share Document